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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, |
6ed161e1 | 3 | @c 2001, 2002, 2003, 2004, 2005, 2006, 2007, 2008, 2009 Free Software Foundation, Inc. |
6bf7aab6 DL |
4 | @c See file emacs.texi for copying conditions. |
5 | @node Programs, Building, Text, Top | |
6 | @chapter Editing Programs | |
7 | @cindex Lisp editing | |
8 | @cindex C editing | |
9 | @cindex program editing | |
10 | ||
e79c6b89 RS |
11 | Emacs provides many features to facilitate editing programs. Some |
12 | of these features can | |
6bf7aab6 DL |
13 | |
14 | @itemize @bullet | |
15 | @item | |
93da5dff | 16 | Find or move over top-level definitions (@pxref{Defuns}). |
6bf7aab6 | 17 | @item |
93da5dff RS |
18 | Apply the usual indentation conventions of the language |
19 | (@pxref{Program Indent}). | |
6bf7aab6 | 20 | @item |
93da5dff | 21 | Balance parentheses (@pxref{Parentheses}). |
cf1c48d4 | 22 | @item |
ea118de1 SE |
23 | Insert, kill or align comments (@pxref{Comments}). |
24 | @item | |
cf1c48d4 | 25 | Highlight program syntax (@pxref{Font Lock}). |
6bf7aab6 DL |
26 | @end itemize |
27 | ||
e79c6b89 RS |
28 | This chapter describes these features and many more. |
29 | ||
6bf7aab6 DL |
30 | @menu |
31 | * Program Modes:: Major modes for editing programs. | |
93da5dff RS |
32 | * Defuns:: Commands to operate on major top-level parts |
33 | of a program. | |
6bf7aab6 | 34 | * Program Indent:: Adjusting indentation to show the nesting. |
93da5dff | 35 | * Parentheses:: Commands that operate on parentheses. |
c8b21b5e | 36 | * Comments:: Inserting, killing, and aligning comments. |
93da5dff | 37 | * Documentation:: Getting documentation of functions you plan to call. |
51ed0ea0 | 38 | * Hideshow:: Displaying blocks selectively. |
93da5dff | 39 | * Symbol Completion:: Completion on symbol names of your program or language. |
3b8b8888 | 40 | * Glasses:: Making identifiersLikeThis more readable. |
93da5dff | 41 | * Misc for Programs:: Other Emacs features useful for editing programs. |
79214ddf | 42 | * C Modes:: Special commands of C, C++, Objective-C, |
6bf7aab6 | 43 | Java, and Pike modes. |
51ed0ea0 | 44 | * Asm Mode:: Asm mode and its special features. |
b23ef7a5 EZ |
45 | @ifnottex |
46 | * Fortran:: Fortran mode and its special features. | |
47 | @end ifnottex | |
6bf7aab6 DL |
48 | @end menu |
49 | ||
50 | @node Program Modes | |
51 | @section Major Modes for Programming Languages | |
6bf7aab6 | 52 | @cindex modes for programming languages |
cf1c48d4 RS |
53 | |
54 | Emacs has specialized major modes for various programming languages. | |
55 | @xref{Major Modes}. A programming language major mode typically | |
56 | specifies the syntax of expressions, the customary rules for | |
57 | indentation, how to do syntax highlighting for the language, and how | |
e722aa81 CY |
58 | to find the beginning or end of a function definition. It often |
59 | customizes or provides facilities for compiling and debugging programs | |
60 | as well. | |
cf1c48d4 RS |
61 | |
62 | Ideally, Emacs should provide a major mode for each programming | |
63 | language that you might want to edit; if it doesn't have a mode for | |
64 | your favorite language, you can contribute one. But often the mode | |
65 | for one language can serve for other syntactically similar languages. | |
66 | The major mode for language @var{l} is called @code{@var{l}-mode}, | |
e79c6b89 | 67 | and you can select it by typing @kbd{M-x @var{l}-mode @key{RET}}. |
cf1c48d4 RS |
68 | @xref{Choosing Modes}. |
69 | ||
6bf7aab6 DL |
70 | @cindex Perl mode |
71 | @cindex Icon mode | |
6bf7aab6 DL |
72 | @cindex Makefile mode |
73 | @cindex Tcl mode | |
74 | @cindex CPerl mode | |
138a8f12 DL |
75 | @cindex DSSSL mode |
76 | @cindex Octave mode | |
77 | @cindex Metafont mode | |
78 | @cindex Modula2 mode | |
79 | @cindex Prolog mode | |
7b703414 | 80 | @cindex Python mode |
e37d4360 | 81 | @cindex Ruby mode |
138a8f12 DL |
82 | @cindex Simula mode |
83 | @cindex VHDL mode | |
84 | @cindex M4 mode | |
85 | @cindex Shell-script mode | |
3b8b8888 DL |
86 | @cindex Delphi mode |
87 | @cindex PostScript mode | |
8758a7da RS |
88 | @cindex Conf mode |
89 | @cindex DNS mode | |
e722aa81 CY |
90 | The existing programming language major modes include Lisp, Scheme |
91 | (a variant of Lisp) and the Scheme-based DSSSL expression language, | |
92 | Ada, ASM, AWK, C, C++, Delphi (Object Pascal), Fortran, Icon, IDL | |
93 | (CORBA), IDLWAVE, Java, Metafont (@TeX{}'s companion for font | |
94 | creation), Modula2, Objective-C, Octave, Pascal, Perl, Pike, | |
e37d4360 CY |
95 | PostScript, Prolog, Python, Ruby, Simula, Tcl, and VHDL. An |
96 | alternative mode for Perl is called CPerl mode. Modes are available | |
97 | for the scripting languages of the common GNU and Unix shells, VMS | |
98 | DCL, and MS-DOS/MS-Windows @samp{BAT} files. There are also major | |
99 | modes for editing makefiles, DNS master files, and various sorts of | |
e722aa81 | 100 | configuration files. |
6bf7aab6 DL |
101 | |
102 | @kindex DEL @r{(programming modes)} | |
4f7666dc | 103 | @findex c-electric-backspace |
93da5dff RS |
104 | In most programming languages, indentation should vary from line to |
105 | line to illustrate the structure of the program. So the major modes | |
e79c6b89 | 106 | for programming languages arrange for @key{TAB} to update the |
e722aa81 CY |
107 | indentation of the current line (@pxref{Program Indent}). They also |
108 | rebind @key{DEL} to treat a tab as if it were the equivalent number of | |
109 | spaces; this lets you delete one column of indentation without | |
110 | worrying whether the whitespace consists of spaces or tabs. Use | |
111 | @kbd{C-b C-d} to delete a tab character before point, in these modes. | |
6bf7aab6 | 112 | |
cf1c48d4 | 113 | Separate manuals are available for the modes for Ada (@pxref{Top, , Ada |
7ae8ad94 | 114 | Mode, ada-mode, Ada Mode}), C/C++/Objective C/Java/Corba IDL/Pike/AWK |
cf1c48d4 | 115 | (@pxref{Top, , CC Mode, ccmode, CC Mode}) and the IDLWAVE modes |
e0fc8fa2 | 116 | (@pxref{Top, , IDLWAVE, idlwave, IDLWAVE User Manual}). For Fortran |
b23ef7a5 EZ |
117 | mode, see |
118 | @iftex | |
9dc999d3 | 119 | @ref{Fortran,,, emacs-xtra, Specialized Emacs Features}. |
b23ef7a5 EZ |
120 | @end iftex |
121 | @ifnottex | |
122 | @ref{Fortran}. | |
123 | @end ifnottex | |
124 | ||
6bf7aab6 DL |
125 | @cindex mode hook |
126 | @vindex c-mode-hook | |
127 | @vindex lisp-mode-hook | |
128 | @vindex emacs-lisp-mode-hook | |
129 | @vindex lisp-interaction-mode-hook | |
130 | @vindex scheme-mode-hook | |
d2fab838 RS |
131 | Turning on a major mode runs a normal hook called the @dfn{mode |
132 | hook}, which is the value of a Lisp variable. Each major mode has a | |
133 | mode hook, and the hook's name is always made from the mode command's | |
134 | name by adding @samp{-hook}. For example, turning on C mode runs the | |
135 | hook @code{c-mode-hook}, while turning on Lisp mode runs the hook | |
136 | @code{lisp-mode-hook}. The purpose of the mode hook is to give you a | |
137 | place to set up customizations for that major mode. @xref{Hooks}. | |
6bf7aab6 | 138 | |
93da5dff RS |
139 | @node Defuns |
140 | @section Top-Level Definitions, or Defuns | |
6bf7aab6 | 141 | |
e722aa81 CY |
142 | In Emacs, a major definition at the top level in the buffer, such as |
143 | a function, is called a @dfn{defun}. The name comes from Lisp, but in | |
144 | Emacs we use it for all languages. | |
6bf7aab6 | 145 | |
93da5dff RS |
146 | @menu |
147 | * Left Margin Paren:: An open-paren or similar opening delimiter | |
148 | starts a defun if it is at the left margin. | |
149 | * Moving by Defuns:: Commands to move over or mark a major definition. | |
150 | * Imenu:: Making buffer indexes as menus. | |
151 | * Which Function:: Which Function mode shows which function you are in. | |
152 | @end menu | |
6bf7aab6 | 153 | |
93da5dff RS |
154 | @node Left Margin Paren |
155 | @subsection Left Margin Convention | |
6bf7aab6 | 156 | |
93da5dff RS |
157 | @cindex open-parenthesis in leftmost column |
158 | @cindex ( in leftmost column | |
e722aa81 CY |
159 | Many programming-language modes assume by default that any opening |
160 | delimiter found at the left margin is the start of a top-level | |
161 | definition, or defun. Therefore, @strong{don't put an opening | |
162 | delimiter at the left margin unless it should have that significance}. | |
163 | For instance, never put an open-parenthesis at the left margin in a | |
164 | Lisp file unless it is the start of a top-level list. | |
165 | ||
166 | The convention speeds up many Emacs operations, which would | |
167 | otherwise have to scan back to the beginning of the buffer to analyze | |
168 | the syntax of the code. | |
93da5dff RS |
169 | |
170 | If you don't follow this convention, not only will you have trouble | |
171 | when you explicitly use the commands for motion by defuns; other | |
e722aa81 CY |
172 | features that use them will also give you trouble. This includes the |
173 | indentation commands (@pxref{Program Indent}) and Font Lock mode | |
174 | (@pxref{Font Lock}). | |
93da5dff RS |
175 | |
176 | The most likely problem case is when you want an opening delimiter | |
177 | at the start of a line inside a string. To avoid trouble, put an | |
aca2cfd2 AM |
178 | escape character (@samp{\}, in C and Emacs Lisp, @samp{/} in some |
179 | other Lisp dialects) before the opening delimiter. This will not | |
180 | affect the contents of the string, but will prevent that opening | |
181 | delimiter from starting a defun. Here's an example: | |
6bf7aab6 | 182 | |
93da5dff RS |
183 | @example |
184 | (insert "Foo: | |
185 | \(bar) | |
186 | ") | |
187 | @end example | |
6bf7aab6 | 188 | |
5b8fe684 RS |
189 | To help you catch violations of this convention, Font Lock mode |
190 | highlights confusing opening delimiters (those that ought to be | |
191 | quoted) in bold red. | |
192 | ||
e722aa81 CY |
193 | If you need to override this convention, you can do so by setting |
194 | this user option: | |
aca2cfd2 AM |
195 | |
196 | @defvar open-paren-in-column-0-is-defun-start | |
197 | If this user option is set to @code{t} (the default), opening | |
198 | parentheses or braces at column zero always start defuns. When it's | |
199 | @code{nil}, defuns are found by searching for parens or braces at the | |
200 | outermost level. | |
201 | @end defvar | |
202 | ||
e722aa81 CY |
203 | Usually, you should leave this option at its default value of |
204 | @code{t}. If your buffer contains parentheses or braces in column | |
205 | zero which don't start defuns, and it is somehow impractical to remove | |
206 | these parentheses or braces, it might be helpful to set the option to | |
207 | @code{nil}. Be aware that this might make scrolling and display in | |
208 | large buffers quite sluggish. Furthermore, the parentheses and braces | |
209 | must be correctly matched throughout the buffer for it to work | |
210 | properly. | |
93da5dff RS |
211 | |
212 | @node Moving by Defuns | |
213 | @subsection Moving by Defuns | |
6bf7aab6 DL |
214 | @cindex defuns |
215 | ||
93da5dff RS |
216 | These commands move point or set up the region based on top-level |
217 | major definitions, also called @dfn{defuns}. | |
520c3f4c | 218 | |
6bf7aab6 DL |
219 | @table @kbd |
220 | @item C-M-a | |
221 | Move to beginning of current or preceding defun | |
222 | (@code{beginning-of-defun}). | |
223 | @item C-M-e | |
224 | Move to end of current or following defun (@code{end-of-defun}). | |
225 | @item C-M-h | |
226 | Put region around whole current or following defun (@code{mark-defun}). | |
227 | @end table | |
228 | ||
f772775c RS |
229 | @cindex move to beginning or end of function |
230 | @cindex function, move to beginning or end | |
231 | @kindex C-M-a | |
232 | @kindex C-M-e | |
233 | @kindex C-M-h | |
234 | @findex beginning-of-defun | |
235 | @findex end-of-defun | |
236 | @findex mark-defun | |
237 | The commands to move to the beginning and end of the current defun | |
238 | are @kbd{C-M-a} (@code{beginning-of-defun}) and @kbd{C-M-e} | |
239 | (@code{end-of-defun}). If you repeat one of these commands, or use a | |
240 | positive numeric argument, each repetition moves to the next defun in | |
241 | the direction of motion. | |
242 | ||
243 | @kbd{C-M-a} with a negative argument @minus{}@var{n} moves forward | |
244 | @var{n} times to the next beginning of a defun. This is not exactly | |
245 | the same place that @kbd{C-M-e} with argument @var{n} would move to; | |
246 | the end of this defun is not usually exactly the same place as the | |
93da5dff RS |
247 | beginning of the following defun. (Whitespace, comments, and perhaps |
248 | declarations can separate them.) Likewise, @kbd{C-M-e} with a | |
249 | negative argument moves back to an end of a defun, which is not quite | |
250 | the same as @kbd{C-M-a} with a positive argument. | |
f772775c | 251 | |
4946337d | 252 | @kindex C-M-h @r{(C mode)} |
6bf7aab6 | 253 | @findex c-mark-function |
25716538 CY |
254 | To operate on the current defun, use @kbd{C-M-h} |
255 | (@code{mark-defun}), which sets the mark at the end of the current | |
256 | defun and puts point at its beginning. @xref{Marking Objects}. This | |
257 | is the easiest way to get ready to kill the defun in order to move it | |
258 | to a different place in the file. If you use the command while point | |
259 | is between defuns, it uses the following defun. If you use the | |
260 | command while the mark is already active, it sets the mark but does | |
261 | not move point; furthermore, each successive use of @kbd{C-M-h} | |
262 | extends the end of the region to include one more defun. | |
93da5dff RS |
263 | |
264 | In C mode, @kbd{C-M-h} runs the function @code{c-mark-function}, | |
265 | which is almost the same as @code{mark-defun}; the difference is that | |
266 | it backs up over the argument declarations, function name and returned | |
e79c6b89 RS |
267 | data type so that the entire C function is inside the region. This is |
268 | an example of how major modes adjust the standard key bindings so that | |
269 | they do their standard jobs in a way better fitting a particular | |
270 | language. Other major modes may replace any or all of these key | |
271 | bindings for that purpose. | |
6bf7aab6 | 272 | |
93da5dff RS |
273 | @node Imenu |
274 | @subsection Imenu | |
e79c6b89 RS |
275 | @cindex index of buffer definitions |
276 | @cindex buffer definitions index | |
93da5dff | 277 | |
269b7745 | 278 | The Imenu facility offers a way to find the major definitions in |
5e6f9132 RS |
279 | a file by name. It is also useful in text formatter major modes, |
280 | where it treats each chapter, section, etc., as a definition. | |
e79c6b89 | 281 | (@xref{Tags}, for a more powerful feature that handles multiple files |
5e6f9132 | 282 | together.) |
93da5dff RS |
283 | |
284 | @findex imenu | |
5e6f9132 | 285 | If you type @kbd{M-x imenu}, it reads the name of a definition using |
e79c6b89 RS |
286 | the minibuffer, then moves point to that definition. You can use |
287 | completion to specify the name; the command always displays the whole | |
288 | list of valid names. | |
d2fab838 | 289 | |
5e6f9132 | 290 | @findex imenu-add-menubar-index |
d2fab838 | 291 | Alternatively, you can bind the command @code{imenu} to a mouse |
e79c6b89 RS |
292 | click. Then it displays mouse menus for you to select a definition |
293 | name. You can also add the buffer's index to the menu bar by calling | |
294 | @code{imenu-add-menubar-index}. If you want to have this menu bar | |
295 | item available for all buffers in a certain major mode, you can do | |
296 | this by adding @code{imenu-add-menubar-index} to its mode hook. But | |
dfec8297 RS |
297 | if you have done that, you will have to wait a little while each time |
298 | you visit a file in that mode, while Emacs finds all the definitions | |
299 | in that buffer. | |
93da5dff RS |
300 | |
301 | @vindex imenu-auto-rescan | |
302 | When you change the contents of a buffer, if you add or delete | |
e79c6b89 | 303 | definitions, you can update the buffer's index based on the |
d2fab838 | 304 | new contents by invoking the @samp{*Rescan*} item in the menu. |
dcace646 EZ |
305 | Rescanning happens automatically if you set @code{imenu-auto-rescan} to |
306 | a non-@code{nil} value. There is no need to rescan because of small | |
e79c6b89 | 307 | changes in the text. |
93da5dff RS |
308 | |
309 | @vindex imenu-sort-function | |
d2fab838 | 310 | You can customize the way the menus are sorted by setting the |
e79c6b89 | 311 | variable @code{imenu-sort-function}. By default, names are ordered as |
5e6f9132 RS |
312 | they occur in the buffer; if you want alphabetic sorting, use the |
313 | symbol @code{imenu--sort-by-name} as the value. You can also | |
314 | define your own comparison function by writing Lisp code. | |
93da5dff RS |
315 | |
316 | Imenu provides the information to guide Which Function mode | |
317 | @ifnottex | |
318 | (@pxref{Which Function}). | |
319 | @end ifnottex | |
320 | @iftex | |
321 | (see below). | |
322 | @end iftex | |
323 | The Speedbar can also use it (@pxref{Speedbar}). | |
324 | ||
325 | @node Which Function | |
326 | @subsection Which Function Mode | |
af056954 | 327 | @cindex current function name in mode line |
93da5dff RS |
328 | |
329 | Which Function mode is a minor mode that displays the current | |
330 | function name in the mode line, updating it as you move around in a | |
331 | buffer. | |
332 | ||
333 | @findex which-function-mode | |
334 | @vindex which-func-modes | |
df7593dd | 335 | To either enable or disable Which Function mode, use the command |
e722aa81 CY |
336 | @kbd{M-x which-function-mode}. This command applies to all buffers, |
337 | both existing ones and those yet to be created. However, it takes | |
338 | effect only in certain major modes, those listed in the value of | |
339 | @code{which-func-modes}. If the value of @code{which-func-modes} is | |
340 | @code{t} rather than a list of modes, then Which Function mode applies | |
341 | to all major modes that know how to support it---in other words, all | |
342 | the major modes that support Imenu. | |
6bf7aab6 DL |
343 | |
344 | @node Program Indent | |
345 | @section Indentation for Programs | |
346 | @cindex indentation for programs | |
347 | ||
348 | The best way to keep a program properly indented is to use Emacs to | |
e722aa81 CY |
349 | reindent it as you change it. Emacs has commands to indent either a |
350 | single line, a specified number of lines, or all of the lines inside a | |
351 | single parenthetical grouping. | |
6bf7aab6 DL |
352 | |
353 | @menu | |
354 | * Basic Indent:: Indenting a single line. | |
355 | * Multi-line Indent:: Commands to reindent many lines at once. | |
356 | * Lisp Indent:: Specifying how each Lisp function should be indented. | |
357 | * C Indent:: Extra features for indenting C and related modes. | |
358 | * Custom C Indent:: Controlling indentation style for C and related modes. | |
359 | @end menu | |
360 | ||
d2fab838 | 361 | @cindex pretty-printer |
6bf7aab6 DL |
362 | Emacs also provides a Lisp pretty-printer in the library @code{pp}. |
363 | This program reformats a Lisp object with indentation chosen to look nice. | |
364 | ||
365 | @node Basic Indent | |
366 | @subsection Basic Program Indentation Commands | |
367 | ||
d2fab838 RS |
368 | The basic indentation commands indent a single line according to the |
369 | usual conventions of the language you are editing. | |
cf1c48d4 | 370 | |
6bf7aab6 DL |
371 | @table @kbd |
372 | @item @key{TAB} | |
373 | Adjust indentation of current line. | |
374 | @item C-j | |
bb63d706 RS |
375 | Insert a newline, then adjust indentation of following line |
376 | (@code{newline-and-indent}). | |
6bf7aab6 DL |
377 | @end table |
378 | ||
379 | @kindex TAB @r{(programming modes)} | |
4f7666dc RS |
380 | @findex c-indent-command |
381 | @findex indent-line-function | |
f772775c | 382 | @findex indent-for-tab-command |
e722aa81 CY |
383 | The basic indentation command is @key{TAB}. In any |
384 | programming-language major mode, @key{TAB} gives the current line the | |
385 | correct indentation as determined from the previous lines. It does | |
386 | this by inserting or deleting whitespace at the beginning of the | |
387 | current line. If point was inside the whitespace at the beginning of | |
388 | the line, @key{TAB} puts it at the end of that whitespace; otherwise, | |
389 | @key{TAB} keeps point fixed with respect to the characters around it. | |
390 | If the region is active (@pxref{Mark}), @key{TAB} indents every line | |
391 | within the region instead of just the current line. The function that | |
392 | @key{TAB} runs depends on the major mode; for instance, it is | |
393 | @code{c-indent-line-or-region} in C mode. Each function is aware of | |
394 | the syntax and conventions for its particular language. | |
6bf7aab6 | 395 | |
64e207c0 | 396 | Use @kbd{C-q @key{TAB}} to insert a tab character at point. |
6bf7aab6 DL |
397 | |
398 | @kindex C-j | |
399 | @findex newline-and-indent | |
cf1c48d4 | 400 | When entering lines of new code, use @kbd{C-j} |
bb63d706 | 401 | (@code{newline-and-indent}), which inserts a newline and then adjusts |
14f4194d | 402 | indentation after it. (It also deletes any trailing whitespace which |
e722aa81 CY |
403 | remains before the new newline.) For instance, @kbd{C-j} at the end |
404 | of a line creates a blank line with appropriate indentation. In | |
405 | programming language modes, it is equivalent to @key{RET} @key{TAB}. | |
406 | ||
407 | When Emacs indents a line that starts within a parenthetical | |
408 | grouping, it usually places the start of the line under the preceding | |
409 | line within the group, or under the text after the parenthesis. If | |
410 | you manually give one of these lines a nonstandard indentation, the | |
411 | lines below will tend to follow it. This behavior is convenient in | |
412 | cases where you have overridden the standard result of @key{TAB} | |
413 | indentation (e.g., for aesthetic purposes). | |
414 | ||
415 | Many programming-language modes assume that an open-parenthesis, | |
416 | open-brace or other opening delimiter at the left margin is the start | |
417 | of a function. This assumption speeds up indentation commands. If | |
418 | the text you are editing contains opening delimiters in column zero | |
419 | that aren't the beginning of a functions---even if these delimiters | |
420 | occur inside strings or comments---then you must set | |
108262a0 | 421 | @code{open-paren-in-column-0-is-defun-start}. @xref{Left Margin |
e722aa81 | 422 | Paren}. |
6bf7aab6 | 423 | |
e722aa81 CY |
424 | Normally, Emacs indents lines using an ``optimal'' mix of tab and |
425 | space characters. If you want Emacs to use spaces only, set | |
426 | @code{indent-tabs-mode} (@pxref{Just Spaces}). | |
5151db0c | 427 | |
6bf7aab6 DL |
428 | @node Multi-line Indent |
429 | @subsection Indenting Several Lines | |
430 | ||
e722aa81 CY |
431 | Sometimes, you may want to reindent several lines of code at a time. |
432 | One way to do this is to use the mark; when the mark is active and the | |
433 | region is non-empty, @key{TAB} indents every line within the region. | |
434 | In addition, Emacs provides several other commands for indenting large | |
435 | chunks of code: | |
6bf7aab6 DL |
436 | |
437 | @table @kbd | |
438 | @item C-M-q | |
e722aa81 | 439 | Reindent all the lines within one parenthetical grouping. |
e79c6b89 RS |
440 | @item C-M-\ |
441 | Reindent all lines in the region (@code{indent-region}). | |
6bf7aab6 | 442 | @item C-u @key{TAB} |
93da5dff RS |
443 | Shift an entire parenthetical grouping rigidly sideways so that its |
444 | first line is properly indented. | |
5cc06e0b EZ |
445 | @item M-x indent-code-rigidly |
446 | Shift all the lines in the region rigidly sideways, but do not alter | |
447 | lines that start inside comments and strings. | |
6bf7aab6 DL |
448 | @end table |
449 | ||
450 | @kindex C-M-q | |
6daf3e15 | 451 | @findex indent-pp-sexp |
e722aa81 CY |
452 | To reindent the contents of a single parenthetical grouping, |
453 | position point before the beginning of the grouping and type | |
454 | @kbd{C-M-q}. This changes the relative indentation within the | |
455 | grouping, without affecting its overall indentation (i.e., the | |
456 | indentation of the line where the grouping starts). The function that | |
457 | @kbd{C-M-q} runs depends on the major mode; it is | |
458 | @code{indent-pp-sexp} in Lisp mode, @code{c-indent-exp} in C mode, | |
459 | etc. To correct the overall indentation as well, type @key{TAB} | |
460 | first. | |
461 | ||
462 | @kbd{C-M-\} (@code{indent-region}) applies @key{TAB} to the region. | |
463 | This is useful when Transient Mark mode is disabled (@pxref{Persistent | |
464 | Mark}), because in that case @key{TAB} does not act on the region. | |
e79c6b89 | 465 | |
6bf7aab6 | 466 | @kindex C-u TAB |
e722aa81 CY |
467 | If you like the relative indentation within a grouping but not the |
468 | indentation of its first line, move point to that first line and type | |
469 | @kbd{C-u @key{TAB}}. In Lisp, C, and some other major modes, | |
470 | @key{TAB} with a numeric argument reindents the current line as usual, | |
471 | then reindents by the same amount all the lines in the parenthetical | |
472 | grouping starting on the current line. It is clever, though, and does | |
473 | not alter lines that start inside strings. Neither does it alter C | |
474 | preprocessor lines when in C mode, but it does reindent any | |
475 | continuation lines that may be attached to them. | |
6bf7aab6 | 476 | |
5cc06e0b | 477 | @findex indent-code-rigidly |
e722aa81 CY |
478 | The command @kbd{M-x indent-code-rigidly} rigidly shifts all the |
479 | lines in the region sideways, like @code{indent-rigidly} does | |
480 | (@pxref{Indentation Commands}). It doesn't alter the indentation of | |
481 | lines that start inside a string, unless the region also starts inside | |
482 | that string. The prefix arg specifies the number of columns to | |
483 | indent. | |
6bf7aab6 DL |
484 | |
485 | @node Lisp Indent | |
486 | @subsection Customizing Lisp Indentation | |
487 | @cindex customizing Lisp indentation | |
488 | ||
489 | The indentation pattern for a Lisp expression can depend on the function | |
490 | called by the expression. For each Lisp function, you can choose among | |
491 | several predefined patterns of indentation, or define an arbitrary one with | |
492 | a Lisp program. | |
493 | ||
494 | The standard pattern of indentation is as follows: the second line of the | |
495 | expression is indented under the first argument, if that is on the same | |
496 | line as the beginning of the expression; otherwise, the second line is | |
497 | indented underneath the function name. Each following line is indented | |
498 | under the previous line whose nesting depth is the same. | |
499 | ||
500 | @vindex lisp-indent-offset | |
501 | If the variable @code{lisp-indent-offset} is non-@code{nil}, it overrides | |
502 | the usual indentation pattern for the second line of an expression, so that | |
503 | such lines are always indented @code{lisp-indent-offset} more columns than | |
504 | the containing list. | |
505 | ||
506 | @vindex lisp-body-indent | |
d2fab838 | 507 | Certain functions override the standard pattern. Functions whose |
269b7745 | 508 | names start with @code{def} treat the second lines as the start of |
d2fab838 RS |
509 | a @dfn{body}, by indenting the second line @code{lisp-body-indent} |
510 | additional columns beyond the open-parenthesis that starts the | |
511 | expression. | |
6bf7aab6 | 512 | |
b771b258 | 513 | @cindex @code{lisp-indent-function} property |
d2fab838 | 514 | You can override the standard pattern in various ways for individual |
690a6d08 RS |
515 | functions, according to the @code{lisp-indent-function} property of |
516 | the function name. Normally you would use this for macro definitions | |
517 | and specify it using the @code{declare} construct (@pxref{Defining | |
518 | Macros,,, elisp, the Emacs Lisp Reference Manual}). | |
6bf7aab6 DL |
519 | |
520 | @node C Indent | |
521 | @subsection Commands for C Indentation | |
522 | ||
93da5dff | 523 | Here are special features for indentation in C mode and related modes: |
6bf7aab6 DL |
524 | |
525 | @table @code | |
526 | @item C-c C-q | |
527 | @kindex C-c C-q @r{(C mode)} | |
528 | @findex c-indent-defun | |
529 | Reindent the current top-level function definition or aggregate type | |
530 | declaration (@code{c-indent-defun}). | |
531 | ||
532 | @item C-M-q | |
533 | @kindex C-M-q @r{(C mode)} | |
534 | @findex c-indent-exp | |
535 | Reindent each line in the balanced expression that follows point | |
7ae8ad94 RS |
536 | (@code{c-indent-exp}). A prefix argument inhibits warning messages |
537 | about invalid syntax. | |
6bf7aab6 DL |
538 | |
539 | @item @key{TAB} | |
540 | @findex c-indent-command | |
541 | Reindent the current line, and/or in some cases insert a tab character | |
542 | (@code{c-indent-command}). | |
543 | ||
7ae8ad94 | 544 | @vindex c-tab-always-indent |
6bf7aab6 DL |
545 | If @code{c-tab-always-indent} is @code{t}, this command always reindents |
546 | the current line and does nothing else. This is the default. | |
547 | ||
548 | If that variable is @code{nil}, this command reindents the current line | |
549 | only if point is at the left margin or in the line's indentation; | |
550 | otherwise, it inserts a tab (or the equivalent number of spaces, | |
551 | if @code{indent-tabs-mode} is @code{nil}). | |
552 | ||
553 | Any other value (not @code{nil} or @code{t}) means always reindent the | |
7ae8ad94 | 554 | line, and also insert a tab if within a comment or a string. |
6bf7aab6 DL |
555 | @end table |
556 | ||
557 | To reindent the whole current buffer, type @kbd{C-x h C-M-\}. This | |
558 | first selects the whole buffer as the region, then reindents that | |
559 | region. | |
560 | ||
561 | To reindent the current block, use @kbd{C-M-u C-M-q}. This moves | |
562 | to the front of the block and then reindents it all. | |
563 | ||
564 | @node Custom C Indent | |
565 | @subsection Customizing C Indentation | |
93da5dff | 566 | @cindex style (for indentation) |
6bf7aab6 | 567 | |
7ae8ad94 RS |
568 | C mode and related modes use a flexible mechanism for customizing |
569 | indentation. C mode indents a source line in two steps: first it | |
570 | classifies the line syntactically according to its contents and | |
571 | context; second, it determines the indentation offset associated by | |
572 | your selected @dfn{style} with the syntactic construct and adds this | |
573 | onto the indentation of the @dfn{anchor statement}. | |
6bf7aab6 | 574 | |
93da5dff | 575 | @table @kbd |
7ae8ad94 RS |
576 | @item C-c . @key{RET} @var{style} @key{RET} |
577 | Select a predefined style @var{style} (@code{c-set-style}). | |
93da5dff | 578 | @end table |
6bf7aab6 | 579 | |
108262a0 AM |
580 | A @dfn{style} is a named collection of customizations that can be |
581 | used in C mode and the related modes. @ref{Styles,,, ccmode, The CC | |
582 | Mode Manual}, for a complete description. Emacs comes with several | |
93da5dff RS |
583 | predefined styles, including @code{gnu}, @code{k&r}, @code{bsd}, |
584 | @code{stroustrup}, @code{linux}, @code{python}, @code{java}, | |
108262a0 AM |
585 | @code{whitesmith}, @code{ellemtel}, and @code{awk}. Some of these |
586 | styles are primarily intended for one language, but any of them can be | |
587 | used with any of the languages supported by these modes. To find out | |
588 | what a style looks like, select it and reindent some code, e.g., by | |
589 | typing @key{C-M-q} at the start of a function definition. | |
6bf7aab6 | 590 | |
7ae8ad94 | 591 | @kindex C-c . @r{(C mode)} |
93da5dff | 592 | @findex c-set-style |
dfec8297 RS |
593 | To choose a style for the current buffer, use the command @w{@kbd{C-c |
594 | .}}. Specify a style name as an argument (case is not significant). | |
7ae8ad94 RS |
595 | This command affects the current buffer only, and it affects only |
596 | future invocations of the indentation commands; it does not reindent | |
108262a0 AM |
597 | the code already in the buffer. To reindent the whole buffer in the |
598 | new style, you can type @kbd{C-x h C-M-\}. | |
6bf7aab6 | 599 | |
93da5dff RS |
600 | @vindex c-default-style |
601 | You can also set the variable @code{c-default-style} to specify the | |
7ae8ad94 RS |
602 | default style for various major modes. Its value should be either the |
603 | style's name (a string) or an alist, in which each element specifies | |
604 | one major mode and which indentation style to use for it. For | |
605 | example, | |
6bf7aab6 DL |
606 | |
607 | @example | |
93da5dff | 608 | (setq c-default-style |
108262a0 | 609 | '((java-mode . "java") (awk-mode . "awk") (other . "gnu"))) |
6bf7aab6 DL |
610 | @end example |
611 | ||
93da5dff | 612 | @noindent |
108262a0 AM |
613 | specifies explicit choices for Java and AWK modes, and the default |
614 | @samp{gnu} style for the other C-like modes. (These settings are | |
615 | actually the defaults.) This variable takes effect when you select | |
616 | one of the C-like major modes; thus, if you specify a new default | |
617 | style for Java mode, you can make it take effect in an existing Java | |
618 | mode buffer by typing @kbd{M-x java-mode} there. | |
6bf7aab6 | 619 | |
93da5dff RS |
620 | The @code{gnu} style specifies the formatting recommended by the GNU |
621 | Project for C; it is the default, so as to encourage use of our | |
622 | recommended style. | |
6bf7aab6 | 623 | |
108262a0 AM |
624 | @xref{Indentation Engine Basics,,, ccmode, the CC Mode Manual}, and |
625 | @ref{Customizing Indentation,,, ccmode, the CC Mode Manual}, for more | |
626 | information on customizing indentation for C and related modes, | |
93da5dff RS |
627 | including how to override parts of an existing style and how to define |
628 | your own styles. | |
6bf7aab6 | 629 | |
93da5dff RS |
630 | @node Parentheses |
631 | @section Commands for Editing with Parentheses | |
6bf7aab6 | 632 | |
93da5dff RS |
633 | @findex check-parens |
634 | @cindex unbalanced parentheses and quotes | |
635 | This section describes the commands and features that take advantage | |
636 | of the parenthesis structure in a program, or help you keep it | |
637 | balanced. | |
6bf7aab6 | 638 | |
93da5dff RS |
639 | When talking about these facilities, the term ``parenthesis'' also |
640 | includes braces, brackets, or whatever delimiters are defined to match | |
e79c6b89 RS |
641 | in pairs. The major mode controls which delimiters are significant, |
642 | through the syntax table (@pxref{Syntax}). In Lisp, only parentheses | |
643 | count; in C, these commands apply to braces and brackets too. | |
6bf7aab6 | 644 | |
93da5dff RS |
645 | You can use @kbd{M-x check-parens} to find any unbalanced |
646 | parentheses and unbalanced string quotes in the buffer. | |
6bf7aab6 | 647 | |
93da5dff RS |
648 | @menu |
649 | * Expressions:: Expressions with balanced parentheses. | |
650 | * Moving by Parens:: Commands for moving up, down and across | |
651 | in the structure of parentheses. | |
652 | * Matching:: Insertion of a close-delimiter flashes matching open. | |
653 | @end menu | |
6bf7aab6 | 654 | |
93da5dff RS |
655 | @node Expressions |
656 | @subsection Expressions with Balanced Parentheses | |
6bf7aab6 | 657 | |
93da5dff RS |
658 | @cindex sexp |
659 | @cindex expression | |
660 | @cindex balanced expression | |
661 | These commands deal with balanced expressions, also called | |
662 | @dfn{sexps}@footnote{The word ``sexp'' is used to refer to an | |
663 | expression in Lisp.}. | |
6bf7aab6 | 664 | |
93da5dff RS |
665 | @table @kbd |
666 | @item C-M-f | |
667 | Move forward over a balanced expression (@code{forward-sexp}). | |
668 | @item C-M-b | |
ea118de1 | 669 | Move backward over a balanced expression (@code{backward-sexp}). |
93da5dff RS |
670 | @item C-M-k |
671 | Kill balanced expression forward (@code{kill-sexp}). | |
93da5dff RS |
672 | @item C-M-t |
673 | Transpose expressions (@code{transpose-sexps}). | |
674 | @item C-M-@@ | |
649d1cbe | 675 | @itemx C-M-@key{SPC} |
93da5dff RS |
676 | Put mark after following expression (@code{mark-sexp}). |
677 | @end table | |
6bf7aab6 | 678 | |
93da5dff RS |
679 | Each programming language major mode customizes the definition of |
680 | balanced expressions to suit that language. Balanced expressions | |
681 | typically include symbols, numbers, and string constants, as well as | |
e79c6b89 | 682 | any pair of matching delimiters and their contents. Some languages |
93da5dff RS |
683 | have obscure forms of expression syntax that nobody has bothered to |
684 | implement in Emacs. | |
6bf7aab6 | 685 | |
93da5dff | 686 | @cindex Control-Meta |
e79c6b89 RS |
687 | By convention, the keys for these commands are all Control-Meta |
688 | characters. They usually act on expressions just as the corresponding | |
689 | Meta characters act on words. For instance, the command @kbd{C-M-b} | |
690 | moves backward over a balanced expression, just as @kbd{M-b} moves | |
691 | back over a word. | |
6bf7aab6 | 692 | |
93da5dff RS |
693 | @kindex C-M-f |
694 | @kindex C-M-b | |
695 | @findex forward-sexp | |
696 | @findex backward-sexp | |
697 | To move forward over a balanced expression, use @kbd{C-M-f} | |
698 | (@code{forward-sexp}). If the first significant character after point | |
699 | is an opening delimiter (@samp{(} in Lisp; @samp{(}, @samp{[} or | |
700 | @samp{@{} in C), @kbd{C-M-f} moves past the matching closing | |
701 | delimiter. If the character begins a symbol, string, or number, | |
702 | @kbd{C-M-f} moves over that. | |
6bf7aab6 | 703 | |
93da5dff RS |
704 | The command @kbd{C-M-b} (@code{backward-sexp}) moves backward over a |
705 | balanced expression. The detailed rules are like those above for | |
706 | @kbd{C-M-f}, but with directions reversed. If there are prefix | |
707 | characters (single-quote, backquote and comma, in Lisp) preceding the | |
708 | expression, @kbd{C-M-b} moves back over them as well. The balanced | |
709 | expression commands move across comments as if they were whitespace, | |
710 | in most modes. | |
6bf7aab6 | 711 | |
93da5dff RS |
712 | @kbd{C-M-f} or @kbd{C-M-b} with an argument repeats that operation the |
713 | specified number of times; with a negative argument, it moves in the | |
714 | opposite direction. | |
6bf7aab6 | 715 | |
93da5dff RS |
716 | @cindex killing expressions |
717 | @kindex C-M-k | |
718 | @findex kill-sexp | |
93da5dff | 719 | Killing a whole balanced expression can be done with @kbd{C-M-k} |
880b0421 RS |
720 | (@code{kill-sexp}). @kbd{C-M-k} kills the characters that @kbd{C-M-f} |
721 | would move over. | |
6bf7aab6 | 722 | |
93da5dff RS |
723 | @cindex transposition of expressions |
724 | @kindex C-M-t | |
725 | @findex transpose-sexps | |
726 | A somewhat random-sounding command which is nevertheless handy is | |
727 | @kbd{C-M-t} (@code{transpose-sexps}), which drags the previous | |
728 | balanced expression across the next one. An argument serves as a | |
108262a0 AM |
729 | repeat count, moving the previous expression over that many following |
730 | ones. A negative argument drags the previous balanced expression | |
731 | backwards across those before it (thus canceling out the effect of | |
732 | @kbd{C-M-t} with a positive argument). An argument of zero, rather | |
733 | than doing nothing, transposes the balanced expressions ending at or | |
734 | after point and the mark. | |
6bf7aab6 | 735 | |
93da5dff | 736 | @kindex C-M-@@ |
649d1cbe | 737 | @kindex C-M-@key{SPC} |
93da5dff RS |
738 | @findex mark-sexp |
739 | To set the region around the next balanced expression in the buffer, | |
25716538 CY |
740 | use @kbd{C-M-@key{SPC}} (@code{mark-sexp}), which sets mark at the |
741 | same place that @kbd{C-M-f} would move to. @kbd{C-M-@key{SPC}} treats | |
742 | numeric arguments in the same way as @kbd{C-M-f}; in particular, a | |
743 | negative argument puts the mark at the beginning of the previous | |
744 | balanced expression. The alias @kbd{C-M-@@} is equivalent to | |
745 | @kbd{C-M-@key{SPC}}. While the mark is active, each successive use of | |
746 | @kbd{C-M-@key{SPC}} extends the region by shifting the mark by one | |
747 | sexp. | |
93da5dff RS |
748 | |
749 | In languages that use infix operators, such as C, it is not possible | |
750 | to recognize all balanced expressions as such because there can be | |
751 | multiple possibilities at a given position. For example, C mode does | |
752 | not treat @samp{foo + bar} as a single expression, even though it | |
753 | @emph{is} one C expression; instead, it recognizes @samp{foo} as one | |
754 | expression and @samp{bar} as another, with the @samp{+} as punctuation | |
755 | between them. Both @samp{foo + bar} and @samp{foo} are legitimate | |
756 | choices for ``the expression following point'' when point is at the | |
e79c6b89 RS |
757 | @samp{f}, so the expression commands must perforce choose one or the |
758 | other to operate on. Note that @samp{(foo + bar)} is recognized as a | |
759 | single expression in C mode, because of the parentheses. | |
93da5dff RS |
760 | |
761 | @node Moving by Parens | |
762 | @subsection Moving in the Parenthesis Structure | |
763 | ||
764 | @cindex parenthetical groupings | |
765 | @cindex parentheses, moving across | |
766 | @cindex matching parenthesis and braces, moving to | |
767 | @cindex braces, moving across | |
768 | @cindex list commands | |
3fbb05ff | 769 | |
93da5dff RS |
770 | The Emacs commands for handling parenthetical groupings see nothing |
771 | except parentheses (or whatever characters must balance in the | |
3fbb05ff AM |
772 | language you are working with). They ignore strings and comments |
773 | (including any parentheses within them) and ignore parentheses quoted | |
774 | by an escape character. They are mainly intended for editing | |
93da5dff RS |
775 | programs, but can be useful for editing any text that has parentheses. |
776 | They are sometimes called ``list'' commands because in Lisp these | |
777 | groupings are lists. | |
6bf7aab6 | 778 | |
3fbb05ff AM |
779 | These commands assume that the starting point is not inside a string |
780 | or a comment. Sometimes you can invoke them usefully from one of | |
781 | these places (for example, when you have a parenthesised clause in a | |
782 | comment) but this is unreliable. | |
783 | ||
6bf7aab6 | 784 | @table @kbd |
93da5dff RS |
785 | @item C-M-n |
786 | Move forward over a parenthetical group (@code{forward-list}). | |
787 | @item C-M-p | |
ea118de1 | 788 | Move backward over a parenthetical group (@code{backward-list}). |
93da5dff RS |
789 | @item C-M-u |
790 | Move up in parenthesis structure (@code{backward-up-list}). | |
791 | @item C-M-d | |
792 | Move down in parenthesis structure (@code{down-list}). | |
6bf7aab6 DL |
793 | @end table |
794 | ||
93da5dff RS |
795 | @kindex C-M-n |
796 | @kindex C-M-p | |
797 | @findex forward-list | |
798 | @findex backward-list | |
799 | The ``list'' commands @kbd{C-M-n} (@code{forward-list}) and | |
3fbb05ff AM |
800 | @kbd{C-M-p} (@code{backward-list}) move forward or backward over one |
801 | (or @var{n}) parenthetical groupings. | |
6bf7aab6 | 802 | |
93da5dff | 803 | @kindex C-M-u |
93da5dff | 804 | @findex backward-up-list |
93da5dff RS |
805 | @kbd{C-M-n} and @kbd{C-M-p} try to stay at the same level in the |
806 | parenthesis structure. To move @emph{up} one (or @var{n}) levels, use | |
807 | @kbd{C-M-u} (@code{backward-up-list}). @kbd{C-M-u} moves backward up | |
808 | past one unmatched opening delimiter. A positive argument serves as a | |
809 | repeat count; a negative argument reverses the direction of motion, so | |
d2fab838 | 810 | that the command moves forward and up one or more levels. |
93da5dff | 811 | |
dfec8297 RS |
812 | @kindex C-M-d |
813 | @findex down-list | |
93da5dff RS |
814 | To move @emph{down} in the parenthesis structure, use @kbd{C-M-d} |
815 | (@code{down-list}). In Lisp mode, where @samp{(} is the only opening | |
816 | delimiter, this is nearly the same as searching for a @samp{(}. An | |
817 | argument specifies the number of levels to go down. | |
6bf7aab6 DL |
818 | |
819 | @node Matching | |
93da5dff | 820 | @subsection Automatic Display Of Matching Parentheses |
6bf7aab6 DL |
821 | @cindex matching parentheses |
822 | @cindex parentheses, displaying matches | |
823 | ||
824 | The Emacs parenthesis-matching feature is designed to show | |
93da5dff RS |
825 | automatically how parentheses (and other matching delimiters) match in |
826 | the text. Whenever you type a self-inserting character that is a | |
827 | closing delimiter, the cursor moves momentarily to the location of the | |
828 | matching opening delimiter, provided that is on the screen. If it is | |
e79c6b89 RS |
829 | not on the screen, Emacs displays some of the text near it in the echo |
830 | area. Either way, you can tell which grouping you are closing off. | |
93da5dff RS |
831 | |
832 | If the opening delimiter and closing delimiter are mismatched---such | |
833 | as in @samp{[x)}---a warning message is displayed in the echo area. | |
6bf7aab6 DL |
834 | |
835 | @vindex blink-matching-paren | |
836 | @vindex blink-matching-paren-distance | |
837 | @vindex blink-matching-delay | |
054af0fd SE |
838 | Three variables control parenthesis match display: |
839 | ||
840 | @code{blink-matching-paren} turns the feature on or off: @code{nil} | |
93da5dff | 841 | disables it, but the default is @code{t} to enable match display. |
f772775c RS |
842 | |
843 | @code{blink-matching-delay} says how many seconds to leave the | |
93da5dff | 844 | cursor on the matching opening delimiter, before bringing it back to |
f772775c RS |
845 | the real location of point; the default is 1, but on some systems it |
846 | is useful to specify a fraction of a second. | |
847 | ||
848 | @code{blink-matching-paren-distance} specifies how many characters | |
849 | back to search to find the matching opening delimiter. If the match | |
8b6f4c0a | 850 | is not found in that distance, scanning stops, and nothing is displayed. |
93da5dff | 851 | This is to prevent the scan for the matching delimiter from wasting |
f772775c | 852 | lots of time when there is no match. The default is 25600. |
6bf7aab6 DL |
853 | |
854 | @cindex Show Paren mode | |
79f9f655 | 855 | @cindex highlighting matching parentheses |
6bf7aab6 | 856 | @findex show-paren-mode |
93da5dff | 857 | Show Paren mode provides a more powerful kind of automatic matching. |
e722aa81 CY |
858 | Whenever point is before an opening delimiter or after a closing |
859 | delimiter, both that delimiter and its opposite delimiter are | |
860 | highlighted. Use the command @kbd{M-x show-paren-mode} to enable or | |
861 | disable this mode. | |
79f9f655 | 862 | |
dfec8297 RS |
863 | Show Paren mode uses the faces @code{show-paren-match} and |
864 | @code{show-paren-mismatch} to highlight parentheses; you can customize | |
865 | them to control how highlighting looks. @xref{Face Customization}. | |
6bf7aab6 DL |
866 | |
867 | @node Comments | |
868 | @section Manipulating Comments | |
869 | @cindex comments | |
870 | ||
871 | Because comments are such an important part of programming, Emacs | |
8f50b630 RS |
872 | provides special commands for editing and inserting comments. It can |
873 | also do spell checking on comments with Flyspell Prog mode | |
874 | (@pxref{Spelling}). | |
6bf7aab6 DL |
875 | |
876 | @menu | |
5b31640c | 877 | * Comment Commands:: Inserting, killing, and aligning comments. |
93da5dff RS |
878 | * Multi-Line Comments:: Commands for adding and editing multi-line comments. |
879 | * Options for Comments::Customizing the comment features. | |
6bf7aab6 DL |
880 | @end menu |
881 | ||
882 | @node Comment Commands | |
883 | @subsection Comment Commands | |
6bf7aab6 | 884 | @cindex indentation for comments |
5b31640c | 885 | @cindex alignment for comments |
6bf7aab6 | 886 | |
e722aa81 | 887 | The commands in this table insert, kill and align comments: |
6bf7aab6 | 888 | |
7ae8ad94 RS |
889 | @table @asis |
890 | @item @kbd{M-;} | |
9234c238 RS |
891 | Insert or realign comment on current line; alternatively, comment or |
892 | uncomment the region (@code{comment-dwim}). | |
7ae8ad94 | 893 | @item @kbd{C-u M-;} |
9234c238 | 894 | Kill comment on current line (@code{comment-kill}). |
7ae8ad94 | 895 | @item @kbd{C-x ;} |
47c1b5f4 | 896 | Set comment column (@code{comment-set-column}). |
7ae8ad94 RS |
897 | @item @kbd{C-M-j} |
898 | @itemx @kbd{M-j} | |
6bf7aab6 | 899 | Like @key{RET} followed by inserting and aligning a comment |
108262a0 | 900 | (@code{comment-indent-new-line}). @xref{Multi-Line Comments}. |
7ae8ad94 RS |
901 | @item @kbd{M-x comment-region} |
902 | @itemx @kbd{C-c C-c} (in C-like modes) | |
6bf7aab6 DL |
903 | Add or remove comment delimiters on all the lines in the region. |
904 | @end table | |
905 | ||
9234c238 RS |
906 | @kindex M-; |
907 | @findex comment-dwim | |
908 | The command to create or align a comment is @kbd{M-;} | |
909 | (@code{comment-dwim}). The word ``dwim'' is an acronym for ``Do What | |
910 | I Mean''; it indicates that this command can be used for many | |
911 | different jobs relating to comments, depending on the situation where | |
912 | you use it. | |
913 | ||
8474de5b CY |
914 | When a region is active, @kbd{M-;} either adds or removes comment |
915 | delimiters on each line of the region. @xref{Mark}. If every line in | |
916 | the region is a comment, it removes comment delimiters from each; | |
917 | otherwise, it adds comment delimiters to each. You can also use the | |
918 | commands @code{comment-region} and @code{uncomment-region} to | |
919 | explicitly comment or uncomment the text in the region | |
920 | (@pxref{Multi-Line Comments}). If you supply a prefix argument to | |
921 | @kbd{M-;} when a region is active, that specifies how many comment | |
922 | delimiters to add or how many to delete. | |
923 | ||
924 | If the region is not active, @kbd{M-;} inserts a new comment if | |
925 | there is no comment already on the line. The new comment is normally | |
926 | aligned at a specific column called the @dfn{comment column}; if the | |
927 | text of the line extends past the comment column, @kbd{M-;} aligns the | |
928 | comment start string to a suitable boundary (usually, at least one | |
929 | space is inserted). The comment begins with the string Emacs thinks | |
930 | comments should start with (the value of @code{comment-start}; see | |
931 | below). Emacs places point after that string, so you can insert the | |
932 | text of the comment right away. If the major mode has specified a | |
933 | string to terminate comments, @kbd{M-;} inserts that string after | |
934 | point, to keep the syntax valid. | |
9234c238 RS |
935 | |
936 | You can also use @kbd{M-;} to align an existing comment. If a line | |
5b31640c | 937 | already contains the comment-start string, @kbd{M-;} realigns it to |
9234c238 RS |
938 | the conventional alignment and moves point after it. (Exception: |
939 | comments starting in column 0 are not moved.) Even when an existing | |
940 | comment is properly aligned, @kbd{M-;} is still useful for moving | |
941 | directly to the start of the text inside the comment. | |
942 | ||
943 | @findex comment-kill | |
944 | @kindex C-u M-; | |
945 | @kbd{C-u M-;} kills any comment on the current line, along with the | |
946 | whitespace before it. To reinsert the comment on another line, move | |
947 | to the end of that line, do @kbd{C-y}, and then do @kbd{M-;} to | |
948 | realign it. | |
949 | ||
950 | Note that @kbd{C-u M-;} is not a distinct key; it is @kbd{M-;} | |
951 | (@code{comment-dwim}) with a prefix argument. That command is | |
952 | programmed so that when it receives a prefix argument it calls | |
953 | @code{comment-kill}. However, @code{comment-kill} is a valid command | |
954 | in its own right, and you can bind it directly to a key if you wish. | |
955 | ||
5b31640c | 956 | Some major modes have special rules for aligning certain kinds of |
6bf7aab6 DL |
957 | comments in certain contexts. For example, in Lisp code, comments which |
958 | start with two semicolons are indented as if they were lines of code, | |
959 | instead of at the comment column. Comments which start with three | |
24a768a0 SM |
960 | semicolons are supposed to start at the left margin and are often used |
961 | for sectioning purposes. Emacs understands | |
6bf7aab6 DL |
962 | these conventions by indenting a double-semicolon comment using @key{TAB}, |
963 | and by not changing the indentation of a triple-semicolon comment at all. | |
964 | ||
965 | @example | |
91ec56a9 | 966 | ;; This function is just an example. |
24a768a0 | 967 | ;;; Here either two or three semicolons are appropriate. |
6bf7aab6 | 968 | (defun foo (x) |
91ec56a9 | 969 | ;;; And now, the first part of the function: |
6bf7aab6 DL |
970 | ;; The following line adds one. |
971 | (1+ x)) ; This line adds one. | |
972 | @end example | |
973 | ||
e722aa81 CY |
974 | For C-like modes, you can configure the exact effect of @kbd{M-;} by |
975 | setting the variables @code{c-indent-comment-alist} and | |
108262a0 AM |
976 | @code{c-indent-comments-syntactically-p}. For example, on a line |
977 | ending in a closing brace, @kbd{M-;} puts the comment one space after | |
978 | the brace rather than at @code{comment-column}. For full details see | |
e722aa81 | 979 | @ref{Comment Commands,,, ccmode, The CC Mode Manual}. |
6bf7aab6 | 980 | |
6bf7aab6 DL |
981 | @node Multi-Line Comments |
982 | @subsection Multiple Lines of Comments | |
983 | ||
984 | @kindex C-M-j | |
7ae8ad94 | 985 | @kindex M-j |
6bf7aab6 | 986 | @cindex blank lines in programs |
47c1b5f4 | 987 | @findex comment-indent-new-line |
108262a0 | 988 | |
6bf7aab6 | 989 | If you are typing a comment and wish to continue it on another line, |
7ae8ad94 | 990 | you can use the command @kbd{C-M-j} or @kbd{M-j} |
f5eb910a RS |
991 | (@code{comment-indent-new-line}). If @code{comment-multi-line} |
992 | (@pxref{Options for Comments}) is non-@code{nil}, it moves to a new | |
993 | line within the comment. Otherwise it closes the comment and starts a | |
994 | new comment on a new line. When Auto Fill mode is on, going past the | |
995 | fill column while typing a comment causes the comment to be continued | |
996 | in just this fashion. | |
7ae8ad94 RS |
997 | |
998 | @kindex C-c C-c (C mode) | |
6bf7aab6 DL |
999 | @findex comment-region |
1000 | To turn existing lines into comment lines, use the @kbd{M-x | |
dfec8297 | 1001 | comment-region} command (or type @kbd{C-c C-c} in C-like modes). It |
108262a0 AM |
1002 | adds comment delimiters to the lines that start in the region, thus |
1003 | commenting them out. With a negative argument, it does the | |
1004 | opposite---it deletes comment delimiters from the lines in the region. | |
6bf7aab6 DL |
1005 | |
1006 | With a positive argument, @code{comment-region} duplicates the last | |
5b31640c RS |
1007 | character of the comment start sequence it adds; the argument |
1008 | specifies how many copies of the character to insert. Thus, in Lisp | |
1009 | mode, @kbd{C-u 2 M-x comment-region} adds @samp{;;} to each line. | |
1010 | Duplicating the comment delimiter is a way of calling attention to the | |
1011 | comment. It can also affect how the comment is aligned or indented. | |
1012 | In Lisp, for proper indentation, you should use an argument of two or | |
1013 | three, if between defuns; if within a defun, it must be three. | |
6bf7aab6 | 1014 | |
108262a0 AM |
1015 | You can configure C Mode such that when you type a @samp{/} at the |
1016 | start of a line in a multi-line block comment, this closes the | |
1017 | comment. Enable the @code{comment-close-slash} clean-up for this. | |
1018 | @xref{Clean-ups,,, ccmode, The CC Mode Manual}. | |
1019 | ||
6bf7aab6 DL |
1020 | @node Options for Comments |
1021 | @subsection Options Controlling Comments | |
1022 | ||
1023 | @vindex comment-column | |
1024 | @kindex C-x ; | |
47c1b5f4 | 1025 | @findex comment-set-column |
7ae8ad94 RS |
1026 | The @dfn{comment column}, the column at which Emacs tries to place |
1027 | comments, is stored in the variable @code{comment-column}. You can | |
1028 | set it to a number explicitly. Alternatively, the command @kbd{C-x ;} | |
1029 | (@code{comment-set-column}) sets the comment column to the column | |
1030 | point is at. @kbd{C-u C-x ;} sets the comment column to match the | |
1031 | last comment before point in the buffer, and then does a @kbd{M-;} to | |
1032 | align the current line's comment under the previous one. | |
6bf7aab6 DL |
1033 | |
1034 | The variable @code{comment-column} is per-buffer: setting the variable | |
1035 | in the normal fashion affects only the current buffer, but there is a | |
1036 | default value which you can change with @code{setq-default}. | |
1037 | @xref{Locals}. Many major modes initialize this variable for the | |
1038 | current buffer. | |
1039 | ||
1040 | @vindex comment-start-skip | |
1041 | The comment commands recognize comments based on the regular | |
1042 | expression that is the value of the variable @code{comment-start-skip}. | |
1043 | Make sure this regexp does not match the null string. It may match more | |
1044 | than the comment starting delimiter in the strictest sense of the word; | |
47c1b5f4 RS |
1045 | for example, in C mode the value of the variable is |
1046 | @c This stops M-q from breaking the line inside that @code. | |
7ae8ad94 | 1047 | @code{@w{"/\\*+ *\\|//+ *"}}, which matches extra stars and spaces |
47c1b5f4 | 1048 | after the @samp{/*} itself, and accepts C++ style comments also. |
6bf7aab6 DL |
1049 | (Note that @samp{\\} is needed in Lisp syntax to include a @samp{\} in |
1050 | the string, which is needed to deny the first star its special meaning | |
bd428736 | 1051 | in regexp syntax. @xref{Regexp Backslash}.) |
6bf7aab6 DL |
1052 | |
1053 | @vindex comment-start | |
1054 | @vindex comment-end | |
1055 | When a comment command makes a new comment, it inserts the value of | |
1056 | @code{comment-start} to begin it. The value of @code{comment-end} is | |
aa2d3478 RS |
1057 | inserted after point, so that it will follow the text that you will |
1058 | insert into the comment. When @code{comment-end} is non-empty, it | |
1059 | should start with a space. For example, in C mode, | |
1060 | @code{comment-start} has the value @w{@code{"/* "}} and | |
1061 | @code{comment-end} has the value @w{@code{" */"}}. | |
6bf7aab6 | 1062 | |
9234c238 RS |
1063 | @vindex comment-padding |
1064 | The variable @code{comment-padding} specifies how many spaces | |
7ae8ad94 RS |
1065 | @code{comment-region} should insert on each line between the comment |
1066 | delimiter and the line's original text. The default is 1, to insert | |
1067 | one space. @code{nil} means 0. Alternatively, @code{comment-padding} | |
1068 | can hold the actual string to insert. | |
9234c238 | 1069 | |
6bf7aab6 DL |
1070 | @vindex comment-multi-line |
1071 | The variable @code{comment-multi-line} controls how @kbd{C-M-j} | |
7ae8ad94 | 1072 | (@code{indent-new-comment-line}) behaves when used inside a comment. |
108262a0 AM |
1073 | Specifically, when @code{comment-multi-line} is @code{nil}, the |
1074 | command inserts a comment terminator, begins a new line, and finally | |
1075 | inserts a comment starter. Otherwise it does not insert the | |
1076 | terminator and starter, so it effectively continues the current | |
1077 | comment across multiple lines. In languages that allow multi-line | |
1078 | comments, the choice of value for this variable is a matter of taste. | |
1079 | The default for this variable depends on the major mode. | |
6bf7aab6 | 1080 | |
4190ce5c | 1081 | @vindex comment-indent-function |
6bf7aab6 | 1082 | The variable @code{comment-indent-function} should contain a function |
5b31640c | 1083 | that will be called to compute the alignment for a newly inserted |
6bf7aab6 DL |
1084 | comment or for aligning an existing comment. It is set differently by |
1085 | various major modes. The function is called with no arguments, but with | |
1086 | point at the beginning of the comment, or at the end of a line if a new | |
1087 | comment is to be inserted. It should return the column in which the | |
1088 | comment ought to start. For example, in Lisp mode, the indent hook | |
1089 | function bases its decision on how many semicolons begin an existing | |
1090 | comment, and on the code in the preceding lines. | |
1091 | ||
93da5dff RS |
1092 | @node Documentation |
1093 | @section Documentation Lookup | |
6bf7aab6 | 1094 | |
93da5dff RS |
1095 | Emacs provides several features you can use to look up the |
1096 | documentation of functions, variables and commands that you plan to | |
1097 | use in your program. | |
6bf7aab6 | 1098 | |
93da5dff RS |
1099 | @menu |
1100 | * Info Lookup:: Looking up library functions and commands | |
1101 | in Info files. | |
1102 | * Man Page:: Looking up man pages of library functions and commands. | |
1103 | * Lisp Doc:: Looking up Emacs Lisp functions, etc. | |
1104 | @end menu | |
6bf7aab6 | 1105 | |
93da5dff RS |
1106 | @node Info Lookup |
1107 | @subsection Info Documentation Lookup | |
85750656 | 1108 | |
93da5dff RS |
1109 | @findex info-lookup-symbol |
1110 | @findex info-lookup-file | |
d2f9ea87 | 1111 | @kindex C-h S |
e722aa81 CY |
1112 | For major modes that apply to languages which have documentation in |
1113 | Info, you can use @kbd{C-h S} (@code{info-lookup-symbol}) to view the | |
1114 | Info documentation for a symbol used in the program. You specify the | |
1115 | symbol with the minibuffer; the default is the symbol appearing in the | |
1116 | buffer at point. For example, in C mode this looks for the symbol in | |
1117 | the C Library Manual. The command only works if the appropriate | |
1118 | manual's Info files are installed. | |
6bf7aab6 | 1119 | |
93da5dff RS |
1120 | The major mode determines where to look for documentation for the |
1121 | symbol---which Info files to look in, and which indices to search. | |
1122 | You can also use @kbd{M-x info-lookup-file} to look for documentation | |
1123 | for a file name. | |
6bf7aab6 | 1124 | |
dfec8297 | 1125 | If you use @kbd{C-h S} in a major mode that does not support it, |
5a7f4c1b | 1126 | it asks you to specify the ``symbol help mode.'' You should enter |
dfec8297 RS |
1127 | a command such as @code{c-mode} that would select a major |
1128 | mode which @kbd{C-h S} does support. | |
6bf7aab6 | 1129 | |
93da5dff RS |
1130 | @node Man Page |
1131 | @subsection Man Page Lookup | |
6bf7aab6 | 1132 | |
e79c6b89 RS |
1133 | @cindex manual page |
1134 | On Unix, the main form of on-line documentation was the @dfn{manual | |
dfec8297 | 1135 | page} or @dfn{man page}. In the GNU operating system, we aim to |
e79c6b89 RS |
1136 | replace man pages with better-organized manuals that you can browse |
1137 | with Info (@pxref{Misc Help}). This process is not finished, so it is | |
1138 | still useful to read manual pages. | |
6bf7aab6 | 1139 | |
93da5dff | 1140 | @findex manual-entry |
e79c6b89 | 1141 | You can read the man page for an operating system command, library |
7ae8ad94 | 1142 | function, or system call, with the @kbd{M-x man} command. It |
e79c6b89 RS |
1143 | runs the @code{man} program to format the man page; if the system |
1144 | permits, it runs @code{man} asynchronously, so that you can keep on | |
1145 | editing while the page is being formatted. (On MS-DOS and MS-Windows | |
1146 | 3, you cannot edit while Emacs waits for @code{man} to finish.) The | |
1147 | result goes in a buffer named @samp{*Man @var{topic}*}. These buffers | |
1148 | use a special major mode, Man mode, that facilitates scrolling and | |
1149 | jumping to other manual pages. For details, type @kbd{C-h m} while in | |
1150 | a man page buffer. | |
6bf7aab6 | 1151 | |
93da5dff | 1152 | @cindex sections of manual pages |
e79c6b89 RS |
1153 | Each man page belongs to one of ten or more @dfn{sections}, each |
1154 | named by a digit or by a digit and a letter. Sometimes there are | |
1155 | multiple man pages with the same name in different sections. To read | |
1156 | a man page from a specific section, type | |
93da5dff RS |
1157 | @samp{@var{topic}(@var{section})} or @samp{@var{section} @var{topic}} |
1158 | when @kbd{M-x manual-entry} prompts for the topic. For example, to | |
1159 | read the man page for the C library function @code{chmod} (as opposed | |
e79c6b89 | 1160 | to a command of the same name), type @kbd{M-x manual-entry @key{RET} |
dfec8297 RS |
1161 | chmod(2) @key{RET}}. (@code{chmod} is a system call, so it is in |
1162 | section @samp{2}.) | |
6bf7aab6 | 1163 | |
08220274 | 1164 | @vindex Man-switches |
93da5dff | 1165 | If you do not specify a section, the results depend on how the |
08220274 | 1166 | @code{man} program works on your system. Some of them display only |
93da5dff RS |
1167 | the first man page they find. Others display all man pages that have |
1168 | the specified name, so you can move between them with the @kbd{M-n} | |
08220274 EZ |
1169 | and @kbd{M-p} keys@footnote{On some systems, the @code{man} program |
1170 | accepts a @samp{-a} command-line option which tells it to display all | |
1171 | the man pages for the specified topic. If you want this behavior, you | |
1172 | can add this option to the value of the variable @code{Man-switches}.}. | |
1173 | The mode line shows how many manual pages are present in the Man buffer. | |
6bf7aab6 | 1174 | |
93da5dff | 1175 | @vindex Man-fontify-manpage-flag |
e79c6b89 RS |
1176 | By default, Emacs highlights the text in man pages. For a long man |
1177 | page, highlighting can take substantial time. You can turn off | |
1178 | highlighting of man pages by setting the variable | |
1179 | @code{Man-fontify-manpage-flag} to @code{nil}. | |
6bf7aab6 | 1180 | |
93da5dff RS |
1181 | @findex Man-fontify-manpage |
1182 | If you insert the text of a man page into an Emacs buffer in some | |
1183 | other fashion, you can use the command @kbd{M-x Man-fontify-manpage} to | |
1184 | perform the same conversions that @kbd{M-x manual-entry} does. | |
1185 | ||
1186 | @findex woman | |
1187 | @cindex manual pages, on MS-DOS/MS-Windows | |
1188 | An alternative way of reading manual pages is the @kbd{M-x woman} | |
1189 | command@footnote{The name of the command, @code{woman}, is an acronym | |
1190 | for ``w/o (without) man,'' since it doesn't use the @code{man} | |
1191 | program.}. Unlike @kbd{M-x man}, it does not run any external | |
1192 | programs to format and display the man pages; instead it does the job | |
1193 | in Emacs Lisp, so it works on systems such as MS-Windows, where the | |
ea118de1 | 1194 | @code{man} program (and other programs it uses) are not generally |
d2fab838 RS |
1195 | available. |
1196 | ||
1197 | @kbd{M-x woman} prompts for a name of a manual page, and provides | |
1198 | completion based on the list of manual pages that are installed on | |
1199 | your machine; the list of available manual pages is computed | |
1200 | automatically the first time you invoke @code{woman}. The word at | |
1201 | point in the current buffer is used to suggest the default for the | |
1202 | name the manual page. | |
93da5dff RS |
1203 | |
1204 | With a numeric argument, @kbd{M-x woman} recomputes the list of the | |
1205 | manual pages used for completion. This is useful if you add or delete | |
1206 | manual pages. | |
1207 | ||
1208 | If you type a name of a manual page and @kbd{M-x woman} finds that | |
1209 | several manual pages by the same name exist in different sections, it | |
1210 | pops up a window with possible candidates asking you to choose one of | |
1211 | them. | |
1212 | ||
93da5dff RS |
1213 | For more information about setting up and using @kbd{M-x woman}, see |
1214 | @ref{Top, WoMan, Browse UN*X Manual Pages WithOut Man, woman, The WoMan | |
1215 | Manual}. | |
1216 | ||
1217 | @node Lisp Doc | |
1218 | @subsection Emacs Lisp Documentation Lookup | |
1219 | ||
1220 | As you edit Lisp code to be run in Emacs, you can use the commands | |
1221 | @kbd{C-h f} (@code{describe-function}) and @kbd{C-h v} | |
1222 | (@code{describe-variable}) to view documentation of functions and | |
1223 | variables that you want to use. These commands use the minibuffer to | |
1224 | read the name of a function or variable to document, and display the | |
1225 | documentation in a window. Their default arguments are based on the | |
1226 | code in the neighborhood of point. For @kbd{C-h f}, the default is | |
1227 | the function called in the innermost list containing point. @kbd{C-h | |
1228 | v} uses the symbol name around or adjacent to point as its default. | |
1229 | ||
1230 | @cindex Eldoc mode | |
1231 | @findex eldoc-mode | |
1232 | A more automatic but less powerful method is Eldoc mode. This minor | |
1233 | mode constantly displays in the echo area the argument list for the | |
1234 | function being called at point. (In other words, it finds the | |
1235 | function call that point is contained in, and displays the argument | |
054af0fd | 1236 | list of that function.) If point is over a documented variable, it |
ea802fce LT |
1237 | shows the first line of the variable's docstring. Eldoc mode applies |
1238 | in Emacs Lisp and Lisp Interaction modes, and perhaps a few others | |
1239 | that provide special support for looking up doc strings. Use the | |
1240 | command @kbd{M-x eldoc-mode} to enable or disable this feature. | |
6bf7aab6 | 1241 | |
51ed0ea0 DL |
1242 | @node Hideshow |
1243 | @section Hideshow minor mode | |
1244 | ||
1245 | @findex hs-minor-mode | |
9234c238 | 1246 | Hideshow minor mode provides selective display of portions of a |
93da5dff RS |
1247 | program, known as @dfn{blocks}. You can use @kbd{M-x hs-minor-mode} |
1248 | to enable or disable this mode, or add @code{hs-minor-mode} to the | |
1249 | mode hook for certain major modes in order to enable it automatically | |
1250 | for those modes. | |
51ed0ea0 | 1251 | |
9234c238 RS |
1252 | Just what constitutes a block depends on the major mode. In C mode |
1253 | or C++ mode, they are delimited by braces, while in Lisp mode and | |
1254 | similar modes they are delimited by parentheses. Multi-line comments | |
1255 | also count as blocks. | |
51ed0ea0 DL |
1256 | |
1257 | @findex hs-hide-all | |
1258 | @findex hs-hide-block | |
1259 | @findex hs-show-all | |
1260 | @findex hs-show-block | |
1261 | @findex hs-show-region | |
1262 | @findex hs-hide-level | |
1263 | @findex hs-minor-mode | |
6401dc86 EZ |
1264 | @kindex C-c @@ C-h |
1265 | @kindex C-c @@ C-s | |
1266 | @kindex C-c @@ C-M-h | |
1267 | @kindex C-c @@ C-M-s | |
1268 | @kindex C-c @@ C-r | |
1269 | @kindex C-c @@ C-l | |
9234c238 RS |
1270 | @kindex S-Mouse-2 |
1271 | @table @kbd | |
6401dc86 | 1272 | @item C-c @@ C-h |
9234c238 | 1273 | Hide the current block (@code{hs-hide-block}). |
6401dc86 | 1274 | @item C-c @@ C-s |
9234c238 | 1275 | Show the current block (@code{hs-show-block}). |
6401dc86 | 1276 | @item C-c @@ C-c |
ea118de1 | 1277 | Either hide or show the current block (@code{hs-toggle-hiding}). |
9234c238 | 1278 | @item S-Mouse-2 |
ea118de1 | 1279 | Either hide or show the block you click on (@code{hs-mouse-toggle-hiding}). |
6401dc86 | 1280 | @item C-c @@ C-M-h |
9234c238 | 1281 | Hide all top-level blocks (@code{hs-hide-all}). |
6401dc86 | 1282 | @item C-c @@ C-M-s |
9234c238 | 1283 | Show everything in the buffer (@code{hs-show-all}). |
6401dc86 | 1284 | @item C-c @@ C-l |
9234c238 RS |
1285 | Hide all blocks @var{n} levels below this block |
1286 | (@code{hs-hide-level}). | |
1287 | @end table | |
51ed0ea0 DL |
1288 | |
1289 | @vindex hs-hide-comments-when-hiding-all | |
51ed0ea0 DL |
1290 | @vindex hs-isearch-open |
1291 | @vindex hs-special-modes-alist | |
19b2c4ca | 1292 | These variables exist for customizing Hideshow mode. |
9234c238 | 1293 | |
51ed0ea0 DL |
1294 | @table @code |
1295 | @item hs-hide-comments-when-hiding-all | |
9234c238 | 1296 | Non-@code{nil} says that @kbd{hs-hide-all} should hide comments too. |
d2fab838 | 1297 | |
51ed0ea0 | 1298 | @item hs-isearch-open |
dfec8297 RS |
1299 | Specifies what kind of hidden blocks incremental search should make |
1300 | visible. The value should be one of these four symbols: | |
d2fab838 RS |
1301 | |
1302 | @table @code | |
9198a323 RS |
1303 | @item code |
1304 | Open only code blocks. | |
d2fab838 RS |
1305 | @item comment |
1306 | Open only comments. | |
1307 | @item t | |
9198a323 | 1308 | Open both code blocks and comments. |
d2fab838 | 1309 | @item nil |
9198a323 | 1310 | Open neither code blocks nor comments. |
d2fab838 RS |
1311 | @end table |
1312 | ||
51ed0ea0 | 1313 | @item hs-special-modes-alist |
e79c6b89 | 1314 | A list of elements, each specifying how to initialize Hideshow |
d2fab838 RS |
1315 | variables for one major mode. See the variable's documentation string |
1316 | for more information. | |
51ed0ea0 DL |
1317 | @end table |
1318 | ||
93da5dff RS |
1319 | @node Symbol Completion |
1320 | @section Completion for Symbol Names | |
1321 | @cindex completion (symbol names) | |
3b8b8888 | 1322 | |
e722aa81 CY |
1323 | In Emacs, completion is something you normally do in the minibuffer |
1324 | (@pxref{Completion}). But one kind of completion is available in all | |
1325 | buffers: completion for symbol names. | |
3b8b8888 | 1326 | |
93da5dff | 1327 | @kindex M-TAB |
e79c6b89 RS |
1328 | The character @kbd{M-@key{TAB}} runs a command to complete the |
1329 | partial symbol before point against the set of meaningful symbol | |
1330 | names. This command inserts at point any additional characters that | |
3a8d6df3 RS |
1331 | it can determine from the partial name. |
1332 | ||
1333 | If your window manager defines @kbd{M-@key{TAB}} to switch windows, | |
1334 | you can type @kbd{@key{ESC} @key{TAB}} or @kbd{C-M-i} instead. | |
8474de5b CY |
1335 | However, most window managers let you customize these shortcuts, so |
1336 | you can change any that interfere with the way you use Emacs. | |
6bf7aab6 | 1337 | |
e79c6b89 RS |
1338 | If the partial name in the buffer has multiple possible completions |
1339 | that differ in the very next character, so that it is impossible to | |
1340 | complete even one more character, @kbd{M-@key{TAB}} displays a list of | |
1341 | all possible completions in another window. | |
6bf7aab6 | 1342 | |
93da5dff RS |
1343 | @cindex tags-based completion |
1344 | @cindex Info index completion | |
1345 | @findex complete-symbol | |
1346 | In most programming language major modes, @kbd{M-@key{TAB}} runs the | |
1347 | command @code{complete-symbol}, which provides two kinds of completion. | |
1348 | Normally it does completion based on a tags table (@pxref{Tags}); with a | |
1349 | numeric argument (regardless of the value), it does completion based on | |
1350 | the names listed in the Info file indexes for your language. Thus, to | |
1351 | complete the name of a symbol defined in your own program, use | |
1352 | @kbd{M-@key{TAB}} with no argument; to complete the name of a standard | |
1353 | library function, use @kbd{C-u M-@key{TAB}}. Of course, Info-based | |
1354 | completion works only if there is an Info file for the standard library | |
1355 | functions of your language, and only if it is installed at your site. | |
6bf7aab6 | 1356 | |
93da5dff RS |
1357 | @cindex Lisp symbol completion |
1358 | @cindex completion (Lisp symbols) | |
1359 | @findex lisp-complete-symbol | |
1360 | In Emacs-Lisp mode, the name space for completion normally consists of | |
1361 | nontrivial symbols present in Emacs---those that have function | |
1362 | definitions, values or properties. However, if there is an | |
1363 | open-parenthesis immediately before the beginning of the partial symbol, | |
1364 | only symbols with function definitions are considered as completions. | |
1365 | The command which implements this is @code{lisp-complete-symbol}. | |
6bf7aab6 | 1366 | |
93da5dff RS |
1367 | In Text mode and related modes, @kbd{M-@key{TAB}} completes words |
1368 | based on the spell-checker's dictionary. @xref{Spelling}. | |
6bf7aab6 | 1369 | |
93da5dff RS |
1370 | @node Glasses |
1371 | @section Glasses minor mode | |
1372 | @cindex Glasses mode | |
1373 | @cindex identifiers, making long ones readable | |
1374 | @cindex StudlyCaps, making them readable | |
1375 | @findex glasses-mode | |
6bf7aab6 | 1376 | |
93da5dff | 1377 | Glasses minor mode makes @samp{unreadableIdentifiersLikeThis} |
e79c6b89 RS |
1378 | readable by altering the way they display. It knows two different |
1379 | ways to do this: by displaying underscores between a lower-case letter | |
1380 | and the following capital letter, and by emboldening the capital | |
1381 | letters. It does not alter the buffer text, only the way they | |
1382 | display, so you can use it even on read-only buffers. You can use the | |
1383 | command @kbd{M-x glasses-mode} to enable or disable the mode in the | |
1384 | current buffer; you can also add @code{glasses-mode} to the mode hook | |
1385 | of the programming language major modes in which you normally want | |
177c0ea7 | 1386 | to use Glasses mode. |
6bf7aab6 | 1387 | |
93da5dff RS |
1388 | @node Misc for Programs |
1389 | @section Other Features Useful for Editing Programs | |
6bf7aab6 | 1390 | |
93da5dff | 1391 | A number of Emacs commands that aren't designed specifically for |
e79c6b89 | 1392 | editing programs are useful for that nonetheless. |
6bf7aab6 | 1393 | |
93da5dff RS |
1394 | The Emacs commands that operate on words, sentences and paragraphs |
1395 | are useful for editing code. Most symbols names contain words | |
1396 | (@pxref{Words}); sentences can be found in strings and comments | |
e79c6b89 | 1397 | (@pxref{Sentences}). Paragraphs in the strict sense can be found in |
93da5dff RS |
1398 | program code (in long comments), but the paragraph commands are useful |
1399 | in other places too, because programming language major modes define | |
1400 | paragraphs to begin and end at blank lines (@pxref{Paragraphs}). | |
1401 | Judicious use of blank lines to make the program clearer will also | |
1402 | provide useful chunks of text for the paragraph commands to work on. | |
1403 | Auto Fill mode, if enabled in a programming language major mode, | |
1404 | indents the new lines which it creates. | |
6bf7aab6 | 1405 | |
93da5dff RS |
1406 | The selective display feature is useful for looking at the overall |
1407 | structure of a function (@pxref{Selective Display}). This feature | |
1408 | hides the lines that are indented more than a specified amount. | |
1409 | Programming modes often support Outline minor mode (@pxref{Outline | |
1410 | Mode}). The Foldout package provides folding-editor features | |
1411 | (@pxref{Foldout}). | |
6bf7aab6 | 1412 | |
93da5dff RS |
1413 | The ``automatic typing'' features may be useful for writing programs. |
1414 | @xref{Top,,Autotyping, autotype, Autotyping}. | |
6bf7aab6 DL |
1415 | |
1416 | @node C Modes | |
1417 | @section C and Related Modes | |
1418 | @cindex C mode | |
1419 | @cindex Java mode | |
1420 | @cindex Pike mode | |
1421 | @cindex IDL mode | |
1422 | @cindex CORBA IDL mode | |
1423 | @cindex Objective C mode | |
1424 | @cindex C++ mode | |
7ae8ad94 | 1425 | @cindex AWK mode |
6bf7aab6 DL |
1426 | @cindex mode, Java |
1427 | @cindex mode, C | |
7ae8ad94 | 1428 | @cindex mode, C++ |
6bf7aab6 DL |
1429 | @cindex mode, Objective C |
1430 | @cindex mode, CORBA IDL | |
1431 | @cindex mode, Pike | |
7ae8ad94 | 1432 | @cindex mode, AWK |
6bf7aab6 | 1433 | |
9234c238 | 1434 | This section gives a brief description of the special features |
7ae8ad94 | 1435 | available in C, C++, Objective-C, Java, CORBA IDL, Pike and AWK modes. |
5d80fe1f EZ |
1436 | (These are called ``C mode and related modes.'') @xref{Top, , CC Mode, |
1437 | ccmode, CC Mode}, for a more extensive description of these modes | |
9234c238 | 1438 | and their special features. |
51ed0ea0 | 1439 | |
6bf7aab6 | 1440 | @menu |
7ae8ad94 RS |
1441 | * Motion in C:: Commands to move by C statements, etc. |
1442 | * Electric C:: Colon and other chars can automatically reindent. | |
1443 | * Hungry Delete:: A more powerful DEL command. | |
1444 | * Other C Commands:: Filling comments, viewing expansion of macros, | |
1445 | and other neat features. | |
6bf7aab6 DL |
1446 | @end menu |
1447 | ||
1448 | @node Motion in C | |
1449 | @subsection C Mode Motion Commands | |
1450 | ||
1451 | This section describes commands for moving point, in C mode and | |
1452 | related modes. | |
1453 | ||
1454 | @table @code | |
7ae8ad94 RS |
1455 | @item M-x c-beginning-of-defun |
1456 | @itemx M-x c-end-of-defun | |
1457 | @findex c-beginning-of-defun | |
1458 | @findex c-end-of-defun | |
1459 | Move point to the beginning or end of the current function or | |
1460 | top-level definition. These are found by searching for the least | |
1461 | enclosing braces. (By contrast, @code{beginning-of-defun} and | |
1462 | @code{end-of-defun} search for braces in column zero.) If you are | |
1463 | editing code where the opening brace of a function isn't placed in | |
1464 | column zero, you may wish to bind @code{C-M-a} and @code{C-M-e} to | |
1465 | these commands. @xref{Moving by Defuns}. | |
1466 | ||
6bf7aab6 DL |
1467 | @item C-c C-u |
1468 | @kindex C-c C-u @r{(C mode)} | |
1469 | @findex c-up-conditional | |
1470 | Move point back to the containing preprocessor conditional, leaving the | |
1471 | mark behind. A prefix argument acts as a repeat count. With a negative | |
1472 | argument, move point forward to the end of the containing | |
7ae8ad94 RS |
1473 | preprocessor conditional. |
1474 | ||
1475 | @samp{#elif} is equivalent to @samp{#else} followed by @samp{#if}, so | |
1476 | the function will stop at a @samp{#elif} when going backward, but not | |
1477 | when going forward. | |
6bf7aab6 DL |
1478 | |
1479 | @item C-c C-p | |
1480 | @kindex C-c C-p @r{(C mode)} | |
1481 | @findex c-backward-conditional | |
1482 | Move point back over a preprocessor conditional, leaving the mark | |
1483 | behind. A prefix argument acts as a repeat count. With a negative | |
1484 | argument, move forward. | |
1485 | ||
1486 | @item C-c C-n | |
1487 | @kindex C-c C-n @r{(C mode)} | |
1488 | @findex c-forward-conditional | |
1489 | Move point forward across a preprocessor conditional, leaving the mark | |
1490 | behind. A prefix argument acts as a repeat count. With a negative | |
1491 | argument, move backward. | |
1492 | ||
1493 | @item M-a | |
7ae8ad94 | 1494 | @kindex M-a (C mode) |
6bf7aab6 DL |
1495 | @findex c-beginning-of-statement |
1496 | Move point to the beginning of the innermost C statement | |
1497 | (@code{c-beginning-of-statement}). If point is already at the beginning | |
1498 | of a statement, move to the beginning of the preceding statement. With | |
1499 | prefix argument @var{n}, move back @var{n} @minus{} 1 statements. | |
1500 | ||
7ae8ad94 RS |
1501 | In comments or in strings which span more than one line, this command |
1502 | moves by sentences instead of statements. | |
6bf7aab6 DL |
1503 | |
1504 | @item M-e | |
7ae8ad94 | 1505 | @kindex M-e (C mode) |
6bf7aab6 | 1506 | @findex c-end-of-statement |
7ae8ad94 RS |
1507 | Move point to the end of the innermost C statement or sentence; like |
1508 | @kbd{M-a} except that it moves in the other direction | |
1509 | (@code{c-end-of-statement}). | |
6bf7aab6 DL |
1510 | @end table |
1511 | ||
1512 | @node Electric C | |
1513 | @subsection Electric C Characters | |
1514 | ||
1515 | In C mode and related modes, certain printing characters are | |
108262a0 AM |
1516 | @dfn{electric}---in addition to inserting themselves, they also |
1517 | reindent the current line, and optionally also insert newlines. The | |
64e207c0 RS |
1518 | ``electric'' characters are @kbd{@{}, @kbd{@}}, @kbd{:}, @kbd{#}, |
1519 | @kbd{;}, @kbd{,}, @kbd{<}, @kbd{>}, @kbd{/}, @kbd{*}, @kbd{(}, and | |
f5eb910a | 1520 | @kbd{)}. |
108262a0 AM |
1521 | |
1522 | You might find electric indentation inconvenient if you are editing | |
1523 | chaotically indented code. If you are new to CC Mode, you might find | |
1524 | it disconcerting. You can toggle electric action with the command | |
1525 | @kbd{C-c C-l}; when it is enabled, @samp{/l} appears in the mode line | |
1526 | after the mode name: | |
6bf7aab6 | 1527 | |
108262a0 AM |
1528 | @table @kbd |
1529 | @item C-c C-l | |
1530 | @kindex C-c C-l @r{(C mode)} | |
1531 | @findex c-toggle-electric-state | |
1532 | Toggle electric action (@code{c-toggle-electric-state}). With a | |
1533 | prefix argument, this command enables electric action if the argument | |
1534 | is positive, disables it if it is negative. | |
1535 | @end table | |
1536 | ||
1537 | Electric characters insert newlines only when, in addition to the | |
1538 | electric state, the @dfn{auto-newline} feature is enabled (indicated | |
1539 | by @samp{/la} in the mode line after the mode name). You can turn | |
1540 | this feature on or off with the command @kbd{C-c C-a}: | |
6bf7aab6 DL |
1541 | |
1542 | @table @kbd | |
1543 | @item C-c C-a | |
1544 | @kindex C-c C-a @r{(C mode)} | |
108262a0 AM |
1545 | @findex c-toggle-auto-newline |
1546 | Toggle the auto-newline feature (@code{c-toggle-auto-newline}). With a | |
6bf7aab6 DL |
1547 | prefix argument, this command turns the auto-newline feature on if the |
1548 | argument is positive, and off if it is negative. | |
1549 | @end table | |
1550 | ||
f5eb910a RS |
1551 | Usually the CC Mode style configures the exact circumstances in |
1552 | which Emacs inserts auto-newlines. You can also configure this | |
1553 | directly. @xref{Custom Auto-newlines,,, ccmode, The CC Mode Manual}. | |
6bf7aab6 DL |
1554 | |
1555 | @node Hungry Delete | |
1556 | @subsection Hungry Delete Feature in C | |
7ae8ad94 | 1557 | @cindex hungry deletion (C Mode) |
6bf7aab6 | 1558 | |
108262a0 AM |
1559 | If you want to delete an entire block of whitespace at point, you |
1560 | can use @dfn{hungry deletion}. This deletes all the contiguous | |
1561 | whitespace either before point or after point in a single operation. | |
1562 | @dfn{Whitespace} here includes tabs and newlines, but not comments or | |
1563 | preprocessor commands. | |
6bf7aab6 DL |
1564 | |
1565 | @table @kbd | |
69d271a7 AM |
1566 | @item C-c C-@key{DEL} |
1567 | @itemx C-c @key{DEL} | |
aca2cfd2 | 1568 | @findex c-hungry-delete-backwards |
69d271a7 AM |
1569 | @kindex C-c C-@key{DEL} (C Mode) |
1570 | @kindex C-c @key{DEL} (C Mode) | |
aca2cfd2 | 1571 | @code{c-hungry-delete-backwards}---Delete the entire block of whitespace |
108262a0 AM |
1572 | preceding point. |
1573 | ||
6bf7aab6 | 1574 | @item C-c C-d |
69d271a7 AM |
1575 | @itemx C-c C-@key{DELETE} |
1576 | @itemx C-c @key{DELETE} | |
108262a0 AM |
1577 | @findex c-hungry-delete-forward |
1578 | @kindex C-c C-d (C Mode) | |
69d271a7 AM |
1579 | @kindex C-c C-@key{DELETE} (C Mode) |
1580 | @kindex C-c @key{DELETE} (C Mode) | |
108262a0 AM |
1581 | @code{c-hungry-delete-forward}---Delete the entire block of whitespace |
1582 | following point. | |
1583 | @end table | |
1584 | ||
1585 | As an alternative to the above commands, you can enable @dfn{hungry | |
1586 | delete mode}. When this feature is enabled (indicated by @samp{/h} in | |
d884be12 RS |
1587 | the mode line after the mode name), a single @key{DEL} deletes all |
1588 | preceding whitespace, not just one space, and a single @kbd{C-c C-d} | |
1589 | (but @emph{not} plain @key{DELETE}) deletes all following whitespace. | |
6bf7aab6 | 1590 | |
108262a0 AM |
1591 | @table @kbd |
1592 | @item M-x c-toggle-hungry-state | |
1593 | @findex c-toggle-hungry-state | |
1594 | Toggle the hungry-delete feature | |
1595 | (@code{c-toggle-hungry-state})@footnote{This command had the binding | |
1596 | @kbd{C-c C-d} in earlier versions of Emacs. @kbd{C-c C-d} is now | |
1597 | bound to @code{c-hungry-delete-forward}.}. With a prefix argument, | |
1598 | this command turns the hungry-delete feature on if the argument is | |
1599 | positive, and off if it is negative. | |
6bf7aab6 DL |
1600 | @end table |
1601 | ||
1602 | @vindex c-hungry-delete-key | |
1603 | The variable @code{c-hungry-delete-key} controls whether the | |
1604 | hungry-delete feature is enabled. | |
1605 | ||
1606 | @node Other C Commands | |
1607 | @subsection Other Commands for C Mode | |
1608 | ||
1609 | @table @kbd | |
108262a0 AM |
1610 | @item C-c C-w |
1611 | @itemx M-x c-subword-mode | |
1612 | @findex c-subword-mode | |
f5eb910a | 1613 | Enable (or disable) @dfn{subword mode}. In subword mode, Emacs's word |
8a75579f | 1614 | commands recognize upper case letters in |
f5eb910a RS |
1615 | @samp{StudlyCapsIdentifiers} as word boundaries. This is indicated by |
1616 | the flag @samp{/w} on the mode line after the mode name | |
1617 | (e.g. @samp{C/law}). You can even use @kbd{M-x c-subword-mode} in | |
1618 | non-CC Mode buffers. | |
108262a0 | 1619 | |
dfec8297 RS |
1620 | In the GNU project, we recommend using underscores to separate words |
1621 | within an identifier in C or C++, rather than using case distinctions. | |
1622 | ||
7ae8ad94 RS |
1623 | @item M-x c-context-line-break |
1624 | @findex c-context-line-break | |
1625 | This command inserts a line break and indents the new line in a manner | |
1626 | appropriate to the context. In normal code, it does the work of | |
1627 | @kbd{C-j} (@code{newline-and-indent}), in a C preprocessor line it | |
1628 | additionally inserts a @samp{\} at the line break, and within comments | |
1629 | it's like @kbd{M-j} (@code{c-indent-new-comment-line}). | |
1630 | ||
1631 | @code{c-context-line-break} isn't bound to a key by default, but it | |
1632 | needs a binding to be useful. The following code will bind it to | |
108262a0 AM |
1633 | @kbd{C-j}. We use @code{c-initialization-hook} here to make sure |
1634 | the keymap is loaded before we try to change it. | |
1635 | ||
444246ca | 1636 | @smallexample |
108262a0 AM |
1637 | (defun my-bind-clb () |
1638 | (define-key c-mode-base-map "\C-j" 'c-context-line-break)) | |
1639 | (add-hook 'c-initialization-hook 'my-bind-clb) | |
444246ca | 1640 | @end smallexample |
7ae8ad94 | 1641 | |
6bf7aab6 | 1642 | @item C-M-h |
6bf7aab6 DL |
1643 | Put mark at the end of a function definition, and put point at the |
1644 | beginning (@code{c-mark-function}). | |
1645 | ||
1646 | @item M-q | |
1647 | @kindex M-q @r{(C mode)} | |
1648 | @findex c-fill-paragraph | |
1649 | Fill a paragraph, handling C and C++ comments (@code{c-fill-paragraph}). | |
1650 | If any part of the current line is a comment or within a comment, this | |
1651 | command fills the comment or the paragraph of it that point is in, | |
1652 | preserving the comment indentation and comment delimiters. | |
1653 | ||
1654 | @item C-c C-e | |
1655 | @cindex macro expansion in C | |
1656 | @cindex expansion of C macros | |
1657 | @findex c-macro-expand | |
1658 | @kindex C-c C-e @r{(C mode)} | |
1659 | Run the C preprocessor on the text in the region, and show the result, | |
1660 | which includes the expansion of all the macro calls | |
1661 | (@code{c-macro-expand}). The buffer text before the region is also | |
1662 | included in preprocessing, for the sake of macros defined there, but the | |
1663 | output from this part isn't shown. | |
1664 | ||
1665 | When you are debugging C code that uses macros, sometimes it is hard to | |
1666 | figure out precisely how the macros expand. With this command, you | |
1667 | don't have to figure it out; you can see the expansions. | |
1668 | ||
1669 | @item C-c C-\ | |
1670 | @findex c-backslash-region | |
1671 | @kindex C-c C-\ @r{(C mode)} | |
1672 | Insert or align @samp{\} characters at the ends of the lines of the | |
1673 | region (@code{c-backslash-region}). This is useful after writing or | |
1674 | editing a C macro definition. | |
1675 | ||
1676 | If a line already ends in @samp{\}, this command adjusts the amount of | |
1677 | whitespace before it. Otherwise, it inserts a new @samp{\}. However, | |
1678 | the last line in the region is treated specially; no @samp{\} is | |
1679 | inserted on that line, and any @samp{\} there is deleted. | |
1680 | ||
1681 | @item M-x cpp-highlight-buffer | |
1682 | @cindex preprocessor highlighting | |
1683 | @findex cpp-highlight-buffer | |
1684 | Highlight parts of the text according to its preprocessor conditionals. | |
1685 | This command displays another buffer named @samp{*CPP Edit*}, which | |
1686 | serves as a graphic menu for selecting how to display particular kinds | |
1687 | of conditionals and their contents. After changing various settings, | |
1688 | click on @samp{[A]pply these settings} (or go to that buffer and type | |
1689 | @kbd{a}) to rehighlight the C mode buffer accordingly. | |
1690 | ||
1691 | @item C-c C-s | |
1692 | @findex c-show-syntactic-information | |
1693 | @kindex C-c C-s @r{(C mode)} | |
1694 | Display the syntactic information about the current source line | |
054af0fd SE |
1695 | (@code{c-show-syntactic-information}). This information directs how |
1696 | the line is indented. | |
3b8b8888 DL |
1697 | |
1698 | @item M-x cwarn-mode | |
1699 | @itemx M-x global-cwarn-mode | |
1700 | @findex cwarn-mode | |
1701 | @findex global-cwarn-mode | |
7ae8ad94 | 1702 | @vindex global-cwarn-mode |
3b8b8888 DL |
1703 | @cindex CWarn mode |
1704 | @cindex suspicious constructions in C, C++ | |
9234c238 | 1705 | CWarn minor mode highlights certain suspicious C and C++ constructions: |
3b8b8888 DL |
1706 | |
1707 | @itemize @bullet{} | |
1708 | @item | |
9234c238 | 1709 | Assignments inside expressions. |
3b8b8888 DL |
1710 | @item |
1711 | Semicolon following immediately after @samp{if}, @samp{for}, and @samp{while} | |
1712 | (except after a @samp{do @dots{} while} statement); | |
1713 | @item | |
1714 | C++ functions with reference parameters. | |
1715 | @end itemize | |
1716 | ||
1717 | @noindent | |
9234c238 RS |
1718 | You can enable the mode for one buffer with the command @kbd{M-x |
1719 | cwarn-mode}, or for all suitable buffers with the command @kbd{M-x | |
1720 | global-cwarn-mode} or by customizing the variable | |
1721 | @code{global-cwarn-mode}. You must also enable Font Lock mode to make | |
1722 | it work. | |
3b8b8888 DL |
1723 | |
1724 | @item M-x hide-ifdef-mode | |
1725 | @findex hide-ifdef-mode | |
1726 | @cindex Hide-ifdef mode | |
8474de5b | 1727 | @vindex hide-ifdef-shadow |
3b8b8888 | 1728 | Hide-ifdef minor mode hides selected code within @samp{#if} and |
8474de5b CY |
1729 | @samp{#ifdef} preprocessor blocks. If you change the variable |
1730 | @code{hide-ifdef-shadow} to @code{t}, Hide-ifdef minor mode | |
1731 | ``shadows'' preprocessor blocks by displaying them with a less | |
1732 | prominent face, instead of hiding them entirely. See the | |
1733 | documentation string of @code{hide-ifdef-mode} for more information. | |
9234c238 RS |
1734 | |
1735 | @item M-x ff-find-related-file | |
1736 | @cindex related files | |
1737 | @findex ff-find-related-file | |
1738 | @vindex ff-related-file-alist | |
1739 | Find a file ``related'' in a special way to the file visited by the | |
1740 | current buffer. Typically this will be the header file corresponding | |
1741 | to a C/C++ source file, or vice versa. The variable | |
1742 | @code{ff-related-file-alist} specifies how to compute related file | |
1743 | names. | |
6bf7aab6 DL |
1744 | @end table |
1745 | ||
6bf7aab6 DL |
1746 | @node Asm Mode |
1747 | @section Asm Mode | |
1748 | ||
1749 | @cindex Asm mode | |
9234c238 | 1750 | @cindex assembler mode |
6bf7aab6 DL |
1751 | Asm mode is a major mode for editing files of assembler code. It |
1752 | defines these commands: | |
1753 | ||
1754 | @table @kbd | |
1755 | @item @key{TAB} | |
1756 | @code{tab-to-tab-stop}. | |
1757 | @item C-j | |
1758 | Insert a newline and then indent using @code{tab-to-tab-stop}. | |
1759 | @item : | |
1760 | Insert a colon and then remove the indentation from before the label | |
1761 | preceding colon. Then do @code{tab-to-tab-stop}. | |
1762 | @item ; | |
1763 | Insert or align a comment. | |
1764 | @end table | |
1765 | ||
1766 | The variable @code{asm-comment-char} specifies which character | |
1767 | starts comments in assembler syntax. | |
ab5796a9 | 1768 | |
b23ef7a5 EZ |
1769 | @ifnottex |
1770 | @include fortran-xtra.texi | |
1771 | @end ifnottex | |
1772 | ||
ab5796a9 MB |
1773 | @ignore |
1774 | arch-tag: c7ee7409-40a4-45c7-bfb7-ae7f2c74d0c0 | |
1775 | @end ignore |