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6bf7aab6 | 1 | @c This is part of the Emacs manual. |
40279251 | 2 | @c Copyright (C) 1985, 1986, 1987, 1993, 1994, 1995, 1997, 1999, 2000, |
8d99e09d | 3 | @c 2001, 2002, 2003, 2004, 2005, 2006 Free Software Foundation, Inc. |
6bf7aab6 DL |
4 | @c See file emacs.texi for copying conditions. |
5 | @node Programs, Building, Text, Top | |
6 | @chapter Editing Programs | |
7 | @cindex Lisp editing | |
8 | @cindex C editing | |
9 | @cindex program editing | |
10 | ||
e79c6b89 RS |
11 | Emacs provides many features to facilitate editing programs. Some |
12 | of these features can | |
6bf7aab6 DL |
13 | |
14 | @itemize @bullet | |
15 | @item | |
93da5dff | 16 | Find or move over top-level definitions (@pxref{Defuns}). |
6bf7aab6 | 17 | @item |
93da5dff RS |
18 | Apply the usual indentation conventions of the language |
19 | (@pxref{Program Indent}). | |
6bf7aab6 | 20 | @item |
93da5dff | 21 | Balance parentheses (@pxref{Parentheses}). |
cf1c48d4 | 22 | @item |
ea118de1 SE |
23 | Insert, kill or align comments (@pxref{Comments}). |
24 | @item | |
cf1c48d4 | 25 | Highlight program syntax (@pxref{Font Lock}). |
6bf7aab6 DL |
26 | @end itemize |
27 | ||
e79c6b89 RS |
28 | This chapter describes these features and many more. |
29 | ||
6bf7aab6 DL |
30 | @menu |
31 | * Program Modes:: Major modes for editing programs. | |
93da5dff RS |
32 | * Defuns:: Commands to operate on major top-level parts |
33 | of a program. | |
6bf7aab6 | 34 | * Program Indent:: Adjusting indentation to show the nesting. |
93da5dff | 35 | * Parentheses:: Commands that operate on parentheses. |
c8b21b5e | 36 | * Comments:: Inserting, killing, and aligning comments. |
93da5dff | 37 | * Documentation:: Getting documentation of functions you plan to call. |
51ed0ea0 | 38 | * Hideshow:: Displaying blocks selectively. |
93da5dff | 39 | * Symbol Completion:: Completion on symbol names of your program or language. |
3b8b8888 | 40 | * Glasses:: Making identifiersLikeThis more readable. |
93da5dff | 41 | * Misc for Programs:: Other Emacs features useful for editing programs. |
79214ddf | 42 | * C Modes:: Special commands of C, C++, Objective-C, |
6bf7aab6 | 43 | Java, and Pike modes. |
51ed0ea0 | 44 | * Asm Mode:: Asm mode and its special features. |
b23ef7a5 EZ |
45 | @ifnottex |
46 | * Fortran:: Fortran mode and its special features. | |
47 | @end ifnottex | |
6bf7aab6 DL |
48 | @end menu |
49 | ||
50 | @node Program Modes | |
51 | @section Major Modes for Programming Languages | |
6bf7aab6 | 52 | @cindex modes for programming languages |
cf1c48d4 RS |
53 | |
54 | Emacs has specialized major modes for various programming languages. | |
55 | @xref{Major Modes}. A programming language major mode typically | |
56 | specifies the syntax of expressions, the customary rules for | |
57 | indentation, how to do syntax highlighting for the language, and how | |
e79c6b89 RS |
58 | to find the beginning of a function definition. It often customizes |
59 | or provides facilities for compiling and debugging programs as well. | |
cf1c48d4 RS |
60 | |
61 | Ideally, Emacs should provide a major mode for each programming | |
62 | language that you might want to edit; if it doesn't have a mode for | |
63 | your favorite language, you can contribute one. But often the mode | |
64 | for one language can serve for other syntactically similar languages. | |
65 | The major mode for language @var{l} is called @code{@var{l}-mode}, | |
e79c6b89 | 66 | and you can select it by typing @kbd{M-x @var{l}-mode @key{RET}}. |
cf1c48d4 RS |
67 | @xref{Choosing Modes}. |
68 | ||
6bf7aab6 DL |
69 | @cindex Perl mode |
70 | @cindex Icon mode | |
6bf7aab6 DL |
71 | @cindex Makefile mode |
72 | @cindex Tcl mode | |
73 | @cindex CPerl mode | |
138a8f12 DL |
74 | @cindex DSSSL mode |
75 | @cindex Octave mode | |
76 | @cindex Metafont mode | |
77 | @cindex Modula2 mode | |
78 | @cindex Prolog mode | |
64e207c0 | 79 | @cindex Python mode |
138a8f12 DL |
80 | @cindex Simula mode |
81 | @cindex VHDL mode | |
82 | @cindex M4 mode | |
83 | @cindex Shell-script mode | |
3b8b8888 DL |
84 | @cindex Delphi mode |
85 | @cindex PostScript mode | |
8758a7da RS |
86 | @cindex Conf mode |
87 | @cindex DNS mode | |
cf1c48d4 RS |
88 | The existing programming language major modes include Lisp, Scheme (a |
89 | variant of Lisp) and the Scheme-based DSSSL expression language, Ada, | |
ea118de1 | 90 | ASM, AWK, C, C++, Delphi (Object Pascal), Fortran (free format and fixed |
cf1c48d4 RS |
91 | format), Icon, IDL (CORBA), IDLWAVE, Java, Metafont (@TeX{}'s |
92 | companion for font creation), Modula2, Objective-C, Octave, Pascal, | |
8758a7da RS |
93 | Perl, Pike, PostScript, Prolog, Python, Simula, Tcl, and VHDL. An |
94 | alternative mode for Perl is called CPerl mode. Modes are available for | |
95 | the scripting languages of the common GNU and Unix shells, VMS DCL, and | |
cf1c48d4 | 96 | MS-DOS/MS-Windows @samp{BAT} files. There are also major modes for |
8758a7da RS |
97 | editing makefiles, DNS master files, and various sorts of configuration |
98 | files. | |
6bf7aab6 DL |
99 | |
100 | @kindex DEL @r{(programming modes)} | |
4f7666dc | 101 | @findex c-electric-backspace |
93da5dff RS |
102 | In most programming languages, indentation should vary from line to |
103 | line to illustrate the structure of the program. So the major modes | |
e79c6b89 RS |
104 | for programming languages arrange for @key{TAB} to update the |
105 | indentation of the current line. They also rebind @key{DEL} to treat | |
106 | a tab as if it were the equivalent number of spaces; this lets you | |
107 | delete one column of indentation without worrying whether the | |
108 | whitespace consists of spaces or tabs. Use @kbd{C-b C-d} to delete a | |
109 | tab character before point, in these modes. | |
6bf7aab6 | 110 | |
cf1c48d4 | 111 | Separate manuals are available for the modes for Ada (@pxref{Top, , Ada |
7ae8ad94 | 112 | Mode, ada-mode, Ada Mode}), C/C++/Objective C/Java/Corba IDL/Pike/AWK |
cf1c48d4 | 113 | (@pxref{Top, , CC Mode, ccmode, CC Mode}) and the IDLWAVE modes |
e0fc8fa2 | 114 | (@pxref{Top, , IDLWAVE, idlwave, IDLWAVE User Manual}). For Fortran |
b23ef7a5 EZ |
115 | mode, see |
116 | @iftex | |
9dc999d3 | 117 | @ref{Fortran,,, emacs-xtra, Specialized Emacs Features}. |
b23ef7a5 EZ |
118 | @end iftex |
119 | @ifnottex | |
120 | @ref{Fortran}. | |
121 | @end ifnottex | |
122 | ||
f9fd7fbc | 123 | |
6bf7aab6 DL |
124 | @cindex mode hook |
125 | @vindex c-mode-hook | |
126 | @vindex lisp-mode-hook | |
127 | @vindex emacs-lisp-mode-hook | |
128 | @vindex lisp-interaction-mode-hook | |
129 | @vindex scheme-mode-hook | |
d2fab838 RS |
130 | Turning on a major mode runs a normal hook called the @dfn{mode |
131 | hook}, which is the value of a Lisp variable. Each major mode has a | |
132 | mode hook, and the hook's name is always made from the mode command's | |
133 | name by adding @samp{-hook}. For example, turning on C mode runs the | |
134 | hook @code{c-mode-hook}, while turning on Lisp mode runs the hook | |
135 | @code{lisp-mode-hook}. The purpose of the mode hook is to give you a | |
136 | place to set up customizations for that major mode. @xref{Hooks}. | |
6bf7aab6 | 137 | |
93da5dff RS |
138 | @node Defuns |
139 | @section Top-Level Definitions, or Defuns | |
6bf7aab6 | 140 | |
108262a0 AM |
141 | In Emacs, a major definition at the top level in the buffer, |
142 | something like a function, is called a @dfn{defun}. The name comes | |
143 | from Lisp, but in Emacs we use it for all languages. | |
6bf7aab6 | 144 | |
93da5dff RS |
145 | @menu |
146 | * Left Margin Paren:: An open-paren or similar opening delimiter | |
147 | starts a defun if it is at the left margin. | |
148 | * Moving by Defuns:: Commands to move over or mark a major definition. | |
149 | * Imenu:: Making buffer indexes as menus. | |
150 | * Which Function:: Which Function mode shows which function you are in. | |
151 | @end menu | |
6bf7aab6 | 152 | |
93da5dff RS |
153 | @node Left Margin Paren |
154 | @subsection Left Margin Convention | |
6bf7aab6 | 155 | |
93da5dff RS |
156 | @cindex open-parenthesis in leftmost column |
157 | @cindex ( in leftmost column | |
108262a0 AM |
158 | Emacs assumes by default that any opening delimiter found at the |
159 | left margin is the start of a top-level definition, or defun. You can | |
160 | override this default by setting this user option: | |
161 | ||
162 | @defvar open-paren-in-column-0-is-defun-start | |
163 | If this user option is set to @code{t} (the default), opening | |
164 | parentheses or braces at column zero always start defuns. When it's | |
165 | @code{nil}, defuns are found by searching for parens or braces at the | |
f5eb910a RS |
166 | outermost level. Some major modes, including C and related modes, set |
167 | @code{open-paren-in-column-0-is-defun-start} buffer-locally to | |
168 | @code{nil} | |
108262a0 AM |
169 | @end defvar |
170 | ||
f5eb910a | 171 | In modes where @code{open-paren-in-column-0-is-defun-start} is |
108262a0 AM |
172 | @code{t}, @strong{don't put an opening delimiter at the left margin |
173 | unless it is a defun start}. For instance, never put an | |
93da5dff | 174 | open-parenthesis at the left margin in a Lisp file unless it is the |
108262a0 | 175 | start of a top-level list. |
93da5dff RS |
176 | |
177 | If you don't follow this convention, not only will you have trouble | |
178 | when you explicitly use the commands for motion by defuns; other | |
179 | features that use them will also give you trouble. This includes | |
180 | the indentation commands (@pxref{Program Indent}) and Font Lock | |
181 | mode (@pxref{Font Lock}). | |
182 | ||
183 | The most likely problem case is when you want an opening delimiter | |
184 | at the start of a line inside a string. To avoid trouble, put an | |
108262a0 AM |
185 | escape character (@samp{\}, in Emacs Lisp, @samp{/} in some other Lisp |
186 | dialects) before the opening delimiter. This will not affect the | |
187 | contents of the string, but will prevent that opening delimiter from | |
188 | starting a defun. Here's an example: | |
6bf7aab6 | 189 | |
93da5dff RS |
190 | @example |
191 | (insert "Foo: | |
192 | \(bar) | |
193 | ") | |
194 | @end example | |
6bf7aab6 | 195 | |
5b8fe684 RS |
196 | To help you catch violations of this convention, Font Lock mode |
197 | highlights confusing opening delimiters (those that ought to be | |
198 | quoted) in bold red. | |
199 | ||
93da5dff RS |
200 | In the earliest days, the original Emacs found defuns by moving |
201 | upward a level of parentheses or braces until there were no more | |
202 | levels to go up. This always required scanning all the way back to | |
203 | the beginning of the buffer, even for a small function. To speed up | |
204 | the operation, we changed Emacs to assume that any opening delimiter | |
205 | at the left margin is the start of a defun. This heuristic is nearly | |
206 | always right, and avoids the need to scan back to the beginning of the | |
108262a0 | 207 | buffer. However, now that modern computers are so powerful, this |
f5eb910a | 208 | scanning is rarely slow enough to annoy, so we've provided a way to |
108262a0 | 209 | disable the heuristic. |
93da5dff RS |
210 | |
211 | @node Moving by Defuns | |
212 | @subsection Moving by Defuns | |
6bf7aab6 DL |
213 | @cindex defuns |
214 | ||
93da5dff RS |
215 | These commands move point or set up the region based on top-level |
216 | major definitions, also called @dfn{defuns}. | |
520c3f4c | 217 | |
6bf7aab6 DL |
218 | @table @kbd |
219 | @item C-M-a | |
220 | Move to beginning of current or preceding defun | |
221 | (@code{beginning-of-defun}). | |
222 | @item C-M-e | |
223 | Move to end of current or following defun (@code{end-of-defun}). | |
224 | @item C-M-h | |
225 | Put region around whole current or following defun (@code{mark-defun}). | |
226 | @end table | |
227 | ||
f772775c RS |
228 | @cindex move to beginning or end of function |
229 | @cindex function, move to beginning or end | |
230 | @kindex C-M-a | |
231 | @kindex C-M-e | |
232 | @kindex C-M-h | |
233 | @findex beginning-of-defun | |
234 | @findex end-of-defun | |
235 | @findex mark-defun | |
236 | The commands to move to the beginning and end of the current defun | |
237 | are @kbd{C-M-a} (@code{beginning-of-defun}) and @kbd{C-M-e} | |
238 | (@code{end-of-defun}). If you repeat one of these commands, or use a | |
239 | positive numeric argument, each repetition moves to the next defun in | |
240 | the direction of motion. | |
241 | ||
242 | @kbd{C-M-a} with a negative argument @minus{}@var{n} moves forward | |
243 | @var{n} times to the next beginning of a defun. This is not exactly | |
244 | the same place that @kbd{C-M-e} with argument @var{n} would move to; | |
245 | the end of this defun is not usually exactly the same place as the | |
93da5dff RS |
246 | beginning of the following defun. (Whitespace, comments, and perhaps |
247 | declarations can separate them.) Likewise, @kbd{C-M-e} with a | |
248 | negative argument moves back to an end of a defun, which is not quite | |
249 | the same as @kbd{C-M-a} with a positive argument. | |
f772775c | 250 | |
4946337d | 251 | @kindex C-M-h @r{(C mode)} |
6bf7aab6 | 252 | @findex c-mark-function |
93da5dff RS |
253 | To operate on the current defun, use @kbd{C-M-h} (@code{mark-defun}) |
254 | which puts point at the beginning and mark at the end of the current | |
5e6f9132 RS |
255 | defun. This is the easiest way to get ready to kill the defun in |
256 | order to move it to a different place in the file. If you use the | |
257 | command while point is between defuns, it uses the following defun. | |
64e207c0 | 258 | Successive uses of @kbd{C-M-h}, or using it in Transient Mark mode |
dfec8297 RS |
259 | when the mark is active, extends the end of the region to include one |
260 | more defun each time. | |
93da5dff RS |
261 | |
262 | In C mode, @kbd{C-M-h} runs the function @code{c-mark-function}, | |
263 | which is almost the same as @code{mark-defun}; the difference is that | |
264 | it backs up over the argument declarations, function name and returned | |
e79c6b89 RS |
265 | data type so that the entire C function is inside the region. This is |
266 | an example of how major modes adjust the standard key bindings so that | |
267 | they do their standard jobs in a way better fitting a particular | |
268 | language. Other major modes may replace any or all of these key | |
269 | bindings for that purpose. | |
6bf7aab6 | 270 | |
93da5dff RS |
271 | @node Imenu |
272 | @subsection Imenu | |
e79c6b89 RS |
273 | @cindex index of buffer definitions |
274 | @cindex buffer definitions index | |
93da5dff RS |
275 | @cindex tags |
276 | ||
269b7745 | 277 | The Imenu facility offers a way to find the major definitions in |
5e6f9132 RS |
278 | a file by name. It is also useful in text formatter major modes, |
279 | where it treats each chapter, section, etc., as a definition. | |
e79c6b89 | 280 | (@xref{Tags}, for a more powerful feature that handles multiple files |
5e6f9132 | 281 | together.) |
93da5dff RS |
282 | |
283 | @findex imenu | |
5e6f9132 | 284 | If you type @kbd{M-x imenu}, it reads the name of a definition using |
e79c6b89 RS |
285 | the minibuffer, then moves point to that definition. You can use |
286 | completion to specify the name; the command always displays the whole | |
287 | list of valid names. | |
d2fab838 | 288 | |
5e6f9132 | 289 | @findex imenu-add-menubar-index |
d2fab838 | 290 | Alternatively, you can bind the command @code{imenu} to a mouse |
e79c6b89 RS |
291 | click. Then it displays mouse menus for you to select a definition |
292 | name. You can also add the buffer's index to the menu bar by calling | |
293 | @code{imenu-add-menubar-index}. If you want to have this menu bar | |
294 | item available for all buffers in a certain major mode, you can do | |
295 | this by adding @code{imenu-add-menubar-index} to its mode hook. But | |
dfec8297 RS |
296 | if you have done that, you will have to wait a little while each time |
297 | you visit a file in that mode, while Emacs finds all the definitions | |
298 | in that buffer. | |
93da5dff RS |
299 | |
300 | @vindex imenu-auto-rescan | |
301 | When you change the contents of a buffer, if you add or delete | |
e79c6b89 | 302 | definitions, you can update the buffer's index based on the |
d2fab838 | 303 | new contents by invoking the @samp{*Rescan*} item in the menu. |
dcace646 EZ |
304 | Rescanning happens automatically if you set @code{imenu-auto-rescan} to |
305 | a non-@code{nil} value. There is no need to rescan because of small | |
e79c6b89 | 306 | changes in the text. |
93da5dff RS |
307 | |
308 | @vindex imenu-sort-function | |
d2fab838 | 309 | You can customize the way the menus are sorted by setting the |
e79c6b89 | 310 | variable @code{imenu-sort-function}. By default, names are ordered as |
5e6f9132 RS |
311 | they occur in the buffer; if you want alphabetic sorting, use the |
312 | symbol @code{imenu--sort-by-name} as the value. You can also | |
313 | define your own comparison function by writing Lisp code. | |
93da5dff RS |
314 | |
315 | Imenu provides the information to guide Which Function mode | |
316 | @ifnottex | |
317 | (@pxref{Which Function}). | |
318 | @end ifnottex | |
319 | @iftex | |
320 | (see below). | |
321 | @end iftex | |
322 | The Speedbar can also use it (@pxref{Speedbar}). | |
323 | ||
324 | @node Which Function | |
325 | @subsection Which Function Mode | |
af056954 | 326 | @cindex current function name in mode line |
93da5dff RS |
327 | |
328 | Which Function mode is a minor mode that displays the current | |
329 | function name in the mode line, updating it as you move around in a | |
330 | buffer. | |
331 | ||
332 | @findex which-function-mode | |
333 | @vindex which-func-modes | |
334 | To enable (or disable) Which Function mode, use the command @kbd{M-x | |
335 | which-function-mode}. This command is global; it applies to all | |
ea118de1 | 336 | buffers, both existing ones and those yet to be created. However, it |
6daf3e15 | 337 | takes effect only in certain major modes, those listed in the value of |
ea118de1 SE |
338 | @code{which-func-modes}. If the value is @code{t}, then Which Function |
339 | mode applies to all major modes that know how to support it---in other | |
340 | words, all the major modes that support Imenu. | |
6bf7aab6 DL |
341 | |
342 | @node Program Indent | |
343 | @section Indentation for Programs | |
344 | @cindex indentation for programs | |
345 | ||
346 | The best way to keep a program properly indented is to use Emacs to | |
347 | reindent it as you change it. Emacs has commands to indent properly | |
348 | either a single line, a specified number of lines, or all of the lines | |
349 | inside a single parenthetical grouping. | |
350 | ||
351 | @menu | |
352 | * Basic Indent:: Indenting a single line. | |
353 | * Multi-line Indent:: Commands to reindent many lines at once. | |
354 | * Lisp Indent:: Specifying how each Lisp function should be indented. | |
355 | * C Indent:: Extra features for indenting C and related modes. | |
356 | * Custom C Indent:: Controlling indentation style for C and related modes. | |
357 | @end menu | |
358 | ||
d2fab838 | 359 | @cindex pretty-printer |
6bf7aab6 DL |
360 | Emacs also provides a Lisp pretty-printer in the library @code{pp}. |
361 | This program reformats a Lisp object with indentation chosen to look nice. | |
362 | ||
363 | @node Basic Indent | |
364 | @subsection Basic Program Indentation Commands | |
365 | ||
d2fab838 RS |
366 | The basic indentation commands indent a single line according to the |
367 | usual conventions of the language you are editing. | |
cf1c48d4 | 368 | |
6bf7aab6 DL |
369 | @table @kbd |
370 | @item @key{TAB} | |
371 | Adjust indentation of current line. | |
372 | @item C-j | |
bb63d706 RS |
373 | Insert a newline, then adjust indentation of following line |
374 | (@code{newline-and-indent}). | |
6bf7aab6 DL |
375 | @end table |
376 | ||
377 | @kindex TAB @r{(programming modes)} | |
4f7666dc RS |
378 | @findex c-indent-command |
379 | @findex indent-line-function | |
f772775c | 380 | @findex indent-for-tab-command |
6bf7aab6 DL |
381 | The basic indentation command is @key{TAB}, which gives the current line |
382 | the correct indentation as determined from the previous lines. The | |
cf1c48d4 | 383 | function that @key{TAB} runs depends on the major mode; it is |
054af0fd | 384 | @code{lisp-indent-line} |
4f7666dc | 385 | in Lisp mode, @code{c-indent-command} in C mode, etc. These functions |
cf1c48d4 RS |
386 | understand the syntax and conventions of different languages, but they all do |
387 | conceptually the same job: @key{TAB} in any programming-language major mode | |
6bf7aab6 | 388 | inserts or deletes whitespace at the beginning of the current line, |
cf1c48d4 RS |
389 | independent of where point is in the line. If point was inside the |
390 | whitespace at the beginning of the line, @key{TAB} puts it at the end of | |
391 | that whitespace; otherwise, @key{TAB} keeps point fixed with respect to | |
6bf7aab6 DL |
392 | the characters around it. |
393 | ||
64e207c0 | 394 | Use @kbd{C-q @key{TAB}} to insert a tab character at point. |
6bf7aab6 DL |
395 | |
396 | @kindex C-j | |
397 | @findex newline-and-indent | |
cf1c48d4 | 398 | When entering lines of new code, use @kbd{C-j} |
bb63d706 | 399 | (@code{newline-and-indent}), which inserts a newline and then adjusts |
14f4194d RS |
400 | indentation after it. (It also deletes any trailing whitespace which |
401 | remains before the new newline.) Thus, @kbd{C-j} at the end of a line | |
402 | creates a blank line with appropriate indentation. In programming | |
403 | language modes, it is equivalent to @key{RET} @key{TAB}. | |
6bf7aab6 | 404 | |
64e207c0 RS |
405 | @key{TAB} indents a line that starts within a parenthetical grouping |
406 | under the preceding line within the grouping, or the text after the | |
407 | parenthesis. Therefore, if you manually give one of these lines a | |
408 | nonstandard indentation, the lines below will tend to follow it. This | |
409 | behavior is convenient in cases where you have overridden the standard | |
410 | result of @key{TAB} because you find it unaesthetic for a particular | |
411 | line. | |
6bf7aab6 | 412 | |
dfec8297 | 413 | In some modes, an open-parenthesis, open-brace or other opening |
108262a0 AM |
414 | delimiter at the left margin is assumed by Emacs (including the |
415 | indentation routines) to be the start of a function. This speeds up | |
416 | indentation commands. If you will be editing text which contains | |
417 | opening delimiters in column zero that aren't the beginning of a | |
418 | functions, even inside strings or comments, you must set | |
419 | @code{open-paren-in-column-0-is-defun-start}. @xref{Left Margin | |
420 | Paren}, for more information on this. | |
6bf7aab6 | 421 | |
5151db0c | 422 | Normally, lines are indented with tabs and spaces. If you want Emacs |
a100894f | 423 | to use spaces only, set @code{indent-tabs-mode} (@pxref{Just Spaces}). |
5151db0c | 424 | |
6bf7aab6 DL |
425 | @node Multi-line Indent |
426 | @subsection Indenting Several Lines | |
427 | ||
93da5dff RS |
428 | When you wish to reindent several lines of code which have been |
429 | altered or moved to a different level in the parenthesis structure, | |
430 | you have several commands available. | |
6bf7aab6 DL |
431 | |
432 | @table @kbd | |
433 | @item C-M-q | |
6daf3e15 | 434 | Reindent all the lines within one parenthetical grouping (@code{indent-pp-sexp}). |
e79c6b89 RS |
435 | @item C-M-\ |
436 | Reindent all lines in the region (@code{indent-region}). | |
6bf7aab6 | 437 | @item C-u @key{TAB} |
93da5dff RS |
438 | Shift an entire parenthetical grouping rigidly sideways so that its |
439 | first line is properly indented. | |
5cc06e0b EZ |
440 | @item M-x indent-code-rigidly |
441 | Shift all the lines in the region rigidly sideways, but do not alter | |
442 | lines that start inside comments and strings. | |
6bf7aab6 DL |
443 | @end table |
444 | ||
445 | @kindex C-M-q | |
6daf3e15 | 446 | @findex indent-pp-sexp |
93da5dff RS |
447 | You can reindent the contents of a single parenthetical grouping by |
448 | positioning point before the beginning of it and typing @kbd{C-M-q} | |
054af0fd | 449 | (@code{indent-pp-sexp} in Lisp mode, @code{c-indent-exp} in C mode; also |
93da5dff | 450 | bound to other suitable commands in other modes). The indentation of |
6daf3e15 | 451 | the line where the grouping starts is not changed; therefore this |
93da5dff RS |
452 | changes only the relative indentation within the grouping, not its |
453 | overall indentation. To correct that as well, type @key{TAB} first. | |
6bf7aab6 | 454 | |
e79c6b89 RS |
455 | Another way to specify the range to be reindented is with the |
456 | region. The command @kbd{C-M-\} (@code{indent-region}) applies | |
457 | @key{TAB} to every line whose first character is between point and | |
458 | mark. | |
459 | ||
6bf7aab6 | 460 | @kindex C-u TAB |
93da5dff RS |
461 | If you like the relative indentation within a grouping, but not the |
462 | indentation of its first line, you can type @kbd{C-u @key{TAB}} to | |
24c7c69c RS |
463 | reindent the whole grouping as a rigid unit. (This works in Lisp |
464 | modes and C and related modes.) @key{TAB} with a numeric argument | |
465 | reindents the current line as usual, then reindents by the same amount | |
466 | all the lines in the parenthetical grouping starting on the current | |
467 | line. It is clever, though, and does not alter lines that start | |
7ae8ad94 RS |
468 | inside strings. Neither does it alter C preprocessor lines when in C |
469 | mode, but it does reindent any continuation lines that may be attached | |
470 | to them. | |
6bf7aab6 | 471 | |
5cc06e0b | 472 | @findex indent-code-rigidly |
e79c6b89 RS |
473 | You can also perform this operation on the region, using the command |
474 | @kbd{M-x indent-code-rigidly}. It rigidly shifts all the lines in the | |
475 | region sideways, like @code{indent-rigidly} does (@pxref{Indentation | |
476 | Commands}). It doesn't alter the indentation of lines that start | |
7ae8ad94 | 477 | inside a string, unless the region also starts inside that string. |
054af0fd | 478 | The prefix arg specifies the number of columns to indent. |
6bf7aab6 DL |
479 | |
480 | @node Lisp Indent | |
481 | @subsection Customizing Lisp Indentation | |
482 | @cindex customizing Lisp indentation | |
483 | ||
484 | The indentation pattern for a Lisp expression can depend on the function | |
485 | called by the expression. For each Lisp function, you can choose among | |
486 | several predefined patterns of indentation, or define an arbitrary one with | |
487 | a Lisp program. | |
488 | ||
489 | The standard pattern of indentation is as follows: the second line of the | |
490 | expression is indented under the first argument, if that is on the same | |
491 | line as the beginning of the expression; otherwise, the second line is | |
492 | indented underneath the function name. Each following line is indented | |
493 | under the previous line whose nesting depth is the same. | |
494 | ||
495 | @vindex lisp-indent-offset | |
496 | If the variable @code{lisp-indent-offset} is non-@code{nil}, it overrides | |
497 | the usual indentation pattern for the second line of an expression, so that | |
498 | such lines are always indented @code{lisp-indent-offset} more columns than | |
499 | the containing list. | |
500 | ||
501 | @vindex lisp-body-indent | |
d2fab838 | 502 | Certain functions override the standard pattern. Functions whose |
269b7745 | 503 | names start with @code{def} treat the second lines as the start of |
d2fab838 RS |
504 | a @dfn{body}, by indenting the second line @code{lisp-body-indent} |
505 | additional columns beyond the open-parenthesis that starts the | |
506 | expression. | |
6bf7aab6 | 507 | |
b771b258 | 508 | @cindex @code{lisp-indent-function} property |
d2fab838 | 509 | You can override the standard pattern in various ways for individual |
690a6d08 RS |
510 | functions, according to the @code{lisp-indent-function} property of |
511 | the function name. Normally you would use this for macro definitions | |
512 | and specify it using the @code{declare} construct (@pxref{Defining | |
513 | Macros,,, elisp, the Emacs Lisp Reference Manual}). | |
6bf7aab6 DL |
514 | |
515 | @node C Indent | |
516 | @subsection Commands for C Indentation | |
517 | ||
93da5dff | 518 | Here are special features for indentation in C mode and related modes: |
6bf7aab6 DL |
519 | |
520 | @table @code | |
521 | @item C-c C-q | |
522 | @kindex C-c C-q @r{(C mode)} | |
523 | @findex c-indent-defun | |
524 | Reindent the current top-level function definition or aggregate type | |
525 | declaration (@code{c-indent-defun}). | |
526 | ||
527 | @item C-M-q | |
528 | @kindex C-M-q @r{(C mode)} | |
529 | @findex c-indent-exp | |
530 | Reindent each line in the balanced expression that follows point | |
7ae8ad94 RS |
531 | (@code{c-indent-exp}). A prefix argument inhibits warning messages |
532 | about invalid syntax. | |
6bf7aab6 DL |
533 | |
534 | @item @key{TAB} | |
535 | @findex c-indent-command | |
536 | Reindent the current line, and/or in some cases insert a tab character | |
537 | (@code{c-indent-command}). | |
538 | ||
7ae8ad94 | 539 | @vindex c-tab-always-indent |
6bf7aab6 DL |
540 | If @code{c-tab-always-indent} is @code{t}, this command always reindents |
541 | the current line and does nothing else. This is the default. | |
542 | ||
543 | If that variable is @code{nil}, this command reindents the current line | |
544 | only if point is at the left margin or in the line's indentation; | |
545 | otherwise, it inserts a tab (or the equivalent number of spaces, | |
546 | if @code{indent-tabs-mode} is @code{nil}). | |
547 | ||
548 | Any other value (not @code{nil} or @code{t}) means always reindent the | |
7ae8ad94 | 549 | line, and also insert a tab if within a comment or a string. |
6bf7aab6 DL |
550 | @end table |
551 | ||
552 | To reindent the whole current buffer, type @kbd{C-x h C-M-\}. This | |
553 | first selects the whole buffer as the region, then reindents that | |
554 | region. | |
555 | ||
556 | To reindent the current block, use @kbd{C-M-u C-M-q}. This moves | |
557 | to the front of the block and then reindents it all. | |
558 | ||
559 | @node Custom C Indent | |
560 | @subsection Customizing C Indentation | |
93da5dff | 561 | @cindex style (for indentation) |
6bf7aab6 | 562 | |
7ae8ad94 RS |
563 | C mode and related modes use a flexible mechanism for customizing |
564 | indentation. C mode indents a source line in two steps: first it | |
565 | classifies the line syntactically according to its contents and | |
566 | context; second, it determines the indentation offset associated by | |
567 | your selected @dfn{style} with the syntactic construct and adds this | |
568 | onto the indentation of the @dfn{anchor statement}. | |
6bf7aab6 | 569 | |
93da5dff | 570 | @table @kbd |
7ae8ad94 RS |
571 | @item C-c . @key{RET} @var{style} @key{RET} |
572 | Select a predefined style @var{style} (@code{c-set-style}). | |
93da5dff | 573 | @end table |
6bf7aab6 | 574 | |
108262a0 AM |
575 | A @dfn{style} is a named collection of customizations that can be |
576 | used in C mode and the related modes. @ref{Styles,,, ccmode, The CC | |
577 | Mode Manual}, for a complete description. Emacs comes with several | |
93da5dff RS |
578 | predefined styles, including @code{gnu}, @code{k&r}, @code{bsd}, |
579 | @code{stroustrup}, @code{linux}, @code{python}, @code{java}, | |
108262a0 AM |
580 | @code{whitesmith}, @code{ellemtel}, and @code{awk}. Some of these |
581 | styles are primarily intended for one language, but any of them can be | |
582 | used with any of the languages supported by these modes. To find out | |
583 | what a style looks like, select it and reindent some code, e.g., by | |
584 | typing @key{C-M-q} at the start of a function definition. | |
6bf7aab6 | 585 | |
7ae8ad94 | 586 | @kindex C-c . @r{(C mode)} |
93da5dff | 587 | @findex c-set-style |
dfec8297 RS |
588 | To choose a style for the current buffer, use the command @w{@kbd{C-c |
589 | .}}. Specify a style name as an argument (case is not significant). | |
7ae8ad94 RS |
590 | This command affects the current buffer only, and it affects only |
591 | future invocations of the indentation commands; it does not reindent | |
108262a0 AM |
592 | the code already in the buffer. To reindent the whole buffer in the |
593 | new style, you can type @kbd{C-x h C-M-\}. | |
6bf7aab6 | 594 | |
93da5dff RS |
595 | @vindex c-default-style |
596 | You can also set the variable @code{c-default-style} to specify the | |
7ae8ad94 RS |
597 | default style for various major modes. Its value should be either the |
598 | style's name (a string) or an alist, in which each element specifies | |
599 | one major mode and which indentation style to use for it. For | |
600 | example, | |
6bf7aab6 DL |
601 | |
602 | @example | |
93da5dff | 603 | (setq c-default-style |
108262a0 | 604 | '((java-mode . "java") (awk-mode . "awk") (other . "gnu"))) |
6bf7aab6 DL |
605 | @end example |
606 | ||
93da5dff | 607 | @noindent |
108262a0 AM |
608 | specifies explicit choices for Java and AWK modes, and the default |
609 | @samp{gnu} style for the other C-like modes. (These settings are | |
610 | actually the defaults.) This variable takes effect when you select | |
611 | one of the C-like major modes; thus, if you specify a new default | |
612 | style for Java mode, you can make it take effect in an existing Java | |
613 | mode buffer by typing @kbd{M-x java-mode} there. | |
6bf7aab6 | 614 | |
93da5dff RS |
615 | The @code{gnu} style specifies the formatting recommended by the GNU |
616 | Project for C; it is the default, so as to encourage use of our | |
617 | recommended style. | |
6bf7aab6 | 618 | |
108262a0 AM |
619 | @xref{Indentation Engine Basics,,, ccmode, the CC Mode Manual}, and |
620 | @ref{Customizing Indentation,,, ccmode, the CC Mode Manual}, for more | |
621 | information on customizing indentation for C and related modes, | |
93da5dff RS |
622 | including how to override parts of an existing style and how to define |
623 | your own styles. | |
6bf7aab6 | 624 | |
93da5dff RS |
625 | @node Parentheses |
626 | @section Commands for Editing with Parentheses | |
6bf7aab6 | 627 | |
93da5dff RS |
628 | @findex check-parens |
629 | @cindex unbalanced parentheses and quotes | |
630 | This section describes the commands and features that take advantage | |
631 | of the parenthesis structure in a program, or help you keep it | |
632 | balanced. | |
6bf7aab6 | 633 | |
93da5dff RS |
634 | When talking about these facilities, the term ``parenthesis'' also |
635 | includes braces, brackets, or whatever delimiters are defined to match | |
e79c6b89 RS |
636 | in pairs. The major mode controls which delimiters are significant, |
637 | through the syntax table (@pxref{Syntax}). In Lisp, only parentheses | |
638 | count; in C, these commands apply to braces and brackets too. | |
6bf7aab6 | 639 | |
93da5dff RS |
640 | You can use @kbd{M-x check-parens} to find any unbalanced |
641 | parentheses and unbalanced string quotes in the buffer. | |
6bf7aab6 | 642 | |
93da5dff RS |
643 | @menu |
644 | * Expressions:: Expressions with balanced parentheses. | |
645 | * Moving by Parens:: Commands for moving up, down and across | |
646 | in the structure of parentheses. | |
647 | * Matching:: Insertion of a close-delimiter flashes matching open. | |
648 | @end menu | |
6bf7aab6 | 649 | |
93da5dff RS |
650 | @node Expressions |
651 | @subsection Expressions with Balanced Parentheses | |
6bf7aab6 | 652 | |
93da5dff RS |
653 | @cindex sexp |
654 | @cindex expression | |
655 | @cindex balanced expression | |
656 | These commands deal with balanced expressions, also called | |
657 | @dfn{sexps}@footnote{The word ``sexp'' is used to refer to an | |
658 | expression in Lisp.}. | |
6bf7aab6 | 659 | |
93da5dff RS |
660 | @table @kbd |
661 | @item C-M-f | |
662 | Move forward over a balanced expression (@code{forward-sexp}). | |
663 | @item C-M-b | |
ea118de1 | 664 | Move backward over a balanced expression (@code{backward-sexp}). |
93da5dff RS |
665 | @item C-M-k |
666 | Kill balanced expression forward (@code{kill-sexp}). | |
93da5dff RS |
667 | @item C-M-t |
668 | Transpose expressions (@code{transpose-sexps}). | |
669 | @item C-M-@@ | |
649d1cbe | 670 | @itemx C-M-@key{SPC} |
93da5dff RS |
671 | Put mark after following expression (@code{mark-sexp}). |
672 | @end table | |
6bf7aab6 | 673 | |
93da5dff RS |
674 | Each programming language major mode customizes the definition of |
675 | balanced expressions to suit that language. Balanced expressions | |
676 | typically include symbols, numbers, and string constants, as well as | |
e79c6b89 | 677 | any pair of matching delimiters and their contents. Some languages |
93da5dff RS |
678 | have obscure forms of expression syntax that nobody has bothered to |
679 | implement in Emacs. | |
6bf7aab6 | 680 | |
93da5dff | 681 | @cindex Control-Meta |
e79c6b89 RS |
682 | By convention, the keys for these commands are all Control-Meta |
683 | characters. They usually act on expressions just as the corresponding | |
684 | Meta characters act on words. For instance, the command @kbd{C-M-b} | |
685 | moves backward over a balanced expression, just as @kbd{M-b} moves | |
686 | back over a word. | |
6bf7aab6 | 687 | |
93da5dff RS |
688 | @kindex C-M-f |
689 | @kindex C-M-b | |
690 | @findex forward-sexp | |
691 | @findex backward-sexp | |
692 | To move forward over a balanced expression, use @kbd{C-M-f} | |
693 | (@code{forward-sexp}). If the first significant character after point | |
694 | is an opening delimiter (@samp{(} in Lisp; @samp{(}, @samp{[} or | |
695 | @samp{@{} in C), @kbd{C-M-f} moves past the matching closing | |
696 | delimiter. If the character begins a symbol, string, or number, | |
697 | @kbd{C-M-f} moves over that. | |
6bf7aab6 | 698 | |
93da5dff RS |
699 | The command @kbd{C-M-b} (@code{backward-sexp}) moves backward over a |
700 | balanced expression. The detailed rules are like those above for | |
701 | @kbd{C-M-f}, but with directions reversed. If there are prefix | |
702 | characters (single-quote, backquote and comma, in Lisp) preceding the | |
703 | expression, @kbd{C-M-b} moves back over them as well. The balanced | |
704 | expression commands move across comments as if they were whitespace, | |
705 | in most modes. | |
6bf7aab6 | 706 | |
93da5dff RS |
707 | @kbd{C-M-f} or @kbd{C-M-b} with an argument repeats that operation the |
708 | specified number of times; with a negative argument, it moves in the | |
709 | opposite direction. | |
6bf7aab6 | 710 | |
93da5dff RS |
711 | @cindex killing expressions |
712 | @kindex C-M-k | |
713 | @findex kill-sexp | |
93da5dff | 714 | Killing a whole balanced expression can be done with @kbd{C-M-k} |
880b0421 RS |
715 | (@code{kill-sexp}). @kbd{C-M-k} kills the characters that @kbd{C-M-f} |
716 | would move over. | |
6bf7aab6 | 717 | |
93da5dff RS |
718 | @cindex transposition of expressions |
719 | @kindex C-M-t | |
720 | @findex transpose-sexps | |
721 | A somewhat random-sounding command which is nevertheless handy is | |
722 | @kbd{C-M-t} (@code{transpose-sexps}), which drags the previous | |
723 | balanced expression across the next one. An argument serves as a | |
108262a0 AM |
724 | repeat count, moving the previous expression over that many following |
725 | ones. A negative argument drags the previous balanced expression | |
726 | backwards across those before it (thus canceling out the effect of | |
727 | @kbd{C-M-t} with a positive argument). An argument of zero, rather | |
728 | than doing nothing, transposes the balanced expressions ending at or | |
729 | after point and the mark. | |
6bf7aab6 | 730 | |
93da5dff | 731 | @kindex C-M-@@ |
649d1cbe | 732 | @kindex C-M-@key{SPC} |
93da5dff RS |
733 | @findex mark-sexp |
734 | To set the region around the next balanced expression in the buffer, | |
735 | use @kbd{C-M-@@} (@code{mark-sexp}), which sets mark at the same place | |
736 | that @kbd{C-M-f} would move to. @kbd{C-M-@@} takes arguments like | |
737 | @kbd{C-M-f}. In particular, a negative argument is useful for putting | |
64e207c0 | 738 | the mark at the beginning of the previous balanced expression. The |
108262a0 AM |
739 | alias @kbd{C-M-@key{SPC}} is equivalent to @kbd{C-M-@@}. When you |
740 | repeat this command, or use it in Transient Mark mode when the mark is | |
dfec8297 | 741 | active, it extends the end of the region by one sexp each time. |
93da5dff RS |
742 | |
743 | In languages that use infix operators, such as C, it is not possible | |
744 | to recognize all balanced expressions as such because there can be | |
745 | multiple possibilities at a given position. For example, C mode does | |
746 | not treat @samp{foo + bar} as a single expression, even though it | |
747 | @emph{is} one C expression; instead, it recognizes @samp{foo} as one | |
748 | expression and @samp{bar} as another, with the @samp{+} as punctuation | |
749 | between them. Both @samp{foo + bar} and @samp{foo} are legitimate | |
750 | choices for ``the expression following point'' when point is at the | |
e79c6b89 RS |
751 | @samp{f}, so the expression commands must perforce choose one or the |
752 | other to operate on. Note that @samp{(foo + bar)} is recognized as a | |
753 | single expression in C mode, because of the parentheses. | |
93da5dff RS |
754 | |
755 | @node Moving by Parens | |
756 | @subsection Moving in the Parenthesis Structure | |
757 | ||
758 | @cindex parenthetical groupings | |
759 | @cindex parentheses, moving across | |
760 | @cindex matching parenthesis and braces, moving to | |
761 | @cindex braces, moving across | |
762 | @cindex list commands | |
763 | The Emacs commands for handling parenthetical groupings see nothing | |
764 | except parentheses (or whatever characters must balance in the | |
765 | language you are working with), and the escape characters that might | |
766 | be used to quote those. They are mainly intended for editing | |
767 | programs, but can be useful for editing any text that has parentheses. | |
768 | They are sometimes called ``list'' commands because in Lisp these | |
769 | groupings are lists. | |
6bf7aab6 DL |
770 | |
771 | @table @kbd | |
93da5dff RS |
772 | @item C-M-n |
773 | Move forward over a parenthetical group (@code{forward-list}). | |
774 | @item C-M-p | |
ea118de1 | 775 | Move backward over a parenthetical group (@code{backward-list}). |
93da5dff RS |
776 | @item C-M-u |
777 | Move up in parenthesis structure (@code{backward-up-list}). | |
778 | @item C-M-d | |
779 | Move down in parenthesis structure (@code{down-list}). | |
6bf7aab6 DL |
780 | @end table |
781 | ||
93da5dff RS |
782 | @kindex C-M-n |
783 | @kindex C-M-p | |
784 | @findex forward-list | |
785 | @findex backward-list | |
786 | The ``list'' commands @kbd{C-M-n} (@code{forward-list}) and | |
787 | @kbd{C-M-p} (@code{backward-list}) move over one (or @var{n}) | |
788 | parenthetical groupings, skipping blithely over any amount of text | |
789 | that doesn't include meaningful parentheses (symbols, strings, etc.). | |
6bf7aab6 | 790 | |
93da5dff | 791 | @kindex C-M-u |
93da5dff | 792 | @findex backward-up-list |
93da5dff RS |
793 | @kbd{C-M-n} and @kbd{C-M-p} try to stay at the same level in the |
794 | parenthesis structure. To move @emph{up} one (or @var{n}) levels, use | |
795 | @kbd{C-M-u} (@code{backward-up-list}). @kbd{C-M-u} moves backward up | |
796 | past one unmatched opening delimiter. A positive argument serves as a | |
797 | repeat count; a negative argument reverses the direction of motion, so | |
d2fab838 | 798 | that the command moves forward and up one or more levels. |
93da5dff | 799 | |
dfec8297 RS |
800 | @kindex C-M-d |
801 | @findex down-list | |
93da5dff RS |
802 | To move @emph{down} in the parenthesis structure, use @kbd{C-M-d} |
803 | (@code{down-list}). In Lisp mode, where @samp{(} is the only opening | |
804 | delimiter, this is nearly the same as searching for a @samp{(}. An | |
805 | argument specifies the number of levels to go down. | |
6bf7aab6 DL |
806 | |
807 | @node Matching | |
93da5dff | 808 | @subsection Automatic Display Of Matching Parentheses |
6bf7aab6 DL |
809 | @cindex matching parentheses |
810 | @cindex parentheses, displaying matches | |
811 | ||
812 | The Emacs parenthesis-matching feature is designed to show | |
93da5dff RS |
813 | automatically how parentheses (and other matching delimiters) match in |
814 | the text. Whenever you type a self-inserting character that is a | |
815 | closing delimiter, the cursor moves momentarily to the location of the | |
816 | matching opening delimiter, provided that is on the screen. If it is | |
e79c6b89 RS |
817 | not on the screen, Emacs displays some of the text near it in the echo |
818 | area. Either way, you can tell which grouping you are closing off. | |
93da5dff RS |
819 | |
820 | If the opening delimiter and closing delimiter are mismatched---such | |
821 | as in @samp{[x)}---a warning message is displayed in the echo area. | |
6bf7aab6 DL |
822 | |
823 | @vindex blink-matching-paren | |
824 | @vindex blink-matching-paren-distance | |
825 | @vindex blink-matching-delay | |
054af0fd SE |
826 | Three variables control parenthesis match display: |
827 | ||
828 | @code{blink-matching-paren} turns the feature on or off: @code{nil} | |
93da5dff | 829 | disables it, but the default is @code{t} to enable match display. |
f772775c RS |
830 | |
831 | @code{blink-matching-delay} says how many seconds to leave the | |
93da5dff | 832 | cursor on the matching opening delimiter, before bringing it back to |
f772775c RS |
833 | the real location of point; the default is 1, but on some systems it |
834 | is useful to specify a fraction of a second. | |
835 | ||
836 | @code{blink-matching-paren-distance} specifies how many characters | |
837 | back to search to find the matching opening delimiter. If the match | |
8b6f4c0a | 838 | is not found in that distance, scanning stops, and nothing is displayed. |
93da5dff | 839 | This is to prevent the scan for the matching delimiter from wasting |
f772775c | 840 | lots of time when there is no match. The default is 25600. |
6bf7aab6 DL |
841 | |
842 | @cindex Show Paren mode | |
79f9f655 | 843 | @cindex highlighting matching parentheses |
6bf7aab6 | 844 | @findex show-paren-mode |
93da5dff RS |
845 | Show Paren mode provides a more powerful kind of automatic matching. |
846 | Whenever point is after a closing delimiter, that delimiter and its | |
847 | matching opening delimiter are both highlighted; otherwise, if point | |
848 | is before an opening delimiter, the matching closing delimiter is | |
849 | highlighted. (There is no need to highlight the opening delimiter in | |
850 | that case, because the cursor appears on top of that character.) Use | |
851 | the command @kbd{M-x show-paren-mode} to enable or disable this mode. | |
79f9f655 | 852 | |
dfec8297 RS |
853 | Show Paren mode uses the faces @code{show-paren-match} and |
854 | @code{show-paren-mismatch} to highlight parentheses; you can customize | |
855 | them to control how highlighting looks. @xref{Face Customization}. | |
6bf7aab6 DL |
856 | |
857 | @node Comments | |
858 | @section Manipulating Comments | |
859 | @cindex comments | |
860 | ||
861 | Because comments are such an important part of programming, Emacs | |
8f50b630 RS |
862 | provides special commands for editing and inserting comments. It can |
863 | also do spell checking on comments with Flyspell Prog mode | |
864 | (@pxref{Spelling}). | |
6bf7aab6 DL |
865 | |
866 | @menu | |
5b31640c | 867 | * Comment Commands:: Inserting, killing, and aligning comments. |
93da5dff RS |
868 | * Multi-Line Comments:: Commands for adding and editing multi-line comments. |
869 | * Options for Comments::Customizing the comment features. | |
6bf7aab6 DL |
870 | @end menu |
871 | ||
872 | @node Comment Commands | |
873 | @subsection Comment Commands | |
6bf7aab6 | 874 | @cindex indentation for comments |
5b31640c | 875 | @cindex alignment for comments |
6bf7aab6 | 876 | |
9234c238 RS |
877 | The comment commands in this table insert, kill and align comments. |
878 | They are described in this section and following sections. | |
6bf7aab6 | 879 | |
7ae8ad94 RS |
880 | @table @asis |
881 | @item @kbd{M-;} | |
9234c238 RS |
882 | Insert or realign comment on current line; alternatively, comment or |
883 | uncomment the region (@code{comment-dwim}). | |
7ae8ad94 | 884 | @item @kbd{C-u M-;} |
9234c238 | 885 | Kill comment on current line (@code{comment-kill}). |
7ae8ad94 | 886 | @item @kbd{C-x ;} |
47c1b5f4 | 887 | Set comment column (@code{comment-set-column}). |
7ae8ad94 RS |
888 | @item @kbd{C-M-j} |
889 | @itemx @kbd{M-j} | |
6bf7aab6 | 890 | Like @key{RET} followed by inserting and aligning a comment |
108262a0 | 891 | (@code{comment-indent-new-line}). @xref{Multi-Line Comments}. |
7ae8ad94 RS |
892 | @item @kbd{M-x comment-region} |
893 | @itemx @kbd{C-c C-c} (in C-like modes) | |
6bf7aab6 DL |
894 | Add or remove comment delimiters on all the lines in the region. |
895 | @end table | |
896 | ||
9234c238 RS |
897 | @kindex M-; |
898 | @findex comment-dwim | |
899 | The command to create or align a comment is @kbd{M-;} | |
900 | (@code{comment-dwim}). The word ``dwim'' is an acronym for ``Do What | |
901 | I Mean''; it indicates that this command can be used for many | |
902 | different jobs relating to comments, depending on the situation where | |
903 | you use it. | |
904 | ||
905 | If there is no comment already on the line, @kbd{M-;} inserts a new | |
906 | comment, aligned at a specific column called the @dfn{comment column}. | |
907 | The new comment begins with the string Emacs thinks comments should | |
908 | start with (the value of @code{comment-start}; see below). Point is | |
909 | after that string, so you can insert the text of the comment right | |
910 | away. If the major mode has specified a string to terminate comments, | |
dfec8297 | 911 | @kbd{M-;} inserts that after point, to keep the syntax valid. |
9234c238 | 912 | |
dfec8297 | 913 | If the text of the line extends past the comment column, this |
5b31640c | 914 | command aligns the comment start string to a suitable boundary |
dfec8297 | 915 | (usually, at least one space is inserted). |
9234c238 RS |
916 | |
917 | You can also use @kbd{M-;} to align an existing comment. If a line | |
5b31640c | 918 | already contains the comment-start string, @kbd{M-;} realigns it to |
9234c238 RS |
919 | the conventional alignment and moves point after it. (Exception: |
920 | comments starting in column 0 are not moved.) Even when an existing | |
921 | comment is properly aligned, @kbd{M-;} is still useful for moving | |
922 | directly to the start of the text inside the comment. | |
923 | ||
924 | @findex comment-kill | |
925 | @kindex C-u M-; | |
926 | @kbd{C-u M-;} kills any comment on the current line, along with the | |
927 | whitespace before it. To reinsert the comment on another line, move | |
928 | to the end of that line, do @kbd{C-y}, and then do @kbd{M-;} to | |
929 | realign it. | |
930 | ||
931 | Note that @kbd{C-u M-;} is not a distinct key; it is @kbd{M-;} | |
932 | (@code{comment-dwim}) with a prefix argument. That command is | |
933 | programmed so that when it receives a prefix argument it calls | |
934 | @code{comment-kill}. However, @code{comment-kill} is a valid command | |
935 | in its own right, and you can bind it directly to a key if you wish. | |
936 | ||
937 | @kbd{M-;} does two other jobs when used with an active region in | |
938 | Transient Mark mode (@pxref{Transient Mark}). Then it either adds or | |
939 | removes comment delimiters on each line of the region. (If every line | |
940 | is a comment, it removes comment delimiters from each; otherwise, it | |
941 | adds comment delimiters to each.) If you are not using Transient Mark | |
942 | mode, then you should use the commands @code{comment-region} and | |
dfec8297 RS |
943 | @code{uncomment-region} to do these jobs (@pxref{Multi-Line Comments}), |
944 | or else enable Transient Mark mode momentarily (@pxref{Momentary Mark}). | |
9234c238 RS |
945 | A prefix argument used in these circumstances specifies how many |
946 | comment delimiters to add or how many to delete. | |
6bf7aab6 | 947 | |
5b31640c | 948 | Some major modes have special rules for aligning certain kinds of |
6bf7aab6 DL |
949 | comments in certain contexts. For example, in Lisp code, comments which |
950 | start with two semicolons are indented as if they were lines of code, | |
951 | instead of at the comment column. Comments which start with three | |
952 | semicolons are supposed to start at the left margin. Emacs understands | |
953 | these conventions by indenting a double-semicolon comment using @key{TAB}, | |
954 | and by not changing the indentation of a triple-semicolon comment at all. | |
955 | ||
956 | @example | |
957 | ;; This function is just an example | |
958 | ;;; Here either two or three semicolons are appropriate. | |
959 | (defun foo (x) | |
960 | ;;; And now, the first part of the function: | |
961 | ;; The following line adds one. | |
962 | (1+ x)) ; This line adds one. | |
963 | @end example | |
964 | ||
dfec8297 RS |
965 | For C-like modes, you can configure the exact effect of @kbd{M-;} |
966 | more flexibly than for most buffers by setting the variables | |
108262a0 AM |
967 | @code{c-indent-comment-alist} and |
968 | @code{c-indent-comments-syntactically-p}. For example, on a line | |
969 | ending in a closing brace, @kbd{M-;} puts the comment one space after | |
970 | the brace rather than at @code{comment-column}. For full details see | |
971 | @ref{Comment Commands,,, ccmode, The CC Mode Manual}. | |
6bf7aab6 | 972 | |
6bf7aab6 DL |
973 | @node Multi-Line Comments |
974 | @subsection Multiple Lines of Comments | |
975 | ||
976 | @kindex C-M-j | |
7ae8ad94 | 977 | @kindex M-j |
6bf7aab6 | 978 | @cindex blank lines in programs |
47c1b5f4 | 979 | @findex comment-indent-new-line |
108262a0 | 980 | |
6bf7aab6 | 981 | If you are typing a comment and wish to continue it on another line, |
7ae8ad94 | 982 | you can use the command @kbd{C-M-j} or @kbd{M-j} |
f5eb910a RS |
983 | (@code{comment-indent-new-line}). If @code{comment-multi-line} |
984 | (@pxref{Options for Comments}) is non-@code{nil}, it moves to a new | |
985 | line within the comment. Otherwise it closes the comment and starts a | |
986 | new comment on a new line. When Auto Fill mode is on, going past the | |
987 | fill column while typing a comment causes the comment to be continued | |
988 | in just this fashion. | |
7ae8ad94 RS |
989 | |
990 | @kindex C-c C-c (C mode) | |
6bf7aab6 DL |
991 | @findex comment-region |
992 | To turn existing lines into comment lines, use the @kbd{M-x | |
dfec8297 | 993 | comment-region} command (or type @kbd{C-c C-c} in C-like modes). It |
108262a0 AM |
994 | adds comment delimiters to the lines that start in the region, thus |
995 | commenting them out. With a negative argument, it does the | |
996 | opposite---it deletes comment delimiters from the lines in the region. | |
6bf7aab6 DL |
997 | |
998 | With a positive argument, @code{comment-region} duplicates the last | |
5b31640c RS |
999 | character of the comment start sequence it adds; the argument |
1000 | specifies how many copies of the character to insert. Thus, in Lisp | |
1001 | mode, @kbd{C-u 2 M-x comment-region} adds @samp{;;} to each line. | |
1002 | Duplicating the comment delimiter is a way of calling attention to the | |
1003 | comment. It can also affect how the comment is aligned or indented. | |
1004 | In Lisp, for proper indentation, you should use an argument of two or | |
1005 | three, if between defuns; if within a defun, it must be three. | |
6bf7aab6 | 1006 | |
108262a0 AM |
1007 | You can configure C Mode such that when you type a @samp{/} at the |
1008 | start of a line in a multi-line block comment, this closes the | |
1009 | comment. Enable the @code{comment-close-slash} clean-up for this. | |
1010 | @xref{Clean-ups,,, ccmode, The CC Mode Manual}. | |
1011 | ||
6bf7aab6 DL |
1012 | @node Options for Comments |
1013 | @subsection Options Controlling Comments | |
1014 | ||
1015 | @vindex comment-column | |
1016 | @kindex C-x ; | |
47c1b5f4 | 1017 | @findex comment-set-column |
7ae8ad94 RS |
1018 | The @dfn{comment column}, the column at which Emacs tries to place |
1019 | comments, is stored in the variable @code{comment-column}. You can | |
1020 | set it to a number explicitly. Alternatively, the command @kbd{C-x ;} | |
1021 | (@code{comment-set-column}) sets the comment column to the column | |
1022 | point is at. @kbd{C-u C-x ;} sets the comment column to match the | |
1023 | last comment before point in the buffer, and then does a @kbd{M-;} to | |
1024 | align the current line's comment under the previous one. | |
6bf7aab6 DL |
1025 | |
1026 | The variable @code{comment-column} is per-buffer: setting the variable | |
1027 | in the normal fashion affects only the current buffer, but there is a | |
1028 | default value which you can change with @code{setq-default}. | |
1029 | @xref{Locals}. Many major modes initialize this variable for the | |
1030 | current buffer. | |
1031 | ||
1032 | @vindex comment-start-skip | |
1033 | The comment commands recognize comments based on the regular | |
1034 | expression that is the value of the variable @code{comment-start-skip}. | |
1035 | Make sure this regexp does not match the null string. It may match more | |
1036 | than the comment starting delimiter in the strictest sense of the word; | |
47c1b5f4 RS |
1037 | for example, in C mode the value of the variable is |
1038 | @c This stops M-q from breaking the line inside that @code. | |
7ae8ad94 | 1039 | @code{@w{"/\\*+ *\\|//+ *"}}, which matches extra stars and spaces |
47c1b5f4 | 1040 | after the @samp{/*} itself, and accepts C++ style comments also. |
6bf7aab6 DL |
1041 | (Note that @samp{\\} is needed in Lisp syntax to include a @samp{\} in |
1042 | the string, which is needed to deny the first star its special meaning | |
bd428736 | 1043 | in regexp syntax. @xref{Regexp Backslash}.) |
6bf7aab6 DL |
1044 | |
1045 | @vindex comment-start | |
1046 | @vindex comment-end | |
1047 | When a comment command makes a new comment, it inserts the value of | |
1048 | @code{comment-start} to begin it. The value of @code{comment-end} is | |
aa2d3478 RS |
1049 | inserted after point, so that it will follow the text that you will |
1050 | insert into the comment. When @code{comment-end} is non-empty, it | |
1051 | should start with a space. For example, in C mode, | |
1052 | @code{comment-start} has the value @w{@code{"/* "}} and | |
1053 | @code{comment-end} has the value @w{@code{" */"}}. | |
6bf7aab6 | 1054 | |
9234c238 RS |
1055 | @vindex comment-padding |
1056 | The variable @code{comment-padding} specifies how many spaces | |
7ae8ad94 RS |
1057 | @code{comment-region} should insert on each line between the comment |
1058 | delimiter and the line's original text. The default is 1, to insert | |
1059 | one space. @code{nil} means 0. Alternatively, @code{comment-padding} | |
1060 | can hold the actual string to insert. | |
9234c238 | 1061 | |
6bf7aab6 DL |
1062 | @vindex comment-multi-line |
1063 | The variable @code{comment-multi-line} controls how @kbd{C-M-j} | |
7ae8ad94 | 1064 | (@code{indent-new-comment-line}) behaves when used inside a comment. |
108262a0 AM |
1065 | Specifically, when @code{comment-multi-line} is @code{nil}, the |
1066 | command inserts a comment terminator, begins a new line, and finally | |
1067 | inserts a comment starter. Otherwise it does not insert the | |
1068 | terminator and starter, so it effectively continues the current | |
1069 | comment across multiple lines. In languages that allow multi-line | |
1070 | comments, the choice of value for this variable is a matter of taste. | |
1071 | The default for this variable depends on the major mode. | |
6bf7aab6 | 1072 | |
4190ce5c | 1073 | @vindex comment-indent-function |
6bf7aab6 | 1074 | The variable @code{comment-indent-function} should contain a function |
5b31640c | 1075 | that will be called to compute the alignment for a newly inserted |
6bf7aab6 DL |
1076 | comment or for aligning an existing comment. It is set differently by |
1077 | various major modes. The function is called with no arguments, but with | |
1078 | point at the beginning of the comment, or at the end of a line if a new | |
1079 | comment is to be inserted. It should return the column in which the | |
1080 | comment ought to start. For example, in Lisp mode, the indent hook | |
1081 | function bases its decision on how many semicolons begin an existing | |
1082 | comment, and on the code in the preceding lines. | |
1083 | ||
93da5dff RS |
1084 | @node Documentation |
1085 | @section Documentation Lookup | |
6bf7aab6 | 1086 | |
93da5dff RS |
1087 | Emacs provides several features you can use to look up the |
1088 | documentation of functions, variables and commands that you plan to | |
1089 | use in your program. | |
6bf7aab6 | 1090 | |
93da5dff RS |
1091 | @menu |
1092 | * Info Lookup:: Looking up library functions and commands | |
1093 | in Info files. | |
1094 | * Man Page:: Looking up man pages of library functions and commands. | |
1095 | * Lisp Doc:: Looking up Emacs Lisp functions, etc. | |
1096 | @end menu | |
6bf7aab6 | 1097 | |
93da5dff RS |
1098 | @node Info Lookup |
1099 | @subsection Info Documentation Lookup | |
85750656 | 1100 | |
93da5dff RS |
1101 | @findex info-lookup-symbol |
1102 | @findex info-lookup-file | |
d2f9ea87 | 1103 | @kindex C-h S |
dfec8297 RS |
1104 | For many major modes, that apply to languages that have |
1105 | documentation in Info, you can use @kbd{C-h S} | |
1106 | (@code{info-lookup-symbol}) to view the Info documentation for a | |
1107 | symbol used in the program. You specify the symbol with the | |
1108 | minibuffer; the default is the symbol appearing in the buffer at | |
1109 | point. For example, in C mode this looks for the symbol in the C | |
1110 | Library Manual. The command only works if the appropriate manual's | |
1111 | Info files are installed. | |
6bf7aab6 | 1112 | |
93da5dff RS |
1113 | The major mode determines where to look for documentation for the |
1114 | symbol---which Info files to look in, and which indices to search. | |
1115 | You can also use @kbd{M-x info-lookup-file} to look for documentation | |
1116 | for a file name. | |
6bf7aab6 | 1117 | |
dfec8297 RS |
1118 | If you use @kbd{C-h S} in a major mode that does not support it, |
1119 | it asks you to specify the ``symbol help mode''. You should enter | |
1120 | a command such as @code{c-mode} that would select a major | |
1121 | mode which @kbd{C-h S} does support. | |
6bf7aab6 | 1122 | |
93da5dff RS |
1123 | @node Man Page |
1124 | @subsection Man Page Lookup | |
6bf7aab6 | 1125 | |
e79c6b89 RS |
1126 | @cindex manual page |
1127 | On Unix, the main form of on-line documentation was the @dfn{manual | |
dfec8297 | 1128 | page} or @dfn{man page}. In the GNU operating system, we aim to |
e79c6b89 RS |
1129 | replace man pages with better-organized manuals that you can browse |
1130 | with Info (@pxref{Misc Help}). This process is not finished, so it is | |
1131 | still useful to read manual pages. | |
6bf7aab6 | 1132 | |
93da5dff | 1133 | @findex manual-entry |
e79c6b89 | 1134 | You can read the man page for an operating system command, library |
7ae8ad94 | 1135 | function, or system call, with the @kbd{M-x man} command. It |
e79c6b89 RS |
1136 | runs the @code{man} program to format the man page; if the system |
1137 | permits, it runs @code{man} asynchronously, so that you can keep on | |
1138 | editing while the page is being formatted. (On MS-DOS and MS-Windows | |
1139 | 3, you cannot edit while Emacs waits for @code{man} to finish.) The | |
1140 | result goes in a buffer named @samp{*Man @var{topic}*}. These buffers | |
1141 | use a special major mode, Man mode, that facilitates scrolling and | |
1142 | jumping to other manual pages. For details, type @kbd{C-h m} while in | |
1143 | a man page buffer. | |
6bf7aab6 | 1144 | |
93da5dff | 1145 | @cindex sections of manual pages |
e79c6b89 RS |
1146 | Each man page belongs to one of ten or more @dfn{sections}, each |
1147 | named by a digit or by a digit and a letter. Sometimes there are | |
1148 | multiple man pages with the same name in different sections. To read | |
1149 | a man page from a specific section, type | |
93da5dff RS |
1150 | @samp{@var{topic}(@var{section})} or @samp{@var{section} @var{topic}} |
1151 | when @kbd{M-x manual-entry} prompts for the topic. For example, to | |
1152 | read the man page for the C library function @code{chmod} (as opposed | |
e79c6b89 | 1153 | to a command of the same name), type @kbd{M-x manual-entry @key{RET} |
dfec8297 RS |
1154 | chmod(2) @key{RET}}. (@code{chmod} is a system call, so it is in |
1155 | section @samp{2}.) | |
6bf7aab6 | 1156 | |
08220274 | 1157 | @vindex Man-switches |
93da5dff | 1158 | If you do not specify a section, the results depend on how the |
08220274 | 1159 | @code{man} program works on your system. Some of them display only |
93da5dff RS |
1160 | the first man page they find. Others display all man pages that have |
1161 | the specified name, so you can move between them with the @kbd{M-n} | |
08220274 EZ |
1162 | and @kbd{M-p} keys@footnote{On some systems, the @code{man} program |
1163 | accepts a @samp{-a} command-line option which tells it to display all | |
1164 | the man pages for the specified topic. If you want this behavior, you | |
1165 | can add this option to the value of the variable @code{Man-switches}.}. | |
1166 | The mode line shows how many manual pages are present in the Man buffer. | |
6bf7aab6 | 1167 | |
93da5dff | 1168 | @vindex Man-fontify-manpage-flag |
e79c6b89 RS |
1169 | By default, Emacs highlights the text in man pages. For a long man |
1170 | page, highlighting can take substantial time. You can turn off | |
1171 | highlighting of man pages by setting the variable | |
1172 | @code{Man-fontify-manpage-flag} to @code{nil}. | |
6bf7aab6 | 1173 | |
93da5dff RS |
1174 | @findex Man-fontify-manpage |
1175 | If you insert the text of a man page into an Emacs buffer in some | |
1176 | other fashion, you can use the command @kbd{M-x Man-fontify-manpage} to | |
1177 | perform the same conversions that @kbd{M-x manual-entry} does. | |
1178 | ||
1179 | @findex woman | |
1180 | @cindex manual pages, on MS-DOS/MS-Windows | |
1181 | An alternative way of reading manual pages is the @kbd{M-x woman} | |
1182 | command@footnote{The name of the command, @code{woman}, is an acronym | |
1183 | for ``w/o (without) man,'' since it doesn't use the @code{man} | |
1184 | program.}. Unlike @kbd{M-x man}, it does not run any external | |
1185 | programs to format and display the man pages; instead it does the job | |
1186 | in Emacs Lisp, so it works on systems such as MS-Windows, where the | |
ea118de1 | 1187 | @code{man} program (and other programs it uses) are not generally |
d2fab838 RS |
1188 | available. |
1189 | ||
1190 | @kbd{M-x woman} prompts for a name of a manual page, and provides | |
1191 | completion based on the list of manual pages that are installed on | |
1192 | your machine; the list of available manual pages is computed | |
1193 | automatically the first time you invoke @code{woman}. The word at | |
1194 | point in the current buffer is used to suggest the default for the | |
1195 | name the manual page. | |
93da5dff RS |
1196 | |
1197 | With a numeric argument, @kbd{M-x woman} recomputes the list of the | |
1198 | manual pages used for completion. This is useful if you add or delete | |
1199 | manual pages. | |
1200 | ||
1201 | If you type a name of a manual page and @kbd{M-x woman} finds that | |
1202 | several manual pages by the same name exist in different sections, it | |
1203 | pops up a window with possible candidates asking you to choose one of | |
1204 | them. | |
1205 | ||
93da5dff RS |
1206 | For more information about setting up and using @kbd{M-x woman}, see |
1207 | @ref{Top, WoMan, Browse UN*X Manual Pages WithOut Man, woman, The WoMan | |
1208 | Manual}. | |
1209 | ||
1210 | @node Lisp Doc | |
1211 | @subsection Emacs Lisp Documentation Lookup | |
1212 | ||
1213 | As you edit Lisp code to be run in Emacs, you can use the commands | |
1214 | @kbd{C-h f} (@code{describe-function}) and @kbd{C-h v} | |
1215 | (@code{describe-variable}) to view documentation of functions and | |
1216 | variables that you want to use. These commands use the minibuffer to | |
1217 | read the name of a function or variable to document, and display the | |
1218 | documentation in a window. Their default arguments are based on the | |
1219 | code in the neighborhood of point. For @kbd{C-h f}, the default is | |
1220 | the function called in the innermost list containing point. @kbd{C-h | |
1221 | v} uses the symbol name around or adjacent to point as its default. | |
1222 | ||
1223 | @cindex Eldoc mode | |
1224 | @findex eldoc-mode | |
1225 | A more automatic but less powerful method is Eldoc mode. This minor | |
1226 | mode constantly displays in the echo area the argument list for the | |
1227 | function being called at point. (In other words, it finds the | |
1228 | function call that point is contained in, and displays the argument | |
054af0fd | 1229 | list of that function.) If point is over a documented variable, it |
ea802fce LT |
1230 | shows the first line of the variable's docstring. Eldoc mode applies |
1231 | in Emacs Lisp and Lisp Interaction modes, and perhaps a few others | |
1232 | that provide special support for looking up doc strings. Use the | |
1233 | command @kbd{M-x eldoc-mode} to enable or disable this feature. | |
6bf7aab6 | 1234 | |
51ed0ea0 DL |
1235 | @node Hideshow |
1236 | @section Hideshow minor mode | |
1237 | ||
1238 | @findex hs-minor-mode | |
9234c238 | 1239 | Hideshow minor mode provides selective display of portions of a |
93da5dff RS |
1240 | program, known as @dfn{blocks}. You can use @kbd{M-x hs-minor-mode} |
1241 | to enable or disable this mode, or add @code{hs-minor-mode} to the | |
1242 | mode hook for certain major modes in order to enable it automatically | |
1243 | for those modes. | |
51ed0ea0 | 1244 | |
9234c238 RS |
1245 | Just what constitutes a block depends on the major mode. In C mode |
1246 | or C++ mode, they are delimited by braces, while in Lisp mode and | |
1247 | similar modes they are delimited by parentheses. Multi-line comments | |
1248 | also count as blocks. | |
51ed0ea0 DL |
1249 | |
1250 | @findex hs-hide-all | |
1251 | @findex hs-hide-block | |
1252 | @findex hs-show-all | |
1253 | @findex hs-show-block | |
1254 | @findex hs-show-region | |
1255 | @findex hs-hide-level | |
1256 | @findex hs-minor-mode | |
6401dc86 EZ |
1257 | @kindex C-c @@ C-h |
1258 | @kindex C-c @@ C-s | |
1259 | @kindex C-c @@ C-M-h | |
1260 | @kindex C-c @@ C-M-s | |
1261 | @kindex C-c @@ C-r | |
1262 | @kindex C-c @@ C-l | |
9234c238 RS |
1263 | @kindex S-Mouse-2 |
1264 | @table @kbd | |
6401dc86 | 1265 | @item C-c @@ C-h |
9234c238 | 1266 | Hide the current block (@code{hs-hide-block}). |
6401dc86 | 1267 | @item C-c @@ C-s |
9234c238 | 1268 | Show the current block (@code{hs-show-block}). |
6401dc86 | 1269 | @item C-c @@ C-c |
ea118de1 | 1270 | Either hide or show the current block (@code{hs-toggle-hiding}). |
9234c238 | 1271 | @item S-Mouse-2 |
ea118de1 | 1272 | Either hide or show the block you click on (@code{hs-mouse-toggle-hiding}). |
6401dc86 | 1273 | @item C-c @@ C-M-h |
9234c238 | 1274 | Hide all top-level blocks (@code{hs-hide-all}). |
6401dc86 | 1275 | @item C-c @@ C-M-s |
9234c238 | 1276 | Show everything in the buffer (@code{hs-show-all}). |
6401dc86 | 1277 | @item C-c @@ C-l |
9234c238 RS |
1278 | Hide all blocks @var{n} levels below this block |
1279 | (@code{hs-hide-level}). | |
1280 | @end table | |
51ed0ea0 DL |
1281 | |
1282 | @vindex hs-hide-comments-when-hiding-all | |
51ed0ea0 DL |
1283 | @vindex hs-isearch-open |
1284 | @vindex hs-special-modes-alist | |
19b2c4ca | 1285 | These variables exist for customizing Hideshow mode. |
9234c238 | 1286 | |
51ed0ea0 DL |
1287 | @table @code |
1288 | @item hs-hide-comments-when-hiding-all | |
9234c238 | 1289 | Non-@code{nil} says that @kbd{hs-hide-all} should hide comments too. |
d2fab838 | 1290 | |
51ed0ea0 | 1291 | @item hs-isearch-open |
dfec8297 RS |
1292 | Specifies what kind of hidden blocks incremental search should make |
1293 | visible. The value should be one of these four symbols: | |
d2fab838 RS |
1294 | |
1295 | @table @code | |
9198a323 RS |
1296 | @item code |
1297 | Open only code blocks. | |
d2fab838 RS |
1298 | @item comment |
1299 | Open only comments. | |
1300 | @item t | |
9198a323 | 1301 | Open both code blocks and comments. |
d2fab838 | 1302 | @item nil |
9198a323 | 1303 | Open neither code blocks nor comments. |
d2fab838 RS |
1304 | @end table |
1305 | ||
51ed0ea0 | 1306 | @item hs-special-modes-alist |
e79c6b89 | 1307 | A list of elements, each specifying how to initialize Hideshow |
d2fab838 RS |
1308 | variables for one major mode. See the variable's documentation string |
1309 | for more information. | |
51ed0ea0 DL |
1310 | @end table |
1311 | ||
93da5dff RS |
1312 | @node Symbol Completion |
1313 | @section Completion for Symbol Names | |
1314 | @cindex completion (symbol names) | |
3b8b8888 | 1315 | |
e79c6b89 RS |
1316 | In Emacs, completion is something you normally do in the minibuffer. |
1317 | But one kind of completion is available in all buffers: completion for | |
1318 | symbol names. | |
3b8b8888 | 1319 | |
93da5dff | 1320 | @kindex M-TAB |
e79c6b89 RS |
1321 | The character @kbd{M-@key{TAB}} runs a command to complete the |
1322 | partial symbol before point against the set of meaningful symbol | |
1323 | names. This command inserts at point any additional characters that | |
64e207c0 | 1324 | it can determine from the partial name. (If your window manager |
7fb36547 RS |
1325 | defines @kbd{M-@key{TAB}} to switch windows, you can type |
1326 | @kbd{@key{ESC} @key{TAB}} or @kbd{C-M-i}.) | |
6bf7aab6 | 1327 | |
e79c6b89 RS |
1328 | If the partial name in the buffer has multiple possible completions |
1329 | that differ in the very next character, so that it is impossible to | |
1330 | complete even one more character, @kbd{M-@key{TAB}} displays a list of | |
1331 | all possible completions in another window. | |
6bf7aab6 | 1332 | |
93da5dff RS |
1333 | @cindex tags-based completion |
1334 | @cindex Info index completion | |
1335 | @findex complete-symbol | |
1336 | In most programming language major modes, @kbd{M-@key{TAB}} runs the | |
1337 | command @code{complete-symbol}, which provides two kinds of completion. | |
1338 | Normally it does completion based on a tags table (@pxref{Tags}); with a | |
1339 | numeric argument (regardless of the value), it does completion based on | |
1340 | the names listed in the Info file indexes for your language. Thus, to | |
1341 | complete the name of a symbol defined in your own program, use | |
1342 | @kbd{M-@key{TAB}} with no argument; to complete the name of a standard | |
1343 | library function, use @kbd{C-u M-@key{TAB}}. Of course, Info-based | |
1344 | completion works only if there is an Info file for the standard library | |
1345 | functions of your language, and only if it is installed at your site. | |
6bf7aab6 | 1346 | |
93da5dff RS |
1347 | @cindex Lisp symbol completion |
1348 | @cindex completion (Lisp symbols) | |
1349 | @findex lisp-complete-symbol | |
1350 | In Emacs-Lisp mode, the name space for completion normally consists of | |
1351 | nontrivial symbols present in Emacs---those that have function | |
1352 | definitions, values or properties. However, if there is an | |
1353 | open-parenthesis immediately before the beginning of the partial symbol, | |
1354 | only symbols with function definitions are considered as completions. | |
1355 | The command which implements this is @code{lisp-complete-symbol}. | |
6bf7aab6 | 1356 | |
93da5dff RS |
1357 | In Text mode and related modes, @kbd{M-@key{TAB}} completes words |
1358 | based on the spell-checker's dictionary. @xref{Spelling}. | |
6bf7aab6 | 1359 | |
93da5dff RS |
1360 | @node Glasses |
1361 | @section Glasses minor mode | |
1362 | @cindex Glasses mode | |
1363 | @cindex identifiers, making long ones readable | |
1364 | @cindex StudlyCaps, making them readable | |
1365 | @findex glasses-mode | |
6bf7aab6 | 1366 | |
93da5dff | 1367 | Glasses minor mode makes @samp{unreadableIdentifiersLikeThis} |
e79c6b89 RS |
1368 | readable by altering the way they display. It knows two different |
1369 | ways to do this: by displaying underscores between a lower-case letter | |
1370 | and the following capital letter, and by emboldening the capital | |
1371 | letters. It does not alter the buffer text, only the way they | |
1372 | display, so you can use it even on read-only buffers. You can use the | |
1373 | command @kbd{M-x glasses-mode} to enable or disable the mode in the | |
1374 | current buffer; you can also add @code{glasses-mode} to the mode hook | |
1375 | of the programming language major modes in which you normally want | |
177c0ea7 | 1376 | to use Glasses mode. |
6bf7aab6 | 1377 | |
93da5dff RS |
1378 | @node Misc for Programs |
1379 | @section Other Features Useful for Editing Programs | |
6bf7aab6 | 1380 | |
93da5dff | 1381 | A number of Emacs commands that aren't designed specifically for |
e79c6b89 | 1382 | editing programs are useful for that nonetheless. |
6bf7aab6 | 1383 | |
93da5dff RS |
1384 | The Emacs commands that operate on words, sentences and paragraphs |
1385 | are useful for editing code. Most symbols names contain words | |
1386 | (@pxref{Words}); sentences can be found in strings and comments | |
e79c6b89 | 1387 | (@pxref{Sentences}). Paragraphs in the strict sense can be found in |
93da5dff RS |
1388 | program code (in long comments), but the paragraph commands are useful |
1389 | in other places too, because programming language major modes define | |
1390 | paragraphs to begin and end at blank lines (@pxref{Paragraphs}). | |
1391 | Judicious use of blank lines to make the program clearer will also | |
1392 | provide useful chunks of text for the paragraph commands to work on. | |
1393 | Auto Fill mode, if enabled in a programming language major mode, | |
1394 | indents the new lines which it creates. | |
6bf7aab6 | 1395 | |
93da5dff RS |
1396 | The selective display feature is useful for looking at the overall |
1397 | structure of a function (@pxref{Selective Display}). This feature | |
1398 | hides the lines that are indented more than a specified amount. | |
1399 | Programming modes often support Outline minor mode (@pxref{Outline | |
1400 | Mode}). The Foldout package provides folding-editor features | |
1401 | (@pxref{Foldout}). | |
6bf7aab6 | 1402 | |
93da5dff RS |
1403 | The ``automatic typing'' features may be useful for writing programs. |
1404 | @xref{Top,,Autotyping, autotype, Autotyping}. | |
6bf7aab6 DL |
1405 | |
1406 | @node C Modes | |
1407 | @section C and Related Modes | |
1408 | @cindex C mode | |
1409 | @cindex Java mode | |
1410 | @cindex Pike mode | |
1411 | @cindex IDL mode | |
1412 | @cindex CORBA IDL mode | |
1413 | @cindex Objective C mode | |
1414 | @cindex C++ mode | |
7ae8ad94 | 1415 | @cindex AWK mode |
6bf7aab6 DL |
1416 | @cindex mode, Java |
1417 | @cindex mode, C | |
7ae8ad94 | 1418 | @cindex mode, C++ |
6bf7aab6 DL |
1419 | @cindex mode, Objective C |
1420 | @cindex mode, CORBA IDL | |
1421 | @cindex mode, Pike | |
7ae8ad94 | 1422 | @cindex mode, AWK |
6bf7aab6 | 1423 | |
9234c238 | 1424 | This section gives a brief description of the special features |
7ae8ad94 | 1425 | available in C, C++, Objective-C, Java, CORBA IDL, Pike and AWK modes. |
5d80fe1f EZ |
1426 | (These are called ``C mode and related modes.'') @xref{Top, , CC Mode, |
1427 | ccmode, CC Mode}, for a more extensive description of these modes | |
9234c238 | 1428 | and their special features. |
51ed0ea0 | 1429 | |
6bf7aab6 | 1430 | @menu |
7ae8ad94 RS |
1431 | * Motion in C:: Commands to move by C statements, etc. |
1432 | * Electric C:: Colon and other chars can automatically reindent. | |
1433 | * Hungry Delete:: A more powerful DEL command. | |
1434 | * Other C Commands:: Filling comments, viewing expansion of macros, | |
1435 | and other neat features. | |
6bf7aab6 DL |
1436 | @end menu |
1437 | ||
1438 | @node Motion in C | |
1439 | @subsection C Mode Motion Commands | |
1440 | ||
1441 | This section describes commands for moving point, in C mode and | |
1442 | related modes. | |
1443 | ||
1444 | @table @code | |
7ae8ad94 RS |
1445 | @item M-x c-beginning-of-defun |
1446 | @itemx M-x c-end-of-defun | |
1447 | @findex c-beginning-of-defun | |
1448 | @findex c-end-of-defun | |
1449 | Move point to the beginning or end of the current function or | |
1450 | top-level definition. These are found by searching for the least | |
1451 | enclosing braces. (By contrast, @code{beginning-of-defun} and | |
1452 | @code{end-of-defun} search for braces in column zero.) If you are | |
1453 | editing code where the opening brace of a function isn't placed in | |
1454 | column zero, you may wish to bind @code{C-M-a} and @code{C-M-e} to | |
1455 | these commands. @xref{Moving by Defuns}. | |
1456 | ||
6bf7aab6 DL |
1457 | @item C-c C-u |
1458 | @kindex C-c C-u @r{(C mode)} | |
1459 | @findex c-up-conditional | |
1460 | Move point back to the containing preprocessor conditional, leaving the | |
1461 | mark behind. A prefix argument acts as a repeat count. With a negative | |
1462 | argument, move point forward to the end of the containing | |
7ae8ad94 RS |
1463 | preprocessor conditional. |
1464 | ||
1465 | @samp{#elif} is equivalent to @samp{#else} followed by @samp{#if}, so | |
1466 | the function will stop at a @samp{#elif} when going backward, but not | |
1467 | when going forward. | |
6bf7aab6 DL |
1468 | |
1469 | @item C-c C-p | |
1470 | @kindex C-c C-p @r{(C mode)} | |
1471 | @findex c-backward-conditional | |
1472 | Move point back over a preprocessor conditional, leaving the mark | |
1473 | behind. A prefix argument acts as a repeat count. With a negative | |
1474 | argument, move forward. | |
1475 | ||
1476 | @item C-c C-n | |
1477 | @kindex C-c C-n @r{(C mode)} | |
1478 | @findex c-forward-conditional | |
1479 | Move point forward across a preprocessor conditional, leaving the mark | |
1480 | behind. A prefix argument acts as a repeat count. With a negative | |
1481 | argument, move backward. | |
1482 | ||
1483 | @item M-a | |
7ae8ad94 | 1484 | @kindex M-a (C mode) |
6bf7aab6 DL |
1485 | @findex c-beginning-of-statement |
1486 | Move point to the beginning of the innermost C statement | |
1487 | (@code{c-beginning-of-statement}). If point is already at the beginning | |
1488 | of a statement, move to the beginning of the preceding statement. With | |
1489 | prefix argument @var{n}, move back @var{n} @minus{} 1 statements. | |
1490 | ||
7ae8ad94 RS |
1491 | In comments or in strings which span more than one line, this command |
1492 | moves by sentences instead of statements. | |
6bf7aab6 DL |
1493 | |
1494 | @item M-e | |
7ae8ad94 | 1495 | @kindex M-e (C mode) |
6bf7aab6 | 1496 | @findex c-end-of-statement |
7ae8ad94 RS |
1497 | Move point to the end of the innermost C statement or sentence; like |
1498 | @kbd{M-a} except that it moves in the other direction | |
1499 | (@code{c-end-of-statement}). | |
6bf7aab6 DL |
1500 | @end table |
1501 | ||
1502 | @node Electric C | |
1503 | @subsection Electric C Characters | |
1504 | ||
1505 | In C mode and related modes, certain printing characters are | |
108262a0 AM |
1506 | @dfn{electric}---in addition to inserting themselves, they also |
1507 | reindent the current line, and optionally also insert newlines. The | |
64e207c0 RS |
1508 | ``electric'' characters are @kbd{@{}, @kbd{@}}, @kbd{:}, @kbd{#}, |
1509 | @kbd{;}, @kbd{,}, @kbd{<}, @kbd{>}, @kbd{/}, @kbd{*}, @kbd{(}, and | |
f5eb910a | 1510 | @kbd{)}. |
108262a0 AM |
1511 | |
1512 | You might find electric indentation inconvenient if you are editing | |
1513 | chaotically indented code. If you are new to CC Mode, you might find | |
1514 | it disconcerting. You can toggle electric action with the command | |
1515 | @kbd{C-c C-l}; when it is enabled, @samp{/l} appears in the mode line | |
1516 | after the mode name: | |
6bf7aab6 | 1517 | |
108262a0 AM |
1518 | @table @kbd |
1519 | @item C-c C-l | |
1520 | @kindex C-c C-l @r{(C mode)} | |
1521 | @findex c-toggle-electric-state | |
1522 | Toggle electric action (@code{c-toggle-electric-state}). With a | |
1523 | prefix argument, this command enables electric action if the argument | |
1524 | is positive, disables it if it is negative. | |
1525 | @end table | |
1526 | ||
1527 | Electric characters insert newlines only when, in addition to the | |
1528 | electric state, the @dfn{auto-newline} feature is enabled (indicated | |
1529 | by @samp{/la} in the mode line after the mode name). You can turn | |
1530 | this feature on or off with the command @kbd{C-c C-a}: | |
6bf7aab6 DL |
1531 | |
1532 | @table @kbd | |
1533 | @item C-c C-a | |
1534 | @kindex C-c C-a @r{(C mode)} | |
108262a0 AM |
1535 | @findex c-toggle-auto-newline |
1536 | Toggle the auto-newline feature (@code{c-toggle-auto-newline}). With a | |
6bf7aab6 DL |
1537 | prefix argument, this command turns the auto-newline feature on if the |
1538 | argument is positive, and off if it is negative. | |
1539 | @end table | |
1540 | ||
f5eb910a RS |
1541 | Usually the CC Mode style configures the exact circumstances in |
1542 | which Emacs inserts auto-newlines. You can also configure this | |
1543 | directly. @xref{Custom Auto-newlines,,, ccmode, The CC Mode Manual}. | |
6bf7aab6 DL |
1544 | |
1545 | @node Hungry Delete | |
1546 | @subsection Hungry Delete Feature in C | |
7ae8ad94 | 1547 | @cindex hungry deletion (C Mode) |
6bf7aab6 | 1548 | |
108262a0 AM |
1549 | If you want to delete an entire block of whitespace at point, you |
1550 | can use @dfn{hungry deletion}. This deletes all the contiguous | |
1551 | whitespace either before point or after point in a single operation. | |
1552 | @dfn{Whitespace} here includes tabs and newlines, but not comments or | |
1553 | preprocessor commands. | |
6bf7aab6 DL |
1554 | |
1555 | @table @kbd | |
69d271a7 AM |
1556 | @item C-c C-@key{DEL} |
1557 | @itemx C-c @key{DEL} | |
108262a0 | 1558 | @findex c-hungry-backspace |
69d271a7 AM |
1559 | @kindex C-c C-@key{DEL} (C Mode) |
1560 | @kindex C-c @key{DEL} (C Mode) | |
108262a0 AM |
1561 | @code{c-hungry-backspace}---Delete the entire block of whitespace |
1562 | preceding point. | |
1563 | ||
6bf7aab6 | 1564 | @item C-c C-d |
69d271a7 AM |
1565 | @itemx C-c C-@key{DELETE} |
1566 | @itemx C-c @key{DELETE} | |
108262a0 AM |
1567 | @findex c-hungry-delete-forward |
1568 | @kindex C-c C-d (C Mode) | |
69d271a7 AM |
1569 | @kindex C-c C-@key{DELETE} (C Mode) |
1570 | @kindex C-c @key{DELETE} (C Mode) | |
108262a0 AM |
1571 | @code{c-hungry-delete-forward}---Delete the entire block of whitespace |
1572 | following point. | |
1573 | @end table | |
1574 | ||
1575 | As an alternative to the above commands, you can enable @dfn{hungry | |
1576 | delete mode}. When this feature is enabled (indicated by @samp{/h} in | |
d884be12 RS |
1577 | the mode line after the mode name), a single @key{DEL} deletes all |
1578 | preceding whitespace, not just one space, and a single @kbd{C-c C-d} | |
1579 | (but @emph{not} plain @key{DELETE}) deletes all following whitespace. | |
6bf7aab6 | 1580 | |
108262a0 AM |
1581 | @table @kbd |
1582 | @item M-x c-toggle-hungry-state | |
1583 | @findex c-toggle-hungry-state | |
1584 | Toggle the hungry-delete feature | |
1585 | (@code{c-toggle-hungry-state})@footnote{This command had the binding | |
1586 | @kbd{C-c C-d} in earlier versions of Emacs. @kbd{C-c C-d} is now | |
1587 | bound to @code{c-hungry-delete-forward}.}. With a prefix argument, | |
1588 | this command turns the hungry-delete feature on if the argument is | |
1589 | positive, and off if it is negative. | |
6bf7aab6 DL |
1590 | @end table |
1591 | ||
1592 | @vindex c-hungry-delete-key | |
1593 | The variable @code{c-hungry-delete-key} controls whether the | |
1594 | hungry-delete feature is enabled. | |
1595 | ||
1596 | @node Other C Commands | |
1597 | @subsection Other Commands for C Mode | |
1598 | ||
1599 | @table @kbd | |
108262a0 AM |
1600 | @item C-c C-w |
1601 | @itemx M-x c-subword-mode | |
1602 | @findex c-subword-mode | |
f5eb910a | 1603 | Enable (or disable) @dfn{subword mode}. In subword mode, Emacs's word |
8a75579f | 1604 | commands recognize upper case letters in |
f5eb910a RS |
1605 | @samp{StudlyCapsIdentifiers} as word boundaries. This is indicated by |
1606 | the flag @samp{/w} on the mode line after the mode name | |
1607 | (e.g. @samp{C/law}). You can even use @kbd{M-x c-subword-mode} in | |
1608 | non-CC Mode buffers. | |
108262a0 | 1609 | |
dfec8297 RS |
1610 | In the GNU project, we recommend using underscores to separate words |
1611 | within an identifier in C or C++, rather than using case distinctions. | |
1612 | ||
7ae8ad94 RS |
1613 | @item M-x c-context-line-break |
1614 | @findex c-context-line-break | |
1615 | This command inserts a line break and indents the new line in a manner | |
1616 | appropriate to the context. In normal code, it does the work of | |
1617 | @kbd{C-j} (@code{newline-and-indent}), in a C preprocessor line it | |
1618 | additionally inserts a @samp{\} at the line break, and within comments | |
1619 | it's like @kbd{M-j} (@code{c-indent-new-comment-line}). | |
1620 | ||
1621 | @code{c-context-line-break} isn't bound to a key by default, but it | |
1622 | needs a binding to be useful. The following code will bind it to | |
108262a0 AM |
1623 | @kbd{C-j}. We use @code{c-initialization-hook} here to make sure |
1624 | the keymap is loaded before we try to change it. | |
1625 | ||
444246ca | 1626 | @smallexample |
108262a0 AM |
1627 | (defun my-bind-clb () |
1628 | (define-key c-mode-base-map "\C-j" 'c-context-line-break)) | |
1629 | (add-hook 'c-initialization-hook 'my-bind-clb) | |
444246ca | 1630 | @end smallexample |
7ae8ad94 | 1631 | |
6bf7aab6 | 1632 | @item C-M-h |
6bf7aab6 DL |
1633 | Put mark at the end of a function definition, and put point at the |
1634 | beginning (@code{c-mark-function}). | |
1635 | ||
1636 | @item M-q | |
1637 | @kindex M-q @r{(C mode)} | |
1638 | @findex c-fill-paragraph | |
1639 | Fill a paragraph, handling C and C++ comments (@code{c-fill-paragraph}). | |
1640 | If any part of the current line is a comment or within a comment, this | |
1641 | command fills the comment or the paragraph of it that point is in, | |
1642 | preserving the comment indentation and comment delimiters. | |
1643 | ||
1644 | @item C-c C-e | |
1645 | @cindex macro expansion in C | |
1646 | @cindex expansion of C macros | |
1647 | @findex c-macro-expand | |
1648 | @kindex C-c C-e @r{(C mode)} | |
1649 | Run the C preprocessor on the text in the region, and show the result, | |
1650 | which includes the expansion of all the macro calls | |
1651 | (@code{c-macro-expand}). The buffer text before the region is also | |
1652 | included in preprocessing, for the sake of macros defined there, but the | |
1653 | output from this part isn't shown. | |
1654 | ||
1655 | When you are debugging C code that uses macros, sometimes it is hard to | |
1656 | figure out precisely how the macros expand. With this command, you | |
1657 | don't have to figure it out; you can see the expansions. | |
1658 | ||
1659 | @item C-c C-\ | |
1660 | @findex c-backslash-region | |
1661 | @kindex C-c C-\ @r{(C mode)} | |
1662 | Insert or align @samp{\} characters at the ends of the lines of the | |
1663 | region (@code{c-backslash-region}). This is useful after writing or | |
1664 | editing a C macro definition. | |
1665 | ||
1666 | If a line already ends in @samp{\}, this command adjusts the amount of | |
1667 | whitespace before it. Otherwise, it inserts a new @samp{\}. However, | |
1668 | the last line in the region is treated specially; no @samp{\} is | |
1669 | inserted on that line, and any @samp{\} there is deleted. | |
1670 | ||
1671 | @item M-x cpp-highlight-buffer | |
1672 | @cindex preprocessor highlighting | |
1673 | @findex cpp-highlight-buffer | |
1674 | Highlight parts of the text according to its preprocessor conditionals. | |
1675 | This command displays another buffer named @samp{*CPP Edit*}, which | |
1676 | serves as a graphic menu for selecting how to display particular kinds | |
1677 | of conditionals and their contents. After changing various settings, | |
1678 | click on @samp{[A]pply these settings} (or go to that buffer and type | |
1679 | @kbd{a}) to rehighlight the C mode buffer accordingly. | |
1680 | ||
1681 | @item C-c C-s | |
1682 | @findex c-show-syntactic-information | |
1683 | @kindex C-c C-s @r{(C mode)} | |
1684 | Display the syntactic information about the current source line | |
054af0fd SE |
1685 | (@code{c-show-syntactic-information}). This information directs how |
1686 | the line is indented. | |
3b8b8888 DL |
1687 | |
1688 | @item M-x cwarn-mode | |
1689 | @itemx M-x global-cwarn-mode | |
1690 | @findex cwarn-mode | |
1691 | @findex global-cwarn-mode | |
7ae8ad94 | 1692 | @vindex global-cwarn-mode |
3b8b8888 DL |
1693 | @cindex CWarn mode |
1694 | @cindex suspicious constructions in C, C++ | |
9234c238 | 1695 | CWarn minor mode highlights certain suspicious C and C++ constructions: |
3b8b8888 DL |
1696 | |
1697 | @itemize @bullet{} | |
1698 | @item | |
9234c238 | 1699 | Assignments inside expressions. |
3b8b8888 DL |
1700 | @item |
1701 | Semicolon following immediately after @samp{if}, @samp{for}, and @samp{while} | |
1702 | (except after a @samp{do @dots{} while} statement); | |
1703 | @item | |
1704 | C++ functions with reference parameters. | |
1705 | @end itemize | |
1706 | ||
1707 | @noindent | |
9234c238 RS |
1708 | You can enable the mode for one buffer with the command @kbd{M-x |
1709 | cwarn-mode}, or for all suitable buffers with the command @kbd{M-x | |
1710 | global-cwarn-mode} or by customizing the variable | |
1711 | @code{global-cwarn-mode}. You must also enable Font Lock mode to make | |
1712 | it work. | |
3b8b8888 DL |
1713 | |
1714 | @item M-x hide-ifdef-mode | |
1715 | @findex hide-ifdef-mode | |
1716 | @cindex Hide-ifdef mode | |
1717 | Hide-ifdef minor mode hides selected code within @samp{#if} and | |
9234c238 RS |
1718 | @samp{#ifdef} preprocessor blocks. See the documentation string of |
1719 | @code{hide-ifdef-mode} for more information. | |
1720 | ||
1721 | @item M-x ff-find-related-file | |
1722 | @cindex related files | |
1723 | @findex ff-find-related-file | |
1724 | @vindex ff-related-file-alist | |
1725 | Find a file ``related'' in a special way to the file visited by the | |
1726 | current buffer. Typically this will be the header file corresponding | |
1727 | to a C/C++ source file, or vice versa. The variable | |
1728 | @code{ff-related-file-alist} specifies how to compute related file | |
1729 | names. | |
6bf7aab6 DL |
1730 | @end table |
1731 | ||
6bf7aab6 DL |
1732 | @node Asm Mode |
1733 | @section Asm Mode | |
1734 | ||
1735 | @cindex Asm mode | |
9234c238 | 1736 | @cindex assembler mode |
6bf7aab6 DL |
1737 | Asm mode is a major mode for editing files of assembler code. It |
1738 | defines these commands: | |
1739 | ||
1740 | @table @kbd | |
1741 | @item @key{TAB} | |
1742 | @code{tab-to-tab-stop}. | |
1743 | @item C-j | |
1744 | Insert a newline and then indent using @code{tab-to-tab-stop}. | |
1745 | @item : | |
1746 | Insert a colon and then remove the indentation from before the label | |
1747 | preceding colon. Then do @code{tab-to-tab-stop}. | |
1748 | @item ; | |
1749 | Insert or align a comment. | |
1750 | @end table | |
1751 | ||
1752 | The variable @code{asm-comment-char} specifies which character | |
1753 | starts comments in assembler syntax. | |
ab5796a9 | 1754 | |
b23ef7a5 EZ |
1755 | @ifnottex |
1756 | @include fortran-xtra.texi | |
1757 | @end ifnottex | |
1758 | ||
ab5796a9 MB |
1759 | @ignore |
1760 | arch-tag: c7ee7409-40a4-45c7-bfb7-ae7f2c74d0c0 | |
1761 | @end ignore |