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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, |
114f9c96 | 3 | @c 2001, 2002, 2003, 2004, 2005, 2006, 2007, 2008, 2009, 2010 |
324a4f6a | 4 | @c Free Software Foundation, Inc. |
6bf7aab6 DL |
5 | @c See file emacs.texi for copying conditions. |
6 | @node Programs, Building, Text, Top | |
7 | @chapter Editing Programs | |
8 | @cindex Lisp editing | |
9 | @cindex C editing | |
10 | @cindex program editing | |
11 | ||
e79c6b89 RS |
12 | Emacs provides many features to facilitate editing programs. Some |
13 | of these features can | |
6bf7aab6 DL |
14 | |
15 | @itemize @bullet | |
16 | @item | |
93da5dff | 17 | Find or move over top-level definitions (@pxref{Defuns}). |
6bf7aab6 | 18 | @item |
93da5dff RS |
19 | Apply the usual indentation conventions of the language |
20 | (@pxref{Program Indent}). | |
6bf7aab6 | 21 | @item |
93da5dff | 22 | Balance parentheses (@pxref{Parentheses}). |
cf1c48d4 | 23 | @item |
ea118de1 SE |
24 | Insert, kill or align comments (@pxref{Comments}). |
25 | @item | |
cf1c48d4 | 26 | Highlight program syntax (@pxref{Font Lock}). |
6bf7aab6 DL |
27 | @end itemize |
28 | ||
e79c6b89 RS |
29 | This chapter describes these features and many more. |
30 | ||
6bf7aab6 DL |
31 | @menu |
32 | * Program Modes:: Major modes for editing programs. | |
93da5dff RS |
33 | * Defuns:: Commands to operate on major top-level parts |
34 | of a program. | |
6bf7aab6 | 35 | * Program Indent:: Adjusting indentation to show the nesting. |
93da5dff | 36 | * Parentheses:: Commands that operate on parentheses. |
c8b21b5e | 37 | * Comments:: Inserting, killing, and aligning comments. |
93da5dff | 38 | * Documentation:: Getting documentation of functions you plan to call. |
51ed0ea0 | 39 | * Hideshow:: Displaying blocks selectively. |
93da5dff | 40 | * Symbol Completion:: Completion on symbol names of your program or language. |
3b8b8888 | 41 | * Glasses:: Making identifiersLikeThis more readable. |
93da5dff | 42 | * Misc for Programs:: Other Emacs features useful for editing programs. |
79214ddf | 43 | * C Modes:: Special commands of C, C++, Objective-C, |
6bf7aab6 | 44 | Java, and Pike modes. |
51ed0ea0 | 45 | * Asm Mode:: Asm mode and its special features. |
b23ef7a5 EZ |
46 | @ifnottex |
47 | * Fortran:: Fortran mode and its special features. | |
48 | @end ifnottex | |
6bf7aab6 DL |
49 | @end menu |
50 | ||
51 | @node Program Modes | |
52 | @section Major Modes for Programming Languages | |
6bf7aab6 | 53 | @cindex modes for programming languages |
cf1c48d4 RS |
54 | |
55 | Emacs has specialized major modes for various programming languages. | |
56 | @xref{Major Modes}. A programming language major mode typically | |
57 | specifies the syntax of expressions, the customary rules for | |
58 | indentation, how to do syntax highlighting for the language, and how | |
e722aa81 CY |
59 | to find the beginning or end of a function definition. It often |
60 | customizes or provides facilities for compiling and debugging programs | |
61 | as well. | |
cf1c48d4 RS |
62 | |
63 | Ideally, Emacs should provide a major mode for each programming | |
64 | language that you might want to edit; if it doesn't have a mode for | |
65 | your favorite language, you can contribute one. But often the mode | |
66 | for one language can serve for other syntactically similar languages. | |
67 | The major mode for language @var{l} is called @code{@var{l}-mode}, | |
e79c6b89 | 68 | and you can select it by typing @kbd{M-x @var{l}-mode @key{RET}}. |
cf1c48d4 RS |
69 | @xref{Choosing Modes}. |
70 | ||
6bf7aab6 DL |
71 | @cindex Perl mode |
72 | @cindex Icon mode | |
6bf7aab6 DL |
73 | @cindex Makefile mode |
74 | @cindex Tcl mode | |
75 | @cindex CPerl mode | |
138a8f12 DL |
76 | @cindex DSSSL mode |
77 | @cindex Octave mode | |
78 | @cindex Metafont mode | |
79 | @cindex Modula2 mode | |
80 | @cindex Prolog mode | |
7b703414 | 81 | @cindex Python mode |
e37d4360 | 82 | @cindex Ruby mode |
138a8f12 DL |
83 | @cindex Simula mode |
84 | @cindex VHDL mode | |
85 | @cindex M4 mode | |
86 | @cindex Shell-script mode | |
3b8b8888 DL |
87 | @cindex Delphi mode |
88 | @cindex PostScript mode | |
8758a7da RS |
89 | @cindex Conf mode |
90 | @cindex DNS mode | |
e722aa81 CY |
91 | The existing programming language major modes include Lisp, Scheme |
92 | (a variant of Lisp) and the Scheme-based DSSSL expression language, | |
93 | Ada, ASM, AWK, C, C++, Delphi (Object Pascal), Fortran, Icon, IDL | |
94 | (CORBA), IDLWAVE, Java, Metafont (@TeX{}'s companion for font | |
95 | creation), Modula2, Objective-C, Octave, Pascal, Perl, Pike, | |
e37d4360 CY |
96 | PostScript, Prolog, Python, Ruby, Simula, Tcl, and VHDL. An |
97 | alternative mode for Perl is called CPerl mode. Modes are available | |
98 | for the scripting languages of the common GNU and Unix shells, VMS | |
99 | DCL, and MS-DOS/MS-Windows @samp{BAT} files. There are also major | |
100 | modes for editing makefiles, DNS master files, and various sorts of | |
e722aa81 | 101 | configuration files. |
6bf7aab6 DL |
102 | |
103 | @kindex DEL @r{(programming modes)} | |
4f7666dc | 104 | @findex c-electric-backspace |
93da5dff RS |
105 | In most programming languages, indentation should vary from line to |
106 | line to illustrate the structure of the program. So the major modes | |
e79c6b89 | 107 | for programming languages arrange for @key{TAB} to update the |
e722aa81 CY |
108 | indentation of the current line (@pxref{Program Indent}). They also |
109 | rebind @key{DEL} to treat a tab as if it were the equivalent number of | |
110 | spaces; this lets you delete one column of indentation without | |
111 | worrying whether the whitespace consists of spaces or tabs. Use | |
112 | @kbd{C-b C-d} to delete a tab character before point, in these modes. | |
6bf7aab6 | 113 | |
cf1c48d4 | 114 | Separate manuals are available for the modes for Ada (@pxref{Top, , Ada |
7ae8ad94 | 115 | Mode, ada-mode, Ada Mode}), C/C++/Objective C/Java/Corba IDL/Pike/AWK |
cf1c48d4 | 116 | (@pxref{Top, , CC Mode, ccmode, CC Mode}) and the IDLWAVE modes |
e0fc8fa2 | 117 | (@pxref{Top, , IDLWAVE, idlwave, IDLWAVE User Manual}). For Fortran |
b23ef7a5 EZ |
118 | mode, see |
119 | @iftex | |
9dc999d3 | 120 | @ref{Fortran,,, emacs-xtra, Specialized Emacs Features}. |
b23ef7a5 EZ |
121 | @end iftex |
122 | @ifnottex | |
123 | @ref{Fortran}. | |
124 | @end ifnottex | |
125 | ||
6bf7aab6 DL |
126 | @cindex mode hook |
127 | @vindex c-mode-hook | |
128 | @vindex lisp-mode-hook | |
129 | @vindex emacs-lisp-mode-hook | |
130 | @vindex lisp-interaction-mode-hook | |
131 | @vindex scheme-mode-hook | |
d2fab838 RS |
132 | Turning on a major mode runs a normal hook called the @dfn{mode |
133 | hook}, which is the value of a Lisp variable. Each major mode has a | |
134 | mode hook, and the hook's name is always made from the mode command's | |
135 | name by adding @samp{-hook}. For example, turning on C mode runs the | |
136 | hook @code{c-mode-hook}, while turning on Lisp mode runs the hook | |
137 | @code{lisp-mode-hook}. The purpose of the mode hook is to give you a | |
138 | place to set up customizations for that major mode. @xref{Hooks}. | |
6bf7aab6 | 139 | |
93da5dff RS |
140 | @node Defuns |
141 | @section Top-Level Definitions, or Defuns | |
6bf7aab6 | 142 | |
e722aa81 CY |
143 | In Emacs, a major definition at the top level in the buffer, such as |
144 | a function, is called a @dfn{defun}. The name comes from Lisp, but in | |
145 | Emacs we use it for all languages. | |
6bf7aab6 | 146 | |
93da5dff RS |
147 | @menu |
148 | * Left Margin Paren:: An open-paren or similar opening delimiter | |
149 | starts a defun if it is at the left margin. | |
150 | * Moving by Defuns:: Commands to move over or mark a major definition. | |
151 | * Imenu:: Making buffer indexes as menus. | |
152 | * Which Function:: Which Function mode shows which function you are in. | |
153 | @end menu | |
6bf7aab6 | 154 | |
93da5dff RS |
155 | @node Left Margin Paren |
156 | @subsection Left Margin Convention | |
6bf7aab6 | 157 | |
93da5dff RS |
158 | @cindex open-parenthesis in leftmost column |
159 | @cindex ( in leftmost column | |
e722aa81 CY |
160 | Many programming-language modes assume by default that any opening |
161 | delimiter found at the left margin is the start of a top-level | |
162 | definition, or defun. Therefore, @strong{don't put an opening | |
163 | delimiter at the left margin unless it should have that significance}. | |
164 | For instance, never put an open-parenthesis at the left margin in a | |
165 | Lisp file unless it is the start of a top-level list. | |
166 | ||
167 | The convention speeds up many Emacs operations, which would | |
168 | otherwise have to scan back to the beginning of the buffer to analyze | |
169 | the syntax of the code. | |
93da5dff RS |
170 | |
171 | If you don't follow this convention, not only will you have trouble | |
172 | when you explicitly use the commands for motion by defuns; other | |
e722aa81 CY |
173 | features that use them will also give you trouble. This includes the |
174 | indentation commands (@pxref{Program Indent}) and Font Lock mode | |
175 | (@pxref{Font Lock}). | |
93da5dff RS |
176 | |
177 | The most likely problem case is when you want an opening delimiter | |
178 | at the start of a line inside a string. To avoid trouble, put an | |
aca2cfd2 AM |
179 | escape character (@samp{\}, in C and Emacs Lisp, @samp{/} in some |
180 | other Lisp dialects) before the opening delimiter. This will not | |
181 | affect the contents of the string, but will prevent that opening | |
182 | delimiter from starting a defun. Here's an example: | |
6bf7aab6 | 183 | |
93da5dff RS |
184 | @example |
185 | (insert "Foo: | |
186 | \(bar) | |
187 | ") | |
188 | @end example | |
6bf7aab6 | 189 | |
5b8fe684 RS |
190 | To help you catch violations of this convention, Font Lock mode |
191 | highlights confusing opening delimiters (those that ought to be | |
192 | quoted) in bold red. | |
193 | ||
e722aa81 CY |
194 | If you need to override this convention, you can do so by setting |
195 | this user option: | |
aca2cfd2 AM |
196 | |
197 | @defvar open-paren-in-column-0-is-defun-start | |
198 | If this user option is set to @code{t} (the default), opening | |
199 | parentheses or braces at column zero always start defuns. When it's | |
200 | @code{nil}, defuns are found by searching for parens or braces at the | |
201 | outermost level. | |
202 | @end defvar | |
203 | ||
e722aa81 CY |
204 | Usually, you should leave this option at its default value of |
205 | @code{t}. If your buffer contains parentheses or braces in column | |
206 | zero which don't start defuns, and it is somehow impractical to remove | |
207 | these parentheses or braces, it might be helpful to set the option to | |
208 | @code{nil}. Be aware that this might make scrolling and display in | |
209 | large buffers quite sluggish. Furthermore, the parentheses and braces | |
210 | must be correctly matched throughout the buffer for it to work | |
211 | properly. | |
93da5dff RS |
212 | |
213 | @node Moving by Defuns | |
214 | @subsection Moving by Defuns | |
6bf7aab6 DL |
215 | @cindex defuns |
216 | ||
93da5dff RS |
217 | These commands move point or set up the region based on top-level |
218 | major definitions, also called @dfn{defuns}. | |
520c3f4c | 219 | |
6bf7aab6 DL |
220 | @table @kbd |
221 | @item C-M-a | |
222 | Move to beginning of current or preceding defun | |
223 | (@code{beginning-of-defun}). | |
224 | @item C-M-e | |
225 | Move to end of current or following defun (@code{end-of-defun}). | |
226 | @item C-M-h | |
227 | Put region around whole current or following defun (@code{mark-defun}). | |
228 | @end table | |
229 | ||
f772775c RS |
230 | @cindex move to beginning or end of function |
231 | @cindex function, move to beginning or end | |
232 | @kindex C-M-a | |
233 | @kindex C-M-e | |
234 | @kindex C-M-h | |
235 | @findex beginning-of-defun | |
236 | @findex end-of-defun | |
237 | @findex mark-defun | |
238 | The commands to move to the beginning and end of the current defun | |
239 | are @kbd{C-M-a} (@code{beginning-of-defun}) and @kbd{C-M-e} | |
240 | (@code{end-of-defun}). If you repeat one of these commands, or use a | |
241 | positive numeric argument, each repetition moves to the next defun in | |
242 | the direction of motion. | |
243 | ||
244 | @kbd{C-M-a} with a negative argument @minus{}@var{n} moves forward | |
245 | @var{n} times to the next beginning of a defun. This is not exactly | |
246 | the same place that @kbd{C-M-e} with argument @var{n} would move to; | |
247 | the end of this defun is not usually exactly the same place as the | |
93da5dff RS |
248 | beginning of the following defun. (Whitespace, comments, and perhaps |
249 | declarations can separate them.) Likewise, @kbd{C-M-e} with a | |
250 | negative argument moves back to an end of a defun, which is not quite | |
251 | the same as @kbd{C-M-a} with a positive argument. | |
f772775c | 252 | |
4946337d | 253 | @kindex C-M-h @r{(C mode)} |
6bf7aab6 | 254 | @findex c-mark-function |
25716538 CY |
255 | To operate on the current defun, use @kbd{C-M-h} |
256 | (@code{mark-defun}), which sets the mark at the end of the current | |
257 | defun and puts point at its beginning. @xref{Marking Objects}. This | |
258 | is the easiest way to get ready to kill the defun in order to move it | |
259 | to a different place in the file. If you use the command while point | |
260 | is between defuns, it uses the following defun. If you use the | |
261 | command while the mark is already active, it sets the mark but does | |
262 | not move point; furthermore, each successive use of @kbd{C-M-h} | |
263 | extends the end of the region to include one more defun. | |
93da5dff RS |
264 | |
265 | In C mode, @kbd{C-M-h} runs the function @code{c-mark-function}, | |
266 | which is almost the same as @code{mark-defun}; the difference is that | |
267 | it backs up over the argument declarations, function name and returned | |
e79c6b89 RS |
268 | data type so that the entire C function is inside the region. This is |
269 | an example of how major modes adjust the standard key bindings so that | |
270 | they do their standard jobs in a way better fitting a particular | |
271 | language. Other major modes may replace any or all of these key | |
272 | bindings for that purpose. | |
6bf7aab6 | 273 | |
93da5dff RS |
274 | @node Imenu |
275 | @subsection Imenu | |
e79c6b89 RS |
276 | @cindex index of buffer definitions |
277 | @cindex buffer definitions index | |
93da5dff | 278 | |
269b7745 | 279 | The Imenu facility offers a way to find the major definitions in |
5e6f9132 RS |
280 | a file by name. It is also useful in text formatter major modes, |
281 | where it treats each chapter, section, etc., as a definition. | |
e79c6b89 | 282 | (@xref{Tags}, for a more powerful feature that handles multiple files |
5e6f9132 | 283 | together.) |
93da5dff RS |
284 | |
285 | @findex imenu | |
5e6f9132 | 286 | If you type @kbd{M-x imenu}, it reads the name of a definition using |
e79c6b89 RS |
287 | the minibuffer, then moves point to that definition. You can use |
288 | completion to specify the name; the command always displays the whole | |
289 | list of valid names. | |
d2fab838 | 290 | |
5e6f9132 | 291 | @findex imenu-add-menubar-index |
d2fab838 | 292 | Alternatively, you can bind the command @code{imenu} to a mouse |
e79c6b89 RS |
293 | click. Then it displays mouse menus for you to select a definition |
294 | name. You can also add the buffer's index to the menu bar by calling | |
295 | @code{imenu-add-menubar-index}. If you want to have this menu bar | |
296 | item available for all buffers in a certain major mode, you can do | |
297 | this by adding @code{imenu-add-menubar-index} to its mode hook. But | |
dfec8297 RS |
298 | if you have done that, you will have to wait a little while each time |
299 | you visit a file in that mode, while Emacs finds all the definitions | |
300 | in that buffer. | |
93da5dff RS |
301 | |
302 | @vindex imenu-auto-rescan | |
303 | When you change the contents of a buffer, if you add or delete | |
e79c6b89 | 304 | definitions, you can update the buffer's index based on the |
d2fab838 | 305 | new contents by invoking the @samp{*Rescan*} item in the menu. |
dcace646 EZ |
306 | Rescanning happens automatically if you set @code{imenu-auto-rescan} to |
307 | a non-@code{nil} value. There is no need to rescan because of small | |
e79c6b89 | 308 | changes in the text. |
93da5dff RS |
309 | |
310 | @vindex imenu-sort-function | |
d2fab838 | 311 | You can customize the way the menus are sorted by setting the |
e79c6b89 | 312 | variable @code{imenu-sort-function}. By default, names are ordered as |
5e6f9132 RS |
313 | they occur in the buffer; if you want alphabetic sorting, use the |
314 | symbol @code{imenu--sort-by-name} as the value. You can also | |
315 | define your own comparison function by writing Lisp code. | |
93da5dff RS |
316 | |
317 | Imenu provides the information to guide Which Function mode | |
318 | @ifnottex | |
319 | (@pxref{Which Function}). | |
320 | @end ifnottex | |
321 | @iftex | |
322 | (see below). | |
323 | @end iftex | |
324 | The Speedbar can also use it (@pxref{Speedbar}). | |
325 | ||
326 | @node Which Function | |
327 | @subsection Which Function Mode | |
af056954 | 328 | @cindex current function name in mode line |
93da5dff RS |
329 | |
330 | Which Function mode is a minor mode that displays the current | |
331 | function name in the mode line, updating it as you move around in a | |
332 | buffer. | |
333 | ||
334 | @findex which-function-mode | |
335 | @vindex which-func-modes | |
df7593dd | 336 | To either enable or disable Which Function mode, use the command |
e722aa81 CY |
337 | @kbd{M-x which-function-mode}. This command applies to all buffers, |
338 | both existing ones and those yet to be created. However, it takes | |
339 | effect only in certain major modes, those listed in the value of | |
340 | @code{which-func-modes}. If the value of @code{which-func-modes} is | |
341 | @code{t} rather than a list of modes, then Which Function mode applies | |
342 | to all major modes that know how to support it---in other words, all | |
343 | the major modes that support Imenu. | |
6bf7aab6 DL |
344 | |
345 | @node Program Indent | |
346 | @section Indentation for Programs | |
347 | @cindex indentation for programs | |
348 | ||
349 | The best way to keep a program properly indented is to use Emacs to | |
e722aa81 CY |
350 | reindent it as you change it. Emacs has commands to indent either a |
351 | single line, a specified number of lines, or all of the lines inside a | |
352 | single parenthetical grouping. | |
6bf7aab6 DL |
353 | |
354 | @menu | |
355 | * Basic Indent:: Indenting a single line. | |
356 | * Multi-line Indent:: Commands to reindent many lines at once. | |
357 | * Lisp Indent:: Specifying how each Lisp function should be indented. | |
358 | * C Indent:: Extra features for indenting C and related modes. | |
359 | * Custom C Indent:: Controlling indentation style for C and related modes. | |
360 | @end menu | |
361 | ||
d2fab838 | 362 | @cindex pretty-printer |
6bf7aab6 DL |
363 | Emacs also provides a Lisp pretty-printer in the library @code{pp}. |
364 | This program reformats a Lisp object with indentation chosen to look nice. | |
365 | ||
366 | @node Basic Indent | |
367 | @subsection Basic Program Indentation Commands | |
368 | ||
d2fab838 RS |
369 | The basic indentation commands indent a single line according to the |
370 | usual conventions of the language you are editing. | |
cf1c48d4 | 371 | |
6bf7aab6 DL |
372 | @table @kbd |
373 | @item @key{TAB} | |
374 | Adjust indentation of current line. | |
375 | @item C-j | |
bb63d706 RS |
376 | Insert a newline, then adjust indentation of following line |
377 | (@code{newline-and-indent}). | |
6bf7aab6 DL |
378 | @end table |
379 | ||
380 | @kindex TAB @r{(programming modes)} | |
4f7666dc RS |
381 | @findex c-indent-command |
382 | @findex indent-line-function | |
f772775c | 383 | @findex indent-for-tab-command |
e722aa81 CY |
384 | The basic indentation command is @key{TAB}. In any |
385 | programming-language major mode, @key{TAB} gives the current line the | |
386 | correct indentation as determined from the previous lines. It does | |
387 | this by inserting or deleting whitespace at the beginning of the | |
388 | current line. If point was inside the whitespace at the beginning of | |
389 | the line, @key{TAB} puts it at the end of that whitespace; otherwise, | |
390 | @key{TAB} keeps point fixed with respect to the characters around it. | |
391 | If the region is active (@pxref{Mark}), @key{TAB} indents every line | |
392 | within the region instead of just the current line. The function that | |
393 | @key{TAB} runs depends on the major mode; for instance, it is | |
394 | @code{c-indent-line-or-region} in C mode. Each function is aware of | |
395 | the syntax and conventions for its particular language. | |
6bf7aab6 | 396 | |
64e207c0 | 397 | Use @kbd{C-q @key{TAB}} to insert a tab character at point. |
6bf7aab6 DL |
398 | |
399 | @kindex C-j | |
400 | @findex newline-and-indent | |
cf1c48d4 | 401 | When entering lines of new code, use @kbd{C-j} |
bb63d706 | 402 | (@code{newline-and-indent}), which inserts a newline and then adjusts |
14f4194d | 403 | indentation after it. (It also deletes any trailing whitespace which |
e722aa81 CY |
404 | remains before the new newline.) For instance, @kbd{C-j} at the end |
405 | of a line creates a blank line with appropriate indentation. In | |
406 | programming language modes, it is equivalent to @key{RET} @key{TAB}. | |
407 | ||
408 | When Emacs indents a line that starts within a parenthetical | |
409 | grouping, it usually places the start of the line under the preceding | |
410 | line within the group, or under the text after the parenthesis. If | |
411 | you manually give one of these lines a nonstandard indentation, the | |
412 | lines below will tend to follow it. This behavior is convenient in | |
413 | cases where you have overridden the standard result of @key{TAB} | |
414 | indentation (e.g., for aesthetic purposes). | |
415 | ||
416 | Many programming-language modes assume that an open-parenthesis, | |
417 | open-brace or other opening delimiter at the left margin is the start | |
418 | of a function. This assumption speeds up indentation commands. If | |
419 | the text you are editing contains opening delimiters in column zero | |
420 | that aren't the beginning of a functions---even if these delimiters | |
421 | occur inside strings or comments---then you must set | |
108262a0 | 422 | @code{open-paren-in-column-0-is-defun-start}. @xref{Left Margin |
e722aa81 | 423 | Paren}. |
6bf7aab6 | 424 | |
e722aa81 CY |
425 | Normally, Emacs indents lines using an ``optimal'' mix of tab and |
426 | space characters. If you want Emacs to use spaces only, set | |
427 | @code{indent-tabs-mode} (@pxref{Just Spaces}). | |
5151db0c | 428 | |
6bf7aab6 DL |
429 | @node Multi-line Indent |
430 | @subsection Indenting Several Lines | |
431 | ||
e722aa81 CY |
432 | Sometimes, you may want to reindent several lines of code at a time. |
433 | One way to do this is to use the mark; when the mark is active and the | |
434 | region is non-empty, @key{TAB} indents every line within the region. | |
435 | In addition, Emacs provides several other commands for indenting large | |
436 | chunks of code: | |
6bf7aab6 DL |
437 | |
438 | @table @kbd | |
439 | @item C-M-q | |
e722aa81 | 440 | Reindent all the lines within one parenthetical grouping. |
e79c6b89 RS |
441 | @item C-M-\ |
442 | Reindent all lines in the region (@code{indent-region}). | |
6bf7aab6 | 443 | @item C-u @key{TAB} |
93da5dff RS |
444 | Shift an entire parenthetical grouping rigidly sideways so that its |
445 | first line is properly indented. | |
5cc06e0b EZ |
446 | @item M-x indent-code-rigidly |
447 | Shift all the lines in the region rigidly sideways, but do not alter | |
448 | lines that start inside comments and strings. | |
6bf7aab6 DL |
449 | @end table |
450 | ||
451 | @kindex C-M-q | |
6daf3e15 | 452 | @findex indent-pp-sexp |
e722aa81 CY |
453 | To reindent the contents of a single parenthetical grouping, |
454 | position point before the beginning of the grouping and type | |
455 | @kbd{C-M-q}. This changes the relative indentation within the | |
456 | grouping, without affecting its overall indentation (i.e., the | |
457 | indentation of the line where the grouping starts). The function that | |
458 | @kbd{C-M-q} runs depends on the major mode; it is | |
459 | @code{indent-pp-sexp} in Lisp mode, @code{c-indent-exp} in C mode, | |
460 | etc. To correct the overall indentation as well, type @key{TAB} | |
461 | first. | |
462 | ||
463 | @kbd{C-M-\} (@code{indent-region}) applies @key{TAB} to the region. | |
464 | This is useful when Transient Mark mode is disabled (@pxref{Persistent | |
465 | Mark}), because in that case @key{TAB} does not act on the region. | |
e79c6b89 | 466 | |
6bf7aab6 | 467 | @kindex C-u TAB |
e722aa81 CY |
468 | If you like the relative indentation within a grouping but not the |
469 | indentation of its first line, move point to that first line and type | |
470 | @kbd{C-u @key{TAB}}. In Lisp, C, and some other major modes, | |
471 | @key{TAB} with a numeric argument reindents the current line as usual, | |
472 | then reindents by the same amount all the lines in the parenthetical | |
473 | grouping starting on the current line. It is clever, though, and does | |
474 | not alter lines that start inside strings. Neither does it alter C | |
475 | preprocessor lines when in C mode, but it does reindent any | |
476 | continuation lines that may be attached to them. | |
6bf7aab6 | 477 | |
5cc06e0b | 478 | @findex indent-code-rigidly |
e722aa81 CY |
479 | The command @kbd{M-x indent-code-rigidly} rigidly shifts all the |
480 | lines in the region sideways, like @code{indent-rigidly} does | |
481 | (@pxref{Indentation Commands}). It doesn't alter the indentation of | |
482 | lines that start inside a string, unless the region also starts inside | |
483 | that string. The prefix arg specifies the number of columns to | |
484 | indent. | |
6bf7aab6 DL |
485 | |
486 | @node Lisp Indent | |
487 | @subsection Customizing Lisp Indentation | |
488 | @cindex customizing Lisp indentation | |
489 | ||
490 | The indentation pattern for a Lisp expression can depend on the function | |
491 | called by the expression. For each Lisp function, you can choose among | |
492 | several predefined patterns of indentation, or define an arbitrary one with | |
493 | a Lisp program. | |
494 | ||
495 | The standard pattern of indentation is as follows: the second line of the | |
496 | expression is indented under the first argument, if that is on the same | |
497 | line as the beginning of the expression; otherwise, the second line is | |
498 | indented underneath the function name. Each following line is indented | |
499 | under the previous line whose nesting depth is the same. | |
500 | ||
501 | @vindex lisp-indent-offset | |
502 | If the variable @code{lisp-indent-offset} is non-@code{nil}, it overrides | |
503 | the usual indentation pattern for the second line of an expression, so that | |
504 | such lines are always indented @code{lisp-indent-offset} more columns than | |
505 | the containing list. | |
506 | ||
507 | @vindex lisp-body-indent | |
d2fab838 | 508 | Certain functions override the standard pattern. Functions whose |
269b7745 | 509 | names start with @code{def} treat the second lines as the start of |
d2fab838 RS |
510 | a @dfn{body}, by indenting the second line @code{lisp-body-indent} |
511 | additional columns beyond the open-parenthesis that starts the | |
512 | expression. | |
6bf7aab6 | 513 | |
b771b258 | 514 | @cindex @code{lisp-indent-function} property |
d2fab838 | 515 | You can override the standard pattern in various ways for individual |
690a6d08 RS |
516 | functions, according to the @code{lisp-indent-function} property of |
517 | the function name. Normally you would use this for macro definitions | |
518 | and specify it using the @code{declare} construct (@pxref{Defining | |
519 | Macros,,, elisp, the Emacs Lisp Reference Manual}). | |
6bf7aab6 DL |
520 | |
521 | @node C Indent | |
522 | @subsection Commands for C Indentation | |
523 | ||
93da5dff | 524 | Here are special features for indentation in C mode and related modes: |
6bf7aab6 DL |
525 | |
526 | @table @code | |
527 | @item C-c C-q | |
528 | @kindex C-c C-q @r{(C mode)} | |
529 | @findex c-indent-defun | |
530 | Reindent the current top-level function definition or aggregate type | |
531 | declaration (@code{c-indent-defun}). | |
532 | ||
533 | @item C-M-q | |
534 | @kindex C-M-q @r{(C mode)} | |
535 | @findex c-indent-exp | |
536 | Reindent each line in the balanced expression that follows point | |
7ae8ad94 RS |
537 | (@code{c-indent-exp}). A prefix argument inhibits warning messages |
538 | about invalid syntax. | |
6bf7aab6 DL |
539 | |
540 | @item @key{TAB} | |
541 | @findex c-indent-command | |
542 | Reindent the current line, and/or in some cases insert a tab character | |
543 | (@code{c-indent-command}). | |
544 | ||
7ae8ad94 | 545 | @vindex c-tab-always-indent |
6bf7aab6 DL |
546 | If @code{c-tab-always-indent} is @code{t}, this command always reindents |
547 | the current line and does nothing else. This is the default. | |
548 | ||
549 | If that variable is @code{nil}, this command reindents the current line | |
550 | only if point is at the left margin or in the line's indentation; | |
551 | otherwise, it inserts a tab (or the equivalent number of spaces, | |
552 | if @code{indent-tabs-mode} is @code{nil}). | |
553 | ||
554 | Any other value (not @code{nil} or @code{t}) means always reindent the | |
7ae8ad94 | 555 | line, and also insert a tab if within a comment or a string. |
6bf7aab6 DL |
556 | @end table |
557 | ||
558 | To reindent the whole current buffer, type @kbd{C-x h C-M-\}. This | |
559 | first selects the whole buffer as the region, then reindents that | |
560 | region. | |
561 | ||
562 | To reindent the current block, use @kbd{C-M-u C-M-q}. This moves | |
563 | to the front of the block and then reindents it all. | |
564 | ||
565 | @node Custom C Indent | |
566 | @subsection Customizing C Indentation | |
93da5dff | 567 | @cindex style (for indentation) |
6bf7aab6 | 568 | |
7ae8ad94 RS |
569 | C mode and related modes use a flexible mechanism for customizing |
570 | indentation. C mode indents a source line in two steps: first it | |
571 | classifies the line syntactically according to its contents and | |
572 | context; second, it determines the indentation offset associated by | |
573 | your selected @dfn{style} with the syntactic construct and adds this | |
574 | onto the indentation of the @dfn{anchor statement}. | |
6bf7aab6 | 575 | |
93da5dff | 576 | @table @kbd |
7ae8ad94 RS |
577 | @item C-c . @key{RET} @var{style} @key{RET} |
578 | Select a predefined style @var{style} (@code{c-set-style}). | |
93da5dff | 579 | @end table |
6bf7aab6 | 580 | |
108262a0 AM |
581 | A @dfn{style} is a named collection of customizations that can be |
582 | used in C mode and the related modes. @ref{Styles,,, ccmode, The CC | |
583 | Mode Manual}, for a complete description. Emacs comes with several | |
93da5dff RS |
584 | predefined styles, including @code{gnu}, @code{k&r}, @code{bsd}, |
585 | @code{stroustrup}, @code{linux}, @code{python}, @code{java}, | |
108262a0 AM |
586 | @code{whitesmith}, @code{ellemtel}, and @code{awk}. Some of these |
587 | styles are primarily intended for one language, but any of them can be | |
588 | used with any of the languages supported by these modes. To find out | |
589 | what a style looks like, select it and reindent some code, e.g., by | |
590 | typing @key{C-M-q} at the start of a function definition. | |
6bf7aab6 | 591 | |
7ae8ad94 | 592 | @kindex C-c . @r{(C mode)} |
93da5dff | 593 | @findex c-set-style |
dfec8297 RS |
594 | To choose a style for the current buffer, use the command @w{@kbd{C-c |
595 | .}}. Specify a style name as an argument (case is not significant). | |
7ae8ad94 RS |
596 | This command affects the current buffer only, and it affects only |
597 | future invocations of the indentation commands; it does not reindent | |
108262a0 AM |
598 | the code already in the buffer. To reindent the whole buffer in the |
599 | new style, you can type @kbd{C-x h C-M-\}. | |
6bf7aab6 | 600 | |
93da5dff RS |
601 | @vindex c-default-style |
602 | You can also set the variable @code{c-default-style} to specify the | |
7ae8ad94 RS |
603 | default style for various major modes. Its value should be either the |
604 | style's name (a string) or an alist, in which each element specifies | |
605 | one major mode and which indentation style to use for it. For | |
606 | example, | |
6bf7aab6 DL |
607 | |
608 | @example | |
93da5dff | 609 | (setq c-default-style |
108262a0 | 610 | '((java-mode . "java") (awk-mode . "awk") (other . "gnu"))) |
6bf7aab6 DL |
611 | @end example |
612 | ||
93da5dff | 613 | @noindent |
108262a0 AM |
614 | specifies explicit choices for Java and AWK modes, and the default |
615 | @samp{gnu} style for the other C-like modes. (These settings are | |
616 | actually the defaults.) This variable takes effect when you select | |
617 | one of the C-like major modes; thus, if you specify a new default | |
618 | style for Java mode, you can make it take effect in an existing Java | |
619 | mode buffer by typing @kbd{M-x java-mode} there. | |
6bf7aab6 | 620 | |
93da5dff RS |
621 | The @code{gnu} style specifies the formatting recommended by the GNU |
622 | Project for C; it is the default, so as to encourage use of our | |
623 | recommended style. | |
6bf7aab6 | 624 | |
108262a0 AM |
625 | @xref{Indentation Engine Basics,,, ccmode, the CC Mode Manual}, and |
626 | @ref{Customizing Indentation,,, ccmode, the CC Mode Manual}, for more | |
627 | information on customizing indentation for C and related modes, | |
93da5dff RS |
628 | including how to override parts of an existing style and how to define |
629 | your own styles. | |
6bf7aab6 | 630 | |
93da5dff RS |
631 | @node Parentheses |
632 | @section Commands for Editing with Parentheses | |
6bf7aab6 | 633 | |
93da5dff RS |
634 | @findex check-parens |
635 | @cindex unbalanced parentheses and quotes | |
636 | This section describes the commands and features that take advantage | |
637 | of the parenthesis structure in a program, or help you keep it | |
638 | balanced. | |
6bf7aab6 | 639 | |
93da5dff RS |
640 | When talking about these facilities, the term ``parenthesis'' also |
641 | includes braces, brackets, or whatever delimiters are defined to match | |
e79c6b89 RS |
642 | in pairs. The major mode controls which delimiters are significant, |
643 | through the syntax table (@pxref{Syntax}). In Lisp, only parentheses | |
644 | count; in C, these commands apply to braces and brackets too. | |
6bf7aab6 | 645 | |
93da5dff RS |
646 | You can use @kbd{M-x check-parens} to find any unbalanced |
647 | parentheses and unbalanced string quotes in the buffer. | |
6bf7aab6 | 648 | |
93da5dff RS |
649 | @menu |
650 | * Expressions:: Expressions with balanced parentheses. | |
651 | * Moving by Parens:: Commands for moving up, down and across | |
652 | in the structure of parentheses. | |
653 | * Matching:: Insertion of a close-delimiter flashes matching open. | |
654 | @end menu | |
6bf7aab6 | 655 | |
93da5dff RS |
656 | @node Expressions |
657 | @subsection Expressions with Balanced Parentheses | |
6bf7aab6 | 658 | |
93da5dff RS |
659 | @cindex sexp |
660 | @cindex expression | |
661 | @cindex balanced expression | |
662 | These commands deal with balanced expressions, also called | |
663 | @dfn{sexps}@footnote{The word ``sexp'' is used to refer to an | |
664 | expression in Lisp.}. | |
6bf7aab6 | 665 | |
93da5dff RS |
666 | @table @kbd |
667 | @item C-M-f | |
668 | Move forward over a balanced expression (@code{forward-sexp}). | |
669 | @item C-M-b | |
ea118de1 | 670 | Move backward over a balanced expression (@code{backward-sexp}). |
93da5dff RS |
671 | @item C-M-k |
672 | Kill balanced expression forward (@code{kill-sexp}). | |
93da5dff RS |
673 | @item C-M-t |
674 | Transpose expressions (@code{transpose-sexps}). | |
675 | @item C-M-@@ | |
649d1cbe | 676 | @itemx C-M-@key{SPC} |
93da5dff RS |
677 | Put mark after following expression (@code{mark-sexp}). |
678 | @end table | |
6bf7aab6 | 679 | |
93da5dff RS |
680 | Each programming language major mode customizes the definition of |
681 | balanced expressions to suit that language. Balanced expressions | |
682 | typically include symbols, numbers, and string constants, as well as | |
e79c6b89 | 683 | any pair of matching delimiters and their contents. Some languages |
93da5dff RS |
684 | have obscure forms of expression syntax that nobody has bothered to |
685 | implement in Emacs. | |
6bf7aab6 | 686 | |
93da5dff | 687 | @cindex Control-Meta |
e79c6b89 RS |
688 | By convention, the keys for these commands are all Control-Meta |
689 | characters. They usually act on expressions just as the corresponding | |
690 | Meta characters act on words. For instance, the command @kbd{C-M-b} | |
691 | moves backward over a balanced expression, just as @kbd{M-b} moves | |
692 | back over a word. | |
6bf7aab6 | 693 | |
93da5dff RS |
694 | @kindex C-M-f |
695 | @kindex C-M-b | |
696 | @findex forward-sexp | |
697 | @findex backward-sexp | |
698 | To move forward over a balanced expression, use @kbd{C-M-f} | |
699 | (@code{forward-sexp}). If the first significant character after point | |
700 | is an opening delimiter (@samp{(} in Lisp; @samp{(}, @samp{[} or | |
701 | @samp{@{} in C), @kbd{C-M-f} moves past the matching closing | |
702 | delimiter. If the character begins a symbol, string, or number, | |
703 | @kbd{C-M-f} moves over that. | |
6bf7aab6 | 704 | |
93da5dff RS |
705 | The command @kbd{C-M-b} (@code{backward-sexp}) moves backward over a |
706 | balanced expression. The detailed rules are like those above for | |
707 | @kbd{C-M-f}, but with directions reversed. If there are prefix | |
708 | characters (single-quote, backquote and comma, in Lisp) preceding the | |
709 | expression, @kbd{C-M-b} moves back over them as well. The balanced | |
710 | expression commands move across comments as if they were whitespace, | |
711 | in most modes. | |
6bf7aab6 | 712 | |
93da5dff RS |
713 | @kbd{C-M-f} or @kbd{C-M-b} with an argument repeats that operation the |
714 | specified number of times; with a negative argument, it moves in the | |
715 | opposite direction. | |
6bf7aab6 | 716 | |
93da5dff RS |
717 | @cindex killing expressions |
718 | @kindex C-M-k | |
719 | @findex kill-sexp | |
93da5dff | 720 | Killing a whole balanced expression can be done with @kbd{C-M-k} |
880b0421 RS |
721 | (@code{kill-sexp}). @kbd{C-M-k} kills the characters that @kbd{C-M-f} |
722 | would move over. | |
6bf7aab6 | 723 | |
93da5dff RS |
724 | @cindex transposition of expressions |
725 | @kindex C-M-t | |
726 | @findex transpose-sexps | |
727 | A somewhat random-sounding command which is nevertheless handy is | |
728 | @kbd{C-M-t} (@code{transpose-sexps}), which drags the previous | |
729 | balanced expression across the next one. An argument serves as a | |
108262a0 AM |
730 | repeat count, moving the previous expression over that many following |
731 | ones. A negative argument drags the previous balanced expression | |
732 | backwards across those before it (thus canceling out the effect of | |
733 | @kbd{C-M-t} with a positive argument). An argument of zero, rather | |
734 | than doing nothing, transposes the balanced expressions ending at or | |
735 | after point and the mark. | |
6bf7aab6 | 736 | |
93da5dff | 737 | @kindex C-M-@@ |
649d1cbe | 738 | @kindex C-M-@key{SPC} |
93da5dff RS |
739 | @findex mark-sexp |
740 | To set the region around the next balanced expression in the buffer, | |
25716538 CY |
741 | use @kbd{C-M-@key{SPC}} (@code{mark-sexp}), which sets mark at the |
742 | same place that @kbd{C-M-f} would move to. @kbd{C-M-@key{SPC}} treats | |
743 | numeric arguments in the same way as @kbd{C-M-f}; in particular, a | |
744 | negative argument puts the mark at the beginning of the previous | |
745 | balanced expression. The alias @kbd{C-M-@@} is equivalent to | |
746 | @kbd{C-M-@key{SPC}}. While the mark is active, each successive use of | |
747 | @kbd{C-M-@key{SPC}} extends the region by shifting the mark by one | |
748 | sexp. | |
93da5dff RS |
749 | |
750 | In languages that use infix operators, such as C, it is not possible | |
751 | to recognize all balanced expressions as such because there can be | |
752 | multiple possibilities at a given position. For example, C mode does | |
753 | not treat @samp{foo + bar} as a single expression, even though it | |
754 | @emph{is} one C expression; instead, it recognizes @samp{foo} as one | |
755 | expression and @samp{bar} as another, with the @samp{+} as punctuation | |
756 | between them. Both @samp{foo + bar} and @samp{foo} are legitimate | |
757 | choices for ``the expression following point'' when point is at the | |
e79c6b89 RS |
758 | @samp{f}, so the expression commands must perforce choose one or the |
759 | other to operate on. Note that @samp{(foo + bar)} is recognized as a | |
760 | single expression in C mode, because of the parentheses. | |
93da5dff RS |
761 | |
762 | @node Moving by Parens | |
763 | @subsection Moving in the Parenthesis Structure | |
764 | ||
765 | @cindex parenthetical groupings | |
766 | @cindex parentheses, moving across | |
767 | @cindex matching parenthesis and braces, moving to | |
768 | @cindex braces, moving across | |
769 | @cindex list commands | |
3fbb05ff | 770 | |
93da5dff RS |
771 | The Emacs commands for handling parenthetical groupings see nothing |
772 | except parentheses (or whatever characters must balance in the | |
3fbb05ff AM |
773 | language you are working with). They ignore strings and comments |
774 | (including any parentheses within them) and ignore parentheses quoted | |
775 | by an escape character. They are mainly intended for editing | |
93da5dff RS |
776 | programs, but can be useful for editing any text that has parentheses. |
777 | They are sometimes called ``list'' commands because in Lisp these | |
778 | groupings are lists. | |
6bf7aab6 | 779 | |
3fbb05ff AM |
780 | These commands assume that the starting point is not inside a string |
781 | or a comment. Sometimes you can invoke them usefully from one of | |
782 | these places (for example, when you have a parenthesised clause in a | |
783 | comment) but this is unreliable. | |
784 | ||
6bf7aab6 | 785 | @table @kbd |
93da5dff RS |
786 | @item C-M-n |
787 | Move forward over a parenthetical group (@code{forward-list}). | |
788 | @item C-M-p | |
ea118de1 | 789 | Move backward over a parenthetical group (@code{backward-list}). |
93da5dff RS |
790 | @item C-M-u |
791 | Move up in parenthesis structure (@code{backward-up-list}). | |
792 | @item C-M-d | |
793 | Move down in parenthesis structure (@code{down-list}). | |
6bf7aab6 DL |
794 | @end table |
795 | ||
93da5dff RS |
796 | @kindex C-M-n |
797 | @kindex C-M-p | |
798 | @findex forward-list | |
799 | @findex backward-list | |
800 | The ``list'' commands @kbd{C-M-n} (@code{forward-list}) and | |
3fbb05ff AM |
801 | @kbd{C-M-p} (@code{backward-list}) move forward or backward over one |
802 | (or @var{n}) parenthetical groupings. | |
6bf7aab6 | 803 | |
93da5dff | 804 | @kindex C-M-u |
93da5dff | 805 | @findex backward-up-list |
93da5dff RS |
806 | @kbd{C-M-n} and @kbd{C-M-p} try to stay at the same level in the |
807 | parenthesis structure. To move @emph{up} one (or @var{n}) levels, use | |
808 | @kbd{C-M-u} (@code{backward-up-list}). @kbd{C-M-u} moves backward up | |
809 | past one unmatched opening delimiter. A positive argument serves as a | |
810 | repeat count; a negative argument reverses the direction of motion, so | |
d2fab838 | 811 | that the command moves forward and up one or more levels. |
93da5dff | 812 | |
dfec8297 RS |
813 | @kindex C-M-d |
814 | @findex down-list | |
93da5dff RS |
815 | To move @emph{down} in the parenthesis structure, use @kbd{C-M-d} |
816 | (@code{down-list}). In Lisp mode, where @samp{(} is the only opening | |
817 | delimiter, this is nearly the same as searching for a @samp{(}. An | |
818 | argument specifies the number of levels to go down. | |
6bf7aab6 DL |
819 | |
820 | @node Matching | |
93da5dff | 821 | @subsection Automatic Display Of Matching Parentheses |
6bf7aab6 DL |
822 | @cindex matching parentheses |
823 | @cindex parentheses, displaying matches | |
824 | ||
825 | The Emacs parenthesis-matching feature is designed to show | |
93da5dff RS |
826 | automatically how parentheses (and other matching delimiters) match in |
827 | the text. Whenever you type a self-inserting character that is a | |
828 | closing delimiter, the cursor moves momentarily to the location of the | |
829 | matching opening delimiter, provided that is on the screen. If it is | |
e79c6b89 RS |
830 | not on the screen, Emacs displays some of the text near it in the echo |
831 | area. Either way, you can tell which grouping you are closing off. | |
93da5dff RS |
832 | |
833 | If the opening delimiter and closing delimiter are mismatched---such | |
834 | as in @samp{[x)}---a warning message is displayed in the echo area. | |
6bf7aab6 DL |
835 | |
836 | @vindex blink-matching-paren | |
837 | @vindex blink-matching-paren-distance | |
838 | @vindex blink-matching-delay | |
054af0fd SE |
839 | Three variables control parenthesis match display: |
840 | ||
841 | @code{blink-matching-paren} turns the feature on or off: @code{nil} | |
93da5dff | 842 | disables it, but the default is @code{t} to enable match display. |
f772775c RS |
843 | |
844 | @code{blink-matching-delay} says how many seconds to leave the | |
93da5dff | 845 | cursor on the matching opening delimiter, before bringing it back to |
f772775c RS |
846 | the real location of point; the default is 1, but on some systems it |
847 | is useful to specify a fraction of a second. | |
848 | ||
849 | @code{blink-matching-paren-distance} specifies how many characters | |
850 | back to search to find the matching opening delimiter. If the match | |
8b6f4c0a | 851 | is not found in that distance, scanning stops, and nothing is displayed. |
93da5dff | 852 | This is to prevent the scan for the matching delimiter from wasting |
324a4f6a | 853 | lots of time when there is no match. The default is 102400. |
6bf7aab6 DL |
854 | |
855 | @cindex Show Paren mode | |
79f9f655 | 856 | @cindex highlighting matching parentheses |
6bf7aab6 | 857 | @findex show-paren-mode |
93da5dff | 858 | Show Paren mode provides a more powerful kind of automatic matching. |
e722aa81 CY |
859 | Whenever point is before an opening delimiter or after a closing |
860 | delimiter, both that delimiter and its opposite delimiter are | |
861 | highlighted. Use the command @kbd{M-x show-paren-mode} to enable or | |
862 | disable this mode. | |
79f9f655 | 863 | |
dfec8297 RS |
864 | Show Paren mode uses the faces @code{show-paren-match} and |
865 | @code{show-paren-mismatch} to highlight parentheses; you can customize | |
866 | them to control how highlighting looks. @xref{Face Customization}. | |
6bf7aab6 DL |
867 | |
868 | @node Comments | |
869 | @section Manipulating Comments | |
870 | @cindex comments | |
871 | ||
872 | Because comments are such an important part of programming, Emacs | |
8f50b630 RS |
873 | provides special commands for editing and inserting comments. It can |
874 | also do spell checking on comments with Flyspell Prog mode | |
875 | (@pxref{Spelling}). | |
6bf7aab6 DL |
876 | |
877 | @menu | |
5b31640c | 878 | * Comment Commands:: Inserting, killing, and aligning comments. |
93da5dff RS |
879 | * Multi-Line Comments:: Commands for adding and editing multi-line comments. |
880 | * Options for Comments::Customizing the comment features. | |
6bf7aab6 DL |
881 | @end menu |
882 | ||
883 | @node Comment Commands | |
884 | @subsection Comment Commands | |
6bf7aab6 | 885 | @cindex indentation for comments |
5b31640c | 886 | @cindex alignment for comments |
6bf7aab6 | 887 | |
e722aa81 | 888 | The commands in this table insert, kill and align comments: |
6bf7aab6 | 889 | |
7ae8ad94 RS |
890 | @table @asis |
891 | @item @kbd{M-;} | |
9234c238 RS |
892 | Insert or realign comment on current line; alternatively, comment or |
893 | uncomment the region (@code{comment-dwim}). | |
7ae8ad94 | 894 | @item @kbd{C-u M-;} |
9234c238 | 895 | Kill comment on current line (@code{comment-kill}). |
7ae8ad94 | 896 | @item @kbd{C-x ;} |
47c1b5f4 | 897 | Set comment column (@code{comment-set-column}). |
7ae8ad94 RS |
898 | @item @kbd{C-M-j} |
899 | @itemx @kbd{M-j} | |
6bf7aab6 | 900 | Like @key{RET} followed by inserting and aligning a comment |
108262a0 | 901 | (@code{comment-indent-new-line}). @xref{Multi-Line Comments}. |
7ae8ad94 RS |
902 | @item @kbd{M-x comment-region} |
903 | @itemx @kbd{C-c C-c} (in C-like modes) | |
6bf7aab6 DL |
904 | Add or remove comment delimiters on all the lines in the region. |
905 | @end table | |
906 | ||
9234c238 RS |
907 | @kindex M-; |
908 | @findex comment-dwim | |
909 | The command to create or align a comment is @kbd{M-;} | |
910 | (@code{comment-dwim}). The word ``dwim'' is an acronym for ``Do What | |
911 | I Mean''; it indicates that this command can be used for many | |
912 | different jobs relating to comments, depending on the situation where | |
913 | you use it. | |
914 | ||
8474de5b CY |
915 | When a region is active, @kbd{M-;} either adds or removes comment |
916 | delimiters on each line of the region. @xref{Mark}. If every line in | |
917 | the region is a comment, it removes comment delimiters from each; | |
918 | otherwise, it adds comment delimiters to each. You can also use the | |
919 | commands @code{comment-region} and @code{uncomment-region} to | |
920 | explicitly comment or uncomment the text in the region | |
921 | (@pxref{Multi-Line Comments}). If you supply a prefix argument to | |
922 | @kbd{M-;} when a region is active, that specifies how many comment | |
923 | delimiters to add or how many to delete. | |
924 | ||
925 | If the region is not active, @kbd{M-;} inserts a new comment if | |
926 | there is no comment already on the line. The new comment is normally | |
927 | aligned at a specific column called the @dfn{comment column}; if the | |
928 | text of the line extends past the comment column, @kbd{M-;} aligns the | |
929 | comment start string to a suitable boundary (usually, at least one | |
930 | space is inserted). The comment begins with the string Emacs thinks | |
931 | comments should start with (the value of @code{comment-start}; see | |
932 | below). Emacs places point after that string, so you can insert the | |
933 | text of the comment right away. If the major mode has specified a | |
934 | string to terminate comments, @kbd{M-;} inserts that string after | |
935 | point, to keep the syntax valid. | |
9234c238 RS |
936 | |
937 | You can also use @kbd{M-;} to align an existing comment. If a line | |
5b31640c | 938 | already contains the comment-start string, @kbd{M-;} realigns it to |
9234c238 RS |
939 | the conventional alignment and moves point after it. (Exception: |
940 | comments starting in column 0 are not moved.) Even when an existing | |
941 | comment is properly aligned, @kbd{M-;} is still useful for moving | |
942 | directly to the start of the text inside the comment. | |
943 | ||
944 | @findex comment-kill | |
945 | @kindex C-u M-; | |
946 | @kbd{C-u M-;} kills any comment on the current line, along with the | |
947 | whitespace before it. To reinsert the comment on another line, move | |
948 | to the end of that line, do @kbd{C-y}, and then do @kbd{M-;} to | |
949 | realign it. | |
950 | ||
951 | Note that @kbd{C-u M-;} is not a distinct key; it is @kbd{M-;} | |
952 | (@code{comment-dwim}) with a prefix argument. That command is | |
953 | programmed so that when it receives a prefix argument it calls | |
954 | @code{comment-kill}. However, @code{comment-kill} is a valid command | |
955 | in its own right, and you can bind it directly to a key if you wish. | |
956 | ||
5b31640c | 957 | Some major modes have special rules for aligning certain kinds of |
6bf7aab6 DL |
958 | comments in certain contexts. For example, in Lisp code, comments which |
959 | start with two semicolons are indented as if they were lines of code, | |
960 | instead of at the comment column. Comments which start with three | |
24a768a0 SM |
961 | semicolons are supposed to start at the left margin and are often used |
962 | for sectioning purposes. Emacs understands | |
6bf7aab6 DL |
963 | these conventions by indenting a double-semicolon comment using @key{TAB}, |
964 | and by not changing the indentation of a triple-semicolon comment at all. | |
965 | ||
966 | @example | |
91ec56a9 | 967 | ;; This function is just an example. |
24a768a0 | 968 | ;;; Here either two or three semicolons are appropriate. |
6bf7aab6 | 969 | (defun foo (x) |
91ec56a9 | 970 | ;;; And now, the first part of the function: |
6bf7aab6 DL |
971 | ;; The following line adds one. |
972 | (1+ x)) ; This line adds one. | |
973 | @end example | |
974 | ||
e722aa81 CY |
975 | For C-like modes, you can configure the exact effect of @kbd{M-;} by |
976 | setting the variables @code{c-indent-comment-alist} and | |
108262a0 AM |
977 | @code{c-indent-comments-syntactically-p}. For example, on a line |
978 | ending in a closing brace, @kbd{M-;} puts the comment one space after | |
979 | the brace rather than at @code{comment-column}. For full details see | |
e722aa81 | 980 | @ref{Comment Commands,,, ccmode, The CC Mode Manual}. |
6bf7aab6 | 981 | |
6bf7aab6 DL |
982 | @node Multi-Line Comments |
983 | @subsection Multiple Lines of Comments | |
984 | ||
985 | @kindex C-M-j | |
7ae8ad94 | 986 | @kindex M-j |
6bf7aab6 | 987 | @cindex blank lines in programs |
47c1b5f4 | 988 | @findex comment-indent-new-line |
108262a0 | 989 | |
6bf7aab6 | 990 | If you are typing a comment and wish to continue it on another line, |
7ae8ad94 | 991 | you can use the command @kbd{C-M-j} or @kbd{M-j} |
f5eb910a RS |
992 | (@code{comment-indent-new-line}). If @code{comment-multi-line} |
993 | (@pxref{Options for Comments}) is non-@code{nil}, it moves to a new | |
994 | line within the comment. Otherwise it closes the comment and starts a | |
995 | new comment on a new line. When Auto Fill mode is on, going past the | |
996 | fill column while typing a comment causes the comment to be continued | |
997 | in just this fashion. | |
7ae8ad94 RS |
998 | |
999 | @kindex C-c C-c (C mode) | |
6bf7aab6 DL |
1000 | @findex comment-region |
1001 | To turn existing lines into comment lines, use the @kbd{M-x | |
dfec8297 | 1002 | comment-region} command (or type @kbd{C-c C-c} in C-like modes). It |
108262a0 AM |
1003 | adds comment delimiters to the lines that start in the region, thus |
1004 | commenting them out. With a negative argument, it does the | |
1005 | opposite---it deletes comment delimiters from the lines in the region. | |
6bf7aab6 DL |
1006 | |
1007 | With a positive argument, @code{comment-region} duplicates the last | |
5b31640c RS |
1008 | character of the comment start sequence it adds; the argument |
1009 | specifies how many copies of the character to insert. Thus, in Lisp | |
1010 | mode, @kbd{C-u 2 M-x comment-region} adds @samp{;;} to each line. | |
1011 | Duplicating the comment delimiter is a way of calling attention to the | |
1012 | comment. It can also affect how the comment is aligned or indented. | |
1013 | In Lisp, for proper indentation, you should use an argument of two or | |
1014 | three, if between defuns; if within a defun, it must be three. | |
6bf7aab6 | 1015 | |
108262a0 AM |
1016 | You can configure C Mode such that when you type a @samp{/} at the |
1017 | start of a line in a multi-line block comment, this closes the | |
1018 | comment. Enable the @code{comment-close-slash} clean-up for this. | |
1019 | @xref{Clean-ups,,, ccmode, The CC Mode Manual}. | |
1020 | ||
6bf7aab6 DL |
1021 | @node Options for Comments |
1022 | @subsection Options Controlling Comments | |
1023 | ||
1024 | @vindex comment-column | |
1025 | @kindex C-x ; | |
47c1b5f4 | 1026 | @findex comment-set-column |
7ae8ad94 RS |
1027 | The @dfn{comment column}, the column at which Emacs tries to place |
1028 | comments, is stored in the variable @code{comment-column}. You can | |
1029 | set it to a number explicitly. Alternatively, the command @kbd{C-x ;} | |
1030 | (@code{comment-set-column}) sets the comment column to the column | |
1031 | point is at. @kbd{C-u C-x ;} sets the comment column to match the | |
1032 | last comment before point in the buffer, and then does a @kbd{M-;} to | |
1033 | align the current line's comment under the previous one. | |
6bf7aab6 DL |
1034 | |
1035 | The variable @code{comment-column} is per-buffer: setting the variable | |
1036 | in the normal fashion affects only the current buffer, but there is a | |
1037 | default value which you can change with @code{setq-default}. | |
1038 | @xref{Locals}. Many major modes initialize this variable for the | |
1039 | current buffer. | |
1040 | ||
1041 | @vindex comment-start-skip | |
1042 | The comment commands recognize comments based on the regular | |
1043 | expression that is the value of the variable @code{comment-start-skip}. | |
1044 | Make sure this regexp does not match the null string. It may match more | |
1045 | than the comment starting delimiter in the strictest sense of the word; | |
47c1b5f4 RS |
1046 | for example, in C mode the value of the variable is |
1047 | @c This stops M-q from breaking the line inside that @code. | |
7ae8ad94 | 1048 | @code{@w{"/\\*+ *\\|//+ *"}}, which matches extra stars and spaces |
47c1b5f4 | 1049 | after the @samp{/*} itself, and accepts C++ style comments also. |
6bf7aab6 DL |
1050 | (Note that @samp{\\} is needed in Lisp syntax to include a @samp{\} in |
1051 | the string, which is needed to deny the first star its special meaning | |
bd428736 | 1052 | in regexp syntax. @xref{Regexp Backslash}.) |
6bf7aab6 DL |
1053 | |
1054 | @vindex comment-start | |
1055 | @vindex comment-end | |
1056 | When a comment command makes a new comment, it inserts the value of | |
1057 | @code{comment-start} to begin it. The value of @code{comment-end} is | |
aa2d3478 RS |
1058 | inserted after point, so that it will follow the text that you will |
1059 | insert into the comment. When @code{comment-end} is non-empty, it | |
1060 | should start with a space. For example, in C mode, | |
1061 | @code{comment-start} has the value @w{@code{"/* "}} and | |
1062 | @code{comment-end} has the value @w{@code{" */"}}. | |
6bf7aab6 | 1063 | |
9234c238 RS |
1064 | @vindex comment-padding |
1065 | The variable @code{comment-padding} specifies how many spaces | |
7ae8ad94 RS |
1066 | @code{comment-region} should insert on each line between the comment |
1067 | delimiter and the line's original text. The default is 1, to insert | |
1068 | one space. @code{nil} means 0. Alternatively, @code{comment-padding} | |
1069 | can hold the actual string to insert. | |
9234c238 | 1070 | |
6bf7aab6 DL |
1071 | @vindex comment-multi-line |
1072 | The variable @code{comment-multi-line} controls how @kbd{C-M-j} | |
7ae8ad94 | 1073 | (@code{indent-new-comment-line}) behaves when used inside a comment. |
108262a0 AM |
1074 | Specifically, when @code{comment-multi-line} is @code{nil}, the |
1075 | command inserts a comment terminator, begins a new line, and finally | |
1076 | inserts a comment starter. Otherwise it does not insert the | |
1077 | terminator and starter, so it effectively continues the current | |
1078 | comment across multiple lines. In languages that allow multi-line | |
1079 | comments, the choice of value for this variable is a matter of taste. | |
1080 | The default for this variable depends on the major mode. | |
6bf7aab6 | 1081 | |
4190ce5c | 1082 | @vindex comment-indent-function |
6bf7aab6 | 1083 | The variable @code{comment-indent-function} should contain a function |
5b31640c | 1084 | that will be called to compute the alignment for a newly inserted |
6bf7aab6 DL |
1085 | comment or for aligning an existing comment. It is set differently by |
1086 | various major modes. The function is called with no arguments, but with | |
1087 | point at the beginning of the comment, or at the end of a line if a new | |
1088 | comment is to be inserted. It should return the column in which the | |
1089 | comment ought to start. For example, in Lisp mode, the indent hook | |
1090 | function bases its decision on how many semicolons begin an existing | |
1091 | comment, and on the code in the preceding lines. | |
1092 | ||
93da5dff RS |
1093 | @node Documentation |
1094 | @section Documentation Lookup | |
6bf7aab6 | 1095 | |
93da5dff RS |
1096 | Emacs provides several features you can use to look up the |
1097 | documentation of functions, variables and commands that you plan to | |
1098 | use in your program. | |
6bf7aab6 | 1099 | |
93da5dff RS |
1100 | @menu |
1101 | * Info Lookup:: Looking up library functions and commands | |
1102 | in Info files. | |
1103 | * Man Page:: Looking up man pages of library functions and commands. | |
1104 | * Lisp Doc:: Looking up Emacs Lisp functions, etc. | |
1105 | @end menu | |
6bf7aab6 | 1106 | |
93da5dff RS |
1107 | @node Info Lookup |
1108 | @subsection Info Documentation Lookup | |
85750656 | 1109 | |
93da5dff RS |
1110 | @findex info-lookup-symbol |
1111 | @findex info-lookup-file | |
d2f9ea87 | 1112 | @kindex C-h S |
e722aa81 CY |
1113 | For major modes that apply to languages which have documentation in |
1114 | Info, you can use @kbd{C-h S} (@code{info-lookup-symbol}) to view the | |
1115 | Info documentation for a symbol used in the program. You specify the | |
1116 | symbol with the minibuffer; the default is the symbol appearing in the | |
1117 | buffer at point. For example, in C mode this looks for the symbol in | |
1118 | the C Library Manual. The command only works if the appropriate | |
1119 | manual's Info files are installed. | |
6bf7aab6 | 1120 | |
93da5dff RS |
1121 | The major mode determines where to look for documentation for the |
1122 | symbol---which Info files to look in, and which indices to search. | |
1123 | You can also use @kbd{M-x info-lookup-file} to look for documentation | |
1124 | for a file name. | |
6bf7aab6 | 1125 | |
dfec8297 | 1126 | If you use @kbd{C-h S} in a major mode that does not support it, |
5a7f4c1b | 1127 | it asks you to specify the ``symbol help mode.'' You should enter |
dfec8297 RS |
1128 | a command such as @code{c-mode} that would select a major |
1129 | mode which @kbd{C-h S} does support. | |
6bf7aab6 | 1130 | |
93da5dff RS |
1131 | @node Man Page |
1132 | @subsection Man Page Lookup | |
6bf7aab6 | 1133 | |
e79c6b89 RS |
1134 | @cindex manual page |
1135 | On Unix, the main form of on-line documentation was the @dfn{manual | |
dfec8297 | 1136 | page} or @dfn{man page}. In the GNU operating system, we aim to |
e79c6b89 RS |
1137 | replace man pages with better-organized manuals that you can browse |
1138 | with Info (@pxref{Misc Help}). This process is not finished, so it is | |
1139 | still useful to read manual pages. | |
6bf7aab6 | 1140 | |
93da5dff | 1141 | @findex manual-entry |
e79c6b89 | 1142 | You can read the man page for an operating system command, library |
7ae8ad94 | 1143 | function, or system call, with the @kbd{M-x man} command. It |
e79c6b89 RS |
1144 | runs the @code{man} program to format the man page; if the system |
1145 | permits, it runs @code{man} asynchronously, so that you can keep on | |
1146 | editing while the page is being formatted. (On MS-DOS and MS-Windows | |
1147 | 3, you cannot edit while Emacs waits for @code{man} to finish.) The | |
1148 | result goes in a buffer named @samp{*Man @var{topic}*}. These buffers | |
1149 | use a special major mode, Man mode, that facilitates scrolling and | |
1150 | jumping to other manual pages. For details, type @kbd{C-h m} while in | |
1151 | a man page buffer. | |
6bf7aab6 | 1152 | |
93da5dff | 1153 | @cindex sections of manual pages |
e79c6b89 RS |
1154 | Each man page belongs to one of ten or more @dfn{sections}, each |
1155 | named by a digit or by a digit and a letter. Sometimes there are | |
1156 | multiple man pages with the same name in different sections. To read | |
1157 | a man page from a specific section, type | |
93da5dff RS |
1158 | @samp{@var{topic}(@var{section})} or @samp{@var{section} @var{topic}} |
1159 | when @kbd{M-x manual-entry} prompts for the topic. For example, to | |
1160 | read the man page for the C library function @code{chmod} (as opposed | |
e79c6b89 | 1161 | to a command of the same name), type @kbd{M-x manual-entry @key{RET} |
dfec8297 RS |
1162 | chmod(2) @key{RET}}. (@code{chmod} is a system call, so it is in |
1163 | section @samp{2}.) | |
6bf7aab6 | 1164 | |
08220274 | 1165 | @vindex Man-switches |
93da5dff | 1166 | If you do not specify a section, the results depend on how the |
08220274 | 1167 | @code{man} program works on your system. Some of them display only |
93da5dff RS |
1168 | the first man page they find. Others display all man pages that have |
1169 | the specified name, so you can move between them with the @kbd{M-n} | |
08220274 EZ |
1170 | and @kbd{M-p} keys@footnote{On some systems, the @code{man} program |
1171 | accepts a @samp{-a} command-line option which tells it to display all | |
1172 | the man pages for the specified topic. If you want this behavior, you | |
1173 | can add this option to the value of the variable @code{Man-switches}.}. | |
1174 | The mode line shows how many manual pages are present in the Man buffer. | |
6bf7aab6 | 1175 | |
93da5dff | 1176 | @vindex Man-fontify-manpage-flag |
e79c6b89 RS |
1177 | By default, Emacs highlights the text in man pages. For a long man |
1178 | page, highlighting can take substantial time. You can turn off | |
1179 | highlighting of man pages by setting the variable | |
1180 | @code{Man-fontify-manpage-flag} to @code{nil}. | |
6bf7aab6 | 1181 | |
93da5dff RS |
1182 | @findex Man-fontify-manpage |
1183 | If you insert the text of a man page into an Emacs buffer in some | |
1184 | other fashion, you can use the command @kbd{M-x Man-fontify-manpage} to | |
1185 | perform the same conversions that @kbd{M-x manual-entry} does. | |
1186 | ||
1187 | @findex woman | |
1188 | @cindex manual pages, on MS-DOS/MS-Windows | |
1189 | An alternative way of reading manual pages is the @kbd{M-x woman} | |
1190 | command@footnote{The name of the command, @code{woman}, is an acronym | |
1191 | for ``w/o (without) man,'' since it doesn't use the @code{man} | |
1192 | program.}. Unlike @kbd{M-x man}, it does not run any external | |
1193 | programs to format and display the man pages; instead it does the job | |
1194 | in Emacs Lisp, so it works on systems such as MS-Windows, where the | |
ea118de1 | 1195 | @code{man} program (and other programs it uses) are not generally |
d2fab838 RS |
1196 | available. |
1197 | ||
1198 | @kbd{M-x woman} prompts for a name of a manual page, and provides | |
1199 | completion based on the list of manual pages that are installed on | |
1200 | your machine; the list of available manual pages is computed | |
1201 | automatically the first time you invoke @code{woman}. The word at | |
1202 | point in the current buffer is used to suggest the default for the | |
1203 | name the manual page. | |
93da5dff RS |
1204 | |
1205 | With a numeric argument, @kbd{M-x woman} recomputes the list of the | |
1206 | manual pages used for completion. This is useful if you add or delete | |
1207 | manual pages. | |
1208 | ||
1209 | If you type a name of a manual page and @kbd{M-x woman} finds that | |
1210 | several manual pages by the same name exist in different sections, it | |
1211 | pops up a window with possible candidates asking you to choose one of | |
1212 | them. | |
1213 | ||
93da5dff RS |
1214 | For more information about setting up and using @kbd{M-x woman}, see |
1215 | @ref{Top, WoMan, Browse UN*X Manual Pages WithOut Man, woman, The WoMan | |
1216 | Manual}. | |
1217 | ||
1218 | @node Lisp Doc | |
1219 | @subsection Emacs Lisp Documentation Lookup | |
1220 | ||
1221 | As you edit Lisp code to be run in Emacs, you can use the commands | |
1222 | @kbd{C-h f} (@code{describe-function}) and @kbd{C-h v} | |
1223 | (@code{describe-variable}) to view documentation of functions and | |
1224 | variables that you want to use. These commands use the minibuffer to | |
1225 | read the name of a function or variable to document, and display the | |
1226 | documentation in a window. Their default arguments are based on the | |
1227 | code in the neighborhood of point. For @kbd{C-h f}, the default is | |
1228 | the function called in the innermost list containing point. @kbd{C-h | |
1229 | v} uses the symbol name around or adjacent to point as its default. | |
1230 | ||
1231 | @cindex Eldoc mode | |
1232 | @findex eldoc-mode | |
1233 | A more automatic but less powerful method is Eldoc mode. This minor | |
1234 | mode constantly displays in the echo area the argument list for the | |
1235 | function being called at point. (In other words, it finds the | |
1236 | function call that point is contained in, and displays the argument | |
054af0fd | 1237 | list of that function.) If point is over a documented variable, it |
ea802fce LT |
1238 | shows the first line of the variable's docstring. Eldoc mode applies |
1239 | in Emacs Lisp and Lisp Interaction modes, and perhaps a few others | |
1240 | that provide special support for looking up doc strings. Use the | |
1241 | command @kbd{M-x eldoc-mode} to enable or disable this feature. | |
6bf7aab6 | 1242 | |
51ed0ea0 DL |
1243 | @node Hideshow |
1244 | @section Hideshow minor mode | |
1245 | ||
1246 | @findex hs-minor-mode | |
9234c238 | 1247 | Hideshow minor mode provides selective display of portions of a |
93da5dff RS |
1248 | program, known as @dfn{blocks}. You can use @kbd{M-x hs-minor-mode} |
1249 | to enable or disable this mode, or add @code{hs-minor-mode} to the | |
1250 | mode hook for certain major modes in order to enable it automatically | |
1251 | for those modes. | |
51ed0ea0 | 1252 | |
9234c238 RS |
1253 | Just what constitutes a block depends on the major mode. In C mode |
1254 | or C++ mode, they are delimited by braces, while in Lisp mode and | |
1255 | similar modes they are delimited by parentheses. Multi-line comments | |
1256 | also count as blocks. | |
51ed0ea0 DL |
1257 | |
1258 | @findex hs-hide-all | |
1259 | @findex hs-hide-block | |
1260 | @findex hs-show-all | |
1261 | @findex hs-show-block | |
1262 | @findex hs-show-region | |
1263 | @findex hs-hide-level | |
1264 | @findex hs-minor-mode | |
6401dc86 EZ |
1265 | @kindex C-c @@ C-h |
1266 | @kindex C-c @@ C-s | |
1267 | @kindex C-c @@ C-M-h | |
1268 | @kindex C-c @@ C-M-s | |
1269 | @kindex C-c @@ C-r | |
1270 | @kindex C-c @@ C-l | |
9234c238 RS |
1271 | @kindex S-Mouse-2 |
1272 | @table @kbd | |
6401dc86 | 1273 | @item C-c @@ C-h |
9234c238 | 1274 | Hide the current block (@code{hs-hide-block}). |
6401dc86 | 1275 | @item C-c @@ C-s |
9234c238 | 1276 | Show the current block (@code{hs-show-block}). |
6401dc86 | 1277 | @item C-c @@ C-c |
ea118de1 | 1278 | Either hide or show the current block (@code{hs-toggle-hiding}). |
9234c238 | 1279 | @item S-Mouse-2 |
ea118de1 | 1280 | Either hide or show the block you click on (@code{hs-mouse-toggle-hiding}). |
6401dc86 | 1281 | @item C-c @@ C-M-h |
9234c238 | 1282 | Hide all top-level blocks (@code{hs-hide-all}). |
6401dc86 | 1283 | @item C-c @@ C-M-s |
9234c238 | 1284 | Show everything in the buffer (@code{hs-show-all}). |
6401dc86 | 1285 | @item C-c @@ C-l |
9234c238 RS |
1286 | Hide all blocks @var{n} levels below this block |
1287 | (@code{hs-hide-level}). | |
1288 | @end table | |
51ed0ea0 DL |
1289 | |
1290 | @vindex hs-hide-comments-when-hiding-all | |
51ed0ea0 DL |
1291 | @vindex hs-isearch-open |
1292 | @vindex hs-special-modes-alist | |
19b2c4ca | 1293 | These variables exist for customizing Hideshow mode. |
9234c238 | 1294 | |
51ed0ea0 DL |
1295 | @table @code |
1296 | @item hs-hide-comments-when-hiding-all | |
9234c238 | 1297 | Non-@code{nil} says that @kbd{hs-hide-all} should hide comments too. |
d2fab838 | 1298 | |
51ed0ea0 | 1299 | @item hs-isearch-open |
dfec8297 RS |
1300 | Specifies what kind of hidden blocks incremental search should make |
1301 | visible. The value should be one of these four symbols: | |
d2fab838 RS |
1302 | |
1303 | @table @code | |
9198a323 RS |
1304 | @item code |
1305 | Open only code blocks. | |
d2fab838 RS |
1306 | @item comment |
1307 | Open only comments. | |
1308 | @item t | |
9198a323 | 1309 | Open both code blocks and comments. |
d2fab838 | 1310 | @item nil |
9198a323 | 1311 | Open neither code blocks nor comments. |
d2fab838 RS |
1312 | @end table |
1313 | ||
51ed0ea0 | 1314 | @item hs-special-modes-alist |
e79c6b89 | 1315 | A list of elements, each specifying how to initialize Hideshow |
d2fab838 RS |
1316 | variables for one major mode. See the variable's documentation string |
1317 | for more information. | |
51ed0ea0 DL |
1318 | @end table |
1319 | ||
93da5dff RS |
1320 | @node Symbol Completion |
1321 | @section Completion for Symbol Names | |
1322 | @cindex completion (symbol names) | |
3b8b8888 | 1323 | |
e722aa81 CY |
1324 | In Emacs, completion is something you normally do in the minibuffer |
1325 | (@pxref{Completion}). But one kind of completion is available in all | |
1326 | buffers: completion for symbol names. | |
3b8b8888 | 1327 | |
93da5dff | 1328 | @kindex M-TAB |
e79c6b89 RS |
1329 | The character @kbd{M-@key{TAB}} runs a command to complete the |
1330 | partial symbol before point against the set of meaningful symbol | |
1331 | names. This command inserts at point any additional characters that | |
3a8d6df3 RS |
1332 | it can determine from the partial name. |
1333 | ||
1334 | If your window manager defines @kbd{M-@key{TAB}} to switch windows, | |
1335 | you can type @kbd{@key{ESC} @key{TAB}} or @kbd{C-M-i} instead. | |
8474de5b CY |
1336 | However, most window managers let you customize these shortcuts, so |
1337 | you can change any that interfere with the way you use Emacs. | |
6bf7aab6 | 1338 | |
e79c6b89 RS |
1339 | If the partial name in the buffer has multiple possible completions |
1340 | that differ in the very next character, so that it is impossible to | |
1341 | complete even one more character, @kbd{M-@key{TAB}} displays a list of | |
1342 | all possible completions in another window. | |
6bf7aab6 | 1343 | |
93da5dff RS |
1344 | @cindex tags-based completion |
1345 | @cindex Info index completion | |
1346 | @findex complete-symbol | |
1347 | In most programming language major modes, @kbd{M-@key{TAB}} runs the | |
1348 | command @code{complete-symbol}, which provides two kinds of completion. | |
1349 | Normally it does completion based on a tags table (@pxref{Tags}); with a | |
1350 | numeric argument (regardless of the value), it does completion based on | |
1351 | the names listed in the Info file indexes for your language. Thus, to | |
1352 | complete the name of a symbol defined in your own program, use | |
1353 | @kbd{M-@key{TAB}} with no argument; to complete the name of a standard | |
1354 | library function, use @kbd{C-u M-@key{TAB}}. Of course, Info-based | |
1355 | completion works only if there is an Info file for the standard library | |
1356 | functions of your language, and only if it is installed at your site. | |
6bf7aab6 | 1357 | |
93da5dff RS |
1358 | @cindex Lisp symbol completion |
1359 | @cindex completion (Lisp symbols) | |
1360 | @findex lisp-complete-symbol | |
1361 | In Emacs-Lisp mode, the name space for completion normally consists of | |
1362 | nontrivial symbols present in Emacs---those that have function | |
1363 | definitions, values or properties. However, if there is an | |
1364 | open-parenthesis immediately before the beginning of the partial symbol, | |
1365 | only symbols with function definitions are considered as completions. | |
1366 | The command which implements this is @code{lisp-complete-symbol}. | |
6bf7aab6 | 1367 | |
93da5dff RS |
1368 | In Text mode and related modes, @kbd{M-@key{TAB}} completes words |
1369 | based on the spell-checker's dictionary. @xref{Spelling}. | |
6bf7aab6 | 1370 | |
93da5dff RS |
1371 | @node Glasses |
1372 | @section Glasses minor mode | |
1373 | @cindex Glasses mode | |
1374 | @cindex identifiers, making long ones readable | |
1375 | @cindex StudlyCaps, making them readable | |
1376 | @findex glasses-mode | |
6bf7aab6 | 1377 | |
93da5dff | 1378 | Glasses minor mode makes @samp{unreadableIdentifiersLikeThis} |
e79c6b89 RS |
1379 | readable by altering the way they display. It knows two different |
1380 | ways to do this: by displaying underscores between a lower-case letter | |
1381 | and the following capital letter, and by emboldening the capital | |
1382 | letters. It does not alter the buffer text, only the way they | |
1383 | display, so you can use it even on read-only buffers. You can use the | |
1384 | command @kbd{M-x glasses-mode} to enable or disable the mode in the | |
1385 | current buffer; you can also add @code{glasses-mode} to the mode hook | |
1386 | of the programming language major modes in which you normally want | |
177c0ea7 | 1387 | to use Glasses mode. |
6bf7aab6 | 1388 | |
93da5dff RS |
1389 | @node Misc for Programs |
1390 | @section Other Features Useful for Editing Programs | |
6bf7aab6 | 1391 | |
93da5dff | 1392 | A number of Emacs commands that aren't designed specifically for |
e79c6b89 | 1393 | editing programs are useful for that nonetheless. |
6bf7aab6 | 1394 | |
93da5dff RS |
1395 | The Emacs commands that operate on words, sentences and paragraphs |
1396 | are useful for editing code. Most symbols names contain words | |
1397 | (@pxref{Words}); sentences can be found in strings and comments | |
e79c6b89 | 1398 | (@pxref{Sentences}). Paragraphs in the strict sense can be found in |
93da5dff RS |
1399 | program code (in long comments), but the paragraph commands are useful |
1400 | in other places too, because programming language major modes define | |
1401 | paragraphs to begin and end at blank lines (@pxref{Paragraphs}). | |
1402 | Judicious use of blank lines to make the program clearer will also | |
1403 | provide useful chunks of text for the paragraph commands to work on. | |
1404 | Auto Fill mode, if enabled in a programming language major mode, | |
1405 | indents the new lines which it creates. | |
6bf7aab6 | 1406 | |
93da5dff RS |
1407 | The selective display feature is useful for looking at the overall |
1408 | structure of a function (@pxref{Selective Display}). This feature | |
1409 | hides the lines that are indented more than a specified amount. | |
1410 | Programming modes often support Outline minor mode (@pxref{Outline | |
1411 | Mode}). The Foldout package provides folding-editor features | |
1412 | (@pxref{Foldout}). | |
6bf7aab6 | 1413 | |
93da5dff RS |
1414 | The ``automatic typing'' features may be useful for writing programs. |
1415 | @xref{Top,,Autotyping, autotype, Autotyping}. | |
6bf7aab6 DL |
1416 | |
1417 | @node C Modes | |
1418 | @section C and Related Modes | |
1419 | @cindex C mode | |
1420 | @cindex Java mode | |
1421 | @cindex Pike mode | |
1422 | @cindex IDL mode | |
1423 | @cindex CORBA IDL mode | |
1424 | @cindex Objective C mode | |
1425 | @cindex C++ mode | |
7ae8ad94 | 1426 | @cindex AWK mode |
6bf7aab6 DL |
1427 | @cindex mode, Java |
1428 | @cindex mode, C | |
7ae8ad94 | 1429 | @cindex mode, C++ |
6bf7aab6 DL |
1430 | @cindex mode, Objective C |
1431 | @cindex mode, CORBA IDL | |
1432 | @cindex mode, Pike | |
7ae8ad94 | 1433 | @cindex mode, AWK |
6bf7aab6 | 1434 | |
9234c238 | 1435 | This section gives a brief description of the special features |
7ae8ad94 | 1436 | available in C, C++, Objective-C, Java, CORBA IDL, Pike and AWK modes. |
5d80fe1f EZ |
1437 | (These are called ``C mode and related modes.'') @xref{Top, , CC Mode, |
1438 | ccmode, CC Mode}, for a more extensive description of these modes | |
9234c238 | 1439 | and their special features. |
51ed0ea0 | 1440 | |
6bf7aab6 | 1441 | @menu |
7ae8ad94 RS |
1442 | * Motion in C:: Commands to move by C statements, etc. |
1443 | * Electric C:: Colon and other chars can automatically reindent. | |
1444 | * Hungry Delete:: A more powerful DEL command. | |
1445 | * Other C Commands:: Filling comments, viewing expansion of macros, | |
1446 | and other neat features. | |
6bf7aab6 DL |
1447 | @end menu |
1448 | ||
1449 | @node Motion in C | |
1450 | @subsection C Mode Motion Commands | |
1451 | ||
1452 | This section describes commands for moving point, in C mode and | |
1453 | related modes. | |
1454 | ||
1455 | @table @code | |
7ae8ad94 RS |
1456 | @item M-x c-beginning-of-defun |
1457 | @itemx M-x c-end-of-defun | |
1458 | @findex c-beginning-of-defun | |
1459 | @findex c-end-of-defun | |
1460 | Move point to the beginning or end of the current function or | |
1461 | top-level definition. These are found by searching for the least | |
1462 | enclosing braces. (By contrast, @code{beginning-of-defun} and | |
1463 | @code{end-of-defun} search for braces in column zero.) If you are | |
1464 | editing code where the opening brace of a function isn't placed in | |
1465 | column zero, you may wish to bind @code{C-M-a} and @code{C-M-e} to | |
1466 | these commands. @xref{Moving by Defuns}. | |
1467 | ||
6bf7aab6 DL |
1468 | @item C-c C-u |
1469 | @kindex C-c C-u @r{(C mode)} | |
1470 | @findex c-up-conditional | |
1471 | Move point back to the containing preprocessor conditional, leaving the | |
1472 | mark behind. A prefix argument acts as a repeat count. With a negative | |
1473 | argument, move point forward to the end of the containing | |
7ae8ad94 RS |
1474 | preprocessor conditional. |
1475 | ||
1476 | @samp{#elif} is equivalent to @samp{#else} followed by @samp{#if}, so | |
1477 | the function will stop at a @samp{#elif} when going backward, but not | |
1478 | when going forward. | |
6bf7aab6 DL |
1479 | |
1480 | @item C-c C-p | |
1481 | @kindex C-c C-p @r{(C mode)} | |
1482 | @findex c-backward-conditional | |
1483 | Move point back over a preprocessor conditional, leaving the mark | |
1484 | behind. A prefix argument acts as a repeat count. With a negative | |
1485 | argument, move forward. | |
1486 | ||
1487 | @item C-c C-n | |
1488 | @kindex C-c C-n @r{(C mode)} | |
1489 | @findex c-forward-conditional | |
1490 | Move point forward across a preprocessor conditional, leaving the mark | |
1491 | behind. A prefix argument acts as a repeat count. With a negative | |
1492 | argument, move backward. | |
1493 | ||
1494 | @item M-a | |
7ae8ad94 | 1495 | @kindex M-a (C mode) |
6bf7aab6 DL |
1496 | @findex c-beginning-of-statement |
1497 | Move point to the beginning of the innermost C statement | |
1498 | (@code{c-beginning-of-statement}). If point is already at the beginning | |
1499 | of a statement, move to the beginning of the preceding statement. With | |
1500 | prefix argument @var{n}, move back @var{n} @minus{} 1 statements. | |
1501 | ||
7ae8ad94 RS |
1502 | In comments or in strings which span more than one line, this command |
1503 | moves by sentences instead of statements. | |
6bf7aab6 DL |
1504 | |
1505 | @item M-e | |
7ae8ad94 | 1506 | @kindex M-e (C mode) |
6bf7aab6 | 1507 | @findex c-end-of-statement |
7ae8ad94 RS |
1508 | Move point to the end of the innermost C statement or sentence; like |
1509 | @kbd{M-a} except that it moves in the other direction | |
1510 | (@code{c-end-of-statement}). | |
6bf7aab6 DL |
1511 | @end table |
1512 | ||
1513 | @node Electric C | |
1514 | @subsection Electric C Characters | |
1515 | ||
1516 | In C mode and related modes, certain printing characters are | |
108262a0 AM |
1517 | @dfn{electric}---in addition to inserting themselves, they also |
1518 | reindent the current line, and optionally also insert newlines. The | |
64e207c0 RS |
1519 | ``electric'' characters are @kbd{@{}, @kbd{@}}, @kbd{:}, @kbd{#}, |
1520 | @kbd{;}, @kbd{,}, @kbd{<}, @kbd{>}, @kbd{/}, @kbd{*}, @kbd{(}, and | |
f5eb910a | 1521 | @kbd{)}. |
108262a0 AM |
1522 | |
1523 | You might find electric indentation inconvenient if you are editing | |
1524 | chaotically indented code. If you are new to CC Mode, you might find | |
1525 | it disconcerting. You can toggle electric action with the command | |
1526 | @kbd{C-c C-l}; when it is enabled, @samp{/l} appears in the mode line | |
1527 | after the mode name: | |
6bf7aab6 | 1528 | |
108262a0 AM |
1529 | @table @kbd |
1530 | @item C-c C-l | |
1531 | @kindex C-c C-l @r{(C mode)} | |
1532 | @findex c-toggle-electric-state | |
1533 | Toggle electric action (@code{c-toggle-electric-state}). With a | |
1534 | prefix argument, this command enables electric action if the argument | |
1535 | is positive, disables it if it is negative. | |
1536 | @end table | |
1537 | ||
1538 | Electric characters insert newlines only when, in addition to the | |
1539 | electric state, the @dfn{auto-newline} feature is enabled (indicated | |
1540 | by @samp{/la} in the mode line after the mode name). You can turn | |
1541 | this feature on or off with the command @kbd{C-c C-a}: | |
6bf7aab6 DL |
1542 | |
1543 | @table @kbd | |
1544 | @item C-c C-a | |
1545 | @kindex C-c C-a @r{(C mode)} | |
108262a0 AM |
1546 | @findex c-toggle-auto-newline |
1547 | Toggle the auto-newline feature (@code{c-toggle-auto-newline}). With a | |
6bf7aab6 DL |
1548 | prefix argument, this command turns the auto-newline feature on if the |
1549 | argument is positive, and off if it is negative. | |
1550 | @end table | |
1551 | ||
f5eb910a RS |
1552 | Usually the CC Mode style configures the exact circumstances in |
1553 | which Emacs inserts auto-newlines. You can also configure this | |
1554 | directly. @xref{Custom Auto-newlines,,, ccmode, The CC Mode Manual}. | |
6bf7aab6 DL |
1555 | |
1556 | @node Hungry Delete | |
1557 | @subsection Hungry Delete Feature in C | |
7ae8ad94 | 1558 | @cindex hungry deletion (C Mode) |
6bf7aab6 | 1559 | |
108262a0 AM |
1560 | If you want to delete an entire block of whitespace at point, you |
1561 | can use @dfn{hungry deletion}. This deletes all the contiguous | |
1562 | whitespace either before point or after point in a single operation. | |
1563 | @dfn{Whitespace} here includes tabs and newlines, but not comments or | |
1564 | preprocessor commands. | |
6bf7aab6 DL |
1565 | |
1566 | @table @kbd | |
69d271a7 AM |
1567 | @item C-c C-@key{DEL} |
1568 | @itemx C-c @key{DEL} | |
aca2cfd2 | 1569 | @findex c-hungry-delete-backwards |
69d271a7 AM |
1570 | @kindex C-c C-@key{DEL} (C Mode) |
1571 | @kindex C-c @key{DEL} (C Mode) | |
aca2cfd2 | 1572 | @code{c-hungry-delete-backwards}---Delete the entire block of whitespace |
108262a0 AM |
1573 | preceding point. |
1574 | ||
6bf7aab6 | 1575 | @item C-c C-d |
69d271a7 AM |
1576 | @itemx C-c C-@key{DELETE} |
1577 | @itemx C-c @key{DELETE} | |
108262a0 AM |
1578 | @findex c-hungry-delete-forward |
1579 | @kindex C-c C-d (C Mode) | |
69d271a7 AM |
1580 | @kindex C-c C-@key{DELETE} (C Mode) |
1581 | @kindex C-c @key{DELETE} (C Mode) | |
108262a0 AM |
1582 | @code{c-hungry-delete-forward}---Delete the entire block of whitespace |
1583 | following point. | |
1584 | @end table | |
1585 | ||
1586 | As an alternative to the above commands, you can enable @dfn{hungry | |
1587 | delete mode}. When this feature is enabled (indicated by @samp{/h} in | |
d884be12 RS |
1588 | the mode line after the mode name), a single @key{DEL} deletes all |
1589 | preceding whitespace, not just one space, and a single @kbd{C-c C-d} | |
1590 | (but @emph{not} plain @key{DELETE}) deletes all following whitespace. | |
6bf7aab6 | 1591 | |
108262a0 AM |
1592 | @table @kbd |
1593 | @item M-x c-toggle-hungry-state | |
1594 | @findex c-toggle-hungry-state | |
1595 | Toggle the hungry-delete feature | |
1596 | (@code{c-toggle-hungry-state})@footnote{This command had the binding | |
1597 | @kbd{C-c C-d} in earlier versions of Emacs. @kbd{C-c C-d} is now | |
1598 | bound to @code{c-hungry-delete-forward}.}. With a prefix argument, | |
1599 | this command turns the hungry-delete feature on if the argument is | |
1600 | positive, and off if it is negative. | |
6bf7aab6 DL |
1601 | @end table |
1602 | ||
1603 | @vindex c-hungry-delete-key | |
1604 | The variable @code{c-hungry-delete-key} controls whether the | |
1605 | hungry-delete feature is enabled. | |
1606 | ||
1607 | @node Other C Commands | |
1608 | @subsection Other Commands for C Mode | |
1609 | ||
1610 | @table @kbd | |
108262a0 AM |
1611 | @item C-c C-w |
1612 | @itemx M-x c-subword-mode | |
1613 | @findex c-subword-mode | |
f5eb910a | 1614 | Enable (or disable) @dfn{subword mode}. In subword mode, Emacs's word |
8a75579f | 1615 | commands recognize upper case letters in |
f5eb910a RS |
1616 | @samp{StudlyCapsIdentifiers} as word boundaries. This is indicated by |
1617 | the flag @samp{/w} on the mode line after the mode name | |
1618 | (e.g. @samp{C/law}). You can even use @kbd{M-x c-subword-mode} in | |
1619 | non-CC Mode buffers. | |
108262a0 | 1620 | |
dfec8297 RS |
1621 | In the GNU project, we recommend using underscores to separate words |
1622 | within an identifier in C or C++, rather than using case distinctions. | |
1623 | ||
7ae8ad94 RS |
1624 | @item M-x c-context-line-break |
1625 | @findex c-context-line-break | |
1626 | This command inserts a line break and indents the new line in a manner | |
1627 | appropriate to the context. In normal code, it does the work of | |
1628 | @kbd{C-j} (@code{newline-and-indent}), in a C preprocessor line it | |
1629 | additionally inserts a @samp{\} at the line break, and within comments | |
1630 | it's like @kbd{M-j} (@code{c-indent-new-comment-line}). | |
1631 | ||
1632 | @code{c-context-line-break} isn't bound to a key by default, but it | |
1633 | needs a binding to be useful. The following code will bind it to | |
108262a0 AM |
1634 | @kbd{C-j}. We use @code{c-initialization-hook} here to make sure |
1635 | the keymap is loaded before we try to change it. | |
1636 | ||
444246ca | 1637 | @smallexample |
108262a0 AM |
1638 | (defun my-bind-clb () |
1639 | (define-key c-mode-base-map "\C-j" 'c-context-line-break)) | |
1640 | (add-hook 'c-initialization-hook 'my-bind-clb) | |
444246ca | 1641 | @end smallexample |
7ae8ad94 | 1642 | |
6bf7aab6 | 1643 | @item C-M-h |
6bf7aab6 DL |
1644 | Put mark at the end of a function definition, and put point at the |
1645 | beginning (@code{c-mark-function}). | |
1646 | ||
1647 | @item M-q | |
1648 | @kindex M-q @r{(C mode)} | |
1649 | @findex c-fill-paragraph | |
1650 | Fill a paragraph, handling C and C++ comments (@code{c-fill-paragraph}). | |
1651 | If any part of the current line is a comment or within a comment, this | |
1652 | command fills the comment or the paragraph of it that point is in, | |
1653 | preserving the comment indentation and comment delimiters. | |
1654 | ||
1655 | @item C-c C-e | |
1656 | @cindex macro expansion in C | |
1657 | @cindex expansion of C macros | |
1658 | @findex c-macro-expand | |
1659 | @kindex C-c C-e @r{(C mode)} | |
1660 | Run the C preprocessor on the text in the region, and show the result, | |
1661 | which includes the expansion of all the macro calls | |
1662 | (@code{c-macro-expand}). The buffer text before the region is also | |
1663 | included in preprocessing, for the sake of macros defined there, but the | |
1664 | output from this part isn't shown. | |
1665 | ||
1666 | When you are debugging C code that uses macros, sometimes it is hard to | |
1667 | figure out precisely how the macros expand. With this command, you | |
1668 | don't have to figure it out; you can see the expansions. | |
1669 | ||
1670 | @item C-c C-\ | |
1671 | @findex c-backslash-region | |
1672 | @kindex C-c C-\ @r{(C mode)} | |
1673 | Insert or align @samp{\} characters at the ends of the lines of the | |
1674 | region (@code{c-backslash-region}). This is useful after writing or | |
1675 | editing a C macro definition. | |
1676 | ||
1677 | If a line already ends in @samp{\}, this command adjusts the amount of | |
1678 | whitespace before it. Otherwise, it inserts a new @samp{\}. However, | |
1679 | the last line in the region is treated specially; no @samp{\} is | |
1680 | inserted on that line, and any @samp{\} there is deleted. | |
1681 | ||
1682 | @item M-x cpp-highlight-buffer | |
1683 | @cindex preprocessor highlighting | |
1684 | @findex cpp-highlight-buffer | |
1685 | Highlight parts of the text according to its preprocessor conditionals. | |
1686 | This command displays another buffer named @samp{*CPP Edit*}, which | |
1687 | serves as a graphic menu for selecting how to display particular kinds | |
1688 | of conditionals and their contents. After changing various settings, | |
1689 | click on @samp{[A]pply these settings} (or go to that buffer and type | |
1690 | @kbd{a}) to rehighlight the C mode buffer accordingly. | |
1691 | ||
1692 | @item C-c C-s | |
1693 | @findex c-show-syntactic-information | |
1694 | @kindex C-c C-s @r{(C mode)} | |
1695 | Display the syntactic information about the current source line | |
054af0fd SE |
1696 | (@code{c-show-syntactic-information}). This information directs how |
1697 | the line is indented. | |
3b8b8888 DL |
1698 | |
1699 | @item M-x cwarn-mode | |
1700 | @itemx M-x global-cwarn-mode | |
1701 | @findex cwarn-mode | |
1702 | @findex global-cwarn-mode | |
7ae8ad94 | 1703 | @vindex global-cwarn-mode |
3b8b8888 DL |
1704 | @cindex CWarn mode |
1705 | @cindex suspicious constructions in C, C++ | |
9234c238 | 1706 | CWarn minor mode highlights certain suspicious C and C++ constructions: |
3b8b8888 DL |
1707 | |
1708 | @itemize @bullet{} | |
1709 | @item | |
9234c238 | 1710 | Assignments inside expressions. |
3b8b8888 DL |
1711 | @item |
1712 | Semicolon following immediately after @samp{if}, @samp{for}, and @samp{while} | |
1713 | (except after a @samp{do @dots{} while} statement); | |
1714 | @item | |
1715 | C++ functions with reference parameters. | |
1716 | @end itemize | |
1717 | ||
1718 | @noindent | |
9234c238 RS |
1719 | You can enable the mode for one buffer with the command @kbd{M-x |
1720 | cwarn-mode}, or for all suitable buffers with the command @kbd{M-x | |
1721 | global-cwarn-mode} or by customizing the variable | |
1722 | @code{global-cwarn-mode}. You must also enable Font Lock mode to make | |
1723 | it work. | |
3b8b8888 DL |
1724 | |
1725 | @item M-x hide-ifdef-mode | |
1726 | @findex hide-ifdef-mode | |
1727 | @cindex Hide-ifdef mode | |
8474de5b | 1728 | @vindex hide-ifdef-shadow |
3b8b8888 | 1729 | Hide-ifdef minor mode hides selected code within @samp{#if} and |
8474de5b CY |
1730 | @samp{#ifdef} preprocessor blocks. If you change the variable |
1731 | @code{hide-ifdef-shadow} to @code{t}, Hide-ifdef minor mode | |
1732 | ``shadows'' preprocessor blocks by displaying them with a less | |
1733 | prominent face, instead of hiding them entirely. See the | |
1734 | documentation string of @code{hide-ifdef-mode} for more information. | |
9234c238 RS |
1735 | |
1736 | @item M-x ff-find-related-file | |
1737 | @cindex related files | |
1738 | @findex ff-find-related-file | |
1739 | @vindex ff-related-file-alist | |
1740 | Find a file ``related'' in a special way to the file visited by the | |
1741 | current buffer. Typically this will be the header file corresponding | |
1742 | to a C/C++ source file, or vice versa. The variable | |
1743 | @code{ff-related-file-alist} specifies how to compute related file | |
1744 | names. | |
6bf7aab6 DL |
1745 | @end table |
1746 | ||
6bf7aab6 DL |
1747 | @node Asm Mode |
1748 | @section Asm Mode | |
1749 | ||
1750 | @cindex Asm mode | |
9234c238 | 1751 | @cindex assembler mode |
6bf7aab6 DL |
1752 | Asm mode is a major mode for editing files of assembler code. It |
1753 | defines these commands: | |
1754 | ||
1755 | @table @kbd | |
1756 | @item @key{TAB} | |
1757 | @code{tab-to-tab-stop}. | |
1758 | @item C-j | |
1759 | Insert a newline and then indent using @code{tab-to-tab-stop}. | |
1760 | @item : | |
1761 | Insert a colon and then remove the indentation from before the label | |
1762 | preceding colon. Then do @code{tab-to-tab-stop}. | |
1763 | @item ; | |
1764 | Insert or align a comment. | |
1765 | @end table | |
1766 | ||
1767 | The variable @code{asm-comment-char} specifies which character | |
1768 | starts comments in assembler syntax. | |
ab5796a9 | 1769 | |
b23ef7a5 EZ |
1770 | @ifnottex |
1771 | @include fortran-xtra.texi | |
1772 | @end ifnottex | |
1773 | ||
ab5796a9 MB |
1774 | @ignore |
1775 | arch-tag: c7ee7409-40a4-45c7-bfb7-ae7f2c74d0c0 | |
1776 | @end ignore |