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[bpt/emacs.git] / man / cc-mode.texi
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6bf7aab6 1\input texinfo
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2@c Notes to self regarding line handling:
3@c
4@c Empty lines are often significant before @end directives; avoid them.
5@c
6@c Empty lines before and after @example directives are significant in
7@c info output but not in TeX. Empty lines inside @example directives
8@c are significant.
9
10@c Conventions for formatting examples:
11@c o If the example contains empty lines then put the surrounding empty
12@c lines inside the @example directives. Put them outside otherwise.
13@c o Use @group inside the example only if it shows indentation where
14@c the relation between lines inside is relevant.
15@c o Format line number columns like this:
16@c 1: foo
17@c 2: bar
18@c ^ one space
19@c ^^ two columns, right alignment
20@c o Check line lengths in TeX output; they can typically be no longer
21@c than 70 chars, 60 if the paragraph is indented.
22
23@comment TBD: Document the finer details of statement anchoring?
24
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25@comment !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
26@comment %**start of header (This is for running Texinfo on a region)
27@comment !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
28
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29
30@comment !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
31@comment How to make the various output formats:
32@comment (Thanks to Robert Chassell for supplying this information.)
33@comment Note that Texinfo 4.7 (or later) is needed.
34@comment !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
35@ignore
36In each of the following pairs of commands, the first generates a
37version with cross references pointing to the GNU Emacs manuals,
38the second with them pointing to the XEmacs manuals.
39 ## Info output
40 makeinfo cc-mode.texi
41 makeinfo -DXEMACS cc-mode.texi
42
43 ## DVI output
44 ## You may need to set up the environment variable TEXINPUTS so
45 ## that tex can find the file texinfo.tex - See the tex
46 ## manpage.
47 texi2dvi cc-mode.texi
48 texi2dvi -t "@set XEMACS " cc-mode.texi
49
50 ## HTML output. (The --no-split parameter is optional)
51 makeinfo --html --no-split cc-mode.texi
52 makeinfo --html --no-split -DXEMACS cc-mode.texi
53
54 ## Plain text output
55 makeinfo --fill-column=70 --no-split --paragraph-indent=0 \
56 --no-headers --output=cc-mode.txt cc-mode.texi
57 makeinfo --fill-column=70 --no-split --paragraph-indent=0 \
58 --no-headers --output=cc-mode.txt -DXEMACS cc-mode.texi
59
60 ## DocBook output
61 makeinfo --docbook --no-split --paragraph-indent=0 \
62 cc-mode.texi
63 makeinfo --docbook --no-split --paragraph-indent=0 \
64 -DXEMACS cc-mode.texi
65
66 ## XML output
67 makeinfo --xml --no-split --paragraph-indent=0 \
68 cc-mode.texi
69 makeinfo --xml --no-split --paragraph-indent=0 \
70 -DXEMACS cc-mode.texi
71
72 #### (You must be in the same directory as the viewed file.)
73
74 ## View DVI output
75 xdvi cc-mode.dvi &
76
77 ## View HTML output
78 mozilla cc-mode.html
79@end ignore
80
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81@comment No overfull hbox marks in the dvi file.
82@finalout
6bf7aab6 83
94cae5a8 84@setfilename ../info/ccmode
cb7f2e96 85@settitle CC Mode Manual
d7bd46ed 86@footnotestyle end
6bf7aab6 87
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88@c The following four macros generate the filenames and titles of the
89@c main (X)Emacs manual and the Elisp/Lispref manual. Leave the
90@c Texinfo variable `XEMACS' unset to generate a GNU Emacs version, set it
91@c to generate an XEmacs version, e.g. with
92@c "makeinfo -DXEMACS cc-mode.texi".
93@ifset XEMACS
94@macro emacsman
95xemacs
96@end macro
97@macro emacsmantitle
98XEmacs User's Manual
99@end macro
100@macro lispref
101lispref
102@end macro
103@macro lispreftitle
104XEmacs Lisp Reference Manual
105@end macro
106@end ifset
107
108@ifclear XEMACS
109@macro emacsman
110emacs
111@end macro
112@macro emacsmantitle
113GNU Emacs Manual
114@end macro
115@macro lispref
116elisp
117@end macro
118@macro lispreftitle
119GNU Emacs Lisp Reference Manual
120@end macro
121@end ifclear
122
123
124@macro ccmode
125CC Mode
126@end macro
127
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128@comment !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
129@comment @setchapternewpage odd !! we don't want blank pages !!
130@comment %**end of header (This is for running Texinfo on a region)
131@comment !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
132
133
134@comment !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
bf247b6e 135@comment
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136@comment Texinfo manual for CC Mode
137@comment Generated from the original README file by Krishna Padmasola
138@comment <krishna@earth-gw.njit.edu>
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139@comment
140@comment Authors:
141@comment Barry A. Warsaw
142@comment Martin Stjernholm
116e44a1 143@comment Alan Mackenzie
cb7f2e96 144@comment
116e44a1 145@comment Maintained by Martin Stjernholm and Alan Mackenzie <bug-cc-mode@gnu.org>
bf247b6e 146@comment
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147@comment !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
148
3a731e1f 149@comment Define an index for syntactic symbols.
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150@ifnottex @c In texi2dvi, the @defindex would create an empty cc-mode.ss
151 @c For Info, unlike tex, @syncodeindex needs a matching @defindex.
3a731e1f 152@defindex ss
5f36ee6d 153@end ifnottex
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154
155@comment Combine key, syntactic symbol and concept indices into one.
156@syncodeindex ss cp
157@syncodeindex ky cp
158
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159@copying
160This manual is for CC Mode in Emacs.
cb7f2e96 161
3a731e1f 162Copyright @copyright{} 1995, 1996, 1997, 1998, 1999, 2000, 2001, 2002,
b223e22d 1632003, 2004, 2005, 2006 Free Software Foundation, Inc.
94cae5a8 164
18f952d5 165@quotation
94cae5a8 166Permission is granted to copy, distribute and/or modify this document
678e7c71 167under the terms of the GNU Free Documentation License, Version 1.2 or
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168any later version published by the Free Software Foundation; with the
169Invariant Sections being ``The GNU Manifesto'', ``Distribution'' and
170``GNU GENERAL PUBLIC LICENSE'', with the Front-Cover texts being ``A GNU
171Manual'', and with the Back-Cover Texts as in (a) below. A copy of the
172license is included in the section entitled ``GNU Free Documentation
173License'' in the Emacs manual.
174
175(a) The FSF's Back-Cover Text is: ``You have freedom to copy and modify
176this GNU Manual, like GNU software. Copies published by the Free
177Software Foundation raise funds for GNU development.''
178
179This document is part of a collection distributed under the GNU Free
180Documentation License. If you want to distribute this document
181separately from the collection, you can do so by adding a copy of the
182license to the document, as described in section 6 of the license.
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183@end quotation
184@end copying
185
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186@comment Info directory entry for use by install-info. The indentation
187@comment here is by request from the FSF folks.
188@dircategory Emacs
189@direntry
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190* CC Mode: (ccmode). Emacs mode for editing C, C++, Objective-C,
191 Java, Pike, AWK, and CORBA IDL code.
18f952d5 192@end direntry
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193
194@comment !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
cb7f2e96 195@comment TeX title page
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196@comment !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
197
198@titlepage
199@sp 10
200
116e44a1 201@center @titlefont{CC Mode 5.31}
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202@sp 2
203@center @subtitlefont{A GNU Emacs mode for editing C and C-like languages}
204@sp 2
116e44a1 205@center Barry A. Warsaw, Martin Stjernholm, Alan Mackenzie
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206
207@page
208@vskip 0pt plus 1filll
18f952d5 209@insertcopying
116e44a1 210
b223e22d 211This manual was generated from $Revision: 1.36 $ of $RCSfile: cc-mode.texi,v $, which can be
116e44a1 212downloaded from
0d566910 213@url{http://cvs.savannah.gnu.org/viewcvs/emacs/emacs/man/cc-mode.texi}.
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214@end titlepage
215
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216@comment !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
217@comment The Top node contains the master menu for the Info file.
218@comment This appears only in the Info file, not the printed manual.
219@comment !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
220
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221@node Top, Introduction, (dir), (dir)
222@comment node-name, next, previous, up
223
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224@ifinfo
225@top @ccmode{}
6bf7aab6 226
d7bd46ed 227@ccmode{} is a GNU Emacs mode for editing files containing C, C++,
3a731e1f 228Objective-C, Java, CORBA IDL (and the variants PSDL and CIDL), Pike
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229and AWK code. It provides syntax-based indentation, font locking, and
230has several handy commands and some minor modes to make the editing
231easier. It does not provide tools to look up and navigate between
232functions, classes etc - there are other packages for that.
d7bd46ed 233@end ifinfo
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234
235@comment !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
236@comment !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
237
238@menu
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239* Introduction::
240* Overview::
241* Getting Started::
242* Commands::
243* Font Locking::
244* Config Basics::
245* Custom Filling and Breaking::
246* Custom Auto-newlines::
247* Clean-ups::
248* Indentation Engine Basics::
249* Customizing Indentation::
250* Custom Macros::
251* Odds and Ends::
252* Sample .emacs File::
253* Performance Issues::
254* Limitations and Known Bugs::
255* FAQ::
256* Updating CC Mode::
257* Mailing Lists and Bug Reports::
258* Command and Function Index::
259* Variable Index::
260* Concept and Key Index::
d7bd46ed 261
3a731e1f 262@detailmenu
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263 --- The Detailed Node Listing ---
264
116e44a1 265Commands
d7bd46ed 266
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267* Indentation Commands::
268* Comment Commands::
269* Movement Commands::
270* Filling and Breaking::
271* Minor Modes::
272* Electric Keys::
273* Auto-newlines::
274* Hungry WS Deletion::
275* Subword Movement::
276* Other Commands::
d7bd46ed 277
116e44a1 278Font Locking
d7bd46ed 279
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280* Font Locking Preliminaries::
281* Faces::
282* Doc Comments::
283* AWK Mode Font Locking::
d7bd46ed 284
116e44a1 285Configuration Basics
3a731e1f 286
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287* CC Hooks::
288* Style Variables::
289* Styles::
3a731e1f 290
116e44a1 291Styles
d7bd46ed 292
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293* Built-in Styles::
294* Choosing a Style::
295* Adding Styles::
296* File Styles::
d7bd46ed 297
116e44a1 298Customizing Auto-newlines
d7bd46ed 299
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300* Hanging Braces::
301* Hanging Colons::
302* Hanging Semicolons and Commas::
d7bd46ed 303
116e44a1 304Hanging Braces
d7bd46ed 305
116e44a1 306* Custom Braces::
d7bd46ed 307
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308Indentation Engine Basics
309
310* Syntactic Analysis::
311* Syntactic Symbols::
312* Indentation Calculation::
313
314Syntactic Symbols
d7bd46ed 315
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316* Function Symbols::
317* Class Symbols::
318* Conditional Construct Symbols::
319* Switch Statement Symbols::
320* Brace List Symbols::
321* External Scope Symbols::
322* Paren List Symbols::
323* Literal Symbols::
324* Multiline Macro Symbols::
325* Objective-C Method Symbols::
326* Anonymous Class Symbol::
327* Statement Block Symbols::
328* K&R Symbols::
d7bd46ed 329
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330Customizing Indentation
331
332* c-offsets-alist::
333* Interactive Customization::
334* Line-Up Functions::
335* Custom Line-Up::
336* Other Indentation::
d7bd46ed 337
116e44a1 338Line-Up Functions
3a731e1f 339
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340* Brace/Paren Line-Up::
341* List Line-Up::
342* Operator Line-Up::
343* Comment Line-Up::
344* Misc Line-Up::
3a731e1f 345
3a731e1f 346@end detailmenu
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347@end menu
348
349@comment !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
116e44a1 350@node Introduction, Overview, Top, Top
d7bd46ed 351@comment node-name, next, previous, up
3a731e1f 352@chapter Introduction
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353@comment !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
354
6bf7aab6 355@cindex BOCM
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356@cindex history
357@cindex awk-mode.el
358@cindex c-mode.el
359@cindex c++-mode.el
6bf7aab6 360
d7bd46ed 361Welcome to @ccmode{}, a GNU Emacs mode for editing files containing C,
3a731e1f 362C++, Objective-C, Java, CORBA IDL (and the variants CORBA PSDL and
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363CIDL), Pike and AWK code. This incarnation of the mode is descended
364from @file{c-mode.el} (also called ``Boring Old C Mode'' or BOCM
365@t{:-)}, @file{c++-mode.el} version 2, which Barry Warsaw had been
366maintaining since 1992, and @file{awk-mode.el}, a long neglected mode
367in the (X)Emacs base.
368
369Late in 1997, Martin Stjernholm joined Barry on the @ccmode{}
370Maintainers Team, and implemented the Pike support. In 2000 Martin
371took over as the sole maintainer. In 2001 Alan Mackenzie joined the
372team, implementing AWK support in version 5.30. @ccmode{} did not
373originally contain the font lock support for its languages --- that
374was added in version 5.30.
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375
376This manual describes @ccmode{}
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377@comment The following line must appear on its own, so that the
378version 5.31.
d7bd46ed 379@comment Release.py script can update the version number automatically
6bf7aab6 380
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381@ccmode{} supports the editing of K&R and ANSI C, C++, Objective-C,
382Java, CORBA's Interface Definition Language, Pike@footnote{A C-like
383scripting language with its roots in the LPC language used in some MUD
384engines. See @uref{http://pike.ida.liu.se/}.} and AWK files. In this
385way, you can easily set up consistent font locking and coding styles for
386use in editing all of these languages, although AWK is not yet as
387uniformly integrated as the other languages.
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388
389@findex c-mode
390@findex c++-mode
391@findex objc-mode
392@findex java-mode
393@findex idl-mode
d7bd46ed 394@findex pike-mode
3a731e1f 395@findex awk-mode
116e44a1 396Note that the name of this package is ``@ccmode{}'', but there is no top
6bf7aab6 397level @code{cc-mode} entry point. All of the variables, commands, and
3a731e1f 398functions in @ccmode{} are prefixed with @code{c-@var{thing}}, and
d7bd46ed 399@code{c-mode}, @code{c++-mode}, @code{objc-mode}, @code{java-mode},
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400@code{idl-mode}, @code{pike-mode}, and @code{awk-mode} entry points are
401provided. This package is intended to be a replacement for
402@file{c-mode.el}, @file{c++-mode.el} and @file{awk-mode.el}.
403
6bf7aab6 404A special word of thanks goes to Krishna Padmasola for his work in
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405converting the original @file{README} file to Texinfo format. I'd
406also like to thank all the @ccmode{} victims who help enormously
407during the early beta stages of @ccmode{}'s development.
6bf7aab6 408
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409@comment !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
410@node Overview, Getting Started, Introduction, Top
411@comment node-name, next, previous, up@cindex organization of the manual
412@chapter Overview of the Manual
413@comment !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
6bf7aab6 414
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415@noindent
416The manual starts with several introductory chapters (including this
417one).
6bf7aab6 418
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419@noindent
420The next chunk of the manual describes the day to day @emph{use} of
421@ccmode{} (as contrasted with how to customize it).
6bf7aab6 422
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423@itemize @bullet
424@item
425The chapter ``Commands'' describes in detail how to use (nearly) all
426of @ccmode{}'s features. There are extensive cross-references from
427here to the corresponding sections later in the manual which tell you
428how to customize these features.
6bf7aab6 429
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430@item
431``Font Locking'' describes how ``syntax highlighting'' is applied to
432your buffers. It is mainly background information and can be skipped
433over at a first reading.
434@end itemize
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435
436@noindent
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437The next chunk of the manual describes how to @emph{customize}
438@ccmode{}. Typically, an overview of a topic is given at the chapter
439level, then the sections and subsections describe the material in
440increasing detail.
441
442@itemize @bullet
443@item
444The chapter ``Configuration Basics'' tells you @emph{how} to write
445customizations - whether in hooks, in styles, in both, or in neither,
446depending on your needs. It describes the @ccmode{} style system and
447lists the standard styles that @ccmode{} supplies.
6bf7aab6 448
116e44a1 449@item
0d566910 450The next few chapters describe in detail how to customize the various
116e44a1 451features of @ccmode{}.
6bf7aab6 452
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453@item
454Finally, there is a sample @file{.emacs} fragment, which might help you
455in creating your own customization.
456@end itemize
6bf7aab6 457
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458@noindent
459The manual ends with ``this and that'', things that don't fit cleanly
460into any of the previous chunks.
6bf7aab6 461
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462@itemize @bullet
463@item
464Two chapters discuss the performance of @ccmode{} and known
465bugs/limitations.
3a731e1f 466
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467@item
468The FAQ contains a list of common problems and questions.
6bf7aab6 469
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470@item
471The next two chapters tell you how to get in touch with the @ccmode{}
472project - whether for updating @ccmode{} or submitting bug reports.
473@end itemize
6bf7aab6 474
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475@noindent
476Finally, there are the customary indices.
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477
478@comment !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
116e44a1 479@node Getting Started, Commands, Overview, Top
d7bd46ed 480@comment node-name, next, previous, up
116e44a1 481@chapter Getting Started
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482@comment !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
483
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484If you got this version of @ccmode{} with Emacs or XEmacs, it should
485work just fine right out of the box. Note however that you might not
486have the latest @ccmode{} release and might want to upgrade your copy
487(see below).
6bf7aab6 488
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489You should probably start by reading the entire chapter
490@ref{Commands} to get an overview of @ccmode{}'s capabilities.
6bf7aab6 491
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492After trying out some commands, you may dislike some aspects of
493@ccmode{}'s default configuration. Here is an outline of how to
494change some of the settings that newcomers to @ccmode{} most often
495want to change:
6bf7aab6 496
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497@table @asis
498@item c-basic-offset
499This Lisp variable holds an integer, the number of columns @ccmode{}
500indents nested code. To set this value to 6, customize
501@code{c-basic-offset} or put this into your @file{.emacs}:
6bf7aab6 502
3a731e1f 503@example
116e44a1 504(setq c-basic-offset 6)
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505@end example
506
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507@item The (indentation) style
508The basic ``shape'' of indentation created by @ccmode{}---by default,
509this is @code{gnu} style (except for Java and AWK buffers). A list of
510the availables styles and their descriptions can be found in
511@ref{Built-in Styles}. A complete specification of the @ccmode{}
512style system, including how to create your own style, can be found in
513the chapter @ref{Styles}. To set your style to @code{linux}, either
514customize @code{c-default-style} or put this into your @file{.emacs}:
6bf7aab6 515
3a731e1f 516@example
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517(setq c-default-style '((java-mode . "java")
518 (awk-mode . "awk")
519 (other . "linux")))
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520@end example
521
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522@item Electric Indentation
523Normally, when you type ``punctuation'' characters such as @samp{;} or
524@samp{@{}, @ccmode{} instantly reindents the current line. This can
525be disconcerting until you get used to it. To disable @dfn{electric
526indentation} in the current buffer, type @kbd{C-c C-l}. Type the same
527thing to enable it again. To have electric indentation disabled by
0d566910 528default, put the following into your @file{.emacs} file@footnote{There
116e44a1 529is no ``easy customization'' facility for making this change.}:
6bf7aab6 530
3a731e1f 531@example
116e44a1 532(setq-default c-electric-flag nil)
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533@end example
534
535@noindent
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536Details of of this and other similar ``Minor Modes'' appear in the
537section @ref{Minor Modes}.
538
539@item Making the @key{RET} key indent the new line
540The standard Emacs binding for @key{RET} just adds a new line. If you
541want it to reindent the new line as well, rebind the key. Note that
542the action of rebinding will fail if the pertinent keymap doesn't yet
543exist---we thus need to delay the action until after @ccmode{} has
544been loaded. Put the following code into your @file{.emacs}:
6bf7aab6 545
3a731e1f 546@example
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547(defun my-make-CR-do-indent ()
548 (define-key c-mode-base-map "\C-m" 'c-context-line-break))
549(add-hook 'c-initialization-hook 'my-make-CR-do-indent)
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550@end example
551
6bf7aab6 552@noindent
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553This example demonstrates the use of a very powerful @ccmode{} (and
554Emacs) facility, the hook. The use of @ccmode{}'s hooks is described
555in @ref{CC Hooks}.
556@end table
6bf7aab6 557
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558All these settings should occur in your @file{.emacs} @emph{before}
559any @ccmode{} buffers get loaded---in particular, before any call of
560@code{desktop-read}.
6bf7aab6 561
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562As you get to know the mode better, you may want to make more
563ambitious changes to your configuration. For this, you should start
564reading the chapter @ref{Config Basics}.
6bf7aab6 565
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566If you are upgrading an existing @ccmode{} installation, please see
567the @file{README} file for installation details. In particular, if
568you are going to be editing AWK files, @file{README} describes how to
569configure your (X)Emacs so that @ccmode{} will supersede the obsolete
570@code{awk-mode.el} which might have been supplied with your (X)Emacs.
571@ccmode{} might not work with older versions of Emacs or XEmacs. See
572the @ccmode{} release notes at @uref{http://cc-mode.sourceforge.net}
573for the latest information on Emacs version and package compatibility
574(@pxref{Updating CC Mode}).
575
576@deffn Command c-version
577@findex version (c-)
578You can find out what version of @ccmode{} you are using by visiting a C
579file and entering @kbd{M-x c-version RET}. You should see this message in
580the echo area:
6bf7aab6 581
3a731e1f 582@example
116e44a1 583Using CC Mode version 5.XX
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584@end example
585
586@noindent
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587where @samp{XX} is the minor release number.
588@end deffn
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589
590@comment !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
116e44a1 591@node Commands, Font Locking, Getting Started, Top
d7bd46ed 592@comment node-name, next, previous, up
116e44a1 593@chapter Commands
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594@comment !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
595
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596This chapter specifies all of CC Mode's commands, and thus contains
597nearly everything you need to know to @emph{use} @ccmode{} (as
598contrasted with configuring it). @dfn{Commands} here means both
599control key sequences and @dfn{electric keys}, these being characters
600such as @samp{;} which, as well as inserting themselves into the
601buffer, also do other things.
6bf7aab6 602
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603You might well want to review
604@ifset XEMACS
605@ref{Lists,,,@emacsman{}, @emacsmantitle{}},
606@end ifset
607@ifclear XEMACS
608@ref{Moving by Parens,,,@emacsman{}, @emacsmantitle{}},
609@end ifclear
610which describes commands for moving around brace and parenthesis
611structures.
6bf7aab6 612
6bf7aab6 613
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614@menu
615* Indentation Commands::
616* Comment Commands::
617* Movement Commands::
618* Filling and Breaking::
619* Minor Modes::
620* Electric Keys::
621* Auto-newlines::
622* Hungry WS Deletion::
623* Subword Movement::
624* Other Commands::
625@end menu
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626
627@comment !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
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628@node Indentation Commands, Comment Commands, Commands, Commands
629@comment node-name, next, previous,up
630@section Indentation Commands
631@cindex indentation
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632@comment !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
633
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634The following commands reindent C constructs. Note that when you
635change your coding style, either interactively or through some other
636means, your file does @emph{not} automatically get reindented. You
637will need to execute one of the following commands to see the effects
638of your changes.
6bf7aab6 639
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640@cindex GNU indent program
641Also, variables like @code{c-hanging-*} and @code{c-cleanup-list}
642(@pxref{Custom Auto-newlines}) only affect how on-the-fly code is
643formatted. Changing the ``hanginess'' of a brace and then
644reindenting, will not move the brace to a different line. For this,
645you're better off getting an external program like GNU @code{indent},
646which will rearrange brace location, amongst other things.
6bf7aab6 647
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648Preprocessor directives are handled as syntactic whitespace from other
649code, i.e. they can be interspersed anywhere without affecting the
650indentation of the surrounding code, just like comments.
6bf7aab6 651
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652The code inside macro definitions is, by default, still analyzed
653syntactically so that you get relative indentation there just as you'd
654get if the same code was outside a macro. However, since there is no
655hint about the syntactic context, i.e. whether the macro expands to an
656expression, to some statements, or perhaps to whole functions, the
657syntactic recognition can be wrong. @ccmode{} manages to figure it
658out correctly most of the time, though.
6bf7aab6 659
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660Reindenting large sections of code can take a long time. When
661@ccmode{} reindents a region of code, it is essentially equivalent to
662hitting @key{TAB} on every line of the region.
6bf7aab6 663
116e44a1 664These commands indent code:
6bf7aab6 665
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666@table @asis
667@item @kbd{@key{TAB}} (@code{c-indent-command})
668@kindex TAB
669@findex c-indent-command
670@findex indent-command (c-)
671This command indents the current line. That is all you need to know
672about it for normal use.
6bf7aab6 673
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674@code{c-indent-command} does different things, depending on the
675settting of @code{c-syntactic-indentation} (@pxref{Indentation Engine
676Basics}):
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677
678@itemize @bullet
679@item
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680When it's non-@code{nil} (which it normally is), the command indents
681the line according to its syntactic context. With a prefix argument
682(@kbd{C-u @key{TAB}}), it will re-indent the entire
683expression@footnote{this is only useful for a line starting with a
684comment opener or an opening brace, parenthesis, or string quote.}
685that begins at the line's left margin.
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686
687@item
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688When it's @code{nil}, the command indents the line by an extra
689@code{c-basic-offset} columns. A prefix argument acts as a
690multiplier. A bare prefix (@kbd{C-u @key{TAB}} is equivalent to -1,
691removing @code{c-basic-offset} columns from the indentation.
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692@end itemize
693
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694The precise behavior is modified by several variables: With
695@code{c-tab-always-indent}, you can make @key{TAB} insert whitespace
696in some circumstances---@code{c-insert-tab-function} then defines
697precisely what sort of ``whitespace'' this will be. Set the standard
698Emacs variable @code{indent-tabs-mode} to @code{t} if you want real
699@samp{tab} characters to be used in the indentation, to @code{nil} if
700you want only spaces. @xref{Just Spaces,,, @emacsman{},
701@emacsmantitle{}}.
6bf7aab6 702
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703@defopt c-tab-always-indent
704@vindex tab-always-indent (c-)
705@cindex literal
706This variable modifies how @key{TAB} operates.
707@itemize @bullet
708@item
709When it is @code{t} (the default), @key{TAB} simply indents the
710current line.
711@item
712When it is @code{nil}, @key{TAB} (re)indents the line only if point is
713to the left of the first non-whitespace character on the line.
714Otherwise it inserts some whitespace (a tab or an equivalent number of
715spaces - see below) at point.
716@item
717With some other value, the line is reindented. Additionally, if point
718is within a string or comment, some whitespace is inserted.
719@end itemize
720@end defopt
3a731e1f 721
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722@defopt c-insert-tab-function
723@vindex insert-tab-function (c-)
724@findex tab-to-tab-stop
725When ``some whitespace'' is inserted as described above, what actually
726happens is that the function stored in @code{c-insert-tab-function} is
727called. Normally, this is @code{insert-tab}, which inserts a real tab
728character or the equivalent number of spaces (depending on
729@code{indent-tabs-mode}). Some people, however, set
730@code{c-insert-tab-function} to @code{tab-to-tab-stop} so as to get
731hard tab stops when indenting.
732@end defopt
733@end table
d7bd46ed 734
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735@noindent
736The kind of indentation the next five commands do depends on the
737setting of @code{c-syntactic-indentation} (@pxref{Indentation Engine
738Basics}):
739@itemize @bullet
740@item
741when it is non-@code{nil} (the default), the commands indent lines
742according to their syntactic context;
743@item
744when it is @code{nil}, they just indent each line the same amount as
745the previous non-blank line. The commands that indent a region aren't
746very useful in this case.
747@end itemize
3a731e1f 748
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749@table @asis
750@item @kbd{C-j} (@code{newline-and-indent})
751@kindex C-j
752@findex newline-and-indent
0939d23b 753Inserts a newline and indents the new blank line, ready to start
116e44a1 754typing. This is a standard (X)Emacs command.
3a731e1f 755
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756@item @kbd{C-M-q} (@code{c-indent-exp})
757@kindex C-M-q
758@findex c-indent-exp
759@findex indent-exp (c-)
760Indents an entire balanced brace or parenthesis expression. Note that
761point must be on the opening brace or parenthesis of the expression
762you want to indent.
d7bd46ed 763
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764@item @kbd{C-c C-q} (@code{c-indent-defun})
765@kindex C-c C-q
766@findex c-indent-defun
767@findex indent-defun (c-)
768Indents the entire top-level function, class or macro definition
769encompassing point. It leaves point unchanged. This function can't be
770used to reindent a nested brace construct, such as a nested class or
771function, or a Java method. The top-level construct being reindented
772must be complete, i.e. it must have both a beginning brace and an ending
773brace.
d7bd46ed 774
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775@item @kbd{C-M-\} (@code{indent-region})
776@kindex C-M-\
777@findex indent-region
778Indents an arbitrary region of code. This is a standard Emacs command,
779tailored for C code in a @ccmode{} buffer. Note, of course, that point
780and mark must delineate the region you want to indent.
3a731e1f 781
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782@item @kbd{C-M-h} (@code{c-mark-function})
783@kindex C-M-h
784@findex c-mark-function
785@findex mark-function (c-)
786While not strictly an indentation command, this is useful for marking
787the current top-level function or class definition as the current
788region. As with @code{c-indent-defun}, this command operates on
789top-level constructs, and can't be used to mark say, a Java method.
790@end table
6bf7aab6 791
116e44a1 792These variables are also useful when indenting code:
6bf7aab6 793
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794@defopt indent-tabs-mode
795This is a standard Emacs variable that controls how line indentation
796is composed. When it's non-@code{nil}, tabs can be used in a line's
797indentation, otherwise only spaces are used.
798@end defopt
6bf7aab6 799
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800@defopt c-progress-interval
801@vindex progress-interval (c-)
802When indenting large regions of code, this variable controls how often a
803progress message is displayed. Set this variable to @code{nil} to
804inhibit the progress messages, or set it to an integer which is how
805often (in seconds) progress messages are to be displayed.
806@end defopt
6bf7aab6 807
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808@comment !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
809@node Comment Commands, Movement Commands, Indentation Commands, Commands
810@comment node-name, next, previous, up
811@section Comment Commands
812@cindex comments (insertion of)
813@comment !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
d7bd46ed 814
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815@table @asis
816@item @kbd{C-c C-c} (@code{comment-region})
817@kindex C-c C-c
818@findex comment-region
819This command comments out the lines that start in the region. With a
820negative argument, it does the opposite - it deletes the comment
821delimiters from these lines. @xref{Multi-Line Comments,,, emacs, GNU
822Emacs Manual}, for fuller details. @code{comment-region} isn't
823actually part of @ccmode{} - it is given a @ccmode{} binding for
824convenience.
825
826@item @kbd{M-;} (@code{comment-dwim} or @code{indent-for-comment} @footnote{The name of this command varies between (X)Emacs versions.})
827@kindex M-;
828@findex comment-dwim
829@findex indent-for-comment
830Insert a comment at the end of the current line, if none is there
831already. Then reindent the comment according to @code{comment-column}
832@ifclear XEMACS
833(@pxref{Options for Comments,,, emacs, GNU Emacs Manual})
834@end ifclear
835@ifset XEMACS
836(@pxref{Comments,,, xemacs, XEmacs User's Manual})
837@end ifset
838and the variables below. Finally, position the point after the
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839comment starter. @kbd{C-u M-;} kills any comment on the current line,
840together with any whitespace before it. This is a standard Emacs
841command, but @ccmode{} enhances it a bit with two variables:
6bf7aab6 842
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843@defopt c-indent-comment-alist
844@vindex indent-comment-alist (c-)
845@vindex comment-column
846This style variable allows you to vary the column that @kbd{M-;} puts
847the comment at, depending on what sort of code is on the line, and
848possibly the indentation of any similar comment on the preceding line.
849It is an association list that maps different types of lines to
850actions describing how they should be handled. If a certain line type
851isn't present on the list then the line is indented to the column
852specified by @code{comment-column}.
6bf7aab6 853
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854See the documentation string for for a full description of this
855variable (use @kbd{C-h v c-indent-comment-alist}).
3a731e1f 856@end defopt
6bf7aab6 857
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858@defopt c-indent-comments-syntactically-p
859@vindex indent-comments-syntactically-p (c-)
860Normally, when this style variable is @code{nil}, @kbd{M-;} will
861indent comment-only lines according to @code{c-indent-comment-alist},
862just as it does with lines where other code precede the comments.
863However, if you want it to act just like @key{TAB} for comment-only
864lines you can get that by setting
865@code{c-indent-comments-syntactically-p} to non-@code{nil}.
866
867If @code{c-indent-comments-syntactically-p} is non-@code{nil} then
868@code{c-indent-comment-alist} won't be consulted at all for comment-only
869lines.
870@end defopt
871@end table
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872
873@comment !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
116e44a1 874@node Movement Commands, Filling and Breaking, Comment Commands, Commands
d7bd46ed 875@comment node-name, next, previous, up
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876@section Movement Commands
877@cindex movement
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878@comment !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
879
116e44a1 880@ccmode{} contains some useful commands for moving around in C code.
3a731e1f 881
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882@table @asis
883@item @kbd{M-x c-beginning-of-defun}
884@itemx @kbd{M-x c-end-of-defun}
885@findex c-beginning-of-defun
886@findex c-end-of-defun
887@findex beginning-of-defun (c-)
888@findex end-of-defun (c-)
889@findex beginning-of-defun
890@findex end-of-defun
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891Move to the start or end of the current top-level definition. This is
892the outermost brace pair which encloses point, together with the
893function header or similar preamble which precedes the opening brace.
894These functions are analogous to the Emacs built-in commands
895@code{beginning-of-defun} and @code{end-of-defun}, except they
896eliminate the constraint that the top-level opening brace of the defun
897must be in column zero. See @ref{Defuns,,,@emacsman{},
898@emacsmantitle{}}, for more information.
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899
900Depending on the coding style you're using, you might prefer these two
901commands to the standard Emacs ones. If so, consider binding them to
902@kbd{C-M-a} and @kbd{C-M-e}. @xref{Sample .emacs File}. This
903customization won't affect the special bindings for these key
904sequences in force in AWK Mode. For backwards compatibility reasons,
905the default bindings for @kbd{C-M-a} and @kbd{C-M-e} remain in effect.
906
907@item @kbd{C-M-a} (AWK Mode) (@code{c-awk-beginning-of-defun})
908@itemx @kbd{C-M-e} (AWK Mode) (@code{c-awk-end-of-defun})
909@kindex C-M-a (AWK Mode)
910@kindex C-M-e (AWK Mode)
911@findex c-awk-beginning-of-defun
912@findex awk-beginning-of-defun (c-)
913@findex c-awk-end-of-defun
914@findex awk-end-of-defun (c-)
915Move back to the beginning or forward to the end of the current AWK
916defun. These functions are bound to @kbd{C-M-a} and @kbd{C-M-e} by
917default in AWK Mode. They can take prefix-arguments, their
918functionality being entirely equivalent to @code{beginning-of-defun}
919and @code{end-of-defun}.
3a731e1f 920
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921AWK Mode @dfn{defuns} are either pattern/action pairs (either of which
922might be implicit) or user defined functions. Having the @samp{@{} and
923@samp{@}} (if there are any) in column zero, as is suggested for some
924modes, is neither necessary nor helpful in AWK mode.
6bf7aab6 925
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926@item @kbd{M-a} (@code{c-beginning-of-statement})
927@itemx @kbd{M-e} (@code{c-end-of-statement})
928@kindex M-a
929@kindex M-e
930@findex c-beginning-of-statement
931@findex c-end-of-statement
932@findex beginning-of-statement (c-)
933@findex end-of-statement (c-)
934Move to the beginning or end of the innermost C statement. If point
935is already there, move to the next beginning or end of a statement,
936even if that means moving into a block. (Use @kbd{C-M-b} or
937@kbd{C-M-f} to move over a balanced block.) A prefix argument @var{n}
938means move over @var{n} statements.
939
940If point is within or next to a comment or a string which spans more
941than one line, these commands move by sentences instead of statements.
942
943When called from a program, these functions take three optional
944arguments: the repetition count, a buffer position limit which is the
945farthest back to search for the syntactic context, and a flag saying
946whether to do sentence motion in or near comments and multiline
947strings.
948
949@item @kbd{C-c C-u} (@code{c-up-conditional})
950@kindex C-c C-u
951@findex c-up-conditional
952@findex up-conditional (c-)
953Move back to the containing preprocessor conditional, leaving the mark
954behind. A prefix argument acts as a repeat count. With a negative
955argument, move forward to the end of the containing preprocessor
956conditional.
957
958@samp{#elif} is treated like @samp{#else} followed by @samp{#if}, so the
959function stops at them when going backward, but not when going
960forward.
961
962This key sequence is not bound in AWK Mode, which doesn't have
963preprocessor statements.
964
965@item @kbd{M-x c-up-conditional-with-else}
966@findex c-up-conditional-with-else
967@findex up-conditional-with-else (c-)
968A variety of @code{c-up-conditional} that also stops at @samp{#else}
969lines. Normally those lines are ignored.
970
971@item @kbd{M-x c-down-conditional}
972@findex c-down-conditional
973@findex down-conditional (c-)
974Move forward into the next nested preprocessor conditional, leaving
975the mark behind. A prefix argument acts as a repeat count. With a
976negative argument, move backward into the previous nested preprocessor
977conditional.
6bf7aab6 978
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979@samp{#elif} is treated like @samp{#else} followed by @samp{#if}, so the
980function stops at them when going forward, but not when going backward.
6bf7aab6 981
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982@item @kbd{M-x c-down-conditional-with-else}
983@findex c-down-conditional-with-else
984@findex down-conditional-with-else (c-)
985A variety of @code{c-down-conditional} that also stops at @samp{#else}
986lines. Normally those lines are ignored.
987
988@item @kbd{C-c C-p} (@code{c-backward-conditional})
989@itemx @kbd{C-c C-n} (@code{c-forward-conditional})
990@kindex C-c C-p
991@kindex C-c C-n
992@findex c-backward-conditional
993@findex c-forward-conditional
994@findex backward-conditional (c-)
995@findex forward-conditional (c-)
996Move backward or forward across a preprocessor conditional, leaving
997the mark behind. A prefix argument acts as a repeat count. With a
998negative argument, move in the opposite direction.
999
1000These key sequences are not bound in AWK Mode, which doesn't have
1001preprocessor statements.
1002
1003@item @kbd{M-x c-backward-into-nomenclature}
1004@itemx @kbd{M-x c-forward-into-nomenclature}
1005@findex c-backward-into-nomenclature
1006@findex c-forward-into-nomenclature
1007@findex backward-into-nomenclature (c-)
1008@findex forward-into-nomenclature (c-)
1009A popular programming style, especially for object-oriented languages
1010such as C++ is to write symbols in a mixed case format, where the
1011first letter of each word is capitalized, and not separated by
1012underscores. E.g. @samp{SymbolsWithMixedCaseAndNoUnderlines}.
1013
1014These commands move backward or forward to the beginning of the next
1015capitalized word. With prefix argument @var{n}, move @var{n} times.
1016If @var{n} is negative, move in the opposite direction.
1017
1018Note that these two commands have been superseded by
1019@code{c-subword-mode}, which you should use instead. @xref{Subword
1020Movement}. They might be removed from a future release of @ccmode{}.
1021@end table
1022
1023@comment !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
1024@node Filling and Breaking, Minor Modes, Movement Commands, Commands
1025@comment node-name, next, previous, up
1026@section Filling and Line Breaking Commands
1027@cindex text filling
1028@cindex line breaking
1029@cindex comment handling
6bf7aab6 1030@comment !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
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1031
1032Since there's a lot of normal text in comments and string literals,
1033@ccmode{} provides features to edit these like in text mode. The goal
1034is to do it seamlessly, i.e. you can use auto fill mode, sentence and
1035paragraph movement, paragraph filling, adaptive filling etc. wherever
1036there's a piece of normal text without having to think much about it.
1037@ccmode{} keeps the indentation, fixes suitable comment line prefixes,
1038and so on.
1039
1040You can configure the exact way comments get filled and broken, and
1041where Emacs does auto-filling (see @pxref{Custom Filling and
1042Breaking}). Typically, the style system (@pxref{Styles}) will have
1043set this up for you, so you probably won't have to bother.
1044
1045@findex auto-fill-mode
1046@cindex Auto Fill mode
1047@cindex paragraph filling
1048Line breaks are by default handled (almost) the same regardless of
1049whether they are made by auto fill mode (@pxref{Auto Fill,,,
1050@emacsman{}, @emacsmantitle{}}), by paragraph filling (e.g. with
1051@kbd{M-q}), or explicitly with @kbd{M-j} or similar methods. In
1052string literals, the new line gets the same indentation as the
1053previous nonempty line.@footnote{You can change this default by
1054setting the @code{string} syntactic symbol (@pxref{Syntactic Symbols}
1055and @pxref{Customizing Indentation})}.
1056
1057@table @asis
1058@item @kbd{M-q} (@code{c-fill-paragraph})
1059@kindex M-q
1060@findex c-fill-paragraph
1061@findex fill-paragraph (c-)
1062@cindex Javadoc markup
1063@cindex Pike autodoc markup
1064This command fills multiline string literals and both block
1065and line style comments. In Java buffers, the Javadoc markup words
1066are recognized as paragraph starters. The line oriented Pike autodoc
1067markup words are recognized in the same way in Pike mode.
1068
1069The formatting of the starters (@code{/*}) and enders (@code{*/}) of
1070block comments are kept as they were before the filling. I.e., if
1071either the starter or ender were on a line of its own, then it stays
1072on its own line; conversely, if the delimiter has comment text on its
1073line, it keeps at least one word of that text with it on the line.
1074
1075This command is the replacement for @code{fill-paragraph} in @ccmode{}
1076buffers.
1077
1078@item @kbd{M-j} (@code{c-indent-new-comment-line})
1079@kindex M-j
1080@findex c-indent-new-comment-line
1081@findex indent-new-comment-line (c-)
1082This breaks the current line at point and indents the new line. If
1083point was in a comment, the new line gets the proper comment line
1084prefix. If point was inside a macro, a backslash is inserted before
1085the line break. It is the replacement for
1086@code{indent-new-comment-line}.
1087
1088@item @kbd{M-x c-context-line-break}
1089@findex c-context-line-break
1090@findex context-line-break (c-)
1091Insert a line break suitable to the context: If the point is inside a
1092comment, the new line gets the suitable indentation and comment line
1093prefix like @code{c-indent-new-comment-line}. In normal code it's
1094indented like @code{newline-and-indent} would do. In macros it acts
1095like @code{newline-and-indent} but additionally inserts and optionally
1096aligns the line ending backslash so that the macro remains unbroken.
1097@xref{Custom Macros}, for details about the backslash alignment.
1098
1099This function is not bound to a key by default, but it's intended to be
1100used on the @kbd{RET} key. If you like the behavior of
1101@code{newline-and-indent} on @kbd{RET}, you should consider switching to
1102this function. @xref{Sample .emacs File}.
1103
1104@item @kbd{M-x c-context-open-line}
1105@findex c-context-open-line
1106@findex context-open-line (c-)
1107This is to @kbd{C-o} (@kbd{M-x open-line}) as
1108@code{c-context-line-break} is to @kbd{RET}. I.e. it works just like
1109@code{c-context-line-break} but leaves the point before the inserted
1110line break.
1111@end table
1112
1113
1114@comment !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
1115@node Minor Modes, Electric Keys, Filling and Breaking, Commands
d7bd46ed 1116@comment node-name, next, previous, up
116e44a1
AM
1117@section Minor Modes
1118@cindex Minor Modes
6bf7aab6
DL
1119@comment !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
1120
116e44a1
AM
1121@ccmode{} contains several minor-mode-like features that you might
1122find useful while writing new code or editing old code:
1123
1124@table @asis
1125@item electric mode
1126When this is enabled, certain visible characters cause reformatting as
1127they are typed. This is normally helpful, but can be a nuisance when
1128editing chaotically formatted code. It can also be disconcerting,
1129especially for users who are new to @ccmode{}.
1130@item auto-newline mode
1131This automatically inserts newlines where you'd probably want to type
1132them yourself, e.g. after typing @samp{@}}s. Its action is suppressed
1133when electric mode is disabled.
1134@item hungry-delete mode
1135This lets you delete a contiguous block of whitespace with a single
1136key - for example, the newline and indentation just inserted by
1137auto-newline when you want to back up and write a comment after the
1138last statement.
1139@item subword mode
1140This mode makes basic word movement commands like @kbd{M-f}
1141(@code{forward-word}) and @kbd{M-b} (@code{backward-word}) treat the
1142parts of sillycapsed symbols as different words.
1143E.g. @samp{NSGraphicsContext} is treated as three words @samp{NS},
1144@samp{Graphics}, and @samp{Context}.
1145@item syntactic-indentation mode
1146When this is enabled (which it normally is), indentation commands such
1147as @kbd{C-j} indent lines of code according to their syntactic
1148structure. Otherwise, a line is simply indented to the same level as
1149the previous one and @kbd{@key{TAB}} adjusts the indentation in steps
1150of `c-basic-offset'.
1151@end table
1152
1153Full details on how these minor modes work are at @ref{Electric Keys},
1154@ref{Auto-newlines}, @ref{Hungry WS Deletion}, @ref{Subword Movement},
1155and @ref{Indentation Engine Basics}.
1156
1157You can toggle each of these minor modes on and off, and you can
1158configure @ccmode{} so that it starts up with your favourite
1159combination of them (@pxref{Sample .emacs File}). By default, when
1160you initialize a buffer, electric mode and syntactic-indentation mode
1161are enabled but the other two modes are disabled.
1162
1163@ccmode{} displays the current state of the first four of these minor
1164modes on the modeline by appending letters to the major mode's name,
1165one letter for each enabled minor mode - @samp{l} for electric mode,
1166@samp{a} for auto-newline mode, @samp{h} for hungry delete mode, and
1167@samp{w} for subword mode. If all these modes were enabled, you'd see
1168@samp{C/lahw}@footnote{The @samp{C} would be replaced with the name of
1169the language in question for the other languages @ccmode{} supports.}.
1170
1171Here are the commands to toggle these modes:
1172
1173@table @asis
1174@item @kbd{C-c C-l} (@code{c-toggle-electric-state})
1175@kindex C-c C-l
1176@findex c-toggle-electric-state
1177@findex toggle-electric-state (c-)
1178Toggle electric minor mode. When the command turns the mode off, it
1179also suppresses auto-newline mode.
1180
1181@item @kbd{C-c C-a} (@code{c-toggle-auto-newline})
1182@kindex C-c C-a
1183@findex c-toggle-auto-newline
1184@findex toggle-auto-newline (c-)
1185Toggle auto-newline minor mode. When the command turns the mode on,
1186it also enables electric minor mode.
1187
1188@item @kbd{M-x c-toggle-hungry-state}@footnote{Prior to @ccmode{} 5.31, this command was bound to @kbd{C-c C-d}.}
1189@findex c-toggle-hungry-state
1190@findex toggle-hungry-state (c-)
1191Toggle hungry-delete minor mode.
1192
1193@item @kbd{M-x c-toggle-auto-hungry-state}@footnote{Prior to @ccmode{} 5.31, this command was bound to @kbd{C-c C-t}.}
1194@findex c-toggle-auto-hungry-state
1195@findex toggle-auto-hungry-state (c-)
1196Toggle both auto-newline and hungry delete minor modes.
1197
1198@item @kbd{C-c C-w} (@code{M-x c-subword-mode})
1199@kindex C-c C-w
1200@findex c-subword-mode
1201@findex subword-mode (c-)
1202Toggle subword mode.
1203
1204@item @kbd{M-x c-toggle-syntactic-indentation}
1205@findex c-toggle-syntactic-indentation
1206@findex toggle-syntactic-indentation (c-)
1207Toggle syntactic-indentation mode.
1208@end table
1209
1210Common to all the toggle functions above is that if they are called
1211programmatically, they take an optional numerical argument. A
1212positive value will turn on the minor mode (or both of them in the
1213case of @code{c-toggle-auto-hungry-state}) and a negative value will
1214turn it (or them) off.
6bf7aab6
DL
1215
1216
1217@comment !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
116e44a1 1218@node Electric Keys, Auto-newlines, Minor Modes, Commands
d7bd46ed 1219@comment node-name, next, previous, up
116e44a1
AM
1220@section Electric Keys and Keywords
1221@cindex electric characters
6bf7aab6
DL
1222@comment !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
1223
116e44a1
AM
1224Most punctuation keys provide @dfn{electric} behavior - as well as
1225inserting themselves they perform some other action, such as
0d566910
AM
1226reindenting the line. This reindentation saves you from having to
1227reindent a line manually after typing, say, a @samp{@}}. A few
1228keywords, such as @code{else}, also trigger electric action.
116e44a1
AM
1229
1230You can inhibit the electric behaviour described here by disabling
0d566910 1231electric minor mode (@pxref{Minor Modes}).
116e44a1 1232
0d566910
AM
1233Common to all these keys is that they only behave electrically when
1234used in normal code (as contrasted with getting typed in a string
1235literal or comment). Those which cause re-indentation do so only when
116e44a1
AM
1236@code{c-syntactic-indentation} has a non-@code{nil} value (which it
1237does by default).
1238
1239These keys and keywords are:
1240@c ACM, 2004/8/24: c-electric-pound doesn't check c-s-i: this is more
1241@c like a bug in the code than a bug in this document. It'll get
1242@c fixed in the code sometime.
3a731e1f
MS
1243
1244@table @kbd
1245@item #
6bf7aab6
DL
1246@kindex #
1247@findex c-electric-pound
6bf7aab6 1248@findex electric-pound (c-)
3a731e1f 1249@vindex c-electric-pound-behavior
6bf7aab6 1250@vindex electric-pound-behavior (c-)
3a731e1f
MS
1251Pound (bound to @code{c-electric-pound}) is electric when typed as the
1252first non-whitespace character on a line and not within a macro
1253definition. In this case, the variable @code{c-electric-pound-behavior}
1254is consulted for the electric behavior. This variable takes a list
1255value, although the only element currently defined is @code{alignleft},
1256which tells this command to force the @samp{#} character into column
1257zero. This is useful for entering preprocessor macro definitions.
1258
1259Pound is not electric in AWK buffers, where @samp{#} starts a comment,
1260and is bound to @code{self-insert-command} like any typical printable
1261character.
116e44a1
AM
1262@c ACM, 2004/8/24: Change this (and the code) to do AWK comment
1263@c reindentation.
6bf7aab6 1264
3a731e1f
MS
1265@item *
1266@kindex *
1267@itemx /
1268@kindex /
6bf7aab6 1269@findex c-electric-star
6bf7aab6 1270@findex electric-star (c-)
3a731e1f 1271@findex c-electric-slash
6bf7aab6 1272@findex electric-slash (c-)
116e44a1
AM
1273A star (bound to @code{c-electric-star}) or a slash
1274(@code{c-electric-slash}) causes reindentation when you type it as the
1275second component of a C style block comment opener (@samp{/*}) or a
1276C++ line comment opener (@samp{//}) respectively, but only if the
1277comment opener is the first thing on the line (i.e. there's only
1278whitespace before it).
6bf7aab6 1279
116e44a1
AM
1280Additionally, you can configure @ccmode{} so that typing a slash at
1281the start of a line within a block comment will terminate the
1282comment. You don't need to have electric minor mode enabled to get
1283this behaviour. @xref{Clean-ups}.
6bf7aab6 1284
116e44a1
AM
1285In AWK mode, @samp{*} and @samp{/} do not delimit comments and are not
1286electric.
3a731e1f
MS
1287
1288@item <
6bf7aab6 1289@kindex <
3a731e1f 1290@itemx >
6bf7aab6 1291@kindex >
3a731e1f
MS
1292@findex c-electric-lt-gt
1293@findex electric-lt-gt (c-)
116e44a1
AM
1294A less-than or greater-than sign (bound to @code{c-electric-lt-gt}) is
1295electric in two circumstances: when it is an angle bracket in a C++
1296@samp{template} declaration (and similar constructs in other
1297languages) and when it is the second of two @kbd{<} or @kbd{>}
1298characters in a C++ style stream operator. In either case, the line
1299is reindented. Angle brackets in C @samp{#include} directives are not
1300electric.
6bf7aab6 1301
3a731e1f 1302@item (
d7bd46ed 1303@kindex (
3a731e1f 1304@itemx )
d7bd46ed 1305@kindex )
3a731e1f
MS
1306@findex c-electric-paren
1307@findex electric-paren (c-)
116e44a1
AM
1308The normal parenthesis characters @samp{(} and @samp{)} (bound to
1309@code{c-electric-paren}) reindent the current line. This is useful
1310for getting the closing parenthesis of an argument list aligned
1311automatically.
1312
1313You can also configure @ccmode{} to insert a space automatically
1314between a function name and the @samp{(} you've just typed, and to
1315remove it automatically after typing @samp{)}, should the argument
1316list be empty. You don't need to have electric minor mode enabled to
1317get these actions. @xref{Clean-ups}.
1318
1319@item @{
1320@kindex @{
1321@itemx @}
1322@kindex @}
1323@findex c-electric-brace
1324@findex electric-brace (c-)
1325Typing a brace (bound to @code{c-electric-brace}) reindents the
1326current line. Also, one or more newlines might be inserted if
1327auto-newline minor mode is enabled. @xref{Auto-newlines}.
1328Additionally, you can configure @ccmode{} to compact excess whitespace
1329inserted by auto-newline mode in certain circumstances.
1330@xref{Clean-ups}.
1331
1332@item :
1333@kindex :
1334@findex c-electric-colon
1335@findex electric-colon (c-)
1336Typing a colon (bound to @code{c-electric-colon}) reindents the
1337current line. Additionally, one or more newlines might be inserted if
1338auto-newline minor mode is enabled. @xref{Auto-newlines}. If you
1339type a second colon immediately after such an auto-newline, by default
1340the whitespace between the two colons is removed, leaving a C++ scope
1341operator. @xref{Clean-ups}.
1342
1343If you prefer, you can insert @samp{::} in a single operation,
1344avoiding all these spurious reindentations, newlines, and clean-ups.
1345@xref{Other Commands}.
1346
1347@item ;
1348@kindex ;
1349@itemx ,
1350@kindex ,
1351@findex c-electric-semi&comma
1352@findex electric-semi&comma (c-)
1353Typing a semicolon or comma (bound to @code{c-electric-semi&comma})
1354reindents the current line. Also, a newline might be inserted if
1355auto-newline minor mode is enabled. @xref{Auto-newlines}.
1356Additionally, you can configure @ccmode{} so that when auto-newline
1357has inserted whitespace after a @samp{@}}, it will be removed again
1358when you type a semicolon or comma just after it. @xref{Clean-ups}.
1359
3a731e1f
MS
1360@end table
1361
1362@deffn Command c-electric-continued-statement
1363@findex electric-continued-statement (c-)
1364
116e44a1
AM
1365Certain keywords are electric, causing reindentation when they are
1366preceded only by whitespace on the line. The keywords are those that
1367continue an earlier statement instead of starting a new one:
1368@code{else}, @code{while}, @code{catch} (only in C++ and Java) and
1369@code{finally} (only in Java).
3a731e1f
MS
1370
1371An example:
1372
1373@example
1374@group
1375for (i = 0; i < 17; i++)
1376 if (a[i])
1377 res += a[i]->offset;
1378else
1379@end group
1380@end example
1381
1382Here, the @code{else} should be indented like the preceding @code{if},
116e44a1
AM
1383since it continues that statement. @ccmode{} will automatically
1384reindent it after the @code{else} has been typed in full, since only
1385then is it possible to decide whether it's a new statement or a
3a731e1f
MS
1386continuation of the preceding @code{if}.
1387
1388@vindex abbrev-mode
1389@findex abbrev-mode
1390@cindex Abbrev mode
116e44a1 1391@ccmode{} uses Abbrev mode (@pxref{Abbrevs,,, @emacsman{}, @emacsmantitle{}})
3a731e1f
MS
1392to accomplish this. It's therefore turned on by default in all language
1393modes except IDL mode, since CORBA IDL doesn't have any statements.
1394@end deffn
6bf7aab6 1395
6bf7aab6 1396
d7bd46ed 1397@comment !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
116e44a1 1398@node Auto-newlines, Hungry WS Deletion, Electric Keys, Commands
d7bd46ed 1399@comment node-name, next, previous, up
116e44a1
AM
1400@section Auto-newline Insertion
1401@cindex auto-newline
6bf7aab6
DL
1402@comment !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
1403
116e44a1
AM
1404When you have @dfn{Auto-newline minor mode} enabled (@pxref{Minor
1405Modes}), @ccmode{} inserts newlines for you automatically (in certain
1406syntactic contexts) when you type a left or right brace, a colon, a
1407semicolon, or a comma. Sometimes a newline appears before the
1408character you type, sometimes after it, sometimes both.
6bf7aab6 1409
116e44a1 1410Auto-newline only triggers when the following conditions hold:
6bf7aab6 1411
116e44a1
AM
1412@itemize @bullet
1413@item
1414Auto-newline minor mode is enabled, as evidenced by the indicator
1415@samp{a} after the mode name on the modeline (e.g. @samp{C/a} or
1416@samp{C/la}).
6bf7aab6 1417
116e44a1
AM
1418@item
1419The character was typed at the end of a line, or with only whitespace
1420after it, and possibly a @samp{\} escaping the newline.
6bf7aab6 1421
116e44a1
AM
1422@item
1423The character is not on its own line already. (This applies only to
1424insertion of a newline @emph{before} the character.)
3a731e1f 1425
116e44a1
AM
1426@item
1427@cindex literal
1428@cindex syntactic whitespace
1429The character was not typed inside of a literal @footnote{A
1430@dfn{literal} is defined as any comment, string, or preprocessor macro
1431definition. These constructs are also known as @dfn{syntactic
1432whitespace} since they are usually ignored when scanning C code.}.
6bf7aab6 1433
116e44a1
AM
1434@item
1435No numeric argument was supplied to the command (i.e. it was typed as
1436normal, with no @kbd{C-u} prefix).
1437@end itemize
cb7f2e96 1438
116e44a1
AM
1439You can configure the precise circumstances in which newlines get
1440inserted (see @pxref{Custom Auto-newlines}). Typically, the style
1441system (@pxref{Styles}) will have set this up for you, so you probably
1442won't have to bother.
3a731e1f 1443
116e44a1
AM
1444Sometimes @ccmode{} inserts an auto-newline where you don't want one,
1445such as after a @samp{@}} when you're about to type a @samp{;}.
1446Hungry deletion can help here (@pxref{Hungry WS Deletion}), or you can
1447activate an appropriate @dfn{clean-up}, which will remove the excess
1448whitespace after you've typed the @samp{;}. See @ref{Clean-ups} for a
1449full description. See also @ref{Electric Keys} for a summary of
1450clean-ups listed by key.
cb7f2e96 1451
6bf7aab6
DL
1452
1453@comment !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
116e44a1 1454@node Hungry WS Deletion, Subword Movement, Auto-newlines, Commands
d7bd46ed 1455@comment node-name, next, previous, up
116e44a1 1456@section Hungry Deletion of Whitespace
3a731e1f 1457@cindex hungry-deletion
6bf7aab6
DL
1458@comment !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
1459
116e44a1
AM
1460If you want to delete an entire block of whitespace at point, you can
1461use @dfn{hungry deletion}. This deletes all the contiguous whitespace
1462either before point or after point in a single operation.
1463``Whitespace'' here includes tabs and newlines, but not comments or
1464preprocessor commands. Hungry deletion can markedly cut down on the
1465number of times you have to hit deletion keys when, for example,
1466you've made a mistake on the preceding line and have already pressed
1467@kbd{C-j}.
6bf7aab6 1468
116e44a1
AM
1469Hungry deletion is a simple feature that some people find extremely
1470useful. In fact, you might find yourself wanting it in @strong{all}
1471your editing modes!
3a731e1f 1472
0d566910
AM
1473Loosely speaking, in what follows, @dfn{@key{DEL}} means ``the
1474backspace key'' and @dfn{@key{DELETE}} means ``the forward delete
1475key''. This is discussed in more detail below.
1476
116e44a1 1477There are two different ways you can use hungry deletion:
6bf7aab6 1478
116e44a1
AM
1479@table @asis
1480@item Using @dfn{Hungry Delete Mode} with @kbd{@key{DEL}} and @kbd{C-d}
1481Here you toggle Hungry Delete minor mode with @kbd{M-x
1482c-toggle-hungry-state}@footnote{Prior to @ccmode{} 5.31, this command
1483was bound to @kbd{C-c C-d}. @kbd{C-c C-d} is now the default binding
1484for @code{c-hungry-delete-forward}.} (@pxref{Minor Modes}.) This
0d566910 1485makes @kbd{@key{DEL}} and @kbd{C-d} do backwards and forward hungry
116e44a1 1486deletion.
3a731e1f 1487
116e44a1
AM
1488@table @asis
1489@item @kbd{@key{DEL}} (@code{c-electric-backspace})
1490@kindex DEL
1491@findex c-electric-backspace
1492@findex electric-backspace (c-)
1493This command is run by default when you hit the @kbd{DEL} key. When
1494hungry delete mode is enabled, it deletes any amount of whitespace in
1495the backwards direction. Otherwise, or when used with a prefix
1496argument or in a literal (@pxref{Auto-newlines}), the command just
1497deletes backwards in the usual way. (More precisely, it calls the
1498function contained in the variable @code{c-backspace-function},
1499passing it the prefix argument, if any.)
1500
1501@item @code{c-backspace-function}
1502@vindex c-backspace-function
6bf7aab6 1503@vindex backspace-function (c-)
3a731e1f
MS
1504@findex backward-delete-char-untabify
1505Hook that gets called by @code{c-electric-backspace} when it doesn't
1506do an ``electric'' deletion of the preceding whitespace. The default
116e44a1
AM
1507value is @code{backward-delete-char-untabify}
1508(@pxref{Deletion,,,@lispref{}, @lispreftitle{}}, the function which
1509deletes a single character.
3a731e1f 1510
116e44a1
AM
1511@item @kbd{C-d} (@code{c-electric-delete-forward})
1512@kindex C-d
1513@findex c-electric-delete-forward
3a731e1f
MS
1514@findex electric-delete-forward (c-)
1515This function, which is bound to @kbd{C-d} by default, works just like
1516@code{c-electric-backspace} but in the forward direction. When it
1517doesn't do an ``electric'' deletion of the following whitespace, it
116e44a1
AM
1518just does @code{delete-char}, more or less. (Strictly speaking, it
1519calls the function in @code{c-delete-function} with the prefix
1520argument.)
3a731e1f 1521
116e44a1
AM
1522@item @code{c-delete-function}
1523@vindex c-delete-function
3a731e1f
MS
1524@vindex delete-function (c-)
1525@findex delete-char
1526Hook that gets called by @code{c-electric-delete-forward} when it
1527doesn't do an ``electric'' deletion of the following whitespace. The
1528default value is @code{delete-char}.
116e44a1
AM
1529@end table
1530
1531@item Using Distinct Bindings
1532The other (newer and recommended) way to use hungry deletion is to
0d566910
AM
1533perform @code{c-hungry-delete-backwards} and
1534@code{c-hungry-delete-forward} directly through their key sequences
1535rather than using the minor mode toggling.
116e44a1
AM
1536
1537@table @asis
0d566910 1538@item @kbd{C-c C-@key{DEL}}, or @kbd{C-c @key{DEL}} (@code{c-hungry-delete-backwards})@footnote{This command was formerly known as @code{c-hungry-backspace}.}
116e44a1 1539@kindex C-c C-<backspace>
116e44a1 1540@kindex C-c <backspace>
0d566910
AM
1541@kindex C-c C-DEL
1542@kindex C-c DEL
1543@findex c-hungry-delete-backwards
1544@findex hungry-delete-backwards (c-)
116e44a1
AM
1545Delete any amount of whitespace in the backwards direction (regardless
1546whether hungry-delete mode is enabled or not). This command is bound
0d566910
AM
1547to both @kbd{C-c C-@key{DEL}} and @kbd{C-c @key{DEL}}, since the more
1548natural one, @kbd{C-c C-@key{DEL}}, is sometimes difficult to type at
1549a character terminal.
116e44a1 1550
0d566910 1551@item @kbd{C-c C-d}, @kbd{C-c C-@key{DELETE}}, or @kbd{C-c @key{DELETE}} (@code{c-hungry-delete-forward})
116e44a1 1552@kindex C-c C-d
0d566910
AM
1553@kindex C-c C-<DELETE>
1554@kindex C-c <DELETE>
116e44a1
AM
1555@findex c-hungry-delete-forward
1556@findex hungry-delete-forward (c-)
1557Delete any amount of whitespace in the forward direction (regardless
1558whether hungry-delete mode is enabled or not). This command is bound
0d566910
AM
1559to both @kbd{C-c C-@key{DELETE}} and @kbd{C-c @key{DELETE}} for the
1560same reason as for @key{DEL} above.
116e44a1
AM
1561@end table
1562@end table
3a731e1f 1563
116e44a1
AM
1564@kindex <delete>
1565@kindex <backspace>
1566
0d566910
AM
1567When we talk about @kbd{@key{DEL}}, and @kbd{@key{DELETE}} above, we
1568actually do so without connecting them to the physical keys commonly
1569known as @key{Backspace} and @key{Delete}. The default bindings to
1570those two keys depends on the flavor of (X)Emacs you are using.
6bf7aab6
DL
1571
1572@findex c-electric-delete
1573@findex electric-delete (c-)
116e44a1
AM
1574@findex c-hungry-delete
1575@findex hungry-delete (c-)
3a731e1f 1576@vindex delete-key-deletes-forward
3a731e1f
MS
1577In XEmacs 20.3 and beyond, the @key{Backspace} key is bound to
1578@code{c-electric-backspace} and the @key{Delete} key is bound to
1579@code{c-electric-delete}. You control the direction it deletes in by
1580setting the variable @code{delete-key-deletes-forward}, a standard
0d566910
AM
1581XEmacs variable.
1582@c This variable is encapsulated by XEmacs's (defsubst delete-forward-p ...).
1583When this variable is non-@code{nil}, @code{c-electric-delete} will do
1584forward deletion with @code{c-electric-delete-forward}, otherwise it
1585does backward deletion with @code{c-electric-backspace}. Similarly,
1586@kbd{C-c @key{Delete}} and @kbd{C-c C-@key{Delete}} are bound to
1587@code{c-hungry-delete} which is controlled in the same way by
1588@code{delete-key-deletes-forward}.
3a731e1f 1589
116e44a1 1590@findex normal-erase-is-backspace-mode
6bf7aab6 1591
116e44a1
AM
1592Emacs 21 and later automatically binds @key{Backspace} and
1593@key{Delete} to @kbd{DEL} and @kbd{C-d} according to your environment,
1594and @ccmode{} extends those bindings to @kbd{C-c C-@key{Backspace}}
1595etc. If you need to change the bindings through
1596@code{normal-erase-is-backspace-mode} then @ccmode{} will also adapt
1597its extended bindings accordingly.
6bf7aab6 1598
116e44a1
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1599In earlier (X)Emacs versions, @ccmode{} doesn't bind either
1600@key{Backspace} or @key{Delete} directly. Only the key codes
1601@kbd{DEL} and @kbd{C-d} are bound, and it's up to the default bindings
1602to map the physical keys to them. You might need to modify this
1603yourself if the defaults are unsuitable.
6bf7aab6 1604
116e44a1
AM
1605Getting your @key{Backspace} and @key{Delete} keys properly set up can
1606sometimes be tricky. The information in @ref{DEL Does Not
1607Delete,,,emacs, GNU Emacs Manual}, might be helpful if you're having
1608trouble with this in GNU Emacs.
6bf7aab6
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1609
1610
1611@comment !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
116e44a1 1612@node Subword Movement, Other Commands, Hungry WS Deletion, Commands
d7bd46ed 1613@comment node-name, next, previous, up
116e44a1 1614@section Subword Movement and Editing
6bf7aab6
DL
1615@comment !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
1616
116e44a1
AM
1617@cindex nomenclature
1618@cindex subword
1619In spite of the GNU Coding Standards, it is popular to name a symbol
1620by mixing uppercase and lowercase letters, e.g. @samp{GtkWidget},
1621@samp{EmacsFrameClass}, or @samp{NSGraphicsContext}. Here we call
1622these mixed case symbols @dfn{nomenclatures}. Also, each capitalized
1623(or completely uppercase) part of a nomenclature is called a
1624@dfn{subword}. Here are some examples:
1625
1626@multitable {@samp{NSGraphicsContext}} {@samp{NS}, @samp{Graphics}, and @samp{Context}}
1627@headitem Nomenclature
1628 @tab Subwords
1629@item @samp{GtkWindow}
1630 @tab @samp{Gtk} and @samp{Window}
1631@item @samp{EmacsFrameClass}
1632 @tab @samp{Emacs}, @samp{Frame}, and @samp{Class}
1633@item @samp{NSGraphicsContext}
1634 @tab @samp{NS}, @samp{Graphics}, and @samp{Context}
1635@end multitable
1636
1637The subword minor mode replaces the basic word oriented movement and
1638editing commands with variants that recognize subwords in a
1639nomenclature and treat them as separate words:
1640
1641@findex c-forward-subword
1642@findex forward-subword (c-)
1643@findex c-backward-subword
1644@findex backward-subword (c-)
1645@findex c-mark-subword
1646@findex mark-subword (c-)
1647@findex c-kill-subword
1648@findex kill-subword (c-)
1649@findex c-backward-kill-subword
1650@findex backward-kill-subword (c-)
1651@findex c-transpose-subwords
1652@findex transpose-subwords (c-)
1653@findex c-capitalize-subword
1654@findex capitalize-subword (c-)
1655@findex c-upcase-subword
1656@findex upcase-subword (c-)
1657@findex c-downcase-subword
1658@findex downcase-subword (c-)
1659@multitable @columnfractions .20 .40 .40
1660@headitem Key @tab Word oriented command @tab Subword oriented command
1661@item @kbd{M-f} @tab @code{forward-word} @tab @code{c-forward-subword}
1662@item @kbd{M-b} @tab @code{backward-word} @tab @code{c-backward-subword}
1663@item @kbd{M-@@} @tab @code{mark-word} @tab @code{c-mark-subword}
1664@item @kbd{M-d} @tab @code{kill-word} @tab @code{c-kill-subword}
1665@item @kbd{M-DEL} @tab @code{backward-kill-word} @tab @code{c-backward-kill-subword}
1666@item @kbd{M-t} @tab @code{transpose-words} @tab @code{c-transpose-subwords}
1667@item @kbd{M-c} @tab @code{capitalize-word} @tab @code{c-capitalize-subword}
1668@item @kbd{M-u} @tab @code{upcase-word} @tab @code{c-upcase-subword}
1669@item @kbd{M-l} @tab @code{downcase-word} @tab @code{c-downcase-subword}
1670@end multitable
1671
1672Note that if you have changed the key bindings for the word oriented
1673commands in your @file{.emacs} or a similar place, the keys you have
1674configured are also used for the corresponding subword oriented
1675commands.
1676
1677Type @kbd{C-c C-w} to toggle subword mode on and off. To make the
1678mode turn on automatically, put the following code in your
1679@file{.emacs}:
3a731e1f 1680
d7bd46ed 1681@example
116e44a1
AM
1682(add-hook 'c-mode-common-hook
1683 (lambda () (c-subword-mode 1)))
d7bd46ed
GM
1684@end example
1685
116e44a1
AM
1686As a bonus, you can also use @code{c-subword-mode} in non-@ccmode{}
1687buffers by typing @kbd{M-x c-subword-mode}.
d7bd46ed
GM
1688
1689@comment !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
116e44a1 1690@node Other Commands, , Subword Movement, Commands
d7bd46ed 1691@comment node-name, next, previous, up
116e44a1 1692@section Other Commands
6bf7aab6
DL
1693@comment !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
1694
116e44a1 1695Here are the various other commands that didn't fit anywhere else:
3a731e1f
MS
1696
1697@table @asis
116e44a1
AM
1698@item @kbd{C-c :} (@code{c-scope-operator})
1699@kindex C-c :
1700@findex c-scope-operator
1701@findex scope-operator (c-)
1702In C++, it is also sometimes desirable to insert the double-colon scope
1703operator without performing the electric behavior of colon insertion.
1704@kbd{C-c :} does just this.
1705
3a731e1f
MS
1706@item @kbd{C-c C-\} (@code{c-backslash-region})
1707@kindex C-c C-\
1708@findex c-backslash-region
1709@findex backslash-region (c-)
116e44a1
AM
1710This function inserts and aligns or deletes end-of-line backslashes in
1711the current region. These are typically used in multi-line macros.
3a731e1f
MS
1712
1713With no prefix argument, it inserts any missing backslashes and aligns
1714them according to the @code{c-backslash-column} and
1715@code{c-backslash-max-column} variables. With a prefix argument, it
1716deletes any backslashes.
1717
116e44a1
AM
1718The function does not modify blank lines at the start of the region. If
1719the region ends at the start of a line, it always deletes the backslash
1720(if any) at the end of the previous line.
3a731e1f 1721
116e44a1
AM
1722To customize the precise workings of this command, @ref{Custom Macros}.
1723@end table
3a731e1f 1724
116e44a1 1725@noindent
3a731e1f 1726The recommended line breaking function, @code{c-context-line-break}
116e44a1
AM
1727(@pxref{Filling and Breaking}), is especially nice if you edit
1728multiline macros frequently. When used inside a macro, it
1729automatically inserts and adjusts the mandatory backslash at the end
1730of the line to keep the macro together, and it leaves the point at the
1731right indentation column for the code. Thus you can write code inside
1732macros almost exactly as you can elsewhere, without having to bother
1733with the trailing backslashes.
3a731e1f 1734
116e44a1
AM
1735@table @asis
1736@item @kbd{C-c C-e} (@code{c-macro-expand})
1737@kindex C-c C-e
1738@findex c-macro-expand
1739@findex macro-expand (c-)
1740This command expands C, C++, Objective C or Pike macros in the region,
1741using an appropriate external preprocessor program. Normally it
1742displays its output in a temporary buffer, but if you give it a prefix
1743arg (with @kbd{C-u C-c C-e}) it will overwrite the original region
1744with the expansion.
1745
1746The command does not work in any of the other modes, and the key
1747sequence is not bound in these other modes.
1748
1749@code{c-macro-expand} isn't actually part of @ccmode{}, even though it
1750is bound to a @ccmode{} key sequence. If you need help setting it up
1751or have other problems with it, you can either read its source code or
1752ask for help in the standard (X)Emacs forums.
1753@end table
3a731e1f
MS
1754
1755@comment !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
116e44a1 1756@node Font Locking, Config Basics, Commands, Top
3a731e1f
MS
1757@comment node-name, next, previous, up
1758@chapter Font Locking
1759@cindex font locking
1760@comment !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
1761
3a731e1f
MS
1762@cindex Font Lock mode
1763
116e44a1
AM
1764@ccmode{} provides font locking for its supported languages by
1765supplying patterns for use with Font Lock mode. This means that you
1766get distinct faces on the various syntactic parts such as comments,
1767strings, keywords and types, which is very helpful in telling them
1768apart at a glance and discovering syntactic errors. @xref{Font
1769Lock,,, emacs, GNU Emacs Manual}, for ways to enable font locking in
1770@ccmode{} buffers.
1771
1772@strong{Please note:} The font locking in AWK mode is currently not
1773integrated with the rest of @ccmode{}. Only the last section of this
1774chapter, @ref{AWK Mode Font Locking}, applies to AWK. The other
1775sections apply to the other languages.
3a731e1f
MS
1776
1777@menu
116e44a1
AM
1778* Font Locking Preliminaries::
1779* Faces::
1780* Doc Comments::
1781* AWK Mode Font Locking::
3a731e1f
MS
1782@end menu
1783
1784
1785@comment !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
116e44a1 1786@node Font Locking Preliminaries, Faces, Font Locking, Font Locking
3a731e1f
MS
1787@comment node-name, next, previous, up
1788@section Font Locking Preliminaries
1789@comment !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
1790
1791The font locking for most of the @ccmode{} languages were provided
1792directly by the Font Lock package prior to version 5.30 of @ccmode{}.
1793In the transition to @ccmode{} the patterns have been reworked
1794completely and are applied uniformly across all the languages except AWK
1795mode, just like the indentation rules (although each language still has
116e44a1 1796some peculiarities of its own, of course). Since the languages
3a731e1f
MS
1797previously had completely separate font locking patterns, this means
1798that it's a bit different in most languages now.
1799
1800The main goal for the font locking in @ccmode{} is accuracy, to provide
1801a dependable aid in recognizing the various constructs. Some, like
116e44a1
AM
1802strings and comments, are easy to recognize while others, like
1803declarations and types, can be very tricky. @ccmode{} can go to great
3a731e1f
MS
1804lengths to recognize declarations and casts correctly, especially when
1805the types aren't recognized by standard patterns. This is a fairly
1806demanding analysis which can be slow on older hardware, and it can
1807therefore be disabled by choosing a lower decoration level with the
116e44a1
AM
1808variable @code{font-lock-maximum-decoration} (@pxref{Font Lock,,,
1809emacs, GNU Emacs Manual}).
3a731e1f
MS
1810
1811@vindex font-lock-maximum-decoration
1812
1813The decoration levels are used as follows:
1814
1815@enumerate
1816@comment 1
1817@item
1818Minimal font locking: Fontify only comments, strings and preprocessor
1819directives (in the languages that use cpp).
1820
1821@comment 2
1822@item
116e44a1
AM
1823Fast font locking: In addition to level 1, fontify keywords, simple
1824types and declarations that are easy to recognize. The variables
3a731e1f
MS
1825@code{*-font-lock-extra-types} (where @samp{*} is the name of the
1826language) are used to recognize types (see below). Documentation
1827comments like Javadoc are fontified according to
116e44a1 1828@code{c-doc-comment-style} (@pxref{Doc Comments}).
3a731e1f
MS
1829
1830Use this if you think the font locking is too slow. It's the closest
1831corresponding level to level 3 in the old font lock patterns.
1832
1833@comment 3
1834@item
116e44a1
AM
1835Accurate font locking: Like level 2 but uses a different approach that
1836can recognize types and declarations much more accurately. The
3a731e1f
MS
1837@code{*-font-lock-extra-types} variables are still used, but user
1838defined types are recognized correctly anyway in most cases. Therefore
1839those variables should be fairly restrictive and not contain patterns
1840that are uncertain.
1841
1842@cindex Lazy Lock mode
1843@cindex Just-in-time Lock mode
1844
1845This level is designed for fairly modern hardware and a font lock
1846support mode like Lazy Lock or Just-in-time Lock mode that only
116e44a1
AM
1847fontifies the parts that are actually shown. Fontifying the whole
1848buffer at once can easily get bothersomely slow even on contemporary
1849hardware.
1850@c ACM, 2005/8/28: There should be a page in the (X)Emacs manual
1851@c describing these support modes. There wasn't in the
1852@c fourteenth edition of the Emacs manual (released with Emacs 21.3).
1853@c There might be one in the Emacs CVS for 22.1.
3a731e1f
MS
1854@end enumerate
1855
1856@cindex user defined types
1857@cindex types, user defined
1858
1859Since user defined types are hard to recognize you can provide
1860additional regexps to match those you use:
1861
1862@defopt c-font-lock-extra-types
1863@defoptx c++-font-lock-extra-types
1864@defoptx objc-font-lock-extra-types
1865@defoptx java-font-lock-extra-types
1866@defoptx idl-font-lock-extra-types
1867@defoptx pike-font-lock-extra-types
1868For each language there's a variable @code{*-font-lock-extra-types},
1869where @samp{*} stands for the language in question. It contains a list
1870of regexps that matches identifiers that should be recognized as types,
116e44a1 1871e.g. @samp{\\sw+_t} to recognize all identifiers ending with @samp{_t}
3a731e1f
MS
1872as is customary in C code. Each regexp should not match more than a
1873single identifier.
1874
1875The default values contain regexps for many types in standard runtime
1876libraries that are otherwise difficult to recognize, and patterns for
1877standard type naming conventions like the @samp{_t} suffix in C and C++.
1878Java, Objective-C and Pike have as a convention to start class names
1879with capitals, so there are patterns for that in those languages.
1880
1881Despite the names of these variables, they are not only used for
1882fontification but in other places as well where @ccmode{} needs to
1883recognize types.
1884@end defopt
1885
1886
1887@comment !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
116e44a1 1888@node Faces, Doc Comments, Font Locking Preliminaries, Font Locking
3a731e1f
MS
1889@comment node-name, next, previous, up
1890@section Faces
1891@cindex faces
1892@comment !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
1893
1894@ccmode{} attempts to use the standard faces for programming languages
1895in accordance with their intended purposes as far as possible. No extra
1896faces are currently provided, with the exception of a replacement face
1897@code{c-invalid-face} for emacsen that don't provide
1898@code{font-lock-warning-face}.
1899
1900@itemize @bullet
1901@item
1902@vindex font-lock-comment-face
1903Normal comments are fontified in @code{font-lock-comment-face}.
1904
1905@item
1906@vindex font-lock-doc-face
1907@vindex font-lock-doc-string-face
1908@vindex font-lock-comment-face
116e44a1
AM
1909Comments that are recognized as documentation (@pxref{Doc Comments})
1910get @code{font-lock-doc-face} (Emacs) or
1911@code{font-lock-doc-string-face} (XEmacs) if those faces exist. If
1912they don't then @code{font-lock-comment-face} is used.
3a731e1f
MS
1913
1914@item
1915@vindex font-lock-string-face
1916String and character literals are fontified in
1917@code{font-lock-string-face}.
1918
1919@item
1920@vindex font-lock-keyword-face
1921Keywords are fontified with @code{font-lock-keyword-face}.
1922
1923@item
1924@vindex font-lock-function-name-face
1925@code{font-lock-function-name-face} is used for function names in
1926declarations and definitions, and classes in those contexts. It's also
1927used for preprocessor defines with arguments.
1928
1929@item
1930@vindex font-lock-variable-name-face
1931Variables in declarations and definitions, and other identifiers in such
1932variable contexts, get @code{font-lock-variable-name-face}. It's also
1933used for preprocessor defines without arguments.
1934
1935@item
1936@vindex font-lock-constant-face
1937@vindex font-lock-reference-face
1938Builtin constants are fontified in @code{font-lock-constant-face} if it
1939exists, @code{font-lock-reference-face} otherwise. As opposed to the
1940preceding two faces, this is used on the names in expressions, and it's
1941not used in declarations, even if there happen to be a @samp{const} in
1942them somewhere.
1943
1944@item
1945@vindex font-lock-type-face
1946@code{font-lock-type-face} is put on types (both predefined and user
1947defined) and classes in type contexts.
1948
1949@item
1950@vindex font-lock-constant-face
1951@vindex font-lock-reference-face
1952Label identifiers get @code{font-lock-constant-face} if it exists,
1953@code{font-lock-reference-face} otherwise.
1954
1955@item
1956Name qualifiers and identifiers for scope constructs are fontified like
1957labels.
1958
1959@item
1960Special markup inside documentation comments are also fontified like
1961labels.
1962
1963@item
1964@vindex font-lock-preprocessor-face
1965@vindex font-lock-builtin-face
1966@vindex font-lock-reference-face
1967Preprocessor directives get @code{font-lock-preprocessor-face} if it
116e44a1 1968exists (i.e. XEmacs). In Emacs they get @code{font-lock-builtin-face}
3a731e1f
MS
1969or @code{font-lock-reference-face}, for lack of a closer equivalent.
1970
1971@item
1972@vindex font-lock-warning-face
1973@vindex c-invalid-face
1974@vindex invalid-face (c-)
1975Some kinds of syntactic errors are fontified with
1976@code{font-lock-warning-face} in Emacs. In older XEmacs versions
1977there's no corresponding standard face, so there a special
1978@code{c-invalid-face} is used, which is defined to stand out sharply by
1979default.
1980
1981Note that it's not used for @samp{#error} or @samp{#warning} directives,
1982since those aren't syntactic errors in themselves.
1983@end itemize
1984
1985
1986@comment !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
116e44a1 1987@node Doc Comments, AWK Mode Font Locking, Faces, Font Locking
3a731e1f
MS
1988@comment node-name, next, previous, up
1989@section Documentation Comments
1990@cindex documentation comments
1991@comment !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
1992
1993There are various tools to supply documentation in the source as
116e44a1 1994specially structured comments, e.g. the standard Javadoc tool in Java.
3a731e1f
MS
1995@ccmode{} provides an extensible mechanism to fontify such comments and
1996the special markup inside them.
1997
1998@defopt c-doc-comment-style
1999@vindex doc-comment-style (c-)
2000This is a style variable that specifies which documentation comment
116e44a1 2001style to recognize, e.g. @code{javadoc} for Javadoc comments.
3a731e1f
MS
2002
2003The value may also be a list of styles, in which case all of them are
2004recognized simultaneously (presumably with markup cues that don't
2005conflict).
2006
2007The value may also be an association list to specify different comment
2008styles for different languages. The symbol for the major mode is then
2009looked up in the alist, and the value of that element is interpreted as
2010above if found. If it isn't found then the symbol `other' is looked up
2011and its value is used instead.
2012
116e44a1
AM
2013The default value for @code{c-doc-comment-style} is
2014@w{@code{((java-mode . javadoc) (pike-mode . autodoc) (c-mode . gtkdoc))}}.
2015
3a731e1f
MS
2016Note that @ccmode{} uses this variable to set other variables that
2017handle fontification etc. That's done at mode initialization or when
2018you switch to a style which sets this variable. Thus, if you change it
116e44a1 2019in some other way, e.g. interactively in a CC Mode buffer, you will need
3a731e1f
MS
2020to do @kbd{M-x java-mode} (or whatever mode you're currently using) to
2021reinitialize.
2022
2023@findex c-setup-doc-comment-style
2024@findex setup-doc-comment-style (c-)
2025Note also that when @ccmode{} starts up, the other variables are
2026modified before the mode hooks are run. If you change this variable in
116e44a1 2027a mode hook, you'll have to call @code{c-setup-doc-comment-style}
3a731e1f
MS
2028afterwards to redo that work.
2029@end defopt
2030
2031@ccmode{} currently provides handing of the following doc comment
2032styles:
2033
2034@table @code
2035@item javadoc
2036@cindex Javadoc markup
2037Javadoc comments, the standard tool in Java.
2038
2039@item autodoc
2040@cindex Pike autodoc markup
2041For Pike autodoc markup, the standard in Pike.
116e44a1
AM
2042
2043@item gtkdoc
2044@cindex GtkDoc markup
2045For GtkDoc markup, widely used in the Gnome community.
3a731e1f
MS
2046@end table
2047
2048The above is by no means complete. If you'd like to see support for
2049other doc comment styles, please let us know (@pxref{Mailing Lists and
116e44a1 2050Bug Reports}).
3a731e1f
MS
2051
2052You can also write your own doc comment fontification support to use
2053with @code{c-doc-comment-style}: Supply a variable or function
2054@code{*-font-lock-keywords} where @samp{*} is the name you want to use
2055in @code{c-doc-comment-style}. If it's a variable, it's prepended to
2056@code{font-lock-keywords}. If it's a function, it's called at mode
2057initialization and the result is prepended. For an example, see
2058@code{javadoc-font-lock-keywords} in @file{cc-fonts.el}.
2059
2060If you add support for another doc comment style, please consider
116e44a1
AM
2061contributing it - send a note to @email{bug-cc-mode@@gnu.org}.
2062
2063
2064@comment !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
2065@node AWK Mode Font Locking, , Doc Comments, Font Locking
2066@comment node-name, next, previous, up
2067@section AWK Mode Font Locking
2068@comment !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
2069
2070The general appearance of font-locking in AWK mode is much like in any
2071other programming mode. @xref{Faces For Font Lock,,,elisp, GNU Emacs
2072Lisp Reference Manual}.
2073
2074The following faces are, however, used in a non-standard fashion in
2075AWK mode:
2076
2077@table @asis
2078@item @code{font-lock-variable-name-face}
2079This face was intended for variable declarations. Since variables are
2080not declared in AWK, this face is used instead for AWK system
2081variables (such as @code{NF}) and ``Special File Names'' (such as
2082@code{"/dev/stderr"}).
2083
2084@item @code{font-lock-builtin-face} (Emacs)/@code{font-lock-preprocessor-face} (XEmacs)
2085This face is normally used for preprocessor directives in @ccmode{}.
2086There are no such things in AWK, so this face is used instead for
2087standard functions (such as @code{match}).
2088
2089@item @code{font-lock-string-face}
2090As well as being used for strings, including localizable strings,
2091(delimited by @samp{"} and @samp{_"}), this face is also used for AWK
2092regular expressions (delimited by @samp{/}).
2093
2094@item @code{font-lock-warning-face} (Emacs)/@code{c-invalid-face} (XEmacs)
2095This face highlights the following syntactically invalid AWK
2096constructs:
2097
2098@itemize @bullet
2099@item
2100An unterminated string or regular expression. Here the opening
2101delimiter (@samp{"} or @samp{/} or @samp{_"}) is displayed in
2102@code{font-lock-warning-face}. This is most noticeable when typing in a
2103new string/regular expression into a buffer, when the warning-face
2104serves as a continual reminder to terminate the construct.
2105
2106AWK mode fontifies unterminated strings/regular expressions
2107differently from other modes: Only the text up to the end of the line
2108is fontified as a string (escaped newlines being handled correctly),
2109rather than the text up to the next string quote.
2110
2111@item
2112A space between the function name and opening parenthesis when calling
2113a user function. The last character of the function name and the
2114opening parenthesis are highlighted. This font-locking rule will
2115spuriously highlight a valid concatenation expression where an
2116identifier precedes a parenthesised expression. Unfortunately.
2117
2118@item
2119Whitespace following the @samp{\} in what otherwise looks like an
2120escaped newline. The @samp{\} is highlighted.
2121@end itemize
2122@end table
2123
2124
2125@comment !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
2126@node Config Basics, Custom Filling and Breaking, Font Locking, Top
2127@comment node-name, next, previous, up
2128@chapter Configuration Basics
2129@comment !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
2130
2131@cindex Emacs Initiliazation File
2132@cindex Configuration
2133You configure @ccmode{} by setting Lisp variables and calling (and
2134perhaps writing) Lisp functions@footnote{DON'T PANIC!!! This isn't
2135difficult.}, which is usually done by adding code to an Emacs
2136initialization file. This file might be @file{site-start.el} or
2137@file{.emacs} or @file{init.el} or @file{default.el} or perhaps some
2138other file. @xref{Init File,,,@emacsman{}, @emacsmantitle{}}. For
2139the sake of conciseness, we just call this file ``your @file{.emacs}''
2140throughout the rest of the manual.
2141
2142Several of these variables (currently 16), are known collectively as
2143@dfn{style variables}. @ccmode{} provides a special mechanism, known
2144as @dfn{styles} to make it easier to set these variables as a group,
2145to ``inherit'' settings from one style into another, and so on. Style
2146variables remain ordinary Lisp variables, whose values can be read and
2147changed independently of the style system. @xref{Style Variables}.
2148
2149There are several ways you can write the code, depending on the
2150precise effect you want---they are described further down on this page.
2151If you are new to @ccmode{}, we suggest you begin with the simplest
2152method, ``Top-level commands or the customization interface''.
2153
2154If you make conflicting settings in several of these ways, the way
2155that takes precedence is the one that appears latest in this list:
2156@itemize @asis
2157@item
2158@table @asis
2159@item Style
2160@itemx Top-level command or ``customization interface''
2161@itemx Hook
2162@itemx File Style
2163@end table
2164@end itemize
2165
2166Here is a summary of the different ways of writing your configuration
2167settings:
2168
2169@table @asis
2170@item Top-level commands or the ``customization interface''
2171Most simply, you can write @code{setq} and similar commands at the top
2172level of your @file{.emacs} file. When you load a @ccmode{} buffer,
2173it initializes its configuration from these global values (at least,
2174for those settings you have given values to), so it makes sense to
2175have these @code{setq} commands run @emph{before} @ccmode{} is first
2176initialized---in particular, before any call to @code{desktop-read}
2177(@pxref{Saving Emacs Sessions,,, emacs, GNU Emacs Manual}). For
2178example, you might set c-basic-offset thus:
2179
2180@example
2181(setq c-basic-offset 4)
2182@end example
2183
2184You can use the more user friendly Customization interface instead,
2185but this manual does not cover in detail how that works. To do this,
2186start by typing @kbd{M-x customize-group @key{RET} c @key{RET}}.
2187@xref{Easy Customization,,,@emacsman{}, @emacsmantitle{}}.
2188@c The following note really belongs in the Emacs manual.
2189Emacs normally writes the customizations at the end of your
2190@file{.emacs} file. If you use @code{desktop-read}, you should edit
2191your @file{.emacs} to place the call to @code{desktop-read} @emph{after}
2192the customizations.
2193
2194The first initialization of @ccmode{} puts a snapshot of the
2195configuration settings into the special style @code{user}.
2196@xref{Built-in Styles}.
2197
2198For basic use of Emacs, either of these ways of configuring is
2199adequate. However, the settings are then the same in all @ccmode{}
2200buffers and it can be clumsy to communicate them between programmers.
2201For more flexibility, you'll want to use one (or both) of @ccmode{}'s
2202more sophisticated facilities, hooks and styles.
2203
2204@item Hooks
2205An Emacs @dfn{hook} is a place to put Lisp functions that you want
2206Emacs to execute later in specific circumstances.
2207@xref{Hooks,,,@lispref{}, @lispreftitle{}}. @ccmode{} supplies a main
2208hook and a language-specific hook for each language it supports - any
2209functions you put onto these hooks get executed as the last part of a
2210buffer's initialization. Typically you put most of your customization
2211within the main hook, and use the language-specific hooks to vary the
2212customization settings between language modes. For example, if you
2213wanted different (non-standard) values of @code{c-basic-offset} in C
2214Mode and Java Mode buffers, you could do it like this:
2215
2216@example
2217@group
2218(defun my-c-mode-hook ()
2219 (setq c-basic-offset 3))
2220(add-hook 'c-mode-hook 'my-c-mode-hook)
2221
2222(defun my-java-mode-hook ()
2223 (setq c-basic-offset 6))
2224(add-hook 'java-mode-hook 'my-java-mode-hook)
2225@end group
2226@end example
2227
2228See @ref{CC Hooks} for more details on the use of @ccmode{} hooks.
2229
2230@item Styles
2231A @ccmode{} @dfn{style} is a coherent collection of customizations
2232with a name. At any time, exactly one style is active in each
2233@ccmode{} buffer, either the one you have selected or a default.
2234@ccmode{} is delivered with several existing styles. Additionally,
2235you can create your own styles, possibly based on these existing
2236styles. If you worked in a programming team called the ``Free
2237Group'', which had its own coding standards, you might well have this
2238in your @file{.emacs} file:
2239
2240@example
2241(setq c-default-style '((java-mode . "java")
2242 (awk-mode . "awk")
2243 (other . "free-group-style")))
2244@end example
2245
2246See @ref{Styles} for fuller details on using @ccmode{} styles and how
2247to create them.
2248
2249@item File Styles
2250A @dfn{file style} is a rarely used variant of the ``style'' mechanism
2251described above, which applies to an individual source file. To use
2252it, you set certain Emacs local variables in a special block at the
2253end of the source file. @xref{File Styles}.
2254
2255@item Hooks with Styles
2256For ultimate flexibility, you can use hooks and styles together. For
2257example, if your team were developing a product which required a
2258Linux driver, you'd probably want to use the ``linux'' style for the
2259driver, and your own team's style for the rest of the code. You
2260could achieve this with code like this in your @file{.emacs}:
2261
2262@example
2263@group
2264(defun my-c-mode-hook ()
2265 (c-set-style
2266 (if (and (buffer-file-name)
2267 (string-match "/usr/src/linux" (buffer-file-name)))
2268 "linux"
2269 "free-group-style")))
2270(add-hook 'c-mode-hook 'my-c-mode-hook)
2271@end group
2272@end example
2273
2274In a programming team, a hook is a also a good place for each member
2275to put his own personal preferences. For example, you might be the
2276only person in your team who likes Auto-newline minor mode. You could
2277have it enabled by default by placing the following in your
2278@file{.emacs}:
2279
2280@example
2281@group
2282(defun my-turn-on-auto-newline ()
2283 (c-toggle-auto-newline 1))
2284(add-hook 'c-mode-common-hook 'my-turn-on-auto-newline)
2285@end group
2286@end example
2287@end table
2288
2289@menu
2290* CC Hooks::
2291* Style Variables::
2292* Styles::
2293@end menu
2294
2295@comment !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
2296@node CC Hooks, Style Variables, Config Basics, Config Basics
2297@comment node-name, next, previous, up
2298@section Hooks
2299@cindex mode hooks
2300@comment !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
2301@c The node name is "CC Hooks" rather than "Hooks" because of a bug in
2302@c some older versions of Info, e.g. the info.el in GNU Emacs 21.3.
2303@c If you go to "Config Basics" and hit <CR> on the xref to "CC
2304@c Hooks" the function Info-follow-reference searches for "*Note: CC
2305@c Hooks" from the beginning of the page. If this node were instead
2306@c named "Hooks", that search would spuriously find "*Note:
2307@c Hooks(elisp)" and go to the wrong node.
2308
2309@ccmode{} provides several hooks that you can use to customize the
2310mode for your coding style. The main hook is
2311@code{c-mode-common-hook}; typically, you'll put the bulk of your
2312customizations here. In addition, each language mode has its own
2313hook, allowing you to fine tune your settings individually for the
2314different @ccmode{} languages, and there is a package initialization
2315hook. Finally, there is @code{c-special-indent-hook}, which enables
2316you to solve anomalous indentation problems. It is described in
2317@ref{Other Indentation}, not here. All these hooks adhere to the
2318standard Emacs conventions.
2319
2320When you open a buffer, @ccmode{} first initializes it with the
2321currently active style (@pxref{Styles}). Then it calls
2322@code{c-mode-common-hook}, and finally it calls the language-specific
2323hook. Thus, any style settings done in these hooks will override
2324those set by @code{c-default-style}.
2325
2326@defvar c-initialization-hook
2327@vindex initialization-hook (c-)
2328Hook run only once per Emacs session, when @ccmode{} is initialized.
2329This is a good place to change key bindings (or add new ones) in any
2330of the @ccmode{} key maps. @xref{Sample .emacs File}.
2331@end defvar
2332
2333@defvar c-mode-common-hook
2334@vindex mode-common-hook (c-)
2335Common hook across all languages. It's run immediately before the
2336language specific hook.
2337@end defvar
2338
2339@defvar c-mode-hook
2340@defvarx c++-mode-hook
2341@defvarx objc-mode-hook
2342@defvarx java-mode-hook
2343@defvarx idl-mode-hook
2344@defvarx pike-mode-hook
2345@defvarx awk-mode-hook
2346The language specific mode hooks. The appropriate one is run as the
2347last thing when you enter that language mode.
2348@end defvar
2349
2350Although these hooks are variables defined in @ccmode{}, you can give
2351them values before @ccmode{}'s code is loaded - indeed, this is the
2352only way to use @code{c-initialization-hook}. Their values aren't
2353overwritten when @ccmode{} gets loaded.
2354
2355Here's a simplified example of what you can add to your @file{.emacs}
2356file to do things whenever any @ccmode{} language is edited. See the
2357Emacs manuals for more information on customizing Emacs via hooks.
2358@xref{Sample .emacs File}, for a more complete sample @file{.emacs}
2359file.
2360
2361@example
2362(defun my-c-mode-common-hook ()
2363 ;; my customizations for all of c-mode and related modes
2364 (no-case-fold-search)
2365 )
2366(add-hook 'c-mode-common-hook 'my-c-mode-common-hook)
2367@end example
2368
2369@comment !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
2370@node Style Variables, Styles, CC Hooks, Config Basics
2371@comment node-name, next, previous, up
2372@section Style Variables
2373@cindex styles
2374@comment !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
2375
2376@cindex style variables
2377The variables that @ccmode{}'s style system control are called
2378@dfn{style variables}. Note that style variables are ordinary Lisp
2379variables, which the style system initializes; you can change their
2380values at any time (e.g. in a hook function). The style system can
2381also also set other variables, to some extent. @xref{Styles}.
2382
2383@dfn{Style variables} are handled specially in several ways:
2384
2385@itemize @bullet
2386@item
2387Style variables are by default buffer-local variables. However, they
2388can instead be made global by setting
2389@code{c-style-variables-are-local-p} to @code{nil} before @ccmode{} is
2390initialized.
2391
2392@item
2393@vindex c-old-style-variable-behavior
2394@vindex old-style-variable-behavior (c-)
2395The default global binding of any style variable (with two exceptions
2396- see below) is the special symbol @code{set-from-style}. When the
2397style system initializes a buffer-local copy of a style variable for a
2398@ccmode{} buffer, if its global binding is still that symbol then it
2399will be set from the current style. Otherwise it will retain its
2400global default@footnote{This is a big change from versions of
2401@ccmode{} earlier than 5.26, where such settings would get overridden
2402by the style system unless special precautions were taken. That was
2403changed since it was counterintuitive and confusing, especially to
2404novice users. If your configuration depends on the old overriding
2405behavior, you can set the variable
2406@code{c-old-style-variable-behavior} to non-@code{nil}.}. This
2407``otherwise'' happens, for example, when you've set the variable with
2408@code{setq} at the top level of your @file{.emacs} (@pxref{Config
2409Basics}).
2410
2411@item
2412The style variable @code{c-offsets-alist} (@pxref{c-offsets-alist}) is
2413an association list with an element for each syntactic symbol. It's
2414handled a little differently from the other style variables. It's
2415default global binding is the empty list @code{nil}, rather than
2416@code{set-from-style}. Before the style system is initialized, you
2417can add individual elements to @code{c-offsets-alist} by calling
2418@code{c-set-offset}(@pxref{c-offsets-alist}) just like you would set
2419other style variables with @code{setq}. Those elements will then
2420prevail when the style system later initializes a buffer-local copy of
2421@code{c-offsets-alist}.
2422
2423@item
2424The style variable @code{c-special-indent-hook} is also handled in a
2425special way. Styles can only add functions to this hook, not remove
2426them, so any global settings you put on it are always
2427preserved@footnote{This did not change in version 5.26.}. The value
2428you give this variable in a style definition can be either a function
2429or a list of functions.
2430
2431@item
2432The global bindings of the style variables get captured in the special
2433@code{user} style when the style system is first initialized.
2434@xref{Built-in Styles}, for details.
2435@end itemize
2436
2437The style variables are:@*
2438@code{c-indent-comment-alist},
2439@code{c-indent-comments-syntactically-p} (@pxref{Indentation
2440Commands});@*
2441@code{c-doc-comment-style} (@pxref{Doc Comments});@*
2442@code{c-block-comment-prefix}, @code{c-comment-prefix-regexp}
2443(@pxref{Custom Filling and Breaking});@*
2444@code{c-hanging-braces-alist} (@pxref{Hanging Braces});@*
2445@code{c-hanging-colons-alist} (@pxref{Hanging Colons});@*
2446@code{c-hanging-semi&comma-criteria} (@pxref{Hanging Semicolons and
2447Commas});@*
2448@code{c-cleanup-list} (@pxref{Clean-ups});@*
2449@code{c-basic-offset} (@pxref{Customizing Indentation});@*
2450@code{c-offsets-alist} (@pxref{c-offsets-alist});@*
2451@code{c-comment-only-line-offset} (@pxref{Comment Line-Up});@*
2452@code{c-special-indent-hook}, @code{c-label-minimum-indentation}
2453(@pxref{Other Indentation});@*
2454@code{c-backslash-column}, @code{c-backslash-max-column}
2455(@pxref{Custom Macros}).
2456
2457@comment !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
2458@node Styles, , Style Variables, Config Basics
2459@comment node-name, next, previous, up
2460@section Styles
2461@cindex styles
2462@comment !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
2463
2464Most people only need to edit code formatted in just a few well-defined
2465and consistent styles. For example, their organization might impose a
2466``blessed'' style that all its programmers must conform to. Similarly,
2467people who work on GNU software will have to use the GNU coding style.
2468Some shops are more lenient, allowing a variety of coding styles, and as
2469programmers come and go, there could be a number of styles in use. For
2470this reason, @ccmode{} makes it convenient for you to set up logical
2471groupings of customizations called @dfn{styles}, associate a single name
2472for any particular style, and pretty easily start editing new or
2473existing code using these styles.
2474
2475@menu
2476* Built-in Styles::
2477* Choosing a Style::
2478* Adding Styles::
2479* File Styles::
2480@end menu
2481
2482
2483@comment !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
2484@node Built-in Styles, Choosing a Style, Styles, Styles
2485@comment node-name, next, previous, up
2486@subsection Built-in Styles
2487@cindex styles, built-in
2488@comment !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
2489
2490If you're lucky, one of @ccmode{}'s built-in styles might be just
2491what you're looking for. These are:
2492
2493@table @code
2494@item gnu
2495@cindex GNU style
2496Coding style blessed by the Free Software Foundation
2497for C code in GNU programs.
2498
2499@item k&r
2500@cindex K&R style
2501The classic Kernighan and Ritchie style for C code.
2502
2503@item bsd
2504@cindex BSD style
2505Also known as ``Allman style'' after Eric Allman.
2506
2507@item whitesmith
2508@cindex Whitesmith style
2509Popularized by the examples that came with Whitesmiths C, an early
2510commercial C compiler.
2511
2512@item stroustrup
2513@cindex Stroustrup style
2514The classic Stroustrup style for C++ code.
2515
2516@item ellemtel
2517@cindex Ellemtel style
2518Popular C++ coding standards as defined by ``Programming in C++, Rules
2519and Recommendations,'' Erik Nyquist and Mats Henricson,
2520Ellemtel@footnote{This document is available at
2521@uref{http://www.doc.ic.ac.uk/lab/cplus/c++.rules/} among other
2522places.}.
2523@c N.B. This URL was still valid at 2005/8/28 (ACM).
2524
2525@item linux
2526@cindex Linux style
2527C coding standard for Linux (the kernel).
3a731e1f 2528
116e44a1
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2529@item python
2530@cindex Python style
2531C coding standard for Python extension modules@footnote{Python is a
2532high level scripting language with a C/C++ foreign function interface.
2533For more information, see @uref{http://www.python.org/}.}.
3a731e1f 2534
116e44a1
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2535@item java
2536@cindex Java style
2537The style for editing Java code. Note that the default
2538value for @code{c-default-style} installs this style when you enter
2539@code{java-mode}.
3a731e1f 2540
116e44a1
AM
2541@item awk
2542@cindex AWK style
2543The style for editing AWK code. Note that the default value for
2544@code{c-default-style} installs this style when you enter
2545@code{awk-mode}.
3a731e1f 2546
116e44a1
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2547@item user
2548@cindex User style
2549This is a special style created by you. It consists of the factory
2550defaults for all the style variables as modified by the customizations
2551you do either with the Customization interface or by writing
2552@code{setq}s and @code{c-set-offset}s at the top level of your
2553@file{.emacs} file (@pxref{Config Basics}). The style system creates
2554this style as part of its initialization and doesn't modify it
2555afterwards.
2556@end table
3a731e1f
MS
2557
2558
2559@comment !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
116e44a1
AM
2560@node Choosing a Style, Adding Styles, Built-in Styles, Styles
2561@comment node-name, next, previous, up
2562@subsection Choosing a Style
d7bd46ed 2563@comment !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
6bf7aab6 2564
116e44a1 2565Use @kbd{C-c .} to choose a style interactively:
6bf7aab6 2566
116e44a1
AM
2567@deffn Command c-set-style style-name
2568@findex set-style (c-)
2569@kindex C-c .
2570Switch to the specified style in the current buffer. Use
2571interactively like this:
6bf7aab6 2572
116e44a1
AM
2573@example
2574@kbd{C-c . @var{style-name} @key{RET}}
2575@end example
6bf7aab6 2576
116e44a1
AM
2577You can use the @key{TAB} in the normal way to do completion on the
2578style name. Note that all style names are case insensitive, even the
2579ones you define yourself.
6bf7aab6 2580
116e44a1
AM
2581Setting a style in this way does @emph{not} automatically reindent your
2582file. For commands that you can use to view the effect of your changes,
2583see @ref{Indentation Commands} and @ref{Filling and Breaking}.
2584@end deffn
6bf7aab6 2585
116e44a1
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2586The default style in all newly created buffers is @code{gnu}, except
2587in Java and AWK modes where it's @code{java} and @code{awk}.
3a731e1f 2588
116e44a1
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2589Remember that if you set a style variable with the Customization
2590interface or at the top level of your @file{.emacs} file before the
2591style system is initialised (@pxref{Config Basics}), this setting will
2592override the one that the style system would have given the variable.
3a731e1f 2593
116e44a1
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2594@defopt c-default-style
2595@vindex default-style (c-)
2596This variable specifies which style to install by default in new
2597buffers. It takes either a style name string, or an association list
2598of major mode symbols to style names:
3a731e1f 2599
116e44a1
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2600@enumerate
2601@item
2602When @code{c-default-style} is a string, it must be an existing style
2603name. This style is then used for all modes.
3a731e1f 2604
116e44a1
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2605@item
2606When @code{c-default-style} is an association list, the mode language
2607is looked up to find a style name string.
d7bd46ed 2608
116e44a1
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2609@item
2610If @code{c-default-style} is an association list where the mode
2611language mode isn't found then the special symbol @samp{other} is
2612looked up. If it's found then the associated style is used.
d7bd46ed 2613
116e44a1
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2614@item
2615If @samp{other} is not found then the @samp{gnu} style is used.
2616@end enumerate
3a731e1f 2617
116e44a1
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2618In all cases, the style described in @code{c-default-style} is installed
2619@emph{before} the language hooks are run, so you can always override
2620this setting by including an explicit call to @code{c-set-style} in your
2621language mode hook, or in @code{c-mode-common-hook}.
d7bd46ed 2622
116e44a1
AM
2623The standard value of @code{c-default-style} is @w{@code{((java-mode
2624. "java") (awk-mode . "awk") (other . "gnu"))}}.
3a731e1f 2625@end defopt
d7bd46ed 2626
116e44a1
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2627@defvar c-indentation-style
2628@vindex indentation-style (c-)
2629This variable always contains the buffer's current style name, as a
2630string.
2631@end defvar
d7bd46ed
GM
2632
2633
2634@comment !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
116e44a1 2635@node Adding Styles, File Styles, Choosing a Style, Styles
d7bd46ed 2636@comment node-name, next, previous, up
116e44a1 2637@subsection Adding and Amending Styles
6bf7aab6
DL
2638@comment !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
2639
116e44a1
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2640If none of the built-in styles is appropriate, you'll probably want to
2641create a new @dfn{style definition}, possibly based on an existing
2642style. To do this, put the new style's settings into a list with the
2643following format - the list can then be passed as an argument to the
2644function @code{c-add-style}. You can see an example of a style
2645definition in @ref{Sample .emacs File}.
6bf7aab6 2646
116e44a1
AM
2647@cindex style definition
2648@c @defvr {List} style definition
d7bd46ed 2649@table @asis
116e44a1
AM
2650@item Structure of a Style Definition List
2651([@var{base-style}] [(@var{variable} . @var{value}) @dots{}])
6bf7aab6 2652
116e44a1
AM
2653Optional @var{base-style}, if present, must be a string which is the
2654name of the @dfn{base style} from which this style inherits. At most
2655one @var{base-style} is allowed in a style definition. If
2656@var{base-style} is not specified, the style inherits from the table
2657of factory default values@footnote{This table is stored internally in
2658the variable c-fallback-style.} instead. All styles eventually
2659inherit from this internal table. Style loops generate errors. The
2660list of pre-existing styles can be seen in @ref{Built-in Styles}.
6bf7aab6 2661
116e44a1
AM
2662The dotted pairs (@var{variable} . @var{value}) each consist of a
2663variable and the value it is to be set to when the style is later
2664activated.@footnote{Note that if the variable has been given a value
2665by the Customization interface or a @code{setq} at the top level of
2666your @file{.emacs}, this value will override the one the style system
2667tries to give it. @xref{Config Basics}.} The variable can be either a
2668@ccmode{} style variable or an arbitrary Emacs variable. In the
2669latter case, it is @emph{not} made buffer-local by the @ccmode{} style
2670system.
2671@c @end defvr
6bf7aab6 2672
116e44a1 2673Two variables are treated specially in the dotted pair list:
6bf7aab6 2674
116e44a1
AM
2675@table @code
2676@item c-offsets-alist
2677The value is in turn a list of dotted pairs of the form
6bf7aab6 2678
116e44a1
AM
2679@example
2680(@r{@var{syntactic-symbol}} . @r{@var{offset}})
2681@end example
6bf7aab6 2682
116e44a1
AM
2683as described in @ref{c-offsets-alist}. These are passed to
2684@code{c-set-offset} so there is no need to set every syntactic symbol
2685in your style, only those that are different from the inherited style.
6bf7aab6 2686
116e44a1
AM
2687@item c-special-indent-hook
2688The value is added to @code{c-special-indent-hook} using
2689@code{add-hook}, so any functions already on it are kept. If the value
2690is a list, each element of the list is added with @code{add-hook}.
2691@end table
2692@end table
6bf7aab6 2693
116e44a1
AM
2694Styles are kept in the @code{c-style-alist} variable, but you
2695should never modify this variable directly. Instead, @ccmode{}
2696provides the function @code{c-add-style} for this purpose.
6bf7aab6 2697
116e44a1
AM
2698@defun c-add-style stylename description &optional set-p
2699@findex add-style (c-)
2700Add or update a style called @var{stylename}, a string.
2701@var{description} is the new style definition in the form described
2702above. If @var{stylename} already exists in @code{c-style-alist} then
2703it is replaced by @var{description}. (Note, this replacement is
2704total. The old style is @emph{not} merged into the new one.)
2705Otherwise, a new style is added.
d7bd46ed 2706
116e44a1
AM
2707If the optional @var{set-p} is non-@code{nil} then the new style is
2708applied to the current buffer as well. The use of this facility is
2709deprecated and it might be removed from @ccmode{} in a future release.
2710You should use @code{c-set-style} instead.
d7bd46ed 2711
116e44a1
AM
2712The sample @file{.emacs} file provides a concrete example of how a new
2713style can be added and automatically set. @xref{Sample .emacs File}.
2714@end defun
d7bd46ed 2715
116e44a1
AM
2716@defvar c-style-alist
2717@vindex style-alist (c-)
2718This is the variable that holds the definitions for the styles. It
2719should not be changed directly; use @code{c-add-style} instead.
2720@end defvar
d7bd46ed 2721
6bf7aab6 2722
d7bd46ed 2723@comment !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
116e44a1 2724@node File Styles, , Adding Styles, Styles
d7bd46ed 2725@comment node-name, next, previous, up
116e44a1
AM
2726@subsection File Styles
2727@cindex styles, file local
6bf7aab6
DL
2728@comment !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
2729
116e44a1 2730@cindex file local variables
3a731e1f 2731
116e44a1
AM
2732The Emacs manual describes how you can customize certain variables on a
2733per-file basis by including a @dfn{file local variable} block at the end
2734of the file (@pxref{File Variables,, Local Variables in Files, @emacsman{},
2735@emacsmantitle{}}).
d7bd46ed 2736
116e44a1
AM
2737So far, you've only seen a functional interface for setting styles in
2738@ccmode{}, and this can't be used here. @ccmode{} fills the gap by
2739providing two variables for use in a file's local variable list.
2740Don't use them anywhere else! These allow you to customize the style
2741on a per-file basis:
3a731e1f 2742
116e44a1
AM
2743@defvar c-file-style
2744@vindex file-style (c-)
2745Set this variable to a style name string in the Local Variables list.
2746From now on, when you visit the file, @ccmode{} will automatically set
2747the file's style to this one using @code{c-set-style}.
2748@end defvar
6bf7aab6 2749
116e44a1
AM
2750@defvar c-file-offsets
2751@vindex file-offsets (c-)
2752Set this variable (in the Local Variables list) to an association list
2753of the same format as @code{c-offsets-alist}. From now on, when you
2754visit the file, @ccmode{} will automatically institute these offsets
2755using @code{c-set-offset}.
2756@end defvar
6bf7aab6 2757
116e44a1
AM
2758Note that file style settings (i.e. @code{c-file-style}) are applied
2759before file offset settings
2760(i.e. @code{c-file-offsets})@footnote{Also, if either of these are set
2761in a file's local variable section, all the style variable values are
2762made local to that buffer, even if
2763@code{c-style-variables-are-local-p} is @code{nil}. Since this
2764variable is virtually always non-@code{nil} anyhow, you're unlikely to
2765notice this effect.}.
2766
2767If you set any variables, including style variables, by the file local
2768variables mechanism, these settings take priority over all other
2769settings, even those in your mode hooks (@pxref{CC Hooks}). If you
2770use @code{c-file-style} or @code{c-file-offsets} and also explicitly
2771set a style variable in a local variable block, the explicit setting
2772will take priority.
6bf7aab6 2773
116e44a1
AM
2774@comment !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
2775@node Custom Filling and Breaking, Custom Auto-newlines, Config Basics, Top
2776@comment node-name, next, previous, up
2777@chapter Customizing Filling and Line Breaking
2778@comment !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
d7bd46ed 2779
116e44a1
AM
2780Since there's a lot of normal text in comments and string literals,
2781@ccmode{} provides features to edit these like in text mode. It does
2782this by hooking in on the different line breaking functions and tuning
2783relevant variables as necessary.
d7bd46ed 2784
116e44a1
AM
2785@vindex c-comment-prefix-regexp
2786@vindex comment-prefix-regexp (c-)
2787@cindex comment line prefix
2788@vindex comment-start
2789@vindex comment-end
2790@vindex comment-start-skip
2791@vindex paragraph-start
2792@vindex paragraph-separate
2793@vindex paragraph-ignore-fill-prefix
2794@vindex adaptive-fill-mode
2795@vindex adaptive-fill-regexp
2796@vindex adaptive-fill-first-line-regexp
2797To make Emacs recognize comments and treat text in them as normal
2798paragraphs, @ccmode{} makes several standard
2799variables@footnote{@code{comment-start}, @code{comment-end},
2800@code{comment-start-skip}, @code{paragraph-start},
2801@code{paragraph-separate}, @code{paragraph-ignore-fill-prefix},
2802@code{adaptive-fill-mode}, @code{adaptive-fill-regexp}, and
2803@code{adaptive-fill-first-line-regexp}.} buffer-local and modifies them
2804according to the language syntax and the comment line prefix.
cb7f2e96 2805
116e44a1
AM
2806@defopt c-comment-prefix-regexp
2807@vindex comment-prefix-regexp (c-)
2808This style variable contains the regexp used to recognize the
2809@dfn{comment line prefix}, which is the line decoration that starts
2810every line in a comment. The variable is either the comment line
2811prefix itself, or (more usually) an association list with different
2812values for different languages. The symbol for the major mode is
2813looked up in the alist to get the regexp for the language, and if it
2814isn't found then the special symbol @samp{other} is looked up instead.
d7bd46ed 2815
116e44a1
AM
2816When a comment line gets divided by @kbd{M-j} or the like, @ccmode{}
2817inserts the comment line prefix from a neighbouring line at the start
2818of the new line. The default value of c-comment-prefix-regexp is
2819@samp{//+\\|\\**}, which matches C++ style line comments like
6bf7aab6 2820
3a731e1f 2821@example
116e44a1 2822// blah blah
6bf7aab6
DL
2823@end example
2824
2825@noindent
116e44a1
AM
2826with two or more slashes in front of them, and the second and
2827subsequent lines of C style block comments like
3a731e1f 2828
6bf7aab6
DL
2829@example
2830@group
116e44a1
AM
2831/*
2832 * blah blah
2833 */
6bf7aab6
DL
2834@end group
2835@end example
3a731e1f 2836
6bf7aab6 2837@noindent
116e44a1
AM
2838with zero or more stars at the beginning of every line. If you change
2839this variable, please make sure it still matches the comment starter
2840(i.e. @code{//}) of line comments @emph{and} the line prefix inside
2841block comments.
6bf7aab6 2842
116e44a1
AM
2843@findex c-setup-paragraph-variables
2844@findex setup-paragraph-variables (c-)
2845Also note that since @ccmode{} uses the value of
2846@code{c-comment-prefix-regexp} to set up several other variables at
2847mode initialization, there won't be any effect if you just change it
2848inside a @ccmode{} buffer. You need to call the command
2849@code{c-setup-paragraph-variables} too, to update those other
2850variables. That's also the case if you modify
2851@code{c-comment-prefix-regexp} in a mode hook, since @ccmode{} will
2852already have set up these variables before calling the hook.
2853@end defopt
6bf7aab6 2854
116e44a1
AM
2855In comments, @ccmode{} uses @code{c-comment-prefix-regexp} to adapt
2856the line prefix from the other lines in the comment.
6bf7aab6 2857
116e44a1
AM
2858@vindex adaptive-fill-mode
2859@cindex Adaptive Fill mode
2860@ccmode{} uses adaptive fill mode (@pxref{Adaptive Fill,,, emacs, GNU
2861Emacs Manual}) to make Emacs correctly keep the line prefix when
2862filling paragraphs. That also makes Emacs preserve the text
2863indentation @emph{inside} the comment line prefix. E.g. in the
2864following comment, both paragraphs will be filled with the left
2865margins of the texts kept intact:
3a731e1f 2866
6bf7aab6
DL
2867@example
2868@group
116e44a1
AM
2869/* Make a balanced b-tree of the nodes in the incoming
2870 * stream. But, to quote the famous words of Donald E.
2871 * Knuth,
2872 *
2873 * Beware of bugs in the above code; I have only
2874 * proved it correct, not tried it.
2875 */
6bf7aab6
DL
2876@end group
2877@end example
3a731e1f 2878
116e44a1
AM
2879@findex c-setup-filladapt
2880@findex setup-filladapt (c-)
2881@findex filladapt-mode
2882@vindex filladapt-mode
2883@cindex Filladapt mode
2884It's also possible to use other adaptive filling packages, notably Kyle
2885E. Jones' Filladapt package@footnote{It's available from
2886@uref{http://www.wonderworks.com/}. As of version 2.12, it does however
2887lack a feature that makes it work suboptimally when
2888@code{c-comment-prefix-regexp} matches the empty string (which it does
2889by default). A patch for that is available from
2890@uref{http://cc-mode.sourceforge.net/,, the CC Mode web site}.},
2891@c 2005/11/22: The above is still believed to be the case.
2892which handles things like bulleted lists nicely. There's a convenience
2893function @code{c-setup-filladapt} that tunes the relevant variables in
2894Filladapt for use in @ccmode{}. Call it from a mode hook, e.g. with
2895something like this in your @file{.emacs}:
3a731e1f 2896
6bf7aab6 2897@example
116e44a1
AM
2898(defun my-c-mode-common-hook ()
2899 (c-setup-filladapt)
2900 (filladapt-mode 1))
2901(add-hook 'c-mode-common-hook 'my-c-mode-common-hook)
6bf7aab6
DL
2902@end example
2903
116e44a1
AM
2904@defopt c-block-comment-prefix
2905@vindex block-comment-prefix (c-)
2906@vindex c-comment-continuation-stars
2907@vindex comment-continuation-stars (c-)
2908Normally the comment line prefix inserted for a new line inside a
2909comment is deduced from other lines in it. However there's one
2910situation when there's no hint about what the prefix should look like,
2911namely when a block comment is broken for the first time. This style
2912variable@footnote{In versions before 5.26, this variable was called
2913@code{c-comment-continuation-stars}. As a compatibility measure,
2914@ccmode{} still uses the value on that variable if it's set.} is used
2915then as the comment prefix. It defaults to @samp{*
2916}@footnote{Actually, this default setting of
2917@code{c-block-comment-prefix} typically gets overriden by the default
2918style @code{gnu}, which sets it to blank. You can see the line
2919splitting effect described here by setting a different style,
2920e.g. @code{k&r} @xref{Choosing a Style}.}, which makes a comment
6bf7aab6 2921
3a731e1f 2922@example
116e44a1 2923/* Got O(n^2) here, which is a Bad Thing. */
6bf7aab6
DL
2924@end example
2925
6bf7aab6 2926@noindent
116e44a1 2927break into
3a731e1f 2928
6bf7aab6
DL
2929@example
2930@group
116e44a1
AM
2931/* Got O(n^2) here, which
2932 * is a Bad Thing. */
6bf7aab6
DL
2933@end group
2934@end example
2935
116e44a1
AM
2936Note that it won't work to adjust the indentation by putting leading
2937spaces in @code{c-block-comment-prefix}, since @ccmode{} still uses the
2938normal indentation engine to indent the line. Thus, the right way to
2939fix the indentation is by customizing the @code{c} syntactic symbol. It
2940defaults to @code{c-lineup-C-comments}, which handles the indentation of
2941most common comment styles, see @ref{Line-Up Functions}.
2942@end defopt
6bf7aab6 2943
116e44a1
AM
2944@defopt c-ignore-auto-fill
2945@vindex ignore-auto-fill (c-)
2946When auto fill mode is enabled, @ccmode{} can selectively ignore it
2947depending on the context the line break would occur in, e.g. to never
2948break a line automatically inside a string literal. This variable
2949takes a list of symbols for the different contexts where auto-filling
2950never should occur:
3a731e1f 2951
116e44a1
AM
2952@table @code
2953@item string
2954Inside a string or character literal.
2955@item c
2956Inside a C style block comment.
2957@item c++
2958Inside a C++ style line comment.
2959@item cpp
2960Inside a preprocessor directive.
2961@item code
2962Anywhere else, i.e. in normal code.
2963@end table
2964
2965By default, @code{c-ignore-auto-fill} is set to @code{(string cpp
2966code)}, which means that when auto-fill mode is activated,
2967auto-filling only occurs in comments. In literals, it's often
2968desirable to have explicit control over newlines. In preprocessor
2969directives, the necessary @samp{\} escape character before the newline
2970is not automatically inserted, so an automatic line break would
2971produce invalid code. In normal code, line breaks are normally
2972dictated by some logical structure in the code rather than the last
2973whitespace character, so automatic line breaks there will produce poor
2974results in the current implementation.
2975@end defopt
2976
2977@vindex comment-multi-line
2978If inside a comment and @code{comment-multi-line} (@pxref{Auto Fill,,,
2979@emacsman{}, @emacsmantitle{}} is non-@code{nil}, the indentation and
2980line prefix are preserved. If inside a comment and
2981@code{comment-multi-line} is @code{nil}, a new comment of the same
2982type is started on the next line and indented as appropriate for
2983comments.
3a731e1f 2984
116e44a1
AM
2985Note that @ccmode{} sets @code{comment-multi-line} to @code{t} at
2986startup. The reason is that @kbd{M-j} could otherwise produce sequences
2987of single line block comments for texts that should logically be treated
2988as one comment, and the rest of the paragraph handling code
2989(e.g. @kbd{M-q} and @kbd{M-a}) can't cope with that, which would lead to
2990inconsistent behavior.
d7bd46ed
GM
2991
2992@comment !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
116e44a1 2993@node Custom Auto-newlines, Clean-ups, Custom Filling and Breaking, Top
d7bd46ed 2994@comment node-name, next, previous, up
116e44a1 2995@chapter Customizing Auto-newlines
6bf7aab6 2996@comment !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
6bf7aab6 2997
116e44a1
AM
2998@ccmode{} determines whether to insert auto-newlines in two basically
2999different ways, depending on the character just typed:
3000
3001@table @asis
3002@item Braces and Colons
3003@ccmode{} first determines the syntactic context of the brace or colon
3004(@pxref{Syntactic Symbols}), then looks for a corresponding element in
3005an alist. This element specifies where to put newlines - this is any
3006combination of before and after the brace or colon. If no alist
3007element is found, newlines are inserted both before and after a brace,
3008but none are inserted around a colon. See @ref{Hanging Braces} and
3009@ref{Hanging Colons}.
3010
3011@item Semicolons and Commas
3012The variable @code{c-hanging-semi&comma-criteria} contains a list of
3013functions which determine whether to insert a newline after a newly
3014typed semicolon or comma. @xref{Hanging Semicolons and Commas}.
3015@end table
d7bd46ed 3016
116e44a1
AM
3017The names of these configuration variables contain @samp{hanging}
3018because they let you @dfn{hang} the pertinent characters. A character
3019which introduces a C construct is said to @dfn{hang on the right} when
3020it appears at the end of a line after other code, being separated by a
3021line break from the construct it introduces, like the opening brace in:
3a731e1f 3022
d7bd46ed
GM
3023@example
3024@group
116e44a1
AM
3025while (i < MAX) @{
3026 total += entry[i];
3027 entry [i++] = 0;
3028@}
d7bd46ed
GM
3029@end group
3030@end example
3031
116e44a1
AM
3032@noindent
3033A character @dfn{hangs on the left} when it appears at the start of
3034the line after the construct it closes off, like the above closing
3035brace.
3036
3037The next chapter, ``Clean-ups'', describes how to configure @ccmode{}
3038to remove these automatically added newlines in certain specific
3039circumstances. @xref{Clean-ups}.
3040
3041@menu
3042* Hanging Braces::
3043* Hanging Colons::
3044* Hanging Semicolons and Commas::
3045@end menu
d7bd46ed
GM
3046
3047
3048@comment !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
116e44a1 3049@node Hanging Braces, Hanging Colons, Custom Auto-newlines, Custom Auto-newlines
d7bd46ed 3050@comment node-name, next, previous, up
116e44a1
AM
3051@section Hanging Braces
3052@cindex hanging braces
6bf7aab6
DL
3053@comment !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
3054
116e44a1
AM
3055To specify which kinds of braces you want auto-newlines put around,
3056you set the style variable @code{c-hanging-braces-alist}. Its
3057structure and semantics are described in this section. Details of how
3058to set it up, and its relationship to CC Mode's style system are given
3059in @ref{Style Variables}.
6bf7aab6 3060
116e44a1
AM
3061Say you wanted an auto-newline after (but not before) the following
3062@samp{@{}:
6bf7aab6 3063
116e44a1
AM
3064@example
3065if (foo < 17) @{
3066@end example
3a731e1f 3067
116e44a1
AM
3068@noindent
3069First you need to find the @dfn{syntactic context} of the brace---type
3070a @key{RET} before the brace to get it on a line of its
3071own@footnote{Also insert a @samp{\} at the end of the previous line if
3072you're in AWK Mode.}, then type @kbd{C-c C-s}. That will tell you
3073something like:
cb7f2e96 3074
116e44a1
AM
3075@example
3076((substatement-open 1061))
3077@end example
6bf7aab6 3078
116e44a1
AM
3079@noindent
3080So here you need to put the entry @code{(substatement-open . (after))}
3081into @code{c-hanging-braces-alist}.
3082
3083If you don't want any auto-newlines for a particular syntactic symbol,
3084put this into @code{c-hanging-braces-alist}:
6bf7aab6 3085
3a731e1f 3086@example
116e44a1 3087(brace-entry-open)
6bf7aab6
DL
3088@end example
3089
116e44a1
AM
3090If some brace syntactic symbol is not in @code{c-hanging-brace-alist},
3091its entry is taken by default as @code{(before after)}---insert a
3092newline both before and after the brace. In place of a
3093``before/after'' list you can specify a function in this alist---this
3094is useful when the auto newlines depend on the code around the brace.
6bf7aab6 3095
116e44a1
AM
3096@defopt c-hanging-braces-alist
3097@vindex hanging-braces-alist (c-)
6bf7aab6 3098
116e44a1
AM
3099This variable is an association list which maps syntactic symbols to
3100lists of places to insert a newline. @xref{Association
3101Lists,,,@lispref{}, @lispreftitle{}}. The key of each element is the
3102syntactic symbol, the associated value is either @code{nil}, a list,
3103or a function.
d7bd46ed 3104
116e44a1
AM
3105@table @asis
3106@item The Key - the syntactic symbol
3107The syntactic symbols that are useful as keys in this list are
3108@code{brace-list-intro}, @code{statement-cont},
3109@code{inexpr-class-open}, @code{inexpr-class-close}, and all the
3110@code{*-open} and @code{*-close} symbols. @xref{Syntactic Symbols},
3111for a more detailed description of these syntactic symbols, except for
3112@code{inexpr-class-open} and @code{inexpr-class-close}, which aren't
3113actual syntactic symbols. Elements with any other value as a key get
3114ignored.
d7bd46ed 3115
116e44a1
AM
3116The braces of anonymous inner classes in Java are given the special
3117symbols @code{inexpr-class-open} and @code{inexpr-class-close}, so that
3118they can be distinguished from the braces of normal classes@footnote{The
3119braces of anonymous classes produce a combination of
3120@code{inexpr-class}, and @code{class-open} or @code{class-close} in
3121normal indentation analysis.}.
d7bd46ed 3122
116e44a1
AM
3123Note that the aggregate constructs in Pike mode, @samp{(@{}, @samp{@})},
3124@samp{([}, @samp{])}, and @samp{(<}, @samp{>)}, do not count as brace
3125lists in this regard, even though they do for normal indentation
3126purposes. It's currently not possible to set automatic newlines on
3127these constructs.
d7bd46ed 3128
116e44a1
AM
3129@item The associated value - the ``ACTION'' list or function
3130The value associated with each syntactic symbol in this association
3131list is called an @var{action}, which can be either a list or a
3132function which returns a list. @xref{Custom Braces}, for how to use
3133a function as a brace hanging @var{action}.
d7bd46ed 3134
116e44a1
AM
3135The list @var{action} (or the list returned by @var{action} when it's
3136a function) contains some combination of the symbols @code{before} and
3137@code{after}, directing @ccmode{} where to put newlines in
3138relationship to the brace being inserted. Thus, if the list contains
3139only the symbol @code{after}, then the brace hangs on the right side
3140of the line, as in:
d7bd46ed 3141
116e44a1
AM
3142@example
3143// here, open braces always `hang'
3144void spam( int i ) @{
3145 if( i == 7 ) @{
3146 dosomething(i);
3147 @}
3148@}
3149@end example
6bf7aab6 3150
116e44a1
AM
3151When the list contains both @code{after} and @code{before}, the braces
3152will appear on a line by themselves, as shown by the close braces in
3153the above example. The list can also be empty, in which case newlines
3154are added neither before nor after the brace.
3155@end table
6bf7aab6 3156
116e44a1
AM
3157If a syntactic symbol is missing entirely from
3158@code{c-hanging-braces-alist}, it's treated in the same way as an
3159@var{action} with a list containing @code{before} and @code{after}, so
3160that braces by default end up on their own line.
6bf7aab6 3161
116e44a1 3162For example, the default value of @code{c-hanging-braces-alist} is:
6bf7aab6 3163
116e44a1
AM
3164@example
3165((brace-list-open)
3166 (brace-entry-open)
3167 (statement-cont)
3168 (substatement-open after)
3169 (block-close . c-snug-do-while)
3170 (extern-lang-open after)
3171 (namespace-open after)
3172 (module-open after)
3173 (composition-open after)
3174 (inexpr-class-open after)
3175 (inexpr-class-close before))
3176@end example
6bf7aab6 3177
116e44a1
AM
3178@noindent which says that @code{brace-list-open},
3179@code{brace-entry-open} and @code{statement-cont}@footnote{Brace lists
3180inside statements, such as initializers for static array variables
3181inside functions in C, are recognized as @code{statement-cont}. All
3182normal substatement blocks are recognized with other symbols.} braces
3183should both hang on the right side and allow subsequent text to follow
3184on the same line as the brace. Also, @code{substatement-open},
3185@code{extern-lang-open}, and @code{inexpr-class-open} braces should hang
3186on the right side, but subsequent text should follow on the next line.
3187The opposite holds for @code{inexpr-class-close} braces; they won't
3188hang, but the following text continues on the same line. Here, in the
3189@code{block-close} entry, you also see an example of using a function as
3190an @var{action}. In all other cases, braces are put on a line by
3191themselves.
3192@end defopt
6bf7aab6 3193
116e44a1
AM
3194@menu
3195* Custom Braces::
3196@end menu
6bf7aab6 3197
116e44a1
AM
3198@comment !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
3199@node Custom Braces, , Hanging Braces, Hanging Braces
3200@comment node-name, next, previous, up
3201@subsection Custom Brace Hanging
3202@comment !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
6bf7aab6 3203
116e44a1
AM
3204@vindex c-hanging-braces-alist
3205@vindex hanging-braces-alist (c-)
3206@cindex action functions
3207Syntactic symbols aren't the only place where you can customize
3208@ccmode{} with the lisp equivalent of callback functions. Remember
3209that @var{action}s are usually a list containing some combination of
3210the symbols @code{before} and @code{after} (@pxref{Hanging Braces}).
3211For more flexibility, you can instead specify brace ``hanginess'' by
3212giving a synctactic symbol an @dfn{action function} in
3213@code{c-hanging-braces-alist}; this function determines the
3214``hanginess'' of a brace, usually by looking at the code near it.
6bf7aab6 3215
116e44a1
AM
3216@cindex customization, brace hanging
3217An action function is called with two arguments: the syntactic symbol
3218for the brace (e.g. @code{substatement-open}), and the buffer position
3219where the brace has been inserted. Point is undefined on entry to an
3220action function, but the function must preserve it (e.g. by using
3221@code{save-excursion}). The return value should be a list containing
3222some combination of @code{before} and @code{after}, including neither
3223of them (i.e. @code{nil}).
6bf7aab6 3224
116e44a1
AM
3225@defvar c-syntactic-context
3226@vindex syntactic-context (c-)
3227During the call to the indentation or brace hanging @var{action}
3228function, this variable is bound to the full syntactic analysis list.
3229This might be, for example, @samp{((block-close 73))}. Don't ever
3230give @code{c-syntactic-context} a value yourself---this would disrupt
3231the proper functioning of @ccmode{}.
3232
3233This variable is also bound in three other circumstances:
3234(i)@tie{}when calling a c-hanging-semi&comma-criteria function
3235(@pxref{Hanging Semicolons and Commas}; (ii)@tie{}when calling a
3236line-up function (@pxref{Custom Line-Up}; (iii)@tie{}when calling a
3237c-special-indent-hook function (@pxref{Other Indentation}).
3238@end defvar
6bf7aab6 3239
116e44a1
AM
3240As an example, @ccmode{} itself uses this feature to dynamically
3241determine the hanginess of braces which close ``do-while''
3242constructs:
6bf7aab6 3243
116e44a1
AM
3244@example
3245void do_list( int count, char** atleast_one_string )
3246@{
3247 int i=0;
3248 do @{
3249 handle_string( atleast_one_string[i] );
3250 i++;
3251 @} while( i < count );
3252@}
3253@end example
6bf7aab6 3254
116e44a1
AM
3255@ccmode{} assigns the @code{block-close} syntactic symbol to the
3256brace that closes the @code{do} construct, and normally we'd like the
3257line that follows a @code{block-close} brace to begin on a separate
3258line. However, with ``do-while'' constructs, we want the
3259@code{while} clause to follow the closing brace. To do this, we
3260associate the @code{block-close} symbol with the @var{action} function
3261@code{c-snug-do-while}:
6bf7aab6 3262
116e44a1
AM
3263@example
3264(defun c-snug-do-while (syntax pos)
3265 "Dynamically calculate brace hanginess for do-while statements."
3266 (save-excursion
3267 (let (langelem)
3268 (if (and (eq syntax 'block-close)
3269 (setq langelem (assq 'block-close c-syntactic-context))
3270 (progn (goto-char (cdr langelem))
3271 (if (= (following-char) ?@{)
3272 (forward-sexp -1))
3273 (looking-at "\\<do\\>[^_]")))
3274 '(before)
3275 '(before after)))))
3276@end example
d7bd46ed 3277
116e44a1
AM
3278@findex c-snug-do-while
3279@findex snug-do-while (c-)
3280This function simply looks to see if the brace closes a ``do-while''
3281clause and if so, returns the list @samp{(before)} indicating
3282that a newline should be inserted before the brace, but not after it.
3283In all other cases, it returns the list @samp{(before after)} so
3284that the brace appears on a line by itself.
d7bd46ed 3285
3a731e1f 3286@comment !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
116e44a1 3287@node Hanging Colons, Hanging Semicolons and Commas, Hanging Braces, Custom Auto-newlines
3a731e1f 3288@comment node-name, next, previous, up
116e44a1
AM
3289@section Hanging Colons
3290@cindex hanging colons
3a731e1f
MS
3291@comment !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
3292
116e44a1
AM
3293@cindex customization, colon hanging
3294@vindex c-hanging-colons-alist
3295@vindex hanging-colons-alist (c-)
3a731e1f 3296
116e44a1
AM
3297Using a mechanism similar to brace hanging (@pxref{Hanging Braces}),
3298colons can also be made to hang using the style variable
3299@code{c-hanging-colons-alist} - When a colon is typed, @ccmode
3300determines its syntactic context, looks this up in the alist
3301@code{c-changing-colons-alist} and inserts up to two newlines
3302accordingly. Here, however, If @ccmode fails to find an entry for a
3303syntactic symbol in the alist, no newlines are inserted around the
3304newly typed colon.
3a731e1f 3305
116e44a1
AM
3306@defopt c-hanging-colons-alist
3307@vindex hanging-colons-alist (c-)
3a731e1f 3308
116e44a1
AM
3309@table @asis
3310@item The Key - the syntactic symbol
3311The syntactic symbols appropriate as keys in this association list
3312are: @code{case-label}, @code{label}, @code{access-label},
3313@code{member-init-intro}, and @code{inher-intro}. @xref{Syntactic
3314Symbols}. Elements with any other value as a key get ignored.
3315
3316@item The associate value - the ``ACTION'' list
3317The @var{action} here is simply a list containing a combination of the
3318symbols @code{before} and @code{after}. Unlike in
3319@code{c-hanging-braces-alist}, functions as @var{actions} are not
3320supported - there doesn't seem to be any need for them.
3321@end table
3322@end defopt
3a731e1f 3323
116e44a1
AM
3324In C++, double-colons are used as a scope operator but because these
3325colons always appear right next to each other, newlines before and after
3326them are controlled by a different mechanism, called @dfn{clean-ups} in
3327@ccmode{}. @xref{Clean-ups}, for details.
3a731e1f 3328
116e44a1
AM
3329@comment !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
3330@node Hanging Semicolons and Commas, , Hanging Colons, Custom Auto-newlines
3331@comment node-name, next, previous, up
3332@section Hanging Semicolons and Commas
3333@cindex hanging semicolons
3334@cindex hanging commas
3335@cindex customization, semicolon newlines
3336@cindex customization, comma newlines
3337@comment !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
6bf7aab6 3338
116e44a1
AM
3339@defopt c-hanging-semi&comma-criteria
3340@vindex hanging-semi&comma-criteria (c-)
3341This style variable takes a list of functions; these get called when
3342you type a semicolon or comma. The functions are called in order
3343without arguments. When these functions are entered, point is just
3344after the newly inserted @samp{;} or @samp{,} and they must preserve
3345point (e.g., by using @code{save-excursion}). During the call, the
3346variable @code{c-syntactic-context} is bound to the syntactic context
3347of the current line@footnote{This was first introduced in @ccmode{}
33485.31.} @pxref{Custom Braces}. These functions don't insert newlines
3349themselves, rather they direct @ccmode{} whether or not to do so.
3350They should return one of the following values:
d7bd46ed 3351
116e44a1
AM
3352@table @code
3353@item t
3354A newline is to be inserted after the @samp{;} or @samp{,}, and no
3355more functions from the list are to be called.
3356@item stop
3357No more functions from the list are to be called, and no newline is to
3358be inserted.
3359@item nil
3360No determination has been made, and the next function in the list is
3361to be called.
3362@end table
d7bd46ed 3363
116e44a1
AM
3364Note that auto-newlines are never inserted @emph{before} a semicolon
3365or comma. If every function in the list is called without a
3366determination being made, then no newline is added.
d7bd46ed 3367
116e44a1
AM
3368In AWK mode, this variable is set by default to @code{nil}. In the
3369other modes, the default value is a list containing a single function,
3370@code{c-semi&comma-inside-parenlist}. This inserts newlines after all
3371semicolons, apart from those separating @code{for}-clause statements.
3a731e1f 3372@end defopt
6bf7aab6 3373
116e44a1
AM
3374@defun c-semi&comma-no-newlines-before-nonblanks
3375@findex semi&comma-no-newlines-before-nonblanks (c-)
3376This is an example of a criteria function, provided by @ccmode{}. It
3377prevents newlines from being inserted after semicolons when there is a
3378non-blank following line. Otherwise, it makes no determination. To
3379use, add this function to the front of the
3380@code{c-hanging-semi&comma-criteria} list.
3381
3382@example
3383(defun c-semi&comma-no-newlines-before-nonblanks ()
3384 (save-excursion
3385 (if (and (eq last-command-char ?\;)
3386 (zerop (forward-line 1))
3387 (not (looking-at "^[ \t]*$")))
3388 'stop
3389 nil)))
3390@end example
3391@end defun
3392
3393@defun c-semi&comma-inside-parenlist
3394@findex semi&comma-inside-parenlist (c-)
3395@defunx c-semi&comma-no-newlines-for-oneline-inliners
3396@findex semi&comma-no-newlines-for-oneline-inliners (c-)
3397The function @code{c-semi&comma-inside-parenlist} is what prevents
3398newlines from being inserted inside the parenthesis list of @code{for}
3399statements. In addition to
3400@code{c-semi&comma-no-newlines-before-nonblanks} described above,
3401@ccmode{} also comes with the criteria function
3402@code{c-semi&comma-no-newlines-for-oneline-inliners}, which suppresses
3403newlines after semicolons inside one-line inline method definitions
3404(e.g. in C++ or Java).
3405@end defun
6bf7aab6
DL
3406
3407
3408@comment !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
116e44a1 3409@node Clean-ups, Indentation Engine Basics, Custom Auto-newlines, Top
d7bd46ed 3410@comment node-name, next, previous, up
116e44a1
AM
3411@chapter Clean-ups
3412@cindex clean-ups
6bf7aab6
DL
3413@comment !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
3414
116e44a1
AM
3415@dfn{Clean-ups} are mechanisms which remove (or exceptionally, add)
3416whitespace in specific circumstances and are complementary to colon
3417and brace hanging. You enable a clean-up by adding its symbol into
3418@code{c-cleanup-list}.
2a15eb73 3419
116e44a1
AM
3420On the surface, it would seem that clean-ups overlap the functionality
3421provided by the @code{c-hanging-*-alist} variables. Clean-ups,
3422however, are used to adjust code ``after-the-fact'', i.e. to adjust
3423the whitespace in constructs later than when they were typed.
2a15eb73 3424
116e44a1
AM
3425Most of the clean-ups remove automatically inserted newlines, and are
3426only active when auto-newline minor mode is turned on. Others will
3427work all the time. Note that clean-ups are only performed when there
3428is nothing but whitespace appearing between the individual components
3429of the construct, and (apart from @code{comment-close-slash}) when the
3430construct does not occur within a literal (@pxref{Auto-newlines}).
2a15eb73 3431
116e44a1
AM
3432@defopt c-cleanup-list
3433@vindex cleanup-list (c-)
3434@cindex literal
2a15eb73 3435
116e44a1
AM
3436You configure @ccmode{}'s clean-ups by setting the style variable
3437@code{c-cleanup-list}, which is a list of clean-up symbols. By
3438default, @ccmode{} cleans up only the @code{scope-operator} construct,
3439which is necessary for proper C++ support.
3440@end defopt
2a15eb73 3441
116e44a1
AM
3442These are the clean-ups that are only active when electric and
3443auto-newline minor modes are enabled:
2a15eb73 3444
116e44a1
AM
3445@c TBD: Would like to use some sort of @deffoo here; @table indents a
3446@c bit too much in dvi output.
3447@table @code
3448@item brace-else-brace
3449Clean up @samp{@} else @{} constructs by placing the entire construct on
3450a single line. Clean up occurs when the open brace after the
3451@samp{else} is typed. So for example, this:
2a15eb73 3452
116e44a1
AM
3453@example
3454@group
3455void spam(int i)
3456@{
3457 if( i==7 ) @{
3458 dosomething();
3459 @}
3460 else
3461 @{
3462@end group
3463@end example
3a731e1f 3464
116e44a1
AM
3465@noindent
3466appears like this after the last open brace is typed:
6bf7aab6 3467
116e44a1
AM
3468@example
3469@group
3470void spam(int i)
3471@{
3472 if( i==7 ) @{
3473 dosomething();
3474 @} else @{
3475@end group
3476@end example
3a731e1f 3477
116e44a1
AM
3478@item brace-elseif-brace
3479Similar to the @code{brace-else-brace} clean-up, but this cleans up
3480@samp{@} else if (...) @{} constructs. For example:
6bf7aab6 3481
116e44a1
AM
3482@example
3483@group
3484void spam(int i)
3485@{
3486 if( i==7 ) @{
3487 dosomething();
3488 @}
3489 else if( i==3 )
3490 @{
3491@end group
3492@end example
6bf7aab6 3493
116e44a1
AM
3494@noindent
3495appears like this after the last open parenthesis is typed:
6bf7aab6 3496
116e44a1
AM
3497@example
3498@group
3499void spam(int i)
3500@{
3501 if( i==7 ) @{
3502 dosomething();
3503 @} else if(
3504@end group
3505@end example
6bf7aab6 3506
116e44a1
AM
3507@noindent
3508and like this after the last open brace is typed:
6bf7aab6 3509
116e44a1
AM
3510@example
3511@group
3512void spam(int i)
3513@{
3514 if( i==7 ) @{
3515 dosomething();
3516 @} else if( i==3 ) @{
3517@end group
3518@end example
6bf7aab6 3519
116e44a1
AM
3520@item brace-catch-brace
3521Analogous to @code{brace-elseif-brace}, but cleans up @samp{@} catch
3522(...) @{} in C++ and Java mode.
6bf7aab6 3523
116e44a1
AM
3524@item empty-defun-braces
3525Clean up braces following a top-level function or class definition that
3526contains no body. Clean up occurs when the closing brace is typed.
3527Thus the following:
6bf7aab6 3528
116e44a1
AM
3529@example
3530@group
3531class Spam
3532@{
3533@}
3534@end group
3535@end example
6bf7aab6 3536
116e44a1
AM
3537@noindent
3538is transformed into this when the close brace is typed:
6bf7aab6 3539
116e44a1
AM
3540@example
3541@group
3542class Spam
3543@{@}
3544@end group
3545@end example
6bf7aab6 3546
116e44a1
AM
3547@item defun-close-semi
3548Clean up the terminating semicolon on top-level function or class
3549definitions when they follow a close brace. Clean up occurs when the
3550semicolon is typed. So for example, the following:
6bf7aab6 3551
116e44a1
AM
3552@example
3553@group
3554class Spam
3555@{
3556...
3557@}
3558;
3559@end group
3560@end example
6bf7aab6 3561
116e44a1
AM
3562@noindent
3563is transformed into this when the semicolon is typed:
3a731e1f 3564
6bf7aab6
DL
3565@example
3566@group
116e44a1
AM
3567class Spam
3568@{
3569...
3570@};
6bf7aab6
DL
3571@end group
3572@end example
3573
116e44a1
AM
3574@item list-close-comma
3575Clean up commas following braces in array and aggregate initializers.
3576Clean up occurs when the comma is typed. The space before the comma
3577is zapped just like the space before the semicolon in
3578@code{defun-close-semi}.
3a731e1f 3579
116e44a1
AM
3580@item scope-operator
3581Clean up double colons which might designate a C++ scope operator split
3582across multiple lines@footnote{Certain C++ constructs introduce
3583ambiguous situations, so @code{scope-operator} clean-ups might not
3584always be correct. This usually only occurs when scoped identifiers
3585appear in switch label tags.}. Clean up occurs when the second colon is
3586typed. You will always want @code{scope-operator} in the
3587@code{c-cleanup-list} when you are editing C++ code.
d7bd46ed 3588
116e44a1
AM
3589@item one-liner-defun
3590Clean up a single line of code enclosed by defun braces by removing
3591the whitespace before and after the code. The clean-up happens when
3592the closing brace is typed. If the variable
3593@code{c-max-one-liner-length} is set, the cleanup is only done if the
3594resulting line would be no longer than the value of that variable.
6bf7aab6 3595
116e44a1 3596For example, consider this AWK code:
6bf7aab6 3597
3a731e1f 3598@example
116e44a1
AM
3599@group
3600BEGIN @{
3601 FS = "\t" # use <TAB> as a field separator
3602@}
3603@end group
6bf7aab6
DL
3604@end example
3605
116e44a1
AM
3606@noindent
3607It gets compacted to the following when the closing brace is typed:
3a731e1f 3608
6bf7aab6
DL
3609@example
3610@group
116e44a1 3611BEGIN @{FS = "\t"@} # use <TAB> as a field separator
6bf7aab6
DL
3612@end group
3613@end example
3614
116e44a1
AM
3615@defopt c-max-one-liner-length
3616@vindex max-one-liner-length (c-)
3617The maximum length of the resulting line for which the clean-up
3618@code{one-liner-defun} will be triggered. This length is that of the entire
3619line, including any leading whitespace and any trailing comment. Its
3620default value is 80. If the value is zero or @code{nil}, no limit
3621applies.
3622@end defopt
3623@end table
6bf7aab6 3624
116e44a1
AM
3625The following clean-ups are always active when they occur on
3626@code{c-cleanup-list}, regardless of whether Electric minor mode or
3627Auto-newline minor mode are enabled:
6bf7aab6 3628
116e44a1
AM
3629@table @code
3630@item space-before-funcall
3631Insert a space between the function name and the opening parenthesis
3632of a function call. This produces function calls in the style
3633mandated by the GNU coding standards, e.g. @samp{signal@tie{}(SIGINT,
3634SIG_IGN)} and @samp{abort@tie{}()}. Clean up occurs when the opening
3635parenthesis is typed. This clean-up should never be active in AWK
3636Mode, since such a space is syntactically invalid for user defined
3637functions.
6bf7aab6 3638
116e44a1
AM
3639@item compact-empty-funcall
3640Clean up any space between the function name and the opening parenthesis
3641of a function call that has no arguments. This is typically used
3642together with @code{space-before-funcall} if you prefer the GNU function
3643call style for functions with arguments but think it looks ugly when
3644it's only an empty parenthesis pair. I.e. you will get @samp{signal
3645(SIGINT, SIG_IGN)}, but @samp{abort()}. Clean up occurs when the
3646closing parenthesis is typed.
3647
3648@item comment-close-slash
3649When inside a block comment, terminate the comment when you type a
3650slash at the beginning of a line (i.e. immediately after the comment
3651prefix). This clean-up removes whitespace preceding the slash and if
3652needed, inserts a star to complete the token @samp{*/}.
3653@end table
3654
3655
3656@comment !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
3657@node Indentation Engine Basics, Customizing Indentation, Clean-ups, Top
d7bd46ed 3658@comment node-name, next, previous, up
116e44a1 3659@chapter Indentation Engine Basics
6bf7aab6
DL
3660@comment !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
3661
116e44a1
AM
3662This chapter will briefly cover how @ccmode{} indents lines of code.
3663It is helpful to understand the indentation model being used so that
3664you will know how to customize @ccmode{} for your personal coding
3665style. All the details are in @ref{Customizing Indentation}.
6bf7aab6 3666
116e44a1
AM
3667@ccmode{} has an indentation engine that provides a flexible and
3668general mechanism for customizing indentation. When @ccmode{} indents
3669a line of code, it separates its calculations into two steps:
6bf7aab6 3670
116e44a1
AM
3671@enumerate
3672@item
3673@cindex syntactic symbol
3674@cindex anchor position
3675It analyzes the line to determine its @dfn{syntactic symbol(s)} (the
3676kind of language construct it's looking at) and its @dfn{anchor
3677position} (the position earlier in the file that @ccmode{} will indent
3678the line relative to). The anchor position might be the location of
3679an opening brace in the previous line, for example. @xref{Syntactic
3680Analysis}.
3681@item
3682@cindex offsets
3683@cindex indentation offset specifications
3684It looks up the syntactic symbol(s) in the configuration to get the
3685corresponding @dfn{offset(s)}. The symbol @code{+}, which means
3686``indent this line one more level'' is a typical offset. @ccmode{}
3687then applies these offset(s) to the anchor position, giving the
3688indentation for the line. The different sorts of offsets are
3689described in @ref{c-offsets-alist}.
3690@end enumerate
3691
3692In exceptional circumstances, the syntax directed indentation
3693described here may be a nuisance rather than a help. You can disable
3694it by setting @code{c-syntactic-indentation} to @code{nil}. (To set
3695the variable interactively, @ref{Minor Modes}).
3696
3697@defopt c-syntactic-indentation
3698@vindex syntactic-indentation (c-)
3699When this is non-@code{nil} (which it is by default), the indentation
3700of code is done according to its syntactic structure. When it's
3701@code{nil}, every line is just indented to the same level as the
3702previous one, and @kbd{TAB} (@code{c-indent-command}) adjusts the
3703indentation in steps of @code{c-basic-offset}. The current style
3704(@pxref{Config Basics}) then has no effect on indentation, nor do any
3705of the variables associated with indentation, not even
3706@code{c-special-indent-hook}.
3707@end defopt
3708
3709@menu
3710* Syntactic Analysis::
3711* Syntactic Symbols::
3712* Indentation Calculation::
3713@end menu
3714
3715
3716@comment !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
3717@node Syntactic Analysis, Syntactic Symbols, Indentation Engine Basics, Indentation Engine Basics
3718@comment node-name, next, previous, up
3719@section Syntactic Analysis
3720@cindex syntactic analysis
3721@comment !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
3722
3723@cindex syntactic element
3724@cindex syntactic context
3725The first thing @ccmode{} does when indenting a line of code, is to
3726analyze the line, determining the @dfn{syntactic context} of the
3727(first) construct on that line. It's a list of @dfn{syntactic
3728elements}, where each syntactic element in turn is a list@footnote{In
3729@ccmode 5.28 and earlier, a syntactic element was a dotted pair; the
3730cons was the syntactic symbol and the cdr was the anchor position.
3731For compatibility's sake, the parameter passed to a line-up function
3732still has this dotted pair form (@pxref{Custom Line-Up}).} Here is a
3733brief and typical example:
6bf7aab6 3734
3a731e1f 3735@example
116e44a1 3736((defun-block-intro 1959))
6bf7aab6
DL
3737@end example
3738
116e44a1
AM
3739@cindex syntactic symbol
3740@noindent
3741The first thing inside each syntactic element is always a
3742@dfn{syntactic symbol}. It describes the kind of construct that was
3743recognized, e.g. @code{statement}, @code{substatement},
3744@code{class-open}, @code{class-close}, etc. @xref{Syntactic Symbols},
3745for a complete list of currently recognized syntactic symbols and
3746their semantics. The remaining entries are various data associated
3747with the recognized construct - there might be zero or more.
3748
3749@cindex anchor position
3750Conceptually, a line of code is always indented relative to some
3751position higher up in the buffer (typically the indentation of the
3752previous line). That position is the @dfn{anchor position} in the
3753syntactic element. If there is an entry after the syntactic symbol in
3754the syntactic element list then it's either nil or that anchor position.
3755
3756Here is an example. Suppose we had the following code as the only thing
3757in a C++ buffer @footnote{The line numbers in this and future examples
3758don't actually appear in the buffer, of course!}:
6bf7aab6 3759
3a731e1f 3760@example
116e44a1
AM
3761 1: void swap( int& a, int& b )
3762 2: @{
3763 3: int tmp = a;
3764 4: a = b;
3765 5: b = tmp;
3766 6: @}
6bf7aab6
DL
3767@end example
3768
116e44a1
AM
3769@noindent
3770We can use @kbd{C-c C-s} (@code{c-show-syntactic-information}) to
3771report what the syntactic analysis is for the current line:
6bf7aab6 3772
116e44a1
AM
3773@table @asis
3774@item @kbd{C-c C-s} (@code{c-show-syntactic-information})
3775@kindex C-c C-s
3776@findex c-show-syntactic-information
3777@findex show-syntactic-information (c-)
3778This command calculates the syntactic analysis of the current line and
3779displays it in the minibuffer. The command also highlights the anchor
3780position(s).
3781@end table
6bf7aab6 3782
116e44a1
AM
3783 Running this command on line 4 of this example, we'd see in the echo
3784area@footnote{With a universal argument (i.e. @kbd{C-u C-c C-s}) the
3785analysis is inserted into the buffer as a comment on the current
3786line.}:
6bf7aab6 3787
116e44a1
AM
3788@example
3789((statement 35))
3790@end example
6bf7aab6 3791
116e44a1
AM
3792@noindent
3793and the @samp{i} of @code{int} on line 3 would be highlighted. This
3794tells us that the line is a statement and it is indented relative to
3795buffer position 35, the highlighted position. If you were to move
3796point to line 3 and hit @kbd{C-c C-s}, you would see:
6bf7aab6 3797
116e44a1
AM
3798@example
3799((defun-block-intro 29))
3800@end example
6bf7aab6 3801
116e44a1
AM
3802@noindent
3803This indicates that the @samp{int} line is the first statement in a top
3804level function block, and is indented relative to buffer position 29,
3805which is the brace just after the function header.
6bf7aab6 3806
116e44a1 3807Here's another example:
6bf7aab6 3808
116e44a1
AM
3809@example
3810 1: int add( int val, int incr, int doit )
3811 2: @{
3812 3: if( doit )
3813 4: @{
3814 5: return( val + incr );
3815 6: @}
3816 7: return( val );
3817 8: @}
3818@end example
6bf7aab6 3819
116e44a1
AM
3820@noindent
3821Hitting @kbd{C-c C-s} on line 4 gives us:
6bf7aab6
DL
3822
3823@example
116e44a1 3824((substatement-open 46))
6bf7aab6
DL
3825@end example
3826
116e44a1
AM
3827@cindex substatement
3828@cindex substatement block
3829@noindent
3830which tells us that this is a brace that @emph{opens} a substatement
3831block. @footnote{A @dfn{substatement} is the line after a
3832conditional statement, such as @code{if}, @code{else}, @code{while},
3833@code{do}, @code{switch}, etc. A @dfn{substatement
3834block} is a brace block following one of these conditional statements.}
6bf7aab6 3835
116e44a1
AM
3836@cindex comment-only line
3837Syntactic contexts can contain more than one element, and syntactic
3838elements need not have anchor positions. The most common example of
3839this is a @dfn{comment-only line}:
6bf7aab6 3840
116e44a1
AM
3841@example
3842 1: void draw_list( List<Drawables>& drawables )
3843 2: @{
3844 3: // call the virtual draw() method on each element in list
3845 4: for( int i=0; i < drawables.count(), ++i )
3846 5: @{
3847 6: drawables[i].draw();
3848 7: @}
3849 8: @}
3850@end example
6bf7aab6 3851
116e44a1
AM
3852@noindent
3853Hitting @kbd{C-c C-s} on line 3 of this example gives:
3a731e1f 3854
116e44a1
AM
3855@example
3856((comment-intro) (defun-block-intro 46))
3857@end example
6bf7aab6 3858
116e44a1
AM
3859@noindent
3860and you can see that the syntactic context contains two syntactic
3861elements. Notice that the first element, @samp{(comment-intro)}, has no
3862anchor position.
d7bd46ed 3863
6bf7aab6 3864
d7bd46ed 3865@comment !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
116e44a1 3866@node Syntactic Symbols, Indentation Calculation, Syntactic Analysis, Indentation Engine Basics
d7bd46ed 3867@comment node-name, next, previous, up
116e44a1 3868@section Syntactic Symbols
6bf7aab6
DL
3869@comment !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
3870
3a731e1f 3871@cindex syntactic symbols, brief list
6bf7aab6
DL
3872@vindex c-offsets-alist
3873@vindex offsets-alist (c-)
116e44a1
AM
3874This section is a complete list of the syntactic symbols which appear
3875in the @code{c-offsets-alist} style variable, along with brief
3876descriptions. The previous section (@pxref{Syntactic Analysis})
3877states what syntactic symbols are and how the indentation engine uses
3878them.
3879
3880More detailed descriptions of these symbols, together with snippets of
3881source code to which they apply, appear in the examples in the
3882subsections below. Note that, in the interests of brevity, the anchor
3883position associated with most syntactic symbols is @emph{not}
3884specified. In cases of doubt, type @kbd{C-c C-s} on a pertinent
3885line---this highlights the anchor position.
3886
3887@ssindex -open symbols
3888@ssindex -close symbols
3889@ssindex -block-intro symbols
3890The syntactic symbols which indicate brace constructs follow a general
3891naming convention. When a line begins with an open or close brace,
3892its syntactic symbol will contain the suffix @code{-open} or
3893@code{-close} respectively. The first line within the brace block
3894construct will contain the suffix @code{-block-intro}.
3895
3896@ssindex -intro symbols
3897@ssindex -cont symbols
3898In constructs which can span several lines, a distinction is usually
3899made between the first line that introduces the construct and the
3900lines that continue it. The syntactic symbols that indicate these
3901lines will contain the suffixes @code{-intro} or @code{-cont}
3902respectively.
3903
3904The best way to understand how all this works is by looking at some
3905examples. Remember that you can see the syntax of any source code
3906line by using @kbd{C-c C-s}.
6bf7aab6 3907
d7bd46ed
GM
3908@table @code
3909@item string
116e44a1 3910Inside a multiline string. @ref{Literal Symbols}.
d7bd46ed 3911@item c
116e44a1 3912Inside a multiline C style block comment. @ref{Literal Symbols}.
d7bd46ed 3913@item defun-open
116e44a1
AM
3914Brace that opens a top-level function definition. @ref{Function
3915Symbols}.
d7bd46ed 3916@item defun-close
116e44a1
AM
3917Brace that closes a top-level function definition. @ref{Function
3918Symbols}.
d7bd46ed 3919@item defun-block-intro
116e44a1 3920The first line in a top-level defun. @ref{Function Symbols}.
d7bd46ed 3921@item class-open
116e44a1 3922Brace that opens a class definition. @ref{Class Symbols}.
d7bd46ed 3923@item class-close
116e44a1 3924Brace that closes a class definition. @ref{Class Symbols}.
d7bd46ed 3925@item inline-open
116e44a1 3926Brace that opens an in-class inline method. @ref{Class Symbols}.
d7bd46ed 3927@item inline-close
116e44a1 3928Brace that closes an in-class inline method. @ref{Class Symbols}.
d7bd46ed
GM
3929@item func-decl-cont
3930The region between a function definition's argument list and the
116e44a1
AM
3931function opening brace (excluding K&R argument declarations). In C,
3932you cannot put anything but whitespace and comments in this region,
3933however in C++ and Java, @code{throws} declarations and other things
3934can appear here. @ref{Literal Symbols}. @c @emph{FIXME!!! Can it not
3935@c go somewhere better?}
d7bd46ed 3936@item knr-argdecl-intro
116e44a1 3937First line of a K&R C argument declaration. @ref{K&R Symbols}.
d7bd46ed 3938@item knr-argdecl
116e44a1 3939Subsequent lines in a K&R C argument declaration. @ref{K&R Symbols}.
d7bd46ed 3940@item topmost-intro
116e44a1 3941The first line in a ``topmost'' definition. @ref{Function Symbols}.
d7bd46ed 3942@item topmost-intro-cont
3a731e1f
MS
3943Topmost definition continuation lines. This is only used in the parts
3944that aren't covered by other symbols such as @code{func-decl-cont} and
116e44a1 3945@code{knr-argdecl}. @ref{Function Symbols}.
d7bd46ed 3946@item member-init-intro
116e44a1 3947First line in a member initialization list. @ref{Class Symbols}.
d7bd46ed 3948@item member-init-cont
116e44a1 3949Subsequent member initialization list lines. @ref{Class Symbols}.
d7bd46ed 3950@item inher-intro
116e44a1 3951First line of a multiple inheritance list. @ref{Class Symbols}.
d7bd46ed 3952@item inher-cont
116e44a1 3953Subsequent multiple inheritance lines. @ref{Class Symbols}.
d7bd46ed 3954@item block-open
116e44a1 3955Statement block open brace. @ref{Literal Symbols}.
d7bd46ed 3956@item block-close
116e44a1 3957Statement block close brace. @ref{Conditional Construct Symbols}.
d7bd46ed 3958@item brace-list-open
116e44a1 3959Open brace of an enum or static array list. @ref{Brace List Symbols}.
d7bd46ed 3960@item brace-list-close
116e44a1 3961Close brace of an enum or static array list. @ref{Brace List Symbols}.
d7bd46ed 3962@item brace-list-intro
116e44a1 3963First line in an enum or static array list. @ref{Brace List Symbols}.
d7bd46ed 3964@item brace-list-entry
116e44a1
AM
3965Subsequent lines in an enum or static array list. @ref{Brace List
3966Symbols}.
d7bd46ed
GM
3967@item brace-entry-open
3968Subsequent lines in an enum or static array list where the line begins
116e44a1 3969with an open brace. @ref{Brace List Symbols}.
d7bd46ed 3970@item statement
116e44a1 3971A statement. @ref{Function Symbols}.
d7bd46ed 3972@item statement-cont
116e44a1 3973A continuation of a statement. @ref{Function Symbols}.
d7bd46ed 3974@item statement-block-intro
116e44a1
AM
3975The first line in a new statement block. @ref{Conditional Construct
3976Symbols}.
d7bd46ed 3977@item statement-case-intro
116e44a1 3978The first line in a case block. @ref{Switch Statement Symbols}.
d7bd46ed 3979@item statement-case-open
116e44a1
AM
3980The first line in a case block that starts with a brace. @ref{Switch
3981Statement Symbols}.
d7bd46ed
GM
3982@item substatement
3983The first line after a conditional or loop construct.
116e44a1 3984@ref{Conditional Construct Symbols}.
d7bd46ed 3985@item substatement-open
116e44a1
AM
3986The brace that opens a substatement block. @ref{Conditional Construct
3987Symbols}.
3a731e1f
MS
3988@item substatement-label
3989The first line after a conditional or loop construct if it's a label.
116e44a1 3990@ref{Conditional Construct Symbols}.
d7bd46ed 3991@item case-label
116e44a1 3992A label in a @code{switch} block. @ref{Switch Statement Symbols}.
d7bd46ed 3993@item access-label
116e44a1 3994C++ access control label. @ref{Class Symbols}.
d7bd46ed 3995@item label
116e44a1 3996Any other label. @ref{Literal Symbols}.
d7bd46ed
GM
3997@item do-while-closure
3998The @code{while} line that ends a @code{do}-@code{while} construct.
116e44a1 3999@ref{Conditional Construct Symbols}.
d7bd46ed
GM
4000@item else-clause
4001The @code{else} line of an @code{if}-@code{else} construct.
116e44a1 4002@ref{Conditional Construct Symbols}.
d7bd46ed
GM
4003@item catch-clause
4004The @code{catch} or @code{finally} (in Java) line of a
116e44a1
AM
4005@code{try}-@code{catch} construct. @ref{Conditional Construct
4006Symbols}.
d7bd46ed 4007@item comment-intro
116e44a1 4008A line containing only a comment introduction. @ref{Literal Symbols}.
d7bd46ed 4009@item arglist-intro
116e44a1 4010The first line in an argument list. @ref{Paren List Symbols}.
d7bd46ed 4011@item arglist-cont
116e44a1
AM
4012Subsequent argument list lines when no arguments follow on the same
4013line as the arglist opening paren. @ref{Paren List Symbols}.
d7bd46ed 4014@item arglist-cont-nonempty
116e44a1
AM
4015Subsequent argument list lines when at least one argument follows on
4016the same line as the arglist opening paren. @ref{Paren List Symbols}.
d7bd46ed 4017@item arglist-close
116e44a1 4018The solo close paren of an argument list. @ref{Paren List Symbols}.
d7bd46ed 4019@item stream-op
116e44a1
AM
4020Lines continuing a stream operator (C++ only). @ref{Literal
4021Symbols}. @c @emph{FIXME!!! Can this not be moved somewhere better?}
d7bd46ed 4022@item inclass
116e44a1 4023The line is nested inside a class definition. @ref{Class Symbols}.
d7bd46ed 4024@item cpp-macro
116e44a1 4025The start of a preprocessor macro definition. @ref{Literal Symbols}.
3a731e1f
MS
4026@item cpp-define-intro
4027The first line inside a multiline preproprocessor macro if
116e44a1
AM
4028@code{c-syntactic-indentation-in-macros} is set. @ref{Multiline Macro
4029Symbols}.
d7bd46ed 4030@item cpp-macro-cont
3a731e1f
MS
4031All lines inside multiline preprocessor macros if
4032@code{c-syntactic-indentation-in-macros} is @code{nil}.
116e44a1 4033@ref{Multiline Macro Symbols}.
d7bd46ed 4034@item friend
116e44a1 4035A C++ friend declaration. @ref{Class Symbols}.
d7bd46ed 4036@item objc-method-intro
116e44a1
AM
4037The first line of an Objective-C method definition. @ref{Objective-C
4038Method Symbols}.
d7bd46ed 4039@item objc-method-args-cont
116e44a1
AM
4040Lines continuing an Objective-C method definition. @ref{Objective-C
4041Method Symbols}.
d7bd46ed 4042@item objc-method-call-cont
116e44a1
AM
4043Lines continuing an Objective-C method call. @ref{Objective-C Method
4044Symbols}.
d7bd46ed 4045@item extern-lang-open
116e44a1
AM
4046Brace that opens an @code{extern} block (e.g. @code{extern "C"
4047@{...@}}). @ref{External Scope Symbols}.
d7bd46ed 4048@item extern-lang-close
116e44a1
AM
4049Brace that closes an @code{extern} block. @ref{External Scope
4050Symbols}.
d7bd46ed 4051@item inextern-lang
3a731e1f 4052Analogous to @code{inclass} syntactic symbol, but used inside
116e44a1 4053@code{extern} blocks. @ref{External Scope Symbols}.
d7bd46ed 4054@item namespace-open
3a731e1f
MS
4055@itemx namespace-close
4056@itemx innamespace
4057These are analogous to the three @code{extern-lang} symbols above, but
116e44a1 4058are returned for C++ namespace blocks. @ref{External Scope Symbols}.
3a731e1f
MS
4059@item module-open
4060@itemx module-close
4061@itemx inmodule
4062Analogous to the above, but for CORBA IDL @code{module} blocks.
116e44a1 4063@ref{External Scope Symbols}.
3a731e1f
MS
4064@item composition-open
4065@itemx composition-close
4066@itemx incomposition
4067Analogous to the above, but for CORBA CIDL @code{composition} blocks.
116e44a1 4068@ref{External Scope Symbols}.
d7bd46ed 4069@item template-args-cont
116e44a1 4070C++ template argument list continuations. @ref{Class Symbols}.
d7bd46ed
GM
4071@item inlambda
4072Analogous to @code{inclass} syntactic symbol, but used inside lambda
116e44a1
AM
4073(i.e. anonymous) functions. Only used in Pike mode. @ref{Statement
4074Block Symbols}.
d7bd46ed 4075@item lambda-intro-cont
116e44a1 4076Lines continuing the header of a lambda function, i.e. between the
d7bd46ed 4077@code{lambda} keyword and the function body. Only used in Pike mode.
116e44a1 4078@ref{Statement Block Symbols}.
d7bd46ed 4079@item inexpr-statement
116e44a1
AM
4080A statement block inside an expression. The gcc C and C++ extension
4081for this is recognized. It's also used for the special functions that
4082take a statement block as an argument in Pike. @ref{Statement Block
4083Symbols}.
d7bd46ed
GM
4084@item inexpr-class
4085A class definition inside an expression. This is used for anonymous
4086classes in Java. It's also used for anonymous array initializers in
116e44a1 4087Java. @ref{Anonymous Class Symbol}.
d7bd46ed 4088@end table
6bf7aab6 4089
116e44a1
AM
4090@menu
4091* Function Symbols::
4092* Class Symbols::
4093* Conditional Construct Symbols::
4094* Switch Statement Symbols::
4095* Brace List Symbols::
4096* External Scope Symbols::
4097* Paren List Symbols::
4098* Literal Symbols::
4099* Multiline Macro Symbols::
4100* Objective-C Method Symbols::
4101* Anonymous Class Symbol::
4102* Statement Block Symbols::
4103* K&R Symbols::
4104@end menu
6bf7aab6 4105
116e44a1
AM
4106@comment !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
4107@node Function Symbols, Class Symbols, Syntactic Symbols, Syntactic Symbols
4108@comment node-name, next, previous, up
4109@subsection Function Symbols
4110@comment !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
6bf7aab6 4111
116e44a1 4112This example shows a typical function declaration.
6bf7aab6 4113
3a731e1f
MS
4114@example
4115 1: void
4116 2: swap( int& a, int& b )
4117 3: @{
4118 4: int tmp = a;
4119 5: a = b;
4120 6: b = tmp;
4121 7: int ignored =
4122 8: a + b;
4123 9: @}
6bf7aab6
DL
4124@end example
4125
3a731e1f
MS
4126@ssindex topmost-intro
4127@ssindex topmost-intro-cont
4128@ssindex defun-open
4129@ssindex defun-close
4130@ssindex defun-block-intro
6bf7aab6
DL
4131Line 1 shows a @code{topmost-intro} since it is the first line that
4132introduces a top-level construct. Line 2 is a continuation of the
4133top-level construct introduction so it has the syntax
4134@code{topmost-intro-cont}. Line 3 shows a @code{defun-open} since it is
d7bd46ed
GM
4135the brace that opens a top-level function definition. Line 9 is the
4136corresponding
6bf7aab6 4137@code{defun-close} since it contains the brace that closes the top-level
116e44a1 4138function definition. Line 4 is a @code{defun-block-intro}, i.e. it is
6bf7aab6
DL
4139the first line of a brace-block, enclosed in a
4140top-level function definition.
4141
3a731e1f
MS
4142@ssindex statement
4143@ssindex statement-cont
6bf7aab6
DL
4144Lines 5, 6, and 7 are all given @code{statement} syntax since there
4145isn't much special about them. Note however that line 8 is given
4146@code{statement-cont} syntax since it continues the statement begun
4147on the previous line.
4148
116e44a1
AM
4149@comment !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
4150@node Class Symbols, Conditional Construct Symbols, Function Symbols, Syntactic Symbols
4151@comment node-name, next, previous, up
4152@subsection Class related Symbols
4153@comment !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
4154
4155Here's an example which illustrates some C++ class syntactic symbols:
6bf7aab6 4156
3a731e1f
MS
4157@example
4158 1: class Bass
4159 2: : public Guitar,
4160 3: public Amplifiable
4161 4: @{
4162 5: public:
4163 6: Bass()
4164 7: : eString( new BassString( 0.105 )),
4165 8: aString( new BassString( 0.085 )),
4166 9: dString( new BassString( 0.065 )),
416710: gString( new BassString( 0.045 ))
416811: @{
416912: eString.tune( 'E' );
417013: aString.tune( 'A' );
417114: dString.tune( 'D' );
417215: gString.tune( 'G' );
417316: @}
417417: friend class Luthier;
417518: @};
6bf7aab6
DL
4176@end example
4177
3a731e1f
MS
4178@ssindex class-open
4179@ssindex class-close
6bf7aab6
DL
4180As in the previous example, line 1 has the @code{topmost-intro} syntax.
4181Here however, the brace that opens a C++ class definition on line 4 is
4182assigned the @code{class-open} syntax. Note that in C++, classes,
4183structs, and unions are essentially equivalent syntactically (and are
4184very similar semantically), so replacing the @code{class} keyword in the
4185example above with @code{struct} or @code{union} would still result in a
4186syntax of @code{class-open} for line 4 @footnote{This is the case even
4187for C and Objective-C. For consistency, structs in all supported
4188languages are syntactically equivalent to classes. Note however that
4189the keyword @code{class} is meaningless in C and Objective-C.}.
4190Similarly, line 18 is assigned @code{class-close} syntax.
4191
3a731e1f
MS
4192@ssindex inher-intro
4193@ssindex inher-cont
6bf7aab6
DL
4194Line 2 introduces the inheritance list for the class so it is assigned
4195the @code{inher-intro} syntax, and line 3, which continues the
4196inheritance list is given @code{inher-cont} syntax.
4197
3a731e1f
MS
4198@ssindex access-label
4199@ssindex inclass
6bf7aab6
DL
4200Hitting @kbd{C-c C-s} on line 5 shows the following analysis:
4201
4202@example
3a731e1f 4203((inclass 58) (access-label 58))
6bf7aab6
DL
4204@end example
4205
4206@noindent
4207The primary syntactic symbol for this line is @code{access-label} as
4208this a label keyword that specifies access protection in C++. However,
4209because this line is also a top-level construct inside a class
4210definition, the analysis actually shows two syntactic symbols. The
4211other syntactic symbol assigned to this line is @code{inclass}.
4212Similarly, line 6 is given both @code{inclass} and @code{topmost-intro}
4213syntax:
4214
4215@example
3a731e1f 4216((inclass 58) (topmost-intro 60))
6bf7aab6
DL
4217@end example
4218
3a731e1f
MS
4219@ssindex member-init-intro
4220@ssindex member-init-cont
6bf7aab6
DL
4221Line 7 introduces a C++ member initialization list and as such is given
4222@code{member-init-intro} syntax. Note that in this case it is
4223@emph{not} assigned @code{inclass} since this is not considered a
4224top-level construct. Lines 8 through 10 are all assigned
4225@code{member-init-cont} since they continue the member initialization
4226list started on line 7.
4227
4228@cindex in-class inline methods
3a731e1f
MS
4229@ssindex inline-open
4230@ssindex inline-close
6bf7aab6
DL
4231Line 11's analysis is a bit more complicated:
4232
4233@example
3a731e1f 4234((inclass 58) (inline-open))
6bf7aab6
DL
4235@end example
4236
4237This line is assigned a syntax of both @code{inline-open} and
4238@code{inclass} because it opens an @dfn{in-class} C++ inline method
4239definition. This is distinct from, but related to, the C++ notion of an
4240inline function in that its definition occurs inside an enclosing class
4241definition, which in C++ implies that the function should be inlined.
3a731e1f 4242However, if the definition of the @code{Bass} constructor appeared
6bf7aab6
DL
4243outside the class definition, the construct would be given the
4244@code{defun-open} syntax, even if the keyword @code{inline} appeared
4245before the method name, as in:
6bf7aab6 4246
3a731e1f
MS
4247@example
4248 1: class Bass
4249 2: : public Guitar,
4250 3: public Amplifiable
4251 4: @{
4252 5: public:
4253 6: Bass();
4254 7: @};
4255 8:
4256 9: inline
425710: Bass::Bass()
425811: : eString( new BassString( 0.105 )),
425912: aString( new BassString( 0.085 )),
426013: dString( new BassString( 0.065 )),
426114: gString( new BassString( 0.045 ))
426215: @{
426316: eString.tune( 'E' );
426417: aString.tune( 'A' );
426518: dString.tune( 'D' );
426619: gString.tune( 'G' );
426720: @}
6bf7aab6
DL
4268@end example
4269
3a731e1f 4270@ssindex friend
6bf7aab6
DL
4271Returning to the previous example, line 16 is given @code{inline-close}
4272syntax, while line 12 is given @code{defun-block-open} syntax, and lines
427313 through 15 are all given @code{statement} syntax. Line 17 is
4274interesting in that its syntactic analysis list contains three
4275elements:
4276
4277@example
3a731e1f 4278((inclass 58) (topmost-intro 380) (friend))
6bf7aab6
DL
4279@end example
4280
116e44a1
AM
4281The @code{friend} and @code{inline-open} syntactic symbols are
4282modifiers that do not have anchor positions.
6bf7aab6 4283
116e44a1 4284@ssindex template-args-cont
6bf7aab6
DL
4285Template definitions introduce yet another syntactic symbol:
4286
4287@example
3a731e1f
MS
4288 1: ThingManager <int,
4289 2: Framework::Callback *,
4290 3: Mutex> framework_callbacks;
6bf7aab6
DL
4291@end example
4292
4293Here, line 1 is analyzed as a @code{topmost-intro}, but lines 2 and 3
4294are both analyzed as @code{template-args-cont} lines.
4295
116e44a1
AM
4296@comment !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
4297@node Conditional Construct Symbols, Switch Statement Symbols, Class Symbols, Syntactic Symbols
4298@comment node-name, next, previous, up
4299@subsection Conditional Construct Symbols
4300@comment !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
4301
4302Here is a (totally contrived) example which illustrates how syntax is
4303assigned to various conditional constructs:
6bf7aab6 4304
3a731e1f
MS
4305@example
4306 1: void spam( int index )
4307 2: @{
4308 3: for( int i=0; i<index; i++ )
4309 4: @{
4310 5: if( i == 10 )
4311 6: do_something_special();
4312 7: else
4313 8: silly_label:
4314 9: do_something( i );
431510: @}
431611: do @{
431712: another_thing( i-- );
431813: @}
431914: while( i > 0 );
432015: @}
6bf7aab6
DL
4321@end example
4322
6bf7aab6
DL
4323Only the lines that illustrate new syntactic symbols will be discussed.
4324
3a731e1f 4325@ssindex substatement-open
116e44a1 4326@ssindex statement-block-intro
3a731e1f 4327@ssindex block-close
6bf7aab6
DL
4328Line 4 has a brace which opens a conditional's substatement block. It
4329is thus assigned @code{substatement-open} syntax, and since line 5 is
4330the first line in the substatement block, it is assigned
116e44a1
AM
4331@code{statement-block-intro} syntax. Line 10 contains the brace
4332that closes the inner substatement block, and is therefore given the
4333syntax @code{block-close}@footnote{@code{block-open} is used only for
4334``free-standing'' blocks, and is somewhat rare (@pxref{Literal
4335Symbols} for an example.)}. Line 13 is treated the same way.
3a731e1f
MS
4336
4337@ssindex substatement
4338Lines 6 and 9 are also substatements of conditionals, but since they
4339don't start blocks they are given @code{substatement} syntax
4340instead of @code{substatement-open}.
4341
4342@ssindex substatement-label
4343Line 8 contains a label, which is normally given @code{label} syntax.
4344This one is however a bit special since it's between a conditional and
4345its substatement. It's analyzed as @code{substatement-label} to let you
4346handle this rather odd case differently from normal labels.
4347
4348@ssindex else-clause
4349@ssindex catch-clause
4350Line 7 start with an @code{else} that matches the @code{if} statement on
4351line 5. It is therefore given the @code{else-clause} syntax and is
4352anchored on the matching @code{if}. The @code{try}-@code{catch}
4353constructs in C++ and Java are treated this way too, except that
4354@code{catch} and (in Java) @code{finally}, are marked with
4355@code{catch-clause}.
4356
4357@ssindex do-while-closure
4358The @code{while} construct on line 14 that closes a @code{do}
4359conditional is given the special syntax @code{do-while-closure} if it
4360appears on a line by itself. Note that if the @code{while} appeared on
4361the same line as the preceding close brace, that line would still have
4362@code{block-close} syntax.
6bf7aab6 4363
116e44a1
AM
4364@comment !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
4365@node Switch Statement Symbols, Brace List Symbols, Conditional Construct Symbols, Syntactic Symbols
4366@comment node-name, next, previous, up
4367@subsection Switch Statement Symbols
4368@comment !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
4369
6bf7aab6
DL
4370Switch statements have their own set of syntactic symbols. Here's an
4371example:
6bf7aab6 4372
3a731e1f
MS
4373@example
4374 1: void spam( enum Ingredient i )
4375 2: @{
4376 3: switch( i ) @{
4377 4: case Ham:
4378 5: be_a_pig();
4379 6: break;
4380 7: case Salt:
4381 8: drink_some_water();
4382 9: break;
438310: default:
438411: @{
438512: what_is_it();
438613: break;
438714: @}
438815: @}
438914: @}
6bf7aab6
DL
4390@end example
4391
3a731e1f
MS
4392@ssindex case-label
4393@ssindex statement-case-intro
4394@ssindex statement-case-open
6bf7aab6
DL
4395Here, lines 4, 7, and 10 are all assigned @code{case-label} syntax,
4396while lines 5 and 8 are assigned @code{statement-case-intro}. Line 11
4397is treated slightly differently since it contains a brace that opens a
4398block --- it is given @code{statement-case-open} syntax.
4399
116e44a1
AM
4400@comment !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
4401@node Brace List Symbols, External Scope Symbols, Switch Statement Symbols, Syntactic Symbols
4402@comment node-name, next, previous, up
4403@subsection Brace List Symbols
4404@comment !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
4405
6bf7aab6
DL
4406@cindex brace lists
4407There are a set of syntactic symbols that are used to recognize
4408constructs inside of brace lists. A brace list is defined as an
4409@code{enum} or aggregate initializer list, such as might statically
d7bd46ed
GM
4410initialize an array of structs. The three special aggregate constructs
4411in Pike, @code{(@{ @})}, @code{([ ])} and @code{(< >)}, are treated as
4412brace lists too. An example:
6bf7aab6 4413
3a731e1f
MS
4414@example
4415 1: static char* ingredients[] =
4416 2: @{
4417 3: "Ham",
4418 4: "Salt",
4419 5: NULL
4420 6: @};
6bf7aab6
DL
4421@end example
4422
3a731e1f
MS
4423@ssindex brace-list-open
4424@ssindex brace-list-intro
4425@ssindex brace-list-close
4426@ssindex brace-list-entry
6bf7aab6
DL
4427Following convention, line 2 in this example is assigned
4428@code{brace-list-open} syntax, and line 3 is assigned
4429@code{brace-list-intro} syntax. Likewise, line 6 is assigned
4430@code{brace-list-close} syntax. Lines 4 and 5 however, are assigned
4431@code{brace-list-entry} syntax, as would all subsequent lines in this
4432initializer list.
4433
3a731e1f 4434@ssindex brace-entry-open
d7bd46ed
GM
4435Your static initializer might be initializing nested structures, for
4436example:
d7bd46ed 4437
3a731e1f
MS
4438@example
4439 1: struct intpairs[] =
4440 2: @{
4441 3: @{ 1, 2 @},
4442 4: @{
4443 5: 3,
4444 6: 4
4445 7: @}
4446 8: @{ 1,
4447 9: 2 @},
444810: @{ 3, 4 @}
444911: @};
d7bd46ed
GM
4450@end example
4451
4452Here, you've already seen the analysis of lines 1, 2, 3, and 11. On
4453line 4, things get interesting; this line is assigned
4454@code{brace-entry-open} syntactic symbol because it's a bracelist entry
4455line that starts with an open brace. Lines 5 and 6 (and line 9) are
4456pretty standard, and line 7 is a @code{brace-list-close} as you'd
4457expect. Once again, line 8 is assigned as @code{brace-entry-open} as is
4458line 10.
4459
116e44a1
AM
4460@comment !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
4461@node External Scope Symbols, Paren List Symbols, Brace List Symbols, Syntactic Symbols
4462@comment node-name, next, previous, up
4463@subsection External Scope Symbols
4464@comment !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
4465
6bf7aab6
DL
4466External language definition blocks also have their own syntactic
4467symbols. In this example:
6bf7aab6 4468
3a731e1f
MS
4469@example
4470 1: extern "C"
4471 2: @{
4472 3: int thing_one( int );
4473 4: int thing_two( double );
4474 5: @}
6bf7aab6
DL
4475@end example
4476
3a731e1f
MS
4477@ssindex extern-lang-open
4478@ssindex extern-lang-close
4479@ssindex inextern-lang
4480@ssindex inclass
6bf7aab6
DL
4481@noindent
4482line 2 is given the @code{extern-lang-open} syntax, while line 5 is given
4483the @code{extern-lang-close} syntax. The analysis for line 3 yields:
6bf7aab6 4484
6bf7aab6 4485@example
3a731e1f 4486((inextern-lang) (topmost-intro 14))
6bf7aab6
DL
4487@end example
4488
6bf7aab6 4489@noindent
3a731e1f
MS
4490where @code{inextern-lang} is a modifier similar in purpose to
4491@code{inclass}.
4492
4493There are various other top level blocks like @code{extern}, and they
4494are all treated in the same way except that the symbols are named after
116e44a1 4495the keyword that introduces the block. E.g. C++ namespace blocks get
3a731e1f
MS
4496the three symbols @code{namespace-open}, @code{namespace-close} and
4497@code{innamespace}. The currently recognized top level blocks are:
4498
4499@table @asis
4500@item @code{extern-lang-open}, @code{extern-lang-close}, @code{inextern-lang}
4501@code{extern} blocks in C and C++.@footnote{These should logically be
4502named @code{extern-open}, @code{extern-close} and @code{inextern}, but
4503that isn't the case for historical reasons.}
4504
4505@item @code{namespace-open}, @code{namespace-close}, @code{innamespace}
4506@ssindex namespace-open
4507@ssindex namespace-close
4508@ssindex innamespace
4509@code{namespace} blocks in C++.
4510
4511@item @code{module-open}, @code{module-close}, @code{inmodule}
4512@ssindex module-open
4513@ssindex module-close
4514@ssindex inmodule
4515@code{module} blocks in CORBA IDL.
4516
4517@item @code{composition-open}, @code{composition-close}, @code{incomposition}
4518@ssindex composition-open
4519@ssindex composition-close
4520@ssindex incomposition
4521@code{composition} blocks in CORBA CIDL.
4522@end table
6bf7aab6 4523
116e44a1
AM
4524@comment !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
4525@node Paren List Symbols, Literal Symbols, External Scope Symbols, Syntactic Symbols
4526@comment node-name, next, previous, up
4527@subsection Parenthesis (Argument) List Symbols
4528@comment !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
4529
6bf7aab6
DL
4530A number of syntactic symbols are associated with parenthesis lists,
4531a.k.a argument lists, as found in function declarations and function
4532calls. This example illustrates these:
6bf7aab6 4533
3a731e1f
MS
4534@example
4535 1: void a_function( int line1,
4536 2: int line2 );
bf247b6e 4537 3:
3a731e1f
MS
4538 4: void a_longer_function(
4539 5: int line1,
4540 6: int line2
4541 7: );
bf247b6e 4542 8:
3a731e1f
MS
4543 9: void call_them( int line1, int line2 )
454410: @{
454511: a_function(
454612: line1,
454713: line2
454814: );
bf247b6e 454915:
3a731e1f
MS
455016: a_longer_function( line1,
455117: line2 );
455218: @}
6bf7aab6
DL
4553@end example
4554
3a731e1f
MS
4555@ssindex arglist-intro
4556@ssindex arglist-close
6bf7aab6
DL
4557Lines 5 and 12 are assigned @code{arglist-intro} syntax since they are
4558the first line following the open parenthesis, and lines 7 and 14 are
4559assigned @code{arglist-close} syntax since they contain the parenthesis
4560that closes the argument list.
4561
3a731e1f
MS
4562@ssindex arglist-cont-nonempty
4563@ssindex arglist-cont
6bf7aab6
DL
4564Lines that continue argument lists can be assigned one of two syntactic
4565symbols. For example, Lines 2 and 17
4566are assigned @code{arglist-cont-nonempty} syntax. What this means
4567is that they continue an argument list, but that the line containing the
4568parenthesis that opens the list is @emph{not empty} following the open
4569parenthesis. Contrast this against lines 6 and 13 which are assigned
4570@code{arglist-cont} syntax. This is because the parenthesis that opens
4571their argument lists is the last character on that line.
4572
116e44a1
AM
4573Syntactic elements with @code{arglist-intro},
4574@code{arglist-cont-nonempty}, and @code{arglist-close} contain two
4575buffer positions: the anchor position (the beginning of the
4576declaration or statement) and the position of the open parenthesis.
4577The latter position can be used in a line-up function (@pxref{Line-Up
4578Functions}).
4579
6bf7aab6
DL
4580Note that there is no @code{arglist-open} syntax. This is because any
4581parenthesis that opens an argument list, appearing on a separate line,
4582is assigned the @code{statement-cont} syntax instead.
4583
116e44a1
AM
4584@comment !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
4585@node Literal Symbols, Multiline Macro Symbols, Paren List Symbols, Syntactic Symbols
4586@comment node-name, next, previous, up
4587@subsection Comment String Label and Macro Symbols
4588@comment !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
4589
6bf7aab6
DL
4590A few miscellaneous syntactic symbols that haven't been previously
4591covered are illustrated by this C++ example:
6bf7aab6 4592
3a731e1f
MS
4593@example
4594 1: void Bass::play( int volume )
4595 2: const
4596 3: @{
4597 4: /* this line starts a multiline
4598 5: * comment. This line should get `c' syntax */
bf247b6e 4599 6:
3a731e1f
MS
4600 7: char* a_multiline_string = "This line starts a multiline \
4601 8: string. This line should get `string' syntax.";
bf247b6e 4602 9:
3a731e1f
MS
460310: note:
460411: @{
460512: #ifdef LOCK
460613: Lock acquire();
460714: #endif // LOCK
460815: slap_pop();
460916: cout << "I played "
461017: << "a note\n";
461118: @}
461219: @}
6bf7aab6
DL
4613@end example
4614
6bf7aab6
DL
4615The lines to note in this example include:
4616
4617@itemize @bullet
6bf7aab6 4618@item
3a731e1f 4619@ssindex func-decl-cont
f214c025 4620Line 2 is assigned the @code{func-decl-cont} syntax.
6bf7aab6 4621
6bf7aab6 4622@item
3a731e1f 4623@ssindex comment-intro
f214c025 4624Line 4 is assigned both @code{defun-block-intro} @emph{and}
116e44a1
AM
4625@code{comment-intro} syntax. A syntactic element with
4626@code{comment-intro} has no anchor point --- It is always accompanied
4627by another syntactic element which does have one.
6bf7aab6 4628
6bf7aab6 4629@item
3a731e1f 4630@ssindex c
f214c025 4631Line 5 is assigned @code{c} syntax.
6bf7aab6
DL
4632
4633@item
4634@cindex syntactic whitespace
f214c025 4635Line 6 which, even though it contains nothing but whitespace, is
6bf7aab6
DL
4636assigned @code{defun-block-intro}. Note that the appearance of the
4637comment on lines 4 and 5 do not cause line 6 to be assigned
4638@code{statement} syntax because comments are considered to be
4639@dfn{syntactic whitespace}, which are ignored when analyzing
f214c025 4640code.
6bf7aab6 4641
6bf7aab6 4642@item
3a731e1f 4643@ssindex string
f214c025 4644Line 8 is assigned @code{string} syntax.
6bf7aab6 4645
6bf7aab6 4646@item
3a731e1f 4647@ssindex label
f214c025 4648Line 10 is assigned @code{label} syntax.
6bf7aab6 4649
6bf7aab6 4650@item
3a731e1f 4651@ssindex block-open
116e44a1
AM
4652Line 11 is assigned @code{block-open} as well as @code{statement}
4653syntax. A @code{block-open} syntactic element doesn't have an anchor
4654position, since it always appears with another syntactic element which
4655does have one.
6bf7aab6 4656
6bf7aab6 4657@item
3a731e1f 4658@ssindex cpp-macro
f214c025
GM
4659Lines 12 and 14 are assigned @code{cpp-macro} syntax in addition to the
4660normal syntactic symbols (@code{statement-block-intro} and
4661@code{statement}, respectively). Normally @code{cpp-macro} is
4662configured to cancel out the normal syntactic context to make all
4663preprocessor directives stick to the first column, but that's easily
4664changed if you want preprocessor directives to be indented like the rest
116e44a1
AM
4665of the code. Like @code{comment-intro}, a syntactic element with
4666@code{cpp-macro} doesn't contain an anchor position.
6bf7aab6 4667
6bf7aab6 4668@item
3a731e1f 4669@ssindex stream-op
f214c025 4670Line 17 is assigned @code{stream-op} syntax.
6bf7aab6
DL
4671@end itemize
4672
116e44a1
AM
4673@comment !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
4674@node Multiline Macro Symbols, Objective-C Method Symbols, Literal Symbols, Syntactic Symbols
4675@comment node-name, next, previous, up
4676@subsection Multiline Macro Symbols
4677@comment !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
4678
3a731e1f 4679@cindex multiline macros
6bf7aab6 4680@cindex syntactic whitespace
3a731e1f 4681@ssindex cpp-define-intro
116e44a1 4682@ssindex cpp-macro-cont
3a731e1f 4683Multiline preprocessor macro definitions are normally handled just like
116e44a1 4684other code, i.e. the lines inside them are indented according to the
3a731e1f 4685syntactic analysis of the preceding lines inside the macro. The first
116e44a1 4686line inside a macro definition (i.e. the line after the starting line of
3a731e1f 4687the cpp directive itself) gets @code{cpp-define-intro}. In this example:
6bf7aab6 4688
3a731e1f
MS
4689@example
4690 1: #define LIST_LOOP(cons, listp) \
4691 2: for (cons = listp; !NILP (cons); cons = XCDR (cons)) \
4692 3: if (!CONSP (cons)) \
4693 4: signal_error ("Invalid list format", listp); \
4694 5: else
6bf7aab6 4695@end example
3a731e1f 4696
6bf7aab6 4697@noindent
3a731e1f
MS
4698line 1 is given the syntactic symbol @code{cpp-macro}. The first line
4699of a cpp directive is always given that symbol. Line 2 is given
4700@code{cpp-define-intro}, so that you can give the macro body as a whole
4701some extra indentation. Lines 3 through 5 are then analyzed as normal
116e44a1 4702code, i.e. @code{substatement} on lines 3 and 4, and @code{else-clause}
3a731e1f
MS
4703on line 5.
4704
4705The syntactic analysis inside macros can be turned off with
116e44a1
AM
4706@code{c-syntactic-indentation-in-macros} (@pxref{Custom Macros}). In
4707that case, lines 2 through 5 would all be given @code{cpp-macro-cont}
4708with an anchor position pointing to the @code{#} which starts the cpp
3a731e1f
MS
4709directive@footnote{This is how @ccmode{} 5.28 and earlier analyzed
4710macros.}.
4711
116e44a1
AM
4712@xref{Custom Macros}, for more info about the treatment of macros.
4713
4714@comment !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
4715@node Objective-C Method Symbols, Anonymous Class Symbol, Multiline Macro Symbols, Syntactic Symbols
4716@comment node-name, next, previous, up
4717@subsection Objective-C Method Symbols
4718@comment !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
6bf7aab6
DL
4719
4720In Objective-C buffers, there are three additional syntactic symbols
4721assigned to various message calling constructs. Here's an example
4722illustrating these:
6bf7aab6 4723
3a731e1f
MS
4724@example
4725 1: - (void)setDelegate:anObject
4726 2: withStuff:stuff
4727 3: @{
4728 4: [delegate masterWillRebind:self
4729 5: toDelegate:anObject
4730 6: withExtraStuff:stuff];
4731 7: @}
6bf7aab6
DL
4732@end example
4733
3a731e1f
MS
4734@ssindex objc-method-intro
4735@ssindex objc-method-args-cont
4736@ssindex objc-method-call-cont
6bf7aab6
DL
4737Here, line 1 is assigned @code{objc-method-intro} syntax, and line 2 is
4738assigned @code{objc-method-args-cont} syntax. Lines 5 and 6 are both
4739assigned @code{objc-method-call-cont} syntax.
4740
116e44a1
AM
4741@comment !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
4742@node Anonymous Class Symbol, Statement Block Symbols, Objective-C Method Symbols, Syntactic Symbols
4743@comment node-name, next, previous, up
4744@subsection Anonymous Class Symbol (Java)
4745@comment !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
4746
4747Java has a concept of anonymous classes which can look something like
d7bd46ed 4748this:
d7bd46ed 4749
3a731e1f
MS
4750@example
4751 1: public void watch(Observable o) @{
4752 2: o.addObserver(new Observer() @{
4753 3: public void update(Observable o, Object arg) @{
4754 4: history.addElement(arg);
4755 5: @}
4756 6: @});
4757 7: @}
d7bd46ed
GM
4758@end example
4759
3a731e1f 4760@ssindex inexpr-class
d7bd46ed
GM
4761The brace following the @code{new} operator opens the anonymous class.
4762Lines 3 and 6 are assigned the @code{inexpr-class} syntax, besides the
4763@code{inclass} symbol used in normal classes. Thus, the class will be
4764indented just like a normal class, with the added indentation given to
116e44a1
AM
4765@code{inexpr-class}. An @code{inexpr-class} syntactic element doesn't
4766have an anchor position.
4767
4768@comment !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
4769@node Statement Block Symbols, K&R Symbols, Anonymous Class Symbol, Syntactic Symbols
4770@comment node-name, next, previous, up
4771@subsection Statement Block Symbols
4772@comment !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
d7bd46ed 4773
116e44a1
AM
4774There are a few occasions where a statement block might be used inside
4775an expression. One is in C or C++ code using the gcc extension for
4776this, e.g:
d7bd46ed 4777
3a731e1f
MS
4778@example
4779 1: int res = (@{
4780 2: int y = foo (); int z;
4781 3: if (y > 0) z = y; else z = - y;
4782 4: z;
4783 5: @});
d7bd46ed
GM
4784@end example
4785
3a731e1f 4786@ssindex inexpr-statement
d7bd46ed
GM
4787Lines 2 and 5 get the @code{inexpr-statement} syntax, besides the
4788symbols they'd get in a normal block. Therefore, the indentation put on
4789@code{inexpr-statement} is added to the normal statement block
116e44a1
AM
4790indentation. An @code{inexpr-statement} syntactic element doesn't
4791contain an anchor position.
d7bd46ed
GM
4792
4793In Pike code, there are a few other situations where blocks occur inside
4794statements, as illustrated here:
d7bd46ed 4795
3a731e1f
MS
4796@example
4797 1: array itgob()
4798 2: @{
4799 3: string s = map (backtrace()[-2][3..],
4800 4: lambda
4801 5: (mixed arg)
4802 6: @{
4803 7: return sprintf ("%t", arg);
4804 8: @}) * ", " + "\n";
4805 9: return catch @{
480610: write (s + "\n");
480711: @};
480812: @}
d7bd46ed
GM
4809@end example
4810
3a731e1f
MS
4811@ssindex inlambda
4812@ssindex lambda-intro-cont
d7bd46ed
GM
4813Lines 4 through 8 contain a lambda function, which @ccmode{} recognizes
4814by the @code{lambda} keyword. If the function argument list is put
4815on a line of its own, as in line 5, it gets the @code{lambda-intro-cont}
4816syntax. The function body is handled as an inline method body, with the
4817addition of the @code{inlambda} syntactic symbol. This means that line
48186 gets @code{inlambda} and @code{inline-open}, and line 8 gets
4819@code{inline-close}@footnote{You might wonder why it doesn't get
4820@code{inlambda} too. It's because the closing brace is relative to the
4821opening brace, which stands on its own line in this example. If the
4822opening brace was hanging on the previous line, then the closing brace
4823would get the @code{inlambda} syntax too to be indented correctly.}.
4824
3a731e1f 4825@ssindex inexpr-statement
d7bd46ed
GM
4826On line 9, @code{catch} is a special function taking a statement block
4827as its argument. The block is handled as an in-expression statement
4828with the @code{inexpr-statement} syntax, just like the gcc extended C
4829example above. The other similar special function, @code{gauge}, is
4830handled like this too.
4831
116e44a1
AM
4832@comment !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
4833@node K&R Symbols, , Statement Block Symbols, Syntactic Symbols
4834@comment node-name, next, previous, up
4835@subsection K&R Symbols
4836@comment !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
4837
3a731e1f
MS
4838@ssindex knr-argdecl-intro
4839@ssindex knr-argdecl
6bf7aab6
DL
4840Two other syntactic symbols can appear in old style, non-prototyped C
4841code @footnote{a.k.a. K&R C, or Kernighan & Ritchie C}:
6bf7aab6 4842
3a731e1f
MS
4843@example
4844 1: int add_three_integers(a, b, c)
4845 2: int a;
4846 3: int b;
4847 4: int c;
4848 5: @{
4849 6: return a + b + c;
4850 7: @}
6bf7aab6
DL
4851@end example
4852
116e44a1
AM
4853Here, line 2 is the first line in an argument declaration list and so is
4854given the @code{knr-argdecl-intro} syntactic symbol. Subsequent lines
4855(i.e. lines 3 and 4 in this example), are given @code{knr-argdecl}
4856syntax.
4857
4858
4859@comment !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
4860@node Indentation Calculation, , Syntactic Symbols, Indentation Engine Basics
4861@comment node-name, next, previous, up
4862@section Indentation Calculation
4863@cindex indentation
4864@comment !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
4865
4866Indentation for a line is calculated from the syntactic context
4867(@pxref{Syntactic Analysis}).
4868
4869First, a buffer position is found whose column will be the base for the
4870indentation calculation. It's the anchor position in the first
4871syntactic element that provides one that is used. If no syntactic
4872element has an anchor position then column zero is used.
4873
4874Second, the syntactic symbols in each syntactic element are looked up
4875in the @code{c-offsets-alist} style variable
4876(@pxref{c-offsets-alist}), which is an association list of syntactic
4877symbols and the offsets to apply for those symbols. These offsets are
4878added together with the base column to produce the new indentation
4879column.
4880
4881Let's use our two code examples above to see how this works. Here is
4882our first example again:
4883
4884@example
4885 1: void swap( int& a, int& b )
4886 2: @{
4887 3: int tmp = a;
4888 4: a = b;
4889 5: b = tmp;
4890 6: @}
4891@end example
4892
ee6c21a7 4893Let's say point is on line 3 and we hit the @key{TAB} key to reindent
116e44a1
AM
4894the line. The syntactic context for that line is:
4895
4896@example
4897((defun-block-intro 29))
4898@end example
4899
4900@noindent
4901Since buffer position 29 is the first and only anchor position in the
4902list, @ccmode{} goes there and asks for the current column. This brace
4903is in column zero, so @ccmode{} uses @samp{0} as the base column.
4904
4905Next, @ccmode{} looks up @code{defun-block-intro} in the
4906@code{c-offsets-alist} style variable. Let's say it finds the value
4907@samp{4}; it adds this to the base column @samp{0}, yielding a running
4908total indentation of 4 spaces.
4909
4910Since there is only one syntactic element on the list for this line,
4911indentation calculation is complete, and the total indentation for the
4912line is 4 spaces.
4913
4914Here's another example:
4915
4916@example
4917 1: int add( int val, int incr, int doit )
4918 2: @{
4919 3: if( doit )
4920 4: @{
4921 5: return( val + incr );
4922 6: @}
4923 7: return( val );
4924 8: @}
4925@end example
4926
4927If we were to hit @kbd{TAB} on line 4 in the above example, the same
4928basic process is performed, despite the differences in the syntactic
4929context. The context for this line is:
4930
4931@example
4932((substatement-open 46))
4933@end example
4934
4935Here, @ccmode{} goes to buffer position 46, which is the @samp{i} in
4936@code{if} on line 3. This character is in the fourth column on that
4937line so the base column is @samp{4}. Then @ccmode{} looks up the
4938@code{substatement-open} symbol in @code{c-offsets-alist}. Let's say it
4939finds the value @samp{4}. It's added with the base column and yields an
4940indentation for the line of 8 spaces.
4941
4942Simple, huh?
4943
4944Actually, it's a bit more complicated than that since the entries on
4945@code{c-offsets-alist} can be much more than plain offsets.
4946@xref{c-offsets-alist}, for the full story.
4947
4948Anyway, the mode usually just does The Right Thing without you having to
4949think about it in this much detail. But when customizing indentation,
4950it's helpful to understand the general indentation model being used.
4951
4952As you configure @ccmode{}, you might want to set the variable
4953@code{c-echo-syntactic-information-p} to non-@code{nil} so that the
4954syntactic context and calculated offset always is echoed in the
4955minibuffer when you hit @kbd{TAB}.
4956
4957
4958@comment !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
4959@node Customizing Indentation, Custom Macros, Indentation Engine Basics, Top
4960@comment node-name, next, previous, up
4961@chapter Customizing Indentation
4962@cindex customization, indentation
4963@cindex indentation
4964@comment !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
4965
4966The principal variable for customizing indentation is the style
4967variable @code{c-offsets-alist}, which gives an @dfn{offset} (an
4968indentation rule) for each syntactic symbol. Its structure and
4969semantics are completely described in @ref{c-offsets-alist}. The
4970various ways you can set the variable, including the use of the
4971@ccmode{} style system, are described in @ref{Config Basics} and its
4972sections, in particular @ref{Style Variables}.
4973
4974The simplest and most used kind of ``offset'' setting in
4975@code{c-offsets-alist} is in terms of multiples of
4976@code{c-basic-offset}:
4977
4978@defopt c-basic-offset
4979@vindex basic-offset (c-)
4980This style variable holds the basic offset between indentation levels.
4981It's factory default is 4, but all the built-in styles set it
4982themselves, to some value between 2 (for @code{gnu} style) and 8 (for
4983@code{bsd}, @code{linux}, and @code{python} styles).
4984@end defopt
4985
4986The most flexible ``offset'' setting you can make in
4987@code{c-offsets-alist} is a line-up function (or even a list of them),
4988either one supplied by @ccmode{} (@pxref{Line-Up Functions}) or one
4989you write yourself (@pxref{Custom Line-Up}).
4990
4991Finally, in @ref{Other Indentation} you'll find the tool of last
4992resort: a hook which is called after a line has been indented. You
4993can install functions here to make ad-hoc adjustments to any line's
4994indentation.
4995
4996@menu
4997* c-offsets-alist::
4998* Interactive Customization::
4999* Line-Up Functions::
5000* Custom Line-Up::
5001* Other Indentation::
5002@end menu
5003
5004
5005@comment !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
5006@node c-offsets-alist, Interactive Customization, Customizing Indentation, Customizing Indentation
5007@comment node-name, next, previous, up
5008@section c-offsets-alist
5009@comment !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
5010
5011This section explains the structure and semantics of the style
5012variable @code{c-offset-alist}, the principal variable for configuring
5013indentation. Details of how to set it up, and its relationship to
5014@ccmode{}'s style system are given in @ref{Style Variables}.
5015
5016@defopt c-offsets-alist
5017@vindex offsets-alist (c-)
5018This is an alist which associates an offset with each syntactic
5019symbol. This @dfn{offset} is a rule specifying how to indent a line
5020whose syntactic context matches the symbol. @xref{Syntactic
5021Analysis}.
5022
5023Note that the buffer-local binding of this alist in a @ccmode{} buffer
5024contains an entry for @emph{every} syntactic symbol. Its global
5025binding and its settings within style specifications usually contain
5026only a few entries. @xref{Style Variables}.
5027
5028The offset specification associated with any particular syntactic
5029symbol can be an integer, a variable name, a vector, a function or
5030lambda expression, a list, or one of the following special symbols:
5031@code{+}, @code{-}, @code{++}, @code{--}, @code{*}, or @code{/}. The
5032meanings of these values are described in detail below.
5033
5034Here is an example fragment of a @code{c-offsets-alist}, showing some
5035of these kinds of offsets:
5036
5037@example
5038((statement . 0)
5039 (substatement . +)
5040 (cpp-macro . [0])
5041 (topmost-intro-cont . c-lineup-topmost-intro-cont)
5042 (statement-block-intro . (add c-lineup-whitesmith-in-block
5043 c-indent-multi-line-block))
5044 @dots{}
5045@*)
5046@end example
5047@end defopt
5048
5049@deffn Command c-set-offset (@kbd{C-c C-o})
5050@findex set-offset (c-)
5051@kindex C-c C-o
5052This command changes the entry for a syntactic symbol in the current
5053binding of @code{c-offsets-alist}, or it inserts a new entry if there
5054isn't already one for that syntactic symbol.
5055
5056You can use @code{c-set-offsets} interactively within a @ccmode{}
5057buffer to make experimental changes to your indentation settings.
5058@kbd{C-c C-o} prompts you for the syntactic symbol to change
5059(defaulting to that of the current line) and the new offset
5060(defaulting to the current offset).
5061
5062@code{c-set-offsets} takes two arguments when used programmatically:
5063@var{symbol}, the syntactic element symbol to change and @var{offset},
5064the new offset for that syntactic element. You can call the command
5065in your @file{.emacs} to change the global binding of
5066@code{c-offsets-alist} (@pxref{Style Variables}); you can use it in a
5067hook function to make changes from the current style. @ccmode{}
5068itself uses this function when initializing styles.
5069@end deffn
5070
5071@cindex offset specification
5072The ``offset specifications'' in @code{c-offsets-alist} can be any of
5073the following:
5074
5075@table @asis
5076@item An integer
5077The integer specifies a relative offset. All relative
5078offsets@footnote{The syntactic context @code{@w{((defun-block-intro
50792724) (comment-intro))}} would likely have two relative offsets.} will
5080be added together and used to calculate the indentation relative to an
5081anchor position earlier in the buffer. @xref{Indentation
5082Calculation}, for details. Most of the time, it's probably better to
5083use one of the special symbols like @code{+} than an integer (apart
5084from zero).
5085
5086@item One of the symbols @code{+}, @code{-}, @code{++}, @code{--}, @code{*}, or @code{/}
5087These special symbols describe a relative offset in multiples of
5088@code{c-basic-offset}:
5089
5090By defining a style's indentation in terms of @code{c-basic-offset},
5091you can change the amount of whitespace given to an indentation level
5092while maintaining the same basic shape of your code. Here are the
5093values that the special symbols correspond to:
5094
5095@table @code
5096@item +
5097@code{c-basic-offset} times 1
5098@item -
5099@code{c-basic-offset} times -1
5100@item ++
5101@code{c-basic-offset} times 2
5102@item --
5103@code{c-basic-offset} times -2
5104@item *
5105@code{c-basic-offset} times 0.5
5106@item /
5107@code{c-basic-offset} times -0.5
5108@end table
5109
5110@item A vector
5111The first element of the vector, an integer, sets the absolute
5112indentation column. This will override any previously calculated
5113indentation, but won't override relative indentation calculated from
5114syntactic elements later on in the syntactic context of the line being
5115indented. @xref{Indentation Calculation}. Any elements in the vector
5116beyond the first will be ignored.
5117
5118@item A function or lambda expression
5119The function will be called and its return value will in turn be
5120evaluated as an offset specification. Functions are useful when more
5121context than just the syntactic symbol is needed to get the desired
5122indentation. @xref{Line-Up Functions}, and @ref{Custom Line-Up}, for
5123details about them.
5124
5125@item A symbol with a variable binding
5126If the symbol also has a function binding, the function takes
5127precedence over the variable. Otherwise the value of the variable is
5128used. It must be an integer (which is used as relative offset) or a
5129vector (an absolute offset).
5130
5131@item A list
5132The offset can also be a list containing several offset
5133specifications; these are evaluated recursively and combined. A list
5134is typically only useful when some of the offsets are line-up
5135functions. A common strategy is calling a sequence of functions in
5136turn until one of them recognizes that it is appropriate for the
5137source line and returns a non-@code{nil} value.
5138
5139@code{nil} values are always ignored when the offsets are combined.
5140The first element of the list specifies the method of combining the
5141non-@code{nil} offsets from the remaining elements:
5142
5143@table @code
5144@item first
5145Use the first offset that doesn't evaluate to @code{nil}. Subsequent
5146elements of the list don't get evaluated.
5147@item min
5148Use the minimum of all the offsets. All must be either relative or
5149absolute - they can't be mixed.
5150@item max
5151Use the maximum of all the offsets. All must be either relative or
5152absolute - they can't be mixed.
5153@item add
5154Add all the evaluated offsets together. Exactly one of them may be
5155absolute, in which case the result is absolute. Any relative offsets
5156that preceded the absolute one in the list will be ignored in that case.
5157@end table
5158
5159As a compatibility measure, if the first element is none of the above
5160then it too will be taken as an offset specification and the whole list
5161will be combined according to the method @code{first}.
5162@end table
5163
5164@vindex c-strict-syntax-p
5165@vindex strict-syntax-p (c-)
5166If an offset specification evaluates to @code{nil}, then a relative
5167offset of 0 (zero) is used@footnote{There is however a variable
5168@code{c-strict-syntax-p} that when set to non-@code{nil} will cause an
5169error to be signaled in that case. It's now considered obsolete since
5170it doesn't work well with some of the alignment functions that returns
5171@code{nil} instead of zero. You should therefore leave
5172@code{c-strict-syntax-p} set to @code{nil}.}.
5173
5174@comment !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
5175@node Interactive Customization, Line-Up Functions, c-offsets-alist, Customizing Indentation
5176@comment node-name, next, previous, up
5177@section Interactive Customization
5178@cindex customization, interactive
5179@cindex interactive customization
5180@comment !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
5181
5182As an example of how to customize indentation, let's change the
5183style of this example@footnote{In this and subsequent examples, the
5184original code is formatted using the @samp{gnu} style unless otherwise
5185indicated. @xref{Styles}.}:
5186
5187@example
5188@group
5189 1: int add( int val, int incr, int doit )
5190 2: @{
5191 3: if( doit )
5192 4: @{
5193 5: return( val + incr );
5194 6: @}
5195 7: return( val );
5196 8: @}
5197@end group
5198@end example
5199
5200@noindent
5201to:
5202
5203@example
5204@group
5205 1: int add( int val, int incr, int doit )
5206 2: @{
5207 3: if( doit )
5208 4: @{
5209 5: return( val + incr );
5210 6: @}
5211 7: return( val );
5212 8: @}
5213@end group
5214@end example
5215
5216In other words, we want to change the indentation of braces that open a
5217block following a condition so that the braces line up under the
5218conditional, instead of being indented. Notice that the construct we
5219want to change starts on line 4. To change the indentation of a line,
5220we need to see which syntactic symbols affect the offset calculations
5221for that line. Hitting @kbd{C-c C-s} on line 4 yields:
5222
5223@example
5224((substatement-open 44))
5225@end example
5226
5227@noindent
5228so we know that to change the offset of the open brace, we need to
5229change the indentation for the @code{substatement-open} syntactic
5230symbol.
5231
5232To do this interactively, just hit @kbd{C-c C-o}. This prompts
5233you for the syntactic symbol to change, providing a reasonable default.
5234In this case, the default is @code{substatement-open}, which is just the
5235syntactic symbol we want to change!
5236
5237After you hit return, @ccmode{} will then prompt you for the new
5238offset value, with the old value as the default. The default in this
5239case is @samp{+}, but we want no extra indentation so enter
5240@samp{0} and @kbd{RET}. This will associate the offset 0 with the
5241syntactic symbol @code{substatement-open}.
5242
5243To check your changes quickly, just hit @kbd{C-c C-q}
5244(@code{c-indent-defun}) to reindent the entire function. The example
5245should now look like:
5246
5247@example
5248@group
5249 1: int add( int val, int incr, int doit )
5250 2: @{
5251 3: if( doit )
5252 4: @{
5253 5: return( val + incr );
5254 6: @}
5255 7: return( val );
5256 8: @}
5257@end group
5258@end example
5259
5260Notice how just changing the open brace offset on line 4 is all we
5261needed to do. Since the other affected lines are indented relative to
5262line 4, they are automatically indented the way you'd expect. For more
5263complicated examples, this might not always work. The general approach
5264to take is to always start adjusting offsets for lines higher up in the
5265file, then reindent and see if any following lines need further
5266adjustments.
5267
5268@c Move this bit to "Styles" (2005/10/7)
5269@deffn Command c-set-offset symbol offset
5270@findex set-offset (c-)
5271@kindex C-c C-o
5272This is the command bound to @kbd{C-c C-o}. It provides a convenient
5273way to set offsets on @code{c-offsets-alist} both interactively (see
5274the example above) and from your mode hook.
6bf7aab6 5275
116e44a1
AM
5276It takes two arguments when used programmatically: @var{symbol} is the
5277syntactic element symbol to change and @var{offset} is the new offset
5278for that syntactic element.
5279@end deffn
5280@c End of MOVE THIS BIT.
d7bd46ed 5281
6bf7aab6 5282@comment !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
116e44a1 5283@node Line-Up Functions, Custom Line-Up, Interactive Customization, Customizing Indentation
d7bd46ed 5284@comment node-name, next, previous, up
116e44a1 5285@section Line-Up Functions
d7bd46ed
GM
5286@comment !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
5287
3a731e1f 5288@cindex line-up function
116e44a1 5289@cindex indentation function
3a731e1f 5290Often there are cases when a simple offset setting on a syntactic
116e44a1
AM
5291symbol isn't enough to get the desired indentation---for example, you
5292might want to line up a closing parenthesis with the matching opening
5293one rather than indenting relative to its ``anchor point''. @ccmode{}
5294provides this flexibility with @dfn{line-up functions}.
5295
5296The way you associate a line-up function with a syntactic symbol is
5297described in @ref{c-offsets-alist}. @ccmode{} comes with many
5298predefined line-up functions for common situations. If none of these
5299does what you want, you can write your own. @xref{Custom Line-Up}.
5300Sometimes, it is easier to tweak the standard indentation by adding a
5301function to @code{c-special-indent-hook} (@pxref{Other Indentation}).
5302
5303The line-up functions haven't been adapted for AWK buffers or tested
5304with them. Some of them might work serendipitously. There shouldn't be
5305any problems writing custom line-up functions for AWK mode.
5306
5307The calling convention for line-up functions is described fully in
5308@ref{Custom Line-Up}. Roughly speaking, the return value is either an
5309offset itself (such as @code{+} or @code{[0]}) or it's @code{nil},
5310meaning ``this function is inappropriate in this case - try a
5311different one''. @xref{c-offsets-alist}.
5312
5313The subsections below describe all the standard line-up functions,
5314categorized by the sort of token the lining-up centres around. For
5315each of these functions there is a ``works with'' list that indicates
d7bd46ed
GM
5316which syntactic symbols the function is intended to be used with.
5317
5318@macro workswith
cb7f2e96 5319@emph{Works with:@ }
d7bd46ed
GM
5320@end macro
5321@ifinfo
5322@unmacro workswith
5323@macro workswith
5324Works with:
5325@end macro
5326@end ifinfo
5327
3a731e1f
MS
5328@macro sssTBasicOffset
5329<--> @i{c-basic-offset}@c
5330@end macro
d7bd46ed 5331
3a731e1f
MS
5332@macro sssTsssTBasicOffset
5333<--><--> @i{c-basic-offset}@c
5334@end macro
d7bd46ed 5335
3a731e1f
MS
5336@macro hereFn{func}
5337<- @i{\func\}@c
5338@end macro
d7bd46ed 5339
3a731e1f
MS
5340@c The TeX backend seems to insert extra spaces around the argument. :P
5341@iftex
5342@unmacro hereFn
5343@macro hereFn{func}
5344<-@i{\func\}@c
5345@end macro
5346@end iftex
d7bd46ed 5347
116e44a1
AM
5348@menu
5349* Brace/Paren Line-Up::
5350* List Line-Up::
5351* Operator Line-Up::
5352* Comment Line-Up::
5353* Misc Line-Up::
5354@end menu
d7bd46ed 5355
116e44a1
AM
5356@comment !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
5357@node Brace/Paren Line-Up, List Line-Up, Line-Up Functions, Line-Up Functions
5358@comment node-name, next, previous, up
5359@subsection Brace and Parenthesis Line-Up Functions
5360@comment !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
d7bd46ed 5361
116e44a1
AM
5362The line-up functions here calculate the indentation for braces,
5363parentheses and statements within brace blocks.
3a731e1f 5364
116e44a1
AM
5365@defun c-lineup-close-paren
5366@findex lineup-close-paren (c-)
5367Line up the closing paren under its corresponding open paren if the
5368open paren is followed by code. If the open paren ends its line, no
5369indentation is added. E.g:
d7bd46ed 5370
f214c025
GM
5371@example
5372@group
116e44a1
AM
5373main (int,
5374 char **
5375 ) @hereFn{c-lineup-close-paren}
f214c025
GM
5376@end group
5377@end example
3a731e1f 5378
f214c025
GM
5379@noindent
5380and
3a731e1f 5381
f214c025
GM
5382@example
5383@group
116e44a1
AM
5384main (
5385 int, char **
5386) @hereFn{c-lineup-close-paren}
3a731e1f
MS
5387@end group
5388@end example
f214c025 5389
116e44a1
AM
5390As a special case, if a brace block is opened at the same line as the
5391open parenthesis of the argument list, the indentation is
5392@code{c-basic-offset} instead of the open paren column. See
5393@code{c-lineup-arglist} for further discussion of this ``DWIM'' measure.
3a731e1f 5394
116e44a1 5395@workswith All @code{*-close} symbols.
3a731e1f
MS
5396@end defun
5397
5398@comment ------------------------------------------------------------
5399
116e44a1 5400@anchor{c-lineup-arglist-close-under-paren}
3a731e1f
MS
5401@defun c-lineup-arglist-close-under-paren
5402@findex lineup-arglist-close-under-paren (c-)
5403Set your @code{arglist-close} syntactic symbol to this line-up function
5404so that parentheses that close argument lists will line up under the
5405parenthesis that opened the argument list. It can also be used with
5406@code{arglist-cont} and @code{arglist-cont-nonempty} to line up all
5407lines inside a parenthesis under the open paren.
5408
5409As a special case, if a brace block is opened at the same line as the
5410open parenthesis of the argument list, the indentation is
5411@code{c-basic-offset} only. See @code{c-lineup-arglist} for further
5412discussion of this ``DWIM'' measure.
5413
5414@workswith Almost all symbols, but are typically most useful on
5415@code{arglist-close}, @code{brace-list-close}, @code{arglist-cont} and
5416@code{arglist-cont-nonempty}.
5417@end defun
5418
5419@comment ------------------------------------------------------------
5420
116e44a1
AM
5421@defun c-indent-one-line-block
5422@findex indent-one-line-block (c-)
5423Indent a one line block @code{c-basic-offset} extra. E.g:
d7bd46ed 5424
3a731e1f
MS
5425@example
5426@group
116e44a1
AM
5427if (n > 0)
5428 @{m+=n; n=0;@} @hereFn{c-indent-one-line-block}
5429@sssTBasicOffset{}
5430@end group
5431@end example
5432
5433@noindent
5434and
d7bd46ed 5435
d7bd46ed
GM
5436@example
5437@group
116e44a1
AM
5438if (n > 0)
5439@{ @hereFn{c-indent-one-line-block}
5440 m+=n; n=0;
5441@}
3a731e1f
MS
5442@end group
5443@end example
d7bd46ed 5444
116e44a1
AM
5445The block may be surrounded by any kind of parenthesis characters.
5446@code{nil} is returned if the line doesn't start with a one line block,
5447which makes the function usable in list expressions.
3a731e1f 5448
116e44a1
AM
5449@workswith Almost all syntactic symbols, but most useful on the
5450@code{-open} symbols.
3a731e1f 5451@end defun
d7bd46ed 5452
3a731e1f
MS
5453@comment ------------------------------------------------------------
5454
116e44a1
AM
5455@defun c-indent-multi-line-block
5456@findex indent-multi-line-block (c-)
5457Indent a multiline block @code{c-basic-offset} extra. E.g:
d7bd46ed 5458
3a731e1f
MS
5459@example
5460@group
116e44a1
AM
5461int *foo[] = @{
5462 NULL,
5463 @{17@}, @hereFn{c-indent-multi-line-block}
d7bd46ed
GM
5464@end group
5465@end example
3a731e1f 5466
d7bd46ed
GM
5467@noindent
5468and
3a731e1f 5469
d7bd46ed
GM
5470@example
5471@group
116e44a1
AM
5472int *foo[] = @{
5473 NULL,
5474 @{ @hereFn{c-indent-multi-line-block}
5475 17
5476 @},
5477 @sssTBasicOffset{}
3a731e1f
MS
5478@end group
5479@end example
d7bd46ed 5480
116e44a1
AM
5481The block may be surrounded by any kind of parenthesis characters.
5482@code{nil} is returned if the line doesn't start with a multiline
5483block, which makes the function usable in list expressions.
3a731e1f 5484
116e44a1
AM
5485@workswith Almost all syntactic symbols, but most useful on the
5486@code{-open} symbols.
3a731e1f
MS
5487@end defun
5488
5489@comment ------------------------------------------------------------
5490
116e44a1
AM
5491@defun c-lineup-runin-statements
5492@findex lineup-runin-statements (c-)
5493Line up statements for coding standards which place the first statement
5494in a block on the same line as the block opening brace@footnote{Run-in
5495style doesn't really work too well. You might need to write your own
5496custom line-up functions to better support this style.}. E.g:
3a731e1f
MS
5497
5498@example
116e44a1
AM
5499@group
5500int main()
5501@{ puts ("Hello!");
5502 return 0; @hereFn{c-lineup-runin-statements}
5503@}
5504@end group
3a731e1f
MS
5505@end example
5506
116e44a1
AM
5507If there is no statement after the opening brace to align with,
5508@code{nil} is returned. This makes the function usable in list
5509expressions.
3a731e1f 5510
116e44a1 5511@workswith The @code{statement} syntactic symbol.
3a731e1f
MS
5512@end defun
5513
5514@comment ------------------------------------------------------------
5515
116e44a1
AM
5516@defun c-lineup-inexpr-block
5517@findex lineup-inexpr-block (c-)
5518This can be used with the in-expression block symbols to indent the
5519whole block to the column where the construct is started. E.g. for Java
5520anonymous classes, this lines up the class under the @samp{new} keyword,
5521and in Pike it lines up the lambda function body under the @samp{lambda}
5522keyword. Returns @code{nil} if the block isn't part of such a
5523construct.
5524
5525@workswith @code{inlambda}, @code{inexpr-statement},
5526@code{inexpr-class}.
5527@end defun
5528
5529@comment ------------------------------------------------------------
5530
5531@defun c-lineup-after-whitesmith-blocks
5532@findex lineup-after-whitesmith-blocks (c-)
5533Compensate for Whitesmith style indentation of blocks. Due to the way
5534@ccmode{} calculates anchor positions for normal lines inside blocks,
5535this function is necessary for those lines to get correct Whitesmith
5536style indentation. Consider the following examples:
d7bd46ed 5537
3a731e1f
MS
5538@example
5539@group
116e44a1
AM
5540int foo()
5541 @{
5542 a;
5543 x; @hereFn{c-lineup-after-whitesmith-blocks}
d7bd46ed
GM
5544@end group
5545@end example
5546
d7bd46ed
GM
5547@example
5548@group
116e44a1
AM
5549int foo()
5550 @{
5551 @{
5552 a;
5553 @}
5554 x; @hereFn{c-lineup-after-whitesmith-blocks}
3a731e1f
MS
5555@end group
5556@end example
d7bd46ed 5557
116e44a1
AM
5558The fact that the line with @code{x} is preceded by a Whitesmith style
5559indented block in the latter case and not the first should not affect
5560its indentation. But since CC Mode in cases like this uses the
5561indentation of the preceding statement as anchor position, the @code{x}
5562would in the second case be indented too much if the offset for
5563@code{statement} was set simply to zero.
5564
5565This lineup function corrects for this situation by detecting if the
5566anchor position is at an open paren character. In that case, it instead
5567indents relative to the surrounding block just like
5568@code{c-lineup-whitesmith-in-block}.
5569
5570@workswith @code{brace-list-entry}, @code{brace-entry-open},
5571@code{statement}, @code{arglist-cont}.
5572@end defun
5573
5574@comment ------------------------------------------------------------
5575
5576@defun c-lineup-whitesmith-in-block
5577@findex lineup-whitesmith-in-block (c-)
5578Line up lines inside a block in Whitesmith style. It's done in a way
5579that works both when the opening brace hangs and when it doesn't. E.g:
177c0ea7 5580
3a731e1f
MS
5581@example
5582@group
116e44a1
AM
5583something
5584 @{
5585 foo; @hereFn{c-lineup-whitesmith-in-block}
5586 @}
d7bd46ed
GM
5587@end group
5588@end example
3a731e1f 5589
d7bd46ed 5590@noindent
116e44a1 5591and
3a731e1f 5592
d7bd46ed
GM
5593@example
5594@group
116e44a1
AM
5595something @{
5596 foo; @hereFn{c-lineup-whitesmith-in-block}
5597 @}
5598@sssTBasicOffset{}
3a731e1f
MS
5599@end group
5600@end example
d7bd46ed 5601
116e44a1
AM
5602In the first case the indentation is kept unchanged, in the second
5603@code{c-basic-offset} is added.
3a731e1f 5604
116e44a1
AM
5605@workswith @code{defun-close}, @code{defun-block-intro},
5606@code{inline-close}, @code{block-close}, @code{brace-list-close},
5607@code{brace-list-intro}, @code{statement-block-intro},
5608@code{arglist-intro}, @code{arglist-cont-nonempty},
5609@code{arglist-close}, and all @code{in*} symbols, e.g. @code{inclass}
5610and @code{inextern-lang}.
5611@end defun
3a731e1f 5612
116e44a1
AM
5613@comment !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
5614@node List Line-Up, Operator Line-Up, Brace/Paren Line-Up, Line-Up Functions
5615@comment node-name, next, previous, up
5616@subsection List Line-Up Functions
5617@comment !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
3a731e1f 5618
116e44a1
AM
5619The line-up functions here calculate the indentation for lines which
5620form lists of items, usually separated by commas.
5621
5622The function @ref{c-lineup-arglist-close-under-paren}, which is mainly
5623for indenting a close parenthesis, is also useful for the lines
5624contained within parentheses.
5625
5626@defun c-lineup-arglist
5627@findex lineup-arglist (c-)
5628Line up the current argument line under the first argument.
5629
5630As a special case, if an argument on the same line as the open
5631parenthesis starts with a brace block opener, the indentation is
5632@code{c-basic-offset} only. This is intended as a ``DWIM'' measure in
5633cases like macros that contain statement blocks, e.g:
5634
5635@example
5636@group
5637A_VERY_LONG_MACRO_NAME (@{
5638 some (code, with + long, lines * in[it]);
5639 @});
5640@sssTBasicOffset{}
5641@end group
5642@end example
5643
5644This is motivated partly because it's more in line with how code
5645blocks are handled, and partly since it approximates the behavior of
5646earlier CC Mode versions, which due to inaccurate analysis tended to
5647indent such cases this way.
5648
5649@workswith @code{arglist-cont-nonempty}, @code{arglist-close}.
3a731e1f
MS
5650@end defun
5651
5652@comment ------------------------------------------------------------
5653
116e44a1
AM
5654@defun c-lineup-arglist-intro-after-paren
5655@findex lineup-arglist-intro-after-paren (c-)
5656Line up a line to just after the open paren of the surrounding paren or
5657brace block.
3a731e1f 5658
116e44a1
AM
5659@workswith @code{defun-block-intro}, @code{brace-list-intro},
5660@code{statement-block-intro}, @code{statement-case-intro},
5661@code{arglist-intro}.
3a731e1f
MS
5662@end defun
5663
5664@comment ------------------------------------------------------------
d7bd46ed 5665
116e44a1
AM
5666@defun c-lineup-multi-inher
5667@findex lineup-multi-inher (c-)
5668Line up the classes in C++ multiple inheritance clauses and member
5669initializers under each other. E.g:
3a731e1f
MS
5670
5671@example
5672@group
116e44a1
AM
5673Foo::Foo (int a, int b):
5674 Cyphr (a),
5675 Bar (b) @hereFn{c-lineup-multi-inher}
5676@end group
5677@end example
5678
5679@noindent
5680and
5681
5682@example
5683@group
5684class Foo
5685 : public Cyphr,
5686 public Bar @hereFn{c-lineup-multi-inher}
d7bd46ed
GM
5687@end group
5688@end example
5689
116e44a1
AM
5690@noindent
5691and
d7bd46ed 5692
d7bd46ed 5693@example
116e44a1
AM
5694@group
5695Foo::Foo (int a, int b)
5696 : Cyphr (a)
5697 , Bar (b) @hereFn{c-lineup-multi-inher}
5698@end group
3a731e1f 5699@end example
d7bd46ed 5700
116e44a1 5701@workswith @code{inher-cont}, @code{member-init-cont}.
3a731e1f 5702@end defun
d7bd46ed 5703
3a731e1f
MS
5704@comment ------------------------------------------------------------
5705
5706@defun c-lineup-java-inher
5707@findex lineup-java-inher (c-)
5708Line up Java implements and extends declarations. If class names
5709follow on the same line as the @samp{implements}/@samp{extends}
5710keyword, they are lined up under each other. Otherwise, they are
5711indented by adding @code{c-basic-offset} to the column of the keyword.
5712E.g:
5713
5714@example
5715@group
5716class Foo
bf247b6e 5717 extends
3a731e1f
MS
5718 Bar @hereFn{c-lineup-java-inher}
5719 @sssTBasicOffset{}
d7bd46ed
GM
5720@end group
5721@end example
3a731e1f 5722
d7bd46ed
GM
5723@noindent
5724and
3a731e1f 5725
d7bd46ed
GM
5726@example
5727@group
3a731e1f
MS
5728class Foo
5729 extends Cyphr,
5730 Bar @hereFn{c-lineup-java-inher}
5731@end group
5732@end example
d7bd46ed 5733
3a731e1f
MS
5734@workswith @code{inher-cont}.
5735@end defun
5736
5737@comment ------------------------------------------------------------
d7bd46ed 5738
3a731e1f
MS
5739@defun c-lineup-java-throws
5740@findex lineup-java-throws (c-)
5741Line up Java throws declarations. If exception names follow on the
5742same line as the throws keyword, they are lined up under each other.
5743Otherwise, they are indented by adding @code{c-basic-offset} to the
5744column of the @samp{throws} keyword. The @samp{throws} keyword itself
5745is also indented by @code{c-basic-offset} from the function declaration
5746start if it doesn't hang. E.g:
d7bd46ed 5747
3a731e1f
MS
5748@example
5749@group
5750int foo()
5751 throws @hereFn{c-lineup-java-throws}
5752 Bar @hereFn{c-lineup-java-throws}
5753@sssTsssTBasicOffset{}
d7bd46ed
GM
5754@end group
5755@end example
5756
3a731e1f
MS
5757@noindent
5758and
d7bd46ed 5759
d7bd46ed 5760@example
d7bd46ed 5761@group
3a731e1f
MS
5762int foo() throws Cyphr,
5763 Bar, @hereFn{c-lineup-java-throws}
5764 Vlod @hereFn{c-lineup-java-throws}
d7bd46ed 5765@end group
3a731e1f
MS
5766@end example
5767
5768@workswith @code{func-decl-cont}.
5769@end defun
5770
5771@comment ------------------------------------------------------------
d7bd46ed 5772
116e44a1
AM
5773@defun c-lineup-template-args
5774@findex lineup-template-args (c-)
5775Line up the arguments of a template argument list under each other, but
5776only in the case where the first argument is on the same line as the
5777opening @samp{<}.
5778
5779To allow this function to be used in a list expression, @code{nil} is
5780returned if there's no template argument on the first line.
5781
5782@workswith @code{template-args-cont}.
5783@end defun
5784
5785@comment ------------------------------------------------------------
5786
5787@defun c-lineup-ObjC-method-call
5788@findex lineup-ObjC-method-call (c-)
5789For Objective-C code, line up selector args as Emacs Lisp mode does
5790with function args: go to the position right after the message receiver,
5791and if you are at the end of the line, indent the current line
5792c-basic-offset columns from the opening bracket; otherwise you are
5793looking at the first character of the first method call argument, so
5794lineup the current line with it.
5795
5796@workswith @code{objc-method-call-cont}.
5797@end defun
5798
5799@comment ------------------------------------------------------------
5800
5801@defun c-lineup-ObjC-method-args
5802@findex lineup-ObjC-method-args (c-)
5803For Objective-C code, line up the colons that separate args. The colon
5804on the current line is aligned with the one on the first line.
5805
5806@workswith @code{objc-method-args-cont}.
5807@end defun
5808
5809@comment ------------------------------------------------------------
5810
5811@defun c-lineup-ObjC-method-args-2
5812@findex lineup-ObjC-method-args-2 (c-)
5813Similar to @code{c-lineup-ObjC-method-args} but lines up the colon on
5814the current line with the colon on the previous line.
5815
5816@workswith @code{objc-method-args-cont}.
5817@end defun
5818
5819@comment !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
5820@node Operator Line-Up, Comment Line-Up, List Line-Up, Line-Up Functions
5821@comment node-name, next, previous, up
5822@subsection Operator Line-Up Functions
5823@comment !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
5824
5825The line-up functions here calculate the indentation for lines which
5826start with an operator, by lining it up with something on the previous
5827line.
5828
5829@defun c-lineup-argcont
5830@findex lineup-argcont (c-)
5831Line up a continued argument. E.g:
3a731e1f
MS
5832
5833@example
d7bd46ed 5834@group
116e44a1
AM
5835foo (xyz, aaa + bbb + ccc
5836 + ddd + eee + fff); @hereFn{c-lineup-argcont}
d7bd46ed 5837@end group
3a731e1f 5838@end example
d7bd46ed 5839
116e44a1
AM
5840Only continuation lines like this are touched, @code{nil} is returned on
5841lines which are the start of an argument.
5842
5843Within a gcc @code{asm} block, @code{:} is recognised as an argument
5844separator, but of course only between operand specifications, not in the
5845expressions for the operands.
5846
5847@workswith @code{arglist-cont}, @code{arglist-cont-nonempty}.
5848@end defun
5849
5850@comment ------------------------------------------------------------
5851
5852@defun c-lineup-arglist-operators
5853@findex lineup-arglist-operators (c-)
5854Line up lines starting with an infix operator under the open paren.
5855Return @code{nil} on lines that don't start with an operator, to leave
5856those cases to other line-up functions. Example:
5857
5858@example
5859@group
5860if ( x < 10
5861 || at_limit (x, @hereFn{c-lineup-arglist-operators}
5862 list) @hereFn{c-lineup-arglist-operators@r{ returns nil}}
5863 )
5864@end group
5865@end example
5866
5867Since this function doesn't do anything for lines without an infix
5868operator you typically want to use it together with some other lineup
5869settings, e.g. as follows (the @code{arglist-close} setting is just a
5870suggestion to get a consistent style):
5871
5872@example
5873(c-set-offset 'arglist-cont
5874 '(c-lineup-arglist-operators 0))
5875(c-set-offset 'arglist-cont-nonempty
5876 '(c-lineup-arglist-operators c-lineup-arglist))
5877(c-set-offset 'arglist-close
5878 '(c-lineup-arglist-close-under-paren))
5879@end example
5880
5881@workswith @code{arglist-cont}, @code{arglist-cont-nonempty}.
5882@end defun
5883
5884@comment ------------------------------------------------------------
5885
5886@defun c-lineup-assignments
5887@findex lineup-assignments (c-)
5888Line up the current line after the assignment operator on the first line
5889in the statement. If there isn't any, return nil to allow stacking with
5890other line-up functions. If the current line contains an assignment
5891operator too, try to align it with the first one.
5892
5893@workswith @code{topmost-intro-cont}, @code{statement-cont},
5894@code{arglist-cont}, @code{arglist-cont-nonempty}.
3a731e1f 5895
3a731e1f
MS
5896@end defun
5897
5898@comment ------------------------------------------------------------
5899
5900@defun c-lineup-math
5901@findex lineup-math (c-)
116e44a1
AM
5902Like @code{c-lineup-assignments} but indent with @code{c-basic-offset}
5903if no assignment operator was found on the first line. I.e. this
5904function is the same as specifying a list @code{(c-lineup-assignments
5905+)}. It's provided for compatibility with old configurations.
3a731e1f
MS
5906
5907@workswith @code{topmost-intro-cont}, @code{statement-cont},
5908@code{arglist-cont}, @code{arglist-cont-nonempty}.
5909@end defun
5910
5911@comment ------------------------------------------------------------
5912
116e44a1
AM
5913@defun c-lineup-cascaded-calls
5914@findex lineup-cascaded-calls (c-)
5915Line up ``cascaded calls'' under each other. If the line begins with
5916@code{->} or @code{.} and the preceding line ends with one or more
5917function calls preceded by the same token, then the arrow is lined up
5918with the first of those tokens. E.g:
3a731e1f
MS
5919
5920@example
d7bd46ed 5921@group
116e44a1
AM
5922r = proc->add(17)->add(18)
5923 ->add(19) + @hereFn{c-lineup-cascaded-calls}
5924 offset; @hereFn{c-lineup-cascaded-calls@r{ (inactive)}}
d7bd46ed 5925@end group
3a731e1f 5926@end example
d7bd46ed 5927
116e44a1
AM
5928In any other situation @code{nil} is returned to allow use in list
5929expressions.
5930
5931@workswith @code{topmost-intro-cont}, @code{statement-cont},
5932@code{arglist-cont}, @code{arglist-cont-nonempty}.
5933@end defun
5934
5935@comment ------------------------------------------------------------
5936
5937@defun c-lineup-streamop
5938@findex lineup-streamop (c-)
5939Line up C++ stream operators (i.e. @samp{<<} and @samp{>>}).
5940
5941@workswith @code{stream-op}.
5942@end defun
5943
5944@comment ------------------------------------------------------------
5945
5946@defun c-lineup-string-cont
5947@findex lineup-string-cont (c-)
5948Line up a continued string under the one it continues. A continued
5949string in this sense is where a string literal follows directly after
5950another one. E.g:
3a731e1f
MS
5951
5952@example
d7bd46ed 5953@group
116e44a1
AM
5954result = prefix + "A message "
5955 "string."; @hereFn{c-lineup-string-cont}
d7bd46ed 5956@end group
3a731e1f
MS
5957@end example
5958
116e44a1
AM
5959@code{nil} is returned in other situations, to allow stacking with other
5960lineup functions.
5961
5962@workswith @code{topmost-intro-cont}, @code{statement-cont},
5963@code{arglist-cont}, @code{arglist-cont-nonempty}.
5964@end defun
5965
5966
5967@comment !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
5968@node Comment Line-Up, Misc Line-Up, Operator Line-Up, Line-Up Functions
5969@comment node-name, next, previous, up
5970@subsection Comment Line-Up Functions
5971@comment !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
5972
5973The lineup functions here calculate the indentation for several types
5974of comment structure.
5975
5976@defun c-lineup-C-comments
5977@findex lineup-C-comments (c-)
5978Line up C block comment continuation lines. Various heuristics are used
5979to handle most of the common comment styles. Some examples:
d7bd46ed 5980
3a731e1f
MS
5981@example
5982@group
116e44a1
AM
5983/* /** /*
5984 * text * text text
5985 */ */ */
3a731e1f 5986@end group
d7bd46ed
GM
5987@end example
5988
116e44a1
AM
5989@example
5990@group
5991/* text /* /**
5992 text ** text ** text
5993*/ */ */
5994@end group
5995@end example
d7bd46ed 5996
116e44a1
AM
5997@example
5998@group
5999/**************************************************
6000 * text
6001 *************************************************/
6002@end group
6003@end example
d7bd46ed 6004
116e44a1
AM
6005@vindex comment-start-skip
6006@example
6007@group
6008/**************************************************
6009 Free form text comments:
6010 In comments with a long delimiter line at the
6011 start, the indentation is kept unchanged for lines
6012 that start with an empty comment line prefix. The
6013 delimiter line is whatever matches the
6014 @code{comment-start-skip} regexp.
6015**************************************************/
6016@end group
6017@end example
6018
6019The style variable @code{c-comment-prefix-regexp} is used to recognize
6020the comment line prefix, e.g. the @samp{*} that usually starts every
6021line inside a comment.
d7bd46ed 6022
116e44a1 6023@workswith The @code{c} syntactic symbol.
3a731e1f 6024@end defun
d7bd46ed 6025
3a731e1f 6026@comment ------------------------------------------------------------
d7bd46ed 6027
116e44a1
AM
6028@defun c-lineup-comment
6029@findex lineup-comment (c-)
6030Line up a comment-only line according to the style variable
6031@code{c-comment-only-line-offset}. If the comment is lined up with a
6032comment starter on the previous line, that alignment is preserved.
d7bd46ed 6033
116e44a1
AM
6034@defopt c-comment-only-line-offset
6035@vindex comment-only-line-offset (c-)
6036This style variable specifies the extra offset for the line. It can
6037contain an integer or a cons cell of the form
d7bd46ed 6038
116e44a1
AM
6039@example
6040(@r{@var{non-anchored-offset}} . @r{@var{anchored-offset}})
6041@end example
3a731e1f 6042
116e44a1
AM
6043@noindent
6044where @var{non-anchored-offset} is the amount of offset given to
6045non-column-zero anchored lines, and @var{anchored-offset} is the amount
6046of offset to give column-zero anchored lines. Just an integer as value
6047is equivalent to @code{(@r{@var{value}} . -1000)}.
6048@end defopt
3a731e1f 6049
116e44a1 6050@workswith @code{comment-intro}.
3a731e1f
MS
6051@end defun
6052
6053@comment ------------------------------------------------------------
d7bd46ed 6054
116e44a1
AM
6055@defun c-lineup-knr-region-comment
6056@findex lineup-knr-region-comment (c-)
6057Line up a comment in the ``K&R region'' with the declaration. That is
6058the region between the function or class header and the beginning of the
6059block. E.g:
3a731e1f 6060
d7bd46ed
GM
6061@example
6062@group
d7bd46ed 6063int main()
116e44a1
AM
6064/* Called at startup. */ @hereFn{c-lineup-knr-region-comment}
6065@{
6066 return 0;
d7bd46ed 6067@}
d7bd46ed
GM
6068@end group
6069@end example
6070
116e44a1 6071Return @code{nil} if called in any other situation, to be useful in list
d7bd46ed
GM
6072expressions.
6073
116e44a1 6074@workswith @code{comment-intro}.
3a731e1f 6075@end defun
d7bd46ed 6076
116e44a1
AM
6077@comment !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
6078@node Misc Line-Up, , Comment Line-Up, Line-Up Functions
6079@comment node-name, next, previous, up
6080@subsection Miscellaneous Line-Up Functions
6081@comment !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
3a731e1f 6082
116e44a1
AM
6083The line-up functions here are the odds and ends which didn't fit into
6084any earlier category.
3a731e1f 6085
116e44a1
AM
6086@defun c-lineup-dont-change
6087@findex lineup-dont-change (c-)
6088This lineup function makes the line stay at whatever indentation it
6089already has; think of it as an identity function for lineups.
6090
6091@workswith Any syntactic symbol.
3a731e1f
MS
6092@end defun
6093
6094@comment ------------------------------------------------------------
6095
116e44a1
AM
6096@defun c-lineup-cpp-define
6097@findex lineup-cpp-define (c-)
6098Line up macro continuation lines according to the indentation of the
6099construct preceding the macro. E.g:
d7bd46ed 6100
3a731e1f
MS
6101@example
6102@group
116e44a1
AM
6103const char msg[] = @hereFn{@r{The beginning of the preceding construct.}}
6104 \"Some text.\";
6105
6106#define X(A, B) \
6107do @{ \ @hereFn{c-lineup-cpp-define}
6108 printf (A, B); \
6109@} while (0)
3a731e1f
MS
6110@end group
6111@end example
d7bd46ed 6112
116e44a1
AM
6113@noindent
6114and:
d7bd46ed 6115
3a731e1f
MS
6116@example
6117@group
116e44a1
AM
6118int dribble() @{
6119 if (!running) @hereFn{@r{The beginning of the preceding construct.}}
6120 error(\"Not running!\");
6121
6122#define X(A, B) \
6123 do @{ \ @hereFn{c-lineup-cpp-define}
6124 printf (A, B); \
6125 @} while (0)
3a731e1f
MS
6126@end group
6127@end example
d7bd46ed 6128
116e44a1
AM
6129If @code{c-syntactic-indentation-in-macros} is non-@code{nil}, the
6130function returns the relative indentation to the macro start line to
6131allow accumulation with other offsets. E.g. in the following cases,
6132@code{cpp-define-intro} is combined with the
6133@code{statement-block-intro} that comes from the @samp{do @{} that hangs
6134on the @samp{#define} line:
d7bd46ed 6135
3a731e1f
MS
6136@example
6137@group
116e44a1
AM
6138const char msg[] =
6139 \"Some text.\";
6140
6141#define X(A, B) do @{ \
6142 printf (A, B); \ @hereFn{c-lineup-cpp-define}
6143 this->refs++; \
6144@} while (0) @hereFn{c-lineup-cpp-define}
3a731e1f
MS
6145@end group
6146@end example
d7bd46ed 6147
3a731e1f 6148@noindent
116e44a1 6149and:
d7bd46ed 6150
3a731e1f
MS
6151@example
6152@group
116e44a1
AM
6153int dribble() @{
6154 if (!running)
6155 error(\"Not running!\");
6156
6157#define X(A, B) do @{ \
6158 printf (A, B); \ @hereFn{c-lineup-cpp-define}
6159 this->refs++; \
6160 @} while (0) @hereFn{c-lineup-cpp-define}
3a731e1f
MS
6161@end group
6162@end example
d7bd46ed 6163
116e44a1
AM
6164The relative indentation returned by @code{c-lineup-cpp-define} is zero
6165and two, respectively, on the two lines in each of these examples. They
6166are then added to the two column indentation that
6167@code{statement-block-intro} gives in both cases here.
6168
6169If the relative indentation is zero, then @code{nil} is returned
6170instead. That is useful in a list expression to specify the default
6171indentation on the top level.
6172
6173If @code{c-syntactic-indentation-in-macros} is @code{nil} then this
6174function keeps the current indentation, except for empty lines (ignoring
6175the ending backslash) where it takes the indentation from the closest
6176preceding nonempty line in the macro. If there's no such line in the
6177macro then the indentation is taken from the construct preceding it, as
6178described above.
6179
6180@workswith @code{cpp-define-intro}.
3a731e1f
MS
6181@end defun
6182
6183@comment ------------------------------------------------------------
d7bd46ed 6184
116e44a1
AM
6185@defun c-lineup-gcc-asm-reg
6186@findex lineup-gcc-asm-reg (c-)
6187Line up a gcc asm register under one on a previous line.
3a731e1f 6188
d7bd46ed
GM
6189@example
6190@group
116e44a1
AM
6191 asm ("foo %1, %0\n"
6192 "bar %0, %1"
6193 : "=r" (w),
6194 "=r" (x)
6195 : "0" (y),
6196 "1" (z));
d7bd46ed
GM
6197@end group
6198@end example
3a731e1f 6199
116e44a1
AM
6200The @samp{x} line is aligned to the text after the @samp{:} on the
6201@samp{w} line, and similarly @samp{z} under @samp{y}.
6202
6203This is done only in an @samp{asm} or @samp{__asm__} block, and only to
6204those lines mentioned. Anywhere else @code{nil} is returned. The usual
6205arrangement is to have this routine as an extra feature at the start of
6206arglist lineups, e.g.
3a731e1f 6207
d7bd46ed 6208@example
116e44a1 6209(c-lineup-gcc-asm-reg c-lineup-arglist)
d7bd46ed
GM
6210@end example
6211
116e44a1 6212@workswith @code{arglist-cont}, @code{arglist-cont-nonempty}.
3a731e1f 6213@end defun
d7bd46ed 6214
116e44a1 6215@comment ------------------------------------------------------------
d7bd46ed 6216
116e44a1
AM
6217@defun c-lineup-topmost-intro-cont
6218@findex lineup-topmost-intro-cont (c-)
6219Line up declaration continuation lines zero or one indentation
6220step@footnote{This function is mainly provided to mimic the behavior of
6221CC Mode 5.28 and earlier where this case wasn't handled consistently so
6222that those lines could be analyzed as either topmost-intro-cont or
6223statement-cont. It's used for @code{topmost-intro-cont} by default, but
6224you might consider using @code{+} instead.}. For lines preceding a
6225definition, zero is used. For other lines, @code{c-basic-offset} is
6226added to the indentation. E.g:
3a731e1f
MS
6227
6228@example
116e44a1
AM
6229@group
6230int
6231neg (int i) @hereFn{c-lineup-topmost-intro-cont}
6232@{
6233 return -i;
6234@}
6235@end group
6236@end example
3a731e1f 6237
116e44a1
AM
6238@noindent
6239and
3a731e1f 6240
116e44a1
AM
6241@example
6242@group
6243struct
6244larch @hereFn{c-lineup-topmost-intro-cont}
6245@{
6246 double height;
6247@}
6248 the_larch, @hereFn{c-lineup-topmost-intro-cont}
6249 another_larch; @hereFn{c-lineup-topmost-intro-cont}
6250@sssTBasicOffset{}
6251@end group
6252@end example
3a731e1f 6253
116e44a1
AM
6254@noindent
6255and
3a731e1f
MS
6256
6257@example
116e44a1
AM
6258@group
6259struct larch
6260the_larch, @hereFn{c-lineup-topmost-intro-cont}
6261 another_larch; @hereFn{c-lineup-topmost-intro-cont}
6262@end group
3a731e1f
MS
6263@end example
6264
116e44a1
AM
6265@workswith @code{topmost-intro-cont}.
6266@end defun
3a731e1f 6267
116e44a1
AM
6268@comment !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
6269@node Custom Line-Up, Other Indentation, Line-Up Functions, Customizing Indentation
6270@comment node-name, next, previous, up
6271@section Custom Line-Up Functions
6272@cindex customization, indentation functions
6273@comment !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
3a731e1f 6274
116e44a1
AM
6275The most flexible way to customize indentation is by writing custom
6276line-up functions, and associating them with specific syntactic
6277symbols (@pxref{c-offsets-alist}). Depending on the effect you want,
6278it might be better to write a @code{c-special-indent-hook} function
6279rather than a line-up function (@pxref{Other Indentation}).
6280
6281@ccmode{} comes with an extensive set of predefined line-up functions,
6282not all of which are used by the default styles. So there's a good
6283chance the function you want already exists. @xref{Line-Up
6284Functions}, for a list of them. If you write your own line-up
6285function, it's probably a good idea to start working from one of these
6286predefined functions, which can be found in the file
6287@file{cc-align.el}. If you have written a line-up function that you
6288think is generally useful, you're very welcome to contribute it;
6289please contact @email{bug-cc-mode@@gnu.org}.
6290
6291 Line-up functions are passed a single argument, the syntactic
6292element (see below). The return value is a @code{c-offsets-alist}
6293offset specification: for example, an integer, a symbol such as
6294@code{+}, a vector, @code{nil}@footnote{Returning @code{nil} is useful
6295when the offset specification for a syntactic element is a list
6296containing the line-up function (@pxref{c-offsets-alist}).}, or even
6297another line-up function. Full details of these are in
6298@ref{c-offsets-alist}.
6299
6300Line-up functions must not move point or change the content of the
6301buffer (except temporarily). They are however allowed to do
6302@dfn{hidden buffer changes}, i.e. setting text properties for caching
6303purposes etc. Buffer undo recording is disabled while they run.
6304
6305The syntactic element passed as the parameter to a line-up function is
6306a cons cell of the form
3a731e1f 6307
116e44a1
AM
6308@example
6309(@r{@var{syntactic-symbol}} . @r{@var{anchor-position}})
6310@end example
3a731e1f 6311
116e44a1
AM
6312@noindent
6313@c FIXME!!! The following sentence might be better omitted, since the
6314@c information is in the cross reference "Syntactic Analysis". 2005/10/2.
6315where @var{syntactic-symbol} is the symbol that the function was
6316called for, and @var{anchor-position} is the anchor position (if any)
6317for the construct that triggered the syntactic symbol
6318(@pxref{Syntactic Analysis}). This cons cell is how the syntactic
6319element of a line used to be represented in @ccmode{} 5.28 and
6320earlier. Line-up functions are still passed this cons cell, so as to
6321preserve compatibility with older configurations. In the future, we
6322may decide to convert to using the full list format---you can prepare
6323your setup for this by using the access functions
6324(@code{c-langelem-sym}, etc.) described below.
6325
6326@vindex c-syntactic-element
6327@vindex syntactic-element (c-)
6328@vindex c-syntactic-context
6329@vindex syntactic-context (c-)
6330Some syntactic symbols, e.g. @code{arglist-cont-nonempty}, have more
6331info in the syntactic element - typically other positions that can be
6332interesting besides the anchor position. That info can't be accessed
6333through the passed argument, which is a cons cell. Instead, you can
6334get this information from the variable @code{c-syntactic-element},
6335which is dynamically bound to the complete syntactic element. The
6336variable @code{c-syntactic-context} might also be useful - it gets
6337dynamically bound to the complete syntactic context. @xref{Custom
6338Braces}.
6339
6340@ccmode{} provides a few functions to access parts of syntactic
6341elements in a more abstract way. Besides making the code easier to
6342read, they also hide the difference between the old cons cell form
6343used in the line-up function argument and the new list form used in
6344@code{c-syntactic-element} and everywhere else. The functions are:
6345
6346@defun c-langelem-sym langelem
6347@findex langelem-sym (c-)
6348Return the syntactic symbol in @var{langelem}.
6349@end defun
3a731e1f 6350
116e44a1
AM
6351@defun c-langelem-pos langelem
6352@findex langelem-pos (c-)
6353Return the anchor position in @var{langelem}, or nil if there is none.
6354@end defun
3a731e1f 6355
116e44a1
AM
6356@defun c-langelem-col langelem &optional preserve-point
6357@findex langelem-col (c-)
6358Return the column of the anchor position in @var{langelem}. Also move
6359the point to that position unless @var{preserve-point} is
6360non-@code{nil}.
6361@end defun
3a731e1f 6362
116e44a1
AM
6363@defun c-langelem-2nd-pos langelem
6364@findex langelem-2nd-pos (c-)
6365Return the secondary position in @var{langelem}, or @code{nil} if there
6366is none.
3a731e1f 6367
116e44a1
AM
6368Note that the return value of this function is always @code{nil} if
6369@var{langelem} is in the old cons cell form. Thus this function is
6370only meaningful when used on syntactic elements taken from
6371@code{c-syntactic-element} or @code{c-syntactic-context}.
6372@end defun
3a731e1f 6373
116e44a1
AM
6374Custom line-up functions can be as simple or as complex as you like, and
6375any syntactic symbol that appears in @code{c-offsets-alist} can have a
6376custom line-up function associated with it.
3a731e1f 6377
116e44a1
AM
6378@comment !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
6379@node Other Indentation, , Custom Line-Up, Customizing Indentation
6380@comment node-name, next, previous, up
6381@section Other Special Indentations
6382@comment !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
3a731e1f 6383
116e44a1 6384Here are the remaining odds and ends regarding indentation:
3a731e1f 6385
116e44a1
AM
6386@defopt c-label-minimum-indentation
6387@vindex label-minimum-indentation (c-)
6388In @samp{gnu} style (@pxref{Built-in Styles}), a minimum indentation is
6389imposed on lines inside code blocks. This minimum indentation is
6390controlled by this style variable. The default value is 1.
6391
6392@findex c-gnu-impose-minimum
6393@findex gnu-impose-minimum (c-)
6394It's the function @code{c-gnu-impose-minimum} that enforces this minimum
6395indentation. It must be present on @code{c-special-indent-hook} to
6396work.
6397@end defopt
3a731e1f 6398
116e44a1
AM
6399@defopt c-special-indent-hook
6400@vindex special-indent-hook (c-)
6401This style variable is a standard hook variable that is called after
6402every line is indented by @ccmode{}. It is called only if
6403@code{c-syntactic-indentation} is non-@code{nil} (which it is by
6404default (@pxref{Indentation Engine Basics})). You can put a function
6405on this hook to do any special indentation or ad hoc line adjustments
6406your style dictates, such as adding extra indentation to constructors
6407or destructor declarations in a class definition, etc. Sometimes it
6408is better to write a custom Line-up Function instead (@pxref{Custom
6409Line-Up}).
6410
6411When the indentation engine calls this hook, the variable
6412@code{c-syntactic-context} is bound to the current syntactic context
6413(i.e. what you would get by typing @kbd{C-c C-s} on the source line.
6414@xref{Custom Braces}.). Note that you should not change point or mark
6415inside a @code{c-special-indent-hook} function, i.e. you'll probably
6416want to wrap your function in a @code{save-excursion}@footnote{The
6417numerical value returned by @code{point} will change if you change the
6418indentation of the line within a @code{save-excursion} form, but point
6419itself will still be over the same piece of text.}.
6420
6421Setting @code{c-special-indent-hook} in style definitions is handled
6422slightly differently from other variables---A style can only add
6423functions to this hook, not remove them. @xref{Style Variables}.
6424@end defopt
3a731e1f 6425
3a731e1f 6426
116e44a1
AM
6427@comment !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
6428@node Custom Macros, Odds and Ends, Customizing Indentation, Top
6429@comment node-name, next, previous, up
6430@chapter Customizing Macros
6431@cindex macros
6432@cindex preprocessor directives
6433@comment !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
3a731e1f 6434
116e44a1
AM
6435Normally, the lines in a multi-line macro are indented relative to
6436eachother as though they were code. You can suppress this behaviour
6437by setting the following user option:
3a731e1f 6438
116e44a1
AM
6439@defopt c-syntactic-indentation-in-macros
6440@vindex syntactic-indentation-in-macros (c-)
6441Enable syntactic analysis inside macros, which is the default. If this
6442is @code{nil}, all lines inside macro definitions are analyzed as
6443@code{cpp-macro-cont}.
6444@end defopt
3a731e1f 6445
116e44a1
AM
6446@ccmode{} provides some tools to help keep the line continuation
6447backslashes in macros neat and tidy. Their precise action is
6448customized with these variables:
3a731e1f 6449
116e44a1
AM
6450@defopt c-backslash-column
6451@vindex backslash-column (c-)
6452@defoptx c-backslash-max-column
6453@vindex backslash-max-column (c-)
6454These variables control the alignment columns for line continuation
6455backslashes in multiline macros. They are used by the functions that
6456automatically insert or align such backslashes,
6457e.g. @code{c-backslash-region} and @code{c-context-line-break}.
3a731e1f 6458
116e44a1
AM
6459@code{c-backslash-column} specifies the minimum column for the
6460backslashes. If any line in the macro goes past this column, then the
6461next tab stop (i.e. next multiple of @code{tab-width}) in that line is
6462used as the alignment column for all the backslashes, so that they
6463remain in a single column. However, if any lines go past
6464@code{c-backslash-max-column} then the backslashes in the rest of the
6465macro will be kept at that column, so that the lines which are too
6466long ``stick out'' instead.
6467
6468Don't ever set these variables to @code{nil}. If you want to disable
6469the automatic alignment of backslashes, use
6470@code{c-auto-align-backslashes}.
6471@end defopt
d7bd46ed 6472
116e44a1
AM
6473@defopt c-auto-align-backslashes
6474@vindex auto-align-backslashes (c-)
6475Align automatically inserted line continuation backslashes if
6476non-@code{nil}. When line continuation backslashes are inserted
6477automatically for line breaks in multiline macros, e.g. by
6478@code{c-context-line-break}, they are aligned with the other
6479backslashes in the same macro if this flag is set.
6480
6481If @code{c-auto-align-backslashes} is @code{nil}, automatically
6482inserted backslashes are preceded by a single space, and backslashes
6483get aligned only when you explicitly invoke the command
6484@code{c-backslash-region} (@kbd{C-c C-\}).
6485@end defopt
6bf7aab6 6486
d7bd46ed 6487@comment !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
116e44a1 6488@node Odds and Ends, Sample .emacs File, Custom Macros, Top
3a731e1f
MS
6489@comment node-name, next, previous, up
6490@chapter Odds and Ends
6491@comment !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
6492
6493The stuff that didn't fit in anywhere else is documented here.
6494
6495@defopt c-require-final-newline
6496@vindex require-final-newline (c-)
116e44a1
AM
6497Controls whether a final newline is enforced when the file is saved.
6498The value is an association list that for each language mode specifies
6499the value to give to @code{require-final-newline} (@pxref{Saving
6500Buffers,,, @lispref{}, @lispreftitle{}}) at mode initialization. If a
6501language isn't present on the association list, CC Mode won't touch
3a731e1f
MS
6502@code{require-final-newline} in buffers for that language.
6503
6504The default is to set @code{require-final-newline} to @code{t} in the
116e44a1
AM
6505languages that mandate that source files should end with newlines.
6506These are C, C++ and Objective-C.
3a731e1f
MS
6507@end defopt
6508
6509@defopt c-echo-syntactic-information-p
6510@vindex echo-syntactic-information-p (c-)
6511If non-@code{nil}, the syntactic analysis for the current line is shown
6512in the echo area when it's indented (unless
6513@code{c-syntactic-indentation} is @code{nil}). That's useful when
6514finding out which syntactic symbols to modify to get the indentation you
6515want.
6516@end defopt
6517
6518@defopt c-report-syntactic-errors
6519@vindex report-syntactic-errors (c-)
6520If non-@code{nil}, certain syntactic errors are reported with a ding and
6521a message, for example when an @code{else} is indented for which there
6522is no corresponding @code{if}.
6523
6524Note however that @ccmode{} doesn't make any special effort to check for
6525syntactic errors; that's the job of the compiler. The reason it can
6526report cases like the one above is that it can't find the correct
6527anchoring position to indent the line in that case.
6528@end defopt
6529
6530
6531@comment !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
116e44a1
AM
6532@node Sample .emacs File, Performance Issues, Odds and Ends, Top
6533@comment node-name, next, previous, up
6534@appendix Sample .emacs File
6535@comment !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
6536
6537@verbatim
6538;; Here's a sample .emacs file fragment that might help you along the
6539;; way. Just copy this region and paste it into your .emacs file.
6540;; You might want to change some of the actual values.
6541
6542;; Make some non-standard key bindings. We can put these in
6543;; c-mode-base-map because c-mode-map, c++-mode-map, and so on,
6544;; inherit from it.
6545(defun my-c-initialization-hook ()
6546 (define-key c-mode-base-map "\C-m" 'c-context-line-break)
6547 (define-key c-mode-base-map [?\C-\M-a] 'c-beginning-of-defun)
6548 (define-key c-mode-base-map [?\C-\M-e] 'c-end-of-defun)
6549(add-hook 'c-initialization-hook 'my-c-initialization-hook)
6550
6551;; offset customizations not in my-c-style
6552;; This will take precedence over any setting of the syntactic symbol
6553;; made by a style.
6554(setq c-offsets-alist '((member-init-intro . ++)))
6555
6556;; Create my personal style.
6557(defconst my-c-style
6558 '((c-tab-always-indent . t)
6559 (c-comment-only-line-offset . 4)
6560 (c-hanging-braces-alist . ((substatement-open after)
6561 (brace-list-open)))
6562 (c-hanging-colons-alist . ((member-init-intro before)
6563 (inher-intro)
6564 (case-label after)
6565 (label after)
6566 (access-label after)))
6567 (c-cleanup-list . (scope-operator
6568 empty-defun-braces
6569 defun-close-semi))
6570 (c-offsets-alist . ((arglist-close . c-lineup-arglist)
6571 (substatement-open . 0)
6572 (case-label . 4)
6573 (block-open . 0)
6574 (knr-argdecl-intro . -)))
6575 (c-echo-syntactic-information-p . t))
6576 "My C Programming Style")
6577(c-add-style "PERSONAL" my-c-style)
6578
6579;; Customizations for all modes in CC Mode.
6580(defun my-c-mode-common-hook ()
6581 ;; set my personal style for the current buffer
6582 (c-set-style "PERSONAL")
6583 ;; other customizations
6584 (setq tab-width 8
6585 ;; this will make sure spaces are used instead of tabs
6586 indent-tabs-mode nil)
6587 ;; we like auto-newline, but not hungry-delete
6588 (c-toggle-auto-newline 1))
6589(add-hook 'c-mode-common-hook 'my-c-mode-common-hook)
6590@end verbatim
6591
6592@comment !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
6593@node Performance Issues, Limitations and Known Bugs, Sample .emacs File, Top
d7bd46ed 6594@comment node-name, next, previous, up
3a731e1f
MS
6595@chapter Performance Issues
6596@cindex performance
6bf7aab6
DL
6597@comment !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
6598
3a731e1f
MS
6599@comment FIXME: (ACM, 2003/5/24). Check whether AWK needs mentioning here.
6600
6bf7aab6 6601C and its derivative languages are highly complex creatures. Often,
3a731e1f
MS
6602ambiguous code situations arise that require @ccmode{} to scan large
6603portions of the buffer to determine syntactic context. Such
6604pathological code can cause @ccmode{} to perform fairly badly. This
6605section gives some insight in how @ccmode{} operates, how that interacts
6606with some coding styles, and what you can use to improve performance.
6607
116e44a1 6608The overall goal is that @ccmode{} shouldn't be overly slow (i.e. take
3a731e1f 6609more than a fraction of a second) in any interactive operation.
116e44a1
AM
6610I.e. it's tuned to limit the maximum response time in single operations,
6611which is sometimes at the expense of batch-like operations like
3a731e1f
MS
6612reindenting whole blocks. If you find that @ccmode{} gradually gets
6613slower and slower in certain situations, perhaps as the file grows in
6614size or as the macro or comment you're editing gets bigger, then chances
6615are that something isn't working right. You should consider reporting
6616it, unless it's something that's mentioned in this section.
6bf7aab6
DL
6617
6618Because @ccmode{} has to scan the buffer backwards from the current
6619insertion point, and because C's syntax is fairly difficult to parse in
6620the backwards direction, @ccmode{} often tries to find the nearest
3a731e1f 6621position higher up in the buffer from which to begin a forward scan
116e44a1 6622(it's typically an opening or closing parenthesis of some kind). The
3a731e1f
MS
6623farther this position is from the current insertion point, the slower it
6624gets.
6bf7aab6
DL
6625
6626@findex beginning-of-defun
116e44a1
AM
6627In earlier versions of @ccmode{}, we used to recommend putting the
6628opening brace of a top-level construct@footnote{E.g. a function in C,
6629or outermost class definition in C++ or Java.} into the leftmost
6630column. Earlier still, this used to be a rigid Emacs constraint, as
6631embodied in the @code{beginning-of-defun} function. @ccmode now
6632caches syntactic information much better, so that the delay caused by
6633searching for such a brace when it's not in column 0 is minimal,
6634except perhaps when you've just moved a long way inside the file.
6635Don't forget to rebind @kbd{C-M-a} and @kbd{C-M-e} to the @ccmode{}
6636functions @code{beginning-of-defun} and @code{end-of-defun} if you're
6637going to be hanging your braces! @xref{Sample .emacs File}.
6bf7aab6 6638
116e44a1 6639@findex defun-prompt-regexp
6bf7aab6
DL
6640@vindex c-Java-defun-prompt-regexp
6641@vindex Java-defun-prompt-regexp (c-)
3a731e1f
MS
6642A special note about @code{defun-prompt-regexp} in Java mode: The common
6643style is to hang the opening braces of functions and classes on the
6644right side of the line, and that doesn't work well with the Emacs
116e44a1 6645approach. @ccmode{} comes with a constant
6bf7aab6
DL
6646@code{c-Java-defun-prompt-regexp} which tries to define a regular
6647expression usable for this style, but there are problems with it. In
6648some cases it can cause @code{beginning-of-defun} to hang@footnote{This
6649has been observed in Emacs 19.34 and XEmacs 19.15.}. For this reason,
6650it is not used by default, but if you feel adventurous, you can set
6651@code{defun-prompt-regexp} to it in your mode hook. In any event,
3a731e1f
MS
6652setting and relying on @code{defun-prompt-regexp} will definitely slow
6653things down because (X)Emacs will be doing regular expression searches a
6654lot, so you'll probably be taking a hit either way!
6655
6656@ccmode{} maintains a cache of the opening parentheses of the blocks
6657surrounding the point, and it adapts that cache as the point is moved
6658around. That means that in bad cases it can take noticeable time to
6659indent a line in a new surrounding, but after that it gets fast as long
6660as the point isn't moved far off. The farther the point is moved, the
6661less useful is the cache. Since editing typically is done in ``chunks''
6662rather than on single lines far apart from each other, the cache
6663typically gives good performance even when the code doesn't fit the
6664Emacs approach to finding the defun starts.
d7bd46ed
GM
6665
6666@vindex c-enable-xemacs-performance-kludge-p
6667@vindex enable-xemacs-performance-kludge-p (c-)
3a731e1f 6668XEmacs users can set the variable
d7bd46ed
GM
6669@code{c-enable-xemacs-performance-kludge-p} to non-@code{nil}. This
6670tells @ccmode{} to use XEmacs-specific built-in functions which, in some
3a731e1f 6671circumstances, can locate the top-most opening brace much more quickly than
d7bd46ed 6672@code{beginning-of-defun}. Preliminary testing has shown that for
116e44a1 6673styles where these braces are hung (e.g. most JDK-derived Java styles),
d7bd46ed
GM
6674this hack can improve performance of the core syntax parsing routines
6675from 3 to 60 times. However, for styles which @emph{do} conform to
6676Emacs' recommended style of putting top-level braces in column zero,
6677this hack can degrade performance by about as much. Thus this variable
3a731e1f
MS
6678is set to @code{nil} by default, since the Emacs-friendly styles should
6679be more common (and encouraged!). Note that this variable has no effect
6680in Emacs since the necessary built-in functions don't exist (in Emacs
668121.3 as of this writing in May 2003).
6682
6683Text properties are used to speed up skipping over syntactic whitespace,
116e44a1 6684i.e. comments and preprocessor directives. Indenting a line after a
3a731e1f
MS
6685huge macro definition can be slow the first time, but after that the
6686text properties are in place and it should be fast (even after you've
6687edited other parts of the file and then moved back).
6688
6689Font locking can be a CPU hog, especially the font locking done on
6690decoration level 3 which tries to be very accurate. Note that that
6691level is designed to be used with a font lock support mode that only
116e44a1 6692fontifies the text that's actually shown, i.e. Lazy Lock or Just-in-time
3a731e1f
MS
6693Lock mode, so make sure you use one of them. Fontification of a whole
6694buffer with some thousand lines can often take over a minute. That is
6695a known weakness; the idea is that it never should happen.
6696
6697The most effective way to speed up font locking is to reduce the
6698decoration level to 2 by setting @code{font-lock-maximum-decoration}
6699appropriately. That level is designed to be as pretty as possible
6700without sacrificing performance. @xref{Font Locking Preliminaries}, for
6701more info.
6bf7aab6
DL
6702
6703
cb7f2e96 6704@comment !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
116e44a1 6705@node Limitations and Known Bugs, FAQ, Performance Issues, Top
cb7f2e96 6706@comment node-name, next, previous, up
3a731e1f 6707@chapter Limitations and Known Bugs
cb7f2e96
GM
6708@cindex limitations
6709@cindex bugs
6710@comment !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
6711
6712@itemize @bullet
6713@item
116e44a1
AM
6714There is no way to apply auto newline settings (@pxref{Auto-newlines})
6715on already typed lines. That's only a feature to ease interactive
6716editing.
cb7f2e96 6717
3a731e1f
MS
6718To generalize this issue a bit: @ccmode{} is not intended to be used as
6719a reformatter for old code in some more or less batch-like way. With
6720the exception of some functions like @code{c-indent-region}, it's only
6721geared to be used interactively to edit new code. There's currently no
6722intention to change this goal.
6723
6724If you want to reformat old code, you're probably better off using some
116e44a1 6725other tool instead, e.g. @ref{Top, , GNU indent, indent, The `indent'
3a731e1f
MS
6726Manual}, which has more powerful reformatting capabilities than
6727@ccmode{}.
cb7f2e96 6728
cb7f2e96 6729@item
116e44a1
AM
6730The support for C++ templates (in angle brackets) is not yet complete.
6731When a non-nested template is used in a declaration, @ccmode{} indents
6732it and font-locks it OK. Templates used in expressions, and nested
6733templates do not fare so well. Sometimes a workaround is to refontify
6734the expression after typing the closing @samp{>}.
cb7f2e96
GM
6735@end itemize
6736
6bf7aab6 6737@comment !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
116e44a1 6738@node FAQ, Updating CC Mode, Limitations and Known Bugs, Top
d7bd46ed 6739@comment node-name, next, previous, up
cb7f2e96 6740@appendix Frequently Asked Questions
6bf7aab6
DL
6741@comment !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
6742
3a731e1f
MS
6743@itemize @bullet
6744@item
116e44a1 6745@emph{How can I change the indent level from 4 spaces to 2 spaces?}
6bf7aab6 6746
116e44a1 6747Set the variable @code{c-basic-offset}. @xref{Getting Started}.
6bf7aab6 6748
3a731e1f
MS
6749@item
6750@kindex RET
6751@kindex C-j
6752@emph{Why doesn't the @kbd{RET} key indent the new line?}
6bf7aab6 6753
3a731e1f
MS
6754Emacs' convention is that @kbd{RET} just adds a newline, and that
6755@kbd{C-j} adds a newline and indents it. You can make @kbd{RET} do this
116e44a1 6756too by adding this to your @code{c-initialization-hook}:
6bf7aab6 6757
6bf7aab6 6758@example
d7bd46ed 6759(define-key c-mode-base-map "\C-m" 'c-context-line-break)
6bf7aab6
DL
6760@end example
6761
116e44a1
AM
6762@xref{Getting Started}. This is a very common question. If you want
6763this to be the default behavior, don't lobby us, lobby RMS! @t{:-)}
6764
6765@item
6766@emph{How do I stop my code jumping all over the place when I type?}
6767
6768Deactivate ``electric minor mode'' with @kbd{C-c C-l}. @xref{Getting
6769Started}.
6770
6771@item
6772@kindex C-x h
6773@kindex C-M-\
6774@emph{How do I reindent the whole file?}
6775
6776Visit the file and hit @kbd{C-x h} to mark the whole buffer. Then hit
6777@kbd{C-M-\}. @xref{Indentation Commands}.
6778
6779@item
6780@kindex C-M-q
6781@kindex C-M-u
6782@emph{How do I reindent the current block?}
6783
6784First move to the brace which opens the block with @kbd{C-M-u}, then
6785reindent that expression with @kbd{C-M-q}. @xref{Indentation
6786Commands}.
6bf7aab6 6787
3a731e1f
MS
6788@item
6789@emph{I put @code{(c-set-offset 'substatement-open 0)} in my
6790@file{.emacs} file but I get an error saying that @code{c-set-offset}'s
6791function definition is void. What's wrong?}
6bf7aab6 6792
116e44a1
AM
6793This means that @ccmode{} hasn't yet been loaded into your Emacs
6794session by the time the @code{c-set-offset} call is reached, most
6795likely because @ccmode{} is being autoloaded. Instead of putting the
6796@code{c-set-offset} line in your top-level @file{.emacs} file, put it
6797in your @code{c-initialization-hook} (@pxref{CC Hooks}), or simply
6798modify @code{c-offsets-alist} directly:
f214c025 6799
3a731e1f
MS
6800@example
6801(setq c-offsets-alist '((substatement-open . 0)))
6bf7aab6
DL
6802@end example
6803
2a15eb73
MS
6804@item
6805@cindex open paren in column zero
6806@emph{I have an open paren character at column zero inside a comment or
6807multiline string literal, and it causes the fontification and/or
6808indentation to go haywire. What gives?}
6809
6810It's due to the ad-hoc rule in (X)Emacs that such open parens always
6811start defuns (which translates to functions, classes, namespaces or any
6812other top-level block constructs in the @ccmode{} languages).
116e44a1
AM
6813@ifset XEMACS
6814@xref{Defuns,,, xemacs, XEmacs User's Manual}, for details.
6815@end ifset
6816@ifclear XEMACS
6817@xref{Left Margin Paren,,, emacs, GNU Emacs Manual}, for details
6818(@xref{Defuns,,, emacs, GNU Emacs Manual}, in the Emacs 20 manual).
6819@end ifclear
2a15eb73
MS
6820
6821This heuristic is built into the core syntax analysis routines in
116e44a1
AM
6822(X)Emacs, so it's not really a @ccmode{} issue. However, in Emacs
682321.1 it became possible to turn it off@footnote{Using the variable
2a15eb73 6824@code{open-paren-in-column-0-is-defun-start}.} and @ccmode{} does so
116e44a1 6825there since it's got its own system to keep track of blocks.
2a15eb73 6826
3a731e1f 6827@end itemize
6bf7aab6
DL
6828
6829
6830@comment !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
116e44a1 6831@node Updating CC Mode, Mailing Lists and Bug Reports, FAQ, Top
d7bd46ed 6832@comment node-name, next, previous, up
cb7f2e96 6833@appendix Getting the Latest CC Mode Release
6bf7aab6
DL
6834@comment !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
6835
3a731e1f
MS
6836@ccmode{} has been standard with all versions of Emacs since 19.34 and
6837of XEmacs since 19.16.
d7bd46ed 6838
3a731e1f 6839@cindex web site
d7bd46ed 6840Due to release schedule skew, it is likely that all of these Emacsen
177c0ea7 6841have old versions of @ccmode{} and so should be upgraded. Access to the
d7bd46ed 6842@ccmode{} source code, as well as more detailed information on Emacsen
3a731e1f 6843compatibility, etc. are all available on the web site:
6bf7aab6 6844
3a731e1f
MS
6845@quotation
6846@uref{http://cc-mode.sourceforge.net/}
6847@end quotation
6bf7aab6 6848
6bf7aab6 6849
cb7f2e96 6850@comment !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
116e44a1 6851@node Mailing Lists and Bug Reports, Command and Function Index, Updating CC Mode, Top
cb7f2e96
GM
6852@comment node-name, next, previous, up
6853@appendix Mailing Lists and Submitting Bug Reports
cb7f2e96
GM
6854@comment !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
6855
6856@kindex C-c C-b
6857@findex c-submit-bug-report
6858@findex submit-bug-report (c-)
3a731e1f
MS
6859To report bugs, use the @kbd{C-c C-b} (bound to
6860@code{c-submit-bug-report}) command. This provides vital information
6861we need to reproduce your problem. Make sure you include a concise,
6862but complete code example. Please try to boil your example down to
6863just the essential code needed to reproduce the problem, and include
6864an exact recipe of steps needed to expose the bug. Be especially sure
6865to include any code that appears @emph{before} your bug example, if
6866you think it might affect our ability to reproduce it.
cb7f2e96
GM
6867
6868Please try to produce the problem in an Emacs instance without any
116e44a1
AM
6869customizations loaded (i.e. start it with the @samp{-q -no-site-file}
6870arguments). If it works correctly there, the problem might be caused
6871by faulty customizations in either your own or your site
6872configuration. In that case, we'd appreciate if you isolate the Emacs
6873Lisp code that triggers the bug and include it in your report.
cb7f2e96
GM
6874
6875@cindex bug report mailing list
116e44a1
AM
6876Bug reports should be sent to @email{bug-cc-mode@@gnu.org}. You can
6877also send other questions and suggestions (kudos? @t{;-)} to that
6878address. It's a mailing list which you can join or browse an archive
6879of; see the web site at @uref{http://cc-mode.sourceforge.net/} for
6880further details.
cb7f2e96
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6881
6882@cindex announcement mailing list
6883If you want to get announcements of new @ccmode{} releases, send the
6884word @emph{subscribe} in the body of a message to
3a731e1f
MS
6885@email{cc-mode-announce-request@@lists.sourceforge.net}. It's possible
6886to subscribe from the web site too. Announcements will also be posted
116e44a1
AM
6887to the Usenet newsgroups @code{gnu.emacs.sources}, @code{comp.emacs},
6888@code{comp.emacs.xemacs}, @code{comp.lang.c}, @code{comp.lang.c++},
6889@code{comp.lang.objective-c}, @code{comp.lang.java.softwaretools},
6890@code{comp.lang.idl}, and @code{comp.lang.awk}.
6891@c There is no newsgroup for Pike. :-(
cb7f2e96 6892
116e44a1 6893@c Removed the tentative node "Mode Initialization" from here, 2005/8/27.
6bf7aab6 6894@comment !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
116e44a1 6895@node Command and Function Index, Variable Index, Mailing Lists and Bug Reports, Top
d7bd46ed 6896@comment node-name, next, previous, up
3a731e1f 6897@unnumbered Command and Function Index
d7bd46ed 6898@comment !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
6bf7aab6 6899
3a731e1f
MS
6900Since most @ccmode{} commands are prepended with the string
6901@samp{c-}, each appears under its @code{c-@var{thing}} name and its
6902@code{@var{thing} (c-)} name.
6903@iftex
6904@sp 2
6905@end iftex
6906@printindex fn
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6907
6908
d7bd46ed 6909@comment !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
116e44a1 6910@node Variable Index, Concept and Key Index, Command and Function Index, Top
d7bd46ed 6911@comment node-name, next, previous, up
3a731e1f 6912@unnumbered Variable Index
d7bd46ed 6913@comment !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
6bf7aab6 6914
3a731e1f
MS
6915Since most @ccmode{} variables are prepended with the string
6916@samp{c-}, each appears under its @code{c-@var{thing}} name and its
6917@code{@var{thing} (c-)} name.
6bf7aab6
DL
6918@iftex
6919@sp 2
6920@end iftex
3a731e1f 6921@printindex vr
6bf7aab6
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6922
6923
d7bd46ed 6924@comment !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
116e44a1 6925@node Concept and Key Index, , Variable Index, Top
d7bd46ed 6926@comment node-name, next, previous, up
116e44a1 6927@unnumbered Concept and Key Index
d7bd46ed 6928@comment !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
6bf7aab6 6929
3a731e1f 6930@printindex cp
6bf7aab6
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6931
6932
d7bd46ed 6933@comment !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
3a731e1f 6934@comment Epilogue.
d7bd46ed 6935@comment !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
6bf7aab6 6936
cb7f2e96 6937@iftex
6bf7aab6
DL
6938@page
6939@summarycontents
6940@contents
cb7f2e96
GM
6941@end iftex
6942
6bf7aab6 6943@bye
ab5796a9
MB
6944
6945@ignore
6946 arch-tag: c4cab162-5e57-4366-bdce-4a9db2fc97f0
6947@end ignore