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6bf7aab6 | 1 | @c This is part of the Emacs manual. |
93da5dff | 2 | @c Copyright (C) 1985,86,87,93,94,95,97,99,00,2001 Free Software Foundation, Inc. |
6bf7aab6 DL |
3 | @c See file emacs.texi for copying conditions. |
4 | @node Programs, Building, Text, Top | |
5 | @chapter Editing Programs | |
6 | @cindex Lisp editing | |
7 | @cindex C editing | |
8 | @cindex program editing | |
9 | ||
e79c6b89 RS |
10 | Emacs provides many features to facilitate editing programs. Some |
11 | of these features can | |
6bf7aab6 DL |
12 | |
13 | @itemize @bullet | |
14 | @item | |
93da5dff | 15 | Find or move over top-level definitions (@pxref{Defuns}). |
6bf7aab6 | 16 | @item |
93da5dff RS |
17 | Apply the usual indentation conventions of the language |
18 | (@pxref{Program Indent}). | |
6bf7aab6 | 19 | @item |
93da5dff | 20 | Balance parentheses (@pxref{Parentheses}). |
cf1c48d4 | 21 | @item |
ea118de1 SE |
22 | Insert, kill or align comments (@pxref{Comments}). |
23 | @item | |
cf1c48d4 | 24 | Highlight program syntax (@pxref{Font Lock}). |
6bf7aab6 DL |
25 | @end itemize |
26 | ||
e79c6b89 RS |
27 | This chapter describes these features and many more. |
28 | ||
6bf7aab6 DL |
29 | @menu |
30 | * Program Modes:: Major modes for editing programs. | |
93da5dff RS |
31 | * Defuns:: Commands to operate on major top-level parts |
32 | of a program. | |
6bf7aab6 | 33 | * Program Indent:: Adjusting indentation to show the nesting. |
93da5dff | 34 | * Parentheses:: Commands that operate on parentheses. |
c8b21b5e | 35 | * Comments:: Inserting, killing, and aligning comments. |
93da5dff | 36 | * Documentation:: Getting documentation of functions you plan to call. |
51ed0ea0 | 37 | * Hideshow:: Displaying blocks selectively. |
93da5dff | 38 | * Symbol Completion:: Completion on symbol names of your program or language. |
3b8b8888 | 39 | * Glasses:: Making identifiersLikeThis more readable. |
93da5dff | 40 | * Misc for Programs:: Other Emacs features useful for editing programs. |
79214ddf | 41 | * C Modes:: Special commands of C, C++, Objective-C, |
6bf7aab6 | 42 | Java, and Pike modes. |
51ed0ea0 DL |
43 | * Fortran:: Fortran mode and its special features. |
44 | * Asm Mode:: Asm mode and its special features. | |
6bf7aab6 DL |
45 | @end menu |
46 | ||
47 | @node Program Modes | |
48 | @section Major Modes for Programming Languages | |
6bf7aab6 | 49 | @cindex modes for programming languages |
cf1c48d4 RS |
50 | |
51 | Emacs has specialized major modes for various programming languages. | |
52 | @xref{Major Modes}. A programming language major mode typically | |
53 | specifies the syntax of expressions, the customary rules for | |
54 | indentation, how to do syntax highlighting for the language, and how | |
e79c6b89 RS |
55 | to find the beginning of a function definition. It often customizes |
56 | or provides facilities for compiling and debugging programs as well. | |
cf1c48d4 RS |
57 | |
58 | Ideally, Emacs should provide a major mode for each programming | |
59 | language that you might want to edit; if it doesn't have a mode for | |
60 | your favorite language, you can contribute one. But often the mode | |
61 | for one language can serve for other syntactically similar languages. | |
62 | The major mode for language @var{l} is called @code{@var{l}-mode}, | |
e79c6b89 | 63 | and you can select it by typing @kbd{M-x @var{l}-mode @key{RET}}. |
cf1c48d4 RS |
64 | @xref{Choosing Modes}. |
65 | ||
6bf7aab6 DL |
66 | @cindex Perl mode |
67 | @cindex Icon mode | |
6bf7aab6 DL |
68 | @cindex Makefile mode |
69 | @cindex Tcl mode | |
70 | @cindex CPerl mode | |
138a8f12 DL |
71 | @cindex DSSSL mode |
72 | @cindex Octave mode | |
73 | @cindex Metafont mode | |
74 | @cindex Modula2 mode | |
75 | @cindex Prolog mode | |
76 | @cindex Simula mode | |
77 | @cindex VHDL mode | |
78 | @cindex M4 mode | |
79 | @cindex Shell-script mode | |
3b8b8888 DL |
80 | @cindex Delphi mode |
81 | @cindex PostScript mode | |
cf1c48d4 RS |
82 | The existing programming language major modes include Lisp, Scheme (a |
83 | variant of Lisp) and the Scheme-based DSSSL expression language, Ada, | |
ea118de1 | 84 | ASM, AWK, C, C++, Delphi (Object Pascal), Fortran (free format and fixed |
cf1c48d4 RS |
85 | format), Icon, IDL (CORBA), IDLWAVE, Java, Metafont (@TeX{}'s |
86 | companion for font creation), Modula2, Objective-C, Octave, Pascal, | |
93da5dff | 87 | Perl, Pike, PostScript, Prolog, Simula, Tcl, and VHDL. There is |
cf1c48d4 RS |
88 | also a major mode for makefiles, called Makefile mode. An alternative |
89 | mode for Perl is called CPerl mode. Modes are available for the | |
e79c6b89 | 90 | scripting languages of the common GNU and Unix shells, VMS DCL, and |
cf1c48d4 RS |
91 | MS-DOS/MS-Windows @samp{BAT} files. There are also major modes for |
92 | editing various sorts of configuration files. | |
6bf7aab6 DL |
93 | |
94 | @kindex DEL @r{(programming modes)} | |
4f7666dc | 95 | @findex c-electric-backspace |
93da5dff RS |
96 | In most programming languages, indentation should vary from line to |
97 | line to illustrate the structure of the program. So the major modes | |
e79c6b89 RS |
98 | for programming languages arrange for @key{TAB} to update the |
99 | indentation of the current line. They also rebind @key{DEL} to treat | |
100 | a tab as if it were the equivalent number of spaces; this lets you | |
101 | delete one column of indentation without worrying whether the | |
102 | whitespace consists of spaces or tabs. Use @kbd{C-b C-d} to delete a | |
103 | tab character before point, in these modes. | |
6bf7aab6 | 104 | |
cf1c48d4 | 105 | Separate manuals are available for the modes for Ada (@pxref{Top, , Ada |
7ae8ad94 | 106 | Mode, ada-mode, Ada Mode}), C/C++/Objective C/Java/Corba IDL/Pike/AWK |
cf1c48d4 RS |
107 | (@pxref{Top, , CC Mode, ccmode, CC Mode}) and the IDLWAVE modes |
108 | (@pxref{Top, , IDLWAVE, idlwave, IDLWAVE User Manual}). | |
f9fd7fbc | 109 | |
6bf7aab6 DL |
110 | @cindex mode hook |
111 | @vindex c-mode-hook | |
112 | @vindex lisp-mode-hook | |
113 | @vindex emacs-lisp-mode-hook | |
114 | @vindex lisp-interaction-mode-hook | |
115 | @vindex scheme-mode-hook | |
d2fab838 RS |
116 | Turning on a major mode runs a normal hook called the @dfn{mode |
117 | hook}, which is the value of a Lisp variable. Each major mode has a | |
118 | mode hook, and the hook's name is always made from the mode command's | |
119 | name by adding @samp{-hook}. For example, turning on C mode runs the | |
120 | hook @code{c-mode-hook}, while turning on Lisp mode runs the hook | |
121 | @code{lisp-mode-hook}. The purpose of the mode hook is to give you a | |
122 | place to set up customizations for that major mode. @xref{Hooks}. | |
6bf7aab6 | 123 | |
93da5dff RS |
124 | @node Defuns |
125 | @section Top-Level Definitions, or Defuns | |
6bf7aab6 | 126 | |
93da5dff RS |
127 | In Emacs, a major definition at the top level in the buffer is |
128 | called a @dfn{defun}. The name comes from Lisp, but in Emacs we use | |
129 | it for all languages. | |
6bf7aab6 | 130 | |
93da5dff RS |
131 | In most programming language modes, Emacs assumes that a defun is |
132 | any pair of parentheses (or braces, if the language uses braces this | |
133 | way) that starts at the left margin. For example, in C, the body of a | |
134 | function definition is normally a defun, because the open-brace that | |
135 | begins it is normally at the left margin. A variable's initializer | |
136 | can also count as a defun, if the open-brace that begins the | |
137 | initializer is at the left margin. | |
6bf7aab6 | 138 | |
93da5dff RS |
139 | However, some language modes provide their own code for recognizing |
140 | defuns in a way that suits the language syntax and conventions better. | |
6bf7aab6 | 141 | |
93da5dff RS |
142 | @menu |
143 | * Left Margin Paren:: An open-paren or similar opening delimiter | |
144 | starts a defun if it is at the left margin. | |
145 | * Moving by Defuns:: Commands to move over or mark a major definition. | |
146 | * Imenu:: Making buffer indexes as menus. | |
147 | * Which Function:: Which Function mode shows which function you are in. | |
148 | @end menu | |
6bf7aab6 | 149 | |
93da5dff RS |
150 | @node Left Margin Paren |
151 | @subsection Left Margin Convention | |
6bf7aab6 | 152 | |
93da5dff RS |
153 | @cindex open-parenthesis in leftmost column |
154 | @cindex ( in leftmost column | |
155 | In most major modes, Emacs assumes that any opening delimiter found | |
156 | at the left margin is the start of a top-level definition, or defun. | |
157 | Therefore, @strong{never put an opening delimiter at the left margin | |
158 | unless it should have that significance.} For instance, never put an | |
159 | open-parenthesis at the left margin in a Lisp file unless it is the | |
160 | start of a top-level list. Never put an open-brace or other opening | |
161 | delimiter at the beginning of a line of C code unless it is at top | |
162 | level. | |
163 | ||
164 | If you don't follow this convention, not only will you have trouble | |
165 | when you explicitly use the commands for motion by defuns; other | |
166 | features that use them will also give you trouble. This includes | |
167 | the indentation commands (@pxref{Program Indent}) and Font Lock | |
168 | mode (@pxref{Font Lock}). | |
169 | ||
170 | The most likely problem case is when you want an opening delimiter | |
171 | at the start of a line inside a string. To avoid trouble, put an | |
172 | escape character (@samp{\}, in C and Emacs Lisp, @samp{/} in some | |
173 | other Lisp dialects) before the opening delimiter. This will not | |
174 | affect the contents of the string, but will prevent that opening | |
175 | delimiter from starting a defun. Here's an example: | |
6bf7aab6 | 176 | |
93da5dff RS |
177 | @example |
178 | (insert "Foo: | |
179 | \(bar) | |
180 | ") | |
181 | @end example | |
6bf7aab6 | 182 | |
5b8fe684 RS |
183 | To help you catch violations of this convention, Font Lock mode |
184 | highlights confusing opening delimiters (those that ought to be | |
185 | quoted) in bold red. | |
186 | ||
93da5dff RS |
187 | In the earliest days, the original Emacs found defuns by moving |
188 | upward a level of parentheses or braces until there were no more | |
189 | levels to go up. This always required scanning all the way back to | |
190 | the beginning of the buffer, even for a small function. To speed up | |
191 | the operation, we changed Emacs to assume that any opening delimiter | |
192 | at the left margin is the start of a defun. This heuristic is nearly | |
193 | always right, and avoids the need to scan back to the beginning of the | |
194 | buffer. However, it mandates following the convention described | |
195 | above. | |
196 | ||
197 | @node Moving by Defuns | |
198 | @subsection Moving by Defuns | |
6bf7aab6 DL |
199 | @cindex defuns |
200 | ||
93da5dff RS |
201 | These commands move point or set up the region based on top-level |
202 | major definitions, also called @dfn{defuns}. | |
520c3f4c | 203 | |
6bf7aab6 DL |
204 | @table @kbd |
205 | @item C-M-a | |
206 | Move to beginning of current or preceding defun | |
207 | (@code{beginning-of-defun}). | |
208 | @item C-M-e | |
209 | Move to end of current or following defun (@code{end-of-defun}). | |
210 | @item C-M-h | |
211 | Put region around whole current or following defun (@code{mark-defun}). | |
212 | @end table | |
213 | ||
f772775c RS |
214 | @cindex move to beginning or end of function |
215 | @cindex function, move to beginning or end | |
216 | @kindex C-M-a | |
217 | @kindex C-M-e | |
218 | @kindex C-M-h | |
219 | @findex beginning-of-defun | |
220 | @findex end-of-defun | |
221 | @findex mark-defun | |
222 | The commands to move to the beginning and end of the current defun | |
223 | are @kbd{C-M-a} (@code{beginning-of-defun}) and @kbd{C-M-e} | |
224 | (@code{end-of-defun}). If you repeat one of these commands, or use a | |
225 | positive numeric argument, each repetition moves to the next defun in | |
226 | the direction of motion. | |
227 | ||
228 | @kbd{C-M-a} with a negative argument @minus{}@var{n} moves forward | |
229 | @var{n} times to the next beginning of a defun. This is not exactly | |
230 | the same place that @kbd{C-M-e} with argument @var{n} would move to; | |
231 | the end of this defun is not usually exactly the same place as the | |
93da5dff RS |
232 | beginning of the following defun. (Whitespace, comments, and perhaps |
233 | declarations can separate them.) Likewise, @kbd{C-M-e} with a | |
234 | negative argument moves back to an end of a defun, which is not quite | |
235 | the same as @kbd{C-M-a} with a positive argument. | |
f772775c | 236 | |
4946337d | 237 | @kindex C-M-h @r{(C mode)} |
6bf7aab6 | 238 | @findex c-mark-function |
93da5dff RS |
239 | To operate on the current defun, use @kbd{C-M-h} (@code{mark-defun}) |
240 | which puts point at the beginning and mark at the end of the current | |
5e6f9132 RS |
241 | defun. This is the easiest way to get ready to kill the defun in |
242 | order to move it to a different place in the file. If you use the | |
243 | command while point is between defuns, it uses the following defun. | |
93da5dff RS |
244 | |
245 | In C mode, @kbd{C-M-h} runs the function @code{c-mark-function}, | |
246 | which is almost the same as @code{mark-defun}; the difference is that | |
247 | it backs up over the argument declarations, function name and returned | |
e79c6b89 RS |
248 | data type so that the entire C function is inside the region. This is |
249 | an example of how major modes adjust the standard key bindings so that | |
250 | they do their standard jobs in a way better fitting a particular | |
251 | language. Other major modes may replace any or all of these key | |
252 | bindings for that purpose. | |
6bf7aab6 | 253 | |
93da5dff RS |
254 | @node Imenu |
255 | @subsection Imenu | |
e79c6b89 RS |
256 | @cindex index of buffer definitions |
257 | @cindex buffer definitions index | |
93da5dff RS |
258 | @cindex tags |
259 | ||
269b7745 | 260 | The Imenu facility offers a way to find the major definitions in |
5e6f9132 RS |
261 | a file by name. It is also useful in text formatter major modes, |
262 | where it treats each chapter, section, etc., as a definition. | |
e79c6b89 | 263 | (@xref{Tags}, for a more powerful feature that handles multiple files |
5e6f9132 | 264 | together.) |
93da5dff RS |
265 | |
266 | @findex imenu | |
5e6f9132 | 267 | If you type @kbd{M-x imenu}, it reads the name of a definition using |
e79c6b89 RS |
268 | the minibuffer, then moves point to that definition. You can use |
269 | completion to specify the name; the command always displays the whole | |
270 | list of valid names. | |
d2fab838 | 271 | |
5e6f9132 | 272 | @findex imenu-add-menubar-index |
d2fab838 | 273 | Alternatively, you can bind the command @code{imenu} to a mouse |
e79c6b89 RS |
274 | click. Then it displays mouse menus for you to select a definition |
275 | name. You can also add the buffer's index to the menu bar by calling | |
276 | @code{imenu-add-menubar-index}. If you want to have this menu bar | |
277 | item available for all buffers in a certain major mode, you can do | |
278 | this by adding @code{imenu-add-menubar-index} to its mode hook. But | |
279 | if you have done that, you will have to wait each time you visit a | |
280 | file in that mode, while Emacs finds all the definitions in that | |
281 | buffer. | |
93da5dff RS |
282 | |
283 | @vindex imenu-auto-rescan | |
284 | When you change the contents of a buffer, if you add or delete | |
e79c6b89 | 285 | definitions, you can update the buffer's index based on the |
d2fab838 | 286 | new contents by invoking the @samp{*Rescan*} item in the menu. |
dcace646 EZ |
287 | Rescanning happens automatically if you set @code{imenu-auto-rescan} to |
288 | a non-@code{nil} value. There is no need to rescan because of small | |
e79c6b89 | 289 | changes in the text. |
93da5dff RS |
290 | |
291 | @vindex imenu-sort-function | |
d2fab838 | 292 | You can customize the way the menus are sorted by setting the |
e79c6b89 | 293 | variable @code{imenu-sort-function}. By default, names are ordered as |
5e6f9132 RS |
294 | they occur in the buffer; if you want alphabetic sorting, use the |
295 | symbol @code{imenu--sort-by-name} as the value. You can also | |
296 | define your own comparison function by writing Lisp code. | |
93da5dff RS |
297 | |
298 | Imenu provides the information to guide Which Function mode | |
299 | @ifnottex | |
300 | (@pxref{Which Function}). | |
301 | @end ifnottex | |
302 | @iftex | |
303 | (see below). | |
304 | @end iftex | |
305 | The Speedbar can also use it (@pxref{Speedbar}). | |
306 | ||
307 | @node Which Function | |
308 | @subsection Which Function Mode | |
af056954 | 309 | @cindex current function name in mode line |
93da5dff RS |
310 | |
311 | Which Function mode is a minor mode that displays the current | |
312 | function name in the mode line, updating it as you move around in a | |
313 | buffer. | |
314 | ||
315 | @findex which-function-mode | |
316 | @vindex which-func-modes | |
317 | To enable (or disable) Which Function mode, use the command @kbd{M-x | |
318 | which-function-mode}. This command is global; it applies to all | |
ea118de1 | 319 | buffers, both existing ones and those yet to be created. However, it |
6daf3e15 | 320 | takes effect only in certain major modes, those listed in the value of |
ea118de1 SE |
321 | @code{which-func-modes}. If the value is @code{t}, then Which Function |
322 | mode applies to all major modes that know how to support it---in other | |
323 | words, all the major modes that support Imenu. | |
6bf7aab6 DL |
324 | |
325 | @node Program Indent | |
326 | @section Indentation for Programs | |
327 | @cindex indentation for programs | |
328 | ||
329 | The best way to keep a program properly indented is to use Emacs to | |
330 | reindent it as you change it. Emacs has commands to indent properly | |
331 | either a single line, a specified number of lines, or all of the lines | |
332 | inside a single parenthetical grouping. | |
333 | ||
334 | @menu | |
335 | * Basic Indent:: Indenting a single line. | |
336 | * Multi-line Indent:: Commands to reindent many lines at once. | |
337 | * Lisp Indent:: Specifying how each Lisp function should be indented. | |
338 | * C Indent:: Extra features for indenting C and related modes. | |
339 | * Custom C Indent:: Controlling indentation style for C and related modes. | |
340 | @end menu | |
341 | ||
d2fab838 | 342 | @cindex pretty-printer |
6bf7aab6 DL |
343 | Emacs also provides a Lisp pretty-printer in the library @code{pp}. |
344 | This program reformats a Lisp object with indentation chosen to look nice. | |
345 | ||
346 | @node Basic Indent | |
347 | @subsection Basic Program Indentation Commands | |
348 | ||
d2fab838 RS |
349 | The basic indentation commands indent a single line according to the |
350 | usual conventions of the language you are editing. | |
cf1c48d4 | 351 | |
6bf7aab6 DL |
352 | @table @kbd |
353 | @item @key{TAB} | |
354 | Adjust indentation of current line. | |
355 | @item C-j | |
356 | Equivalent to @key{RET} followed by @key{TAB} (@code{newline-and-indent}). | |
d2fab838 | 357 | @item @key{LINEFEED} |
e79c6b89 | 358 | This key, if the keyboard has it, is another way to enter @kbd{C-j}. |
6bf7aab6 DL |
359 | @end table |
360 | ||
361 | @kindex TAB @r{(programming modes)} | |
4f7666dc RS |
362 | @findex c-indent-command |
363 | @findex indent-line-function | |
f772775c | 364 | @findex indent-for-tab-command |
6bf7aab6 DL |
365 | The basic indentation command is @key{TAB}, which gives the current line |
366 | the correct indentation as determined from the previous lines. The | |
cf1c48d4 | 367 | function that @key{TAB} runs depends on the major mode; it is |
054af0fd | 368 | @code{lisp-indent-line} |
4f7666dc | 369 | in Lisp mode, @code{c-indent-command} in C mode, etc. These functions |
cf1c48d4 RS |
370 | understand the syntax and conventions of different languages, but they all do |
371 | conceptually the same job: @key{TAB} in any programming-language major mode | |
6bf7aab6 | 372 | inserts or deletes whitespace at the beginning of the current line, |
cf1c48d4 RS |
373 | independent of where point is in the line. If point was inside the |
374 | whitespace at the beginning of the line, @key{TAB} puts it at the end of | |
375 | that whitespace; otherwise, @key{TAB} keeps point fixed with respect to | |
6bf7aab6 DL |
376 | the characters around it. |
377 | ||
378 | Use @kbd{C-q @key{TAB}} to insert a tab at point. | |
379 | ||
380 | @kindex C-j | |
381 | @findex newline-and-indent | |
cf1c48d4 RS |
382 | When entering lines of new code, use @kbd{C-j} |
383 | (@code{newline-and-indent}), which is equivalent to a @key{RET} | |
384 | followed by a @key{TAB}. @kbd{C-j} at the end of a line creates a | |
385 | blank line and then gives it the appropriate indentation. | |
6bf7aab6 | 386 | |
f772775c RS |
387 | @key{TAB} indents lines that start within a parenthetical grouping |
388 | each under the preceding line (or the text after the parenthesis). | |
389 | Therefore, if you manually give one of these lines a nonstandard | |
390 | indentation, the lines below will tend to follow it. This behavior is | |
391 | convenient in cases where you have overridden the standard result of | |
392 | @key{TAB} because you find it unaesthetic for a particular line. | |
6bf7aab6 DL |
393 | |
394 | Remember that an open-parenthesis, open-brace or other opening delimiter | |
395 | at the left margin is assumed by Emacs (including the indentation routines) | |
396 | to be the start of a function. Therefore, you must never have an opening | |
397 | delimiter in column zero that is not the beginning of a function, not even | |
398 | inside a string. This restriction is vital for making the indentation | |
93da5dff RS |
399 | commands fast; you must simply accept it. @xref{Left Margin Paren}, |
400 | for more information on this. | |
6bf7aab6 | 401 | |
5151db0c EZ |
402 | Normally, lines are indented with tabs and spaces. If you want Emacs |
403 | to use spaces only, see @ref{Just Spaces}. | |
404 | ||
6bf7aab6 DL |
405 | @node Multi-line Indent |
406 | @subsection Indenting Several Lines | |
407 | ||
93da5dff RS |
408 | When you wish to reindent several lines of code which have been |
409 | altered or moved to a different level in the parenthesis structure, | |
410 | you have several commands available. | |
6bf7aab6 DL |
411 | |
412 | @table @kbd | |
413 | @item C-M-q | |
6daf3e15 | 414 | Reindent all the lines within one parenthetical grouping (@code{indent-pp-sexp}). |
e79c6b89 RS |
415 | @item C-M-\ |
416 | Reindent all lines in the region (@code{indent-region}). | |
6bf7aab6 | 417 | @item C-u @key{TAB} |
93da5dff RS |
418 | Shift an entire parenthetical grouping rigidly sideways so that its |
419 | first line is properly indented. | |
5cc06e0b EZ |
420 | @item M-x indent-code-rigidly |
421 | Shift all the lines in the region rigidly sideways, but do not alter | |
422 | lines that start inside comments and strings. | |
6bf7aab6 DL |
423 | @end table |
424 | ||
425 | @kindex C-M-q | |
6daf3e15 | 426 | @findex indent-pp-sexp |
93da5dff RS |
427 | You can reindent the contents of a single parenthetical grouping by |
428 | positioning point before the beginning of it and typing @kbd{C-M-q} | |
054af0fd | 429 | (@code{indent-pp-sexp} in Lisp mode, @code{c-indent-exp} in C mode; also |
93da5dff | 430 | bound to other suitable commands in other modes). The indentation of |
6daf3e15 | 431 | the line where the grouping starts is not changed; therefore this |
93da5dff RS |
432 | changes only the relative indentation within the grouping, not its |
433 | overall indentation. To correct that as well, type @key{TAB} first. | |
6bf7aab6 | 434 | |
e79c6b89 RS |
435 | Another way to specify the range to be reindented is with the |
436 | region. The command @kbd{C-M-\} (@code{indent-region}) applies | |
437 | @key{TAB} to every line whose first character is between point and | |
438 | mark. | |
439 | ||
6bf7aab6 | 440 | @kindex C-u TAB |
93da5dff RS |
441 | If you like the relative indentation within a grouping, but not the |
442 | indentation of its first line, you can type @kbd{C-u @key{TAB}} to | |
24c7c69c RS |
443 | reindent the whole grouping as a rigid unit. (This works in Lisp |
444 | modes and C and related modes.) @key{TAB} with a numeric argument | |
445 | reindents the current line as usual, then reindents by the same amount | |
446 | all the lines in the parenthetical grouping starting on the current | |
447 | line. It is clever, though, and does not alter lines that start | |
7ae8ad94 RS |
448 | inside strings. Neither does it alter C preprocessor lines when in C |
449 | mode, but it does reindent any continuation lines that may be attached | |
450 | to them. | |
6bf7aab6 | 451 | |
5cc06e0b | 452 | @findex indent-code-rigidly |
e79c6b89 RS |
453 | You can also perform this operation on the region, using the command |
454 | @kbd{M-x indent-code-rigidly}. It rigidly shifts all the lines in the | |
455 | region sideways, like @code{indent-rigidly} does (@pxref{Indentation | |
456 | Commands}). It doesn't alter the indentation of lines that start | |
7ae8ad94 | 457 | inside a string, unless the region also starts inside that string. |
054af0fd | 458 | The prefix arg specifies the number of columns to indent. |
6bf7aab6 DL |
459 | |
460 | @node Lisp Indent | |
461 | @subsection Customizing Lisp Indentation | |
462 | @cindex customizing Lisp indentation | |
463 | ||
464 | The indentation pattern for a Lisp expression can depend on the function | |
465 | called by the expression. For each Lisp function, you can choose among | |
466 | several predefined patterns of indentation, or define an arbitrary one with | |
467 | a Lisp program. | |
468 | ||
469 | The standard pattern of indentation is as follows: the second line of the | |
470 | expression is indented under the first argument, if that is on the same | |
471 | line as the beginning of the expression; otherwise, the second line is | |
472 | indented underneath the function name. Each following line is indented | |
473 | under the previous line whose nesting depth is the same. | |
474 | ||
475 | @vindex lisp-indent-offset | |
476 | If the variable @code{lisp-indent-offset} is non-@code{nil}, it overrides | |
477 | the usual indentation pattern for the second line of an expression, so that | |
478 | such lines are always indented @code{lisp-indent-offset} more columns than | |
479 | the containing list. | |
480 | ||
481 | @vindex lisp-body-indent | |
d2fab838 | 482 | Certain functions override the standard pattern. Functions whose |
269b7745 | 483 | names start with @code{def} treat the second lines as the start of |
d2fab838 RS |
484 | a @dfn{body}, by indenting the second line @code{lisp-body-indent} |
485 | additional columns beyond the open-parenthesis that starts the | |
486 | expression. | |
6bf7aab6 | 487 | |
b771b258 | 488 | @cindex @code{lisp-indent-function} property |
d2fab838 | 489 | You can override the standard pattern in various ways for individual |
690a6d08 RS |
490 | functions, according to the @code{lisp-indent-function} property of |
491 | the function name. Normally you would use this for macro definitions | |
492 | and specify it using the @code{declare} construct (@pxref{Defining | |
493 | Macros,,, elisp, the Emacs Lisp Reference Manual}). | |
6bf7aab6 DL |
494 | |
495 | @node C Indent | |
496 | @subsection Commands for C Indentation | |
497 | ||
93da5dff | 498 | Here are special features for indentation in C mode and related modes: |
6bf7aab6 DL |
499 | |
500 | @table @code | |
501 | @item C-c C-q | |
502 | @kindex C-c C-q @r{(C mode)} | |
503 | @findex c-indent-defun | |
504 | Reindent the current top-level function definition or aggregate type | |
505 | declaration (@code{c-indent-defun}). | |
506 | ||
507 | @item C-M-q | |
508 | @kindex C-M-q @r{(C mode)} | |
509 | @findex c-indent-exp | |
510 | Reindent each line in the balanced expression that follows point | |
7ae8ad94 RS |
511 | (@code{c-indent-exp}). A prefix argument inhibits warning messages |
512 | about invalid syntax. | |
6bf7aab6 DL |
513 | |
514 | @item @key{TAB} | |
515 | @findex c-indent-command | |
516 | Reindent the current line, and/or in some cases insert a tab character | |
517 | (@code{c-indent-command}). | |
518 | ||
7ae8ad94 | 519 | @vindex c-tab-always-indent |
6bf7aab6 DL |
520 | If @code{c-tab-always-indent} is @code{t}, this command always reindents |
521 | the current line and does nothing else. This is the default. | |
522 | ||
523 | If that variable is @code{nil}, this command reindents the current line | |
524 | only if point is at the left margin or in the line's indentation; | |
525 | otherwise, it inserts a tab (or the equivalent number of spaces, | |
526 | if @code{indent-tabs-mode} is @code{nil}). | |
527 | ||
528 | Any other value (not @code{nil} or @code{t}) means always reindent the | |
7ae8ad94 | 529 | line, and also insert a tab if within a comment or a string. |
6bf7aab6 DL |
530 | @end table |
531 | ||
532 | To reindent the whole current buffer, type @kbd{C-x h C-M-\}. This | |
533 | first selects the whole buffer as the region, then reindents that | |
534 | region. | |
535 | ||
536 | To reindent the current block, use @kbd{C-M-u C-M-q}. This moves | |
537 | to the front of the block and then reindents it all. | |
538 | ||
539 | @node Custom C Indent | |
540 | @subsection Customizing C Indentation | |
93da5dff | 541 | @cindex style (for indentation) |
6bf7aab6 | 542 | |
7ae8ad94 RS |
543 | C mode and related modes use a flexible mechanism for customizing |
544 | indentation. C mode indents a source line in two steps: first it | |
545 | classifies the line syntactically according to its contents and | |
546 | context; second, it determines the indentation offset associated by | |
547 | your selected @dfn{style} with the syntactic construct and adds this | |
548 | onto the indentation of the @dfn{anchor statement}. | |
6bf7aab6 | 549 | |
93da5dff | 550 | @table @kbd |
7ae8ad94 RS |
551 | @item C-c . @key{RET} @var{style} @key{RET} |
552 | Select a predefined style @var{style} (@code{c-set-style}). | |
93da5dff | 553 | @end table |
6bf7aab6 | 554 | |
7ae8ad94 | 555 | A @dfn{style} is a named collection of customizations that can |
93da5dff RS |
556 | be used in C mode and the related modes. Emacs comes with several |
557 | predefined styles, including @code{gnu}, @code{k&r}, @code{bsd}, | |
558 | @code{stroustrup}, @code{linux}, @code{python}, @code{java}, | |
559 | @code{whitesmith}, @code{ellemtel}, @code{cc-mode}, and @code{user}. | |
560 | Some of these styles are primarily intended for one language, but any | |
561 | of them can be used with any of the languages supported by these | |
562 | modes. To find out what a style looks like, select it and reindent | |
563 | some code, e.g., by typing @key{C-M-q} at the start of a function | |
564 | definition. | |
6bf7aab6 | 565 | |
7ae8ad94 | 566 | @kindex C-c . @r{(C mode)} |
93da5dff | 567 | @findex c-set-style |
7ae8ad94 RS |
568 | To choose a style for the current buffer, use the command @kbd{C-c |
569 | .}. Specify a style name as an argument (case is not significant). | |
570 | This command affects the current buffer only, and it affects only | |
571 | future invocations of the indentation commands; it does not reindent | |
572 | the code in the buffer. To reindent the whole buffer in the new | |
573 | style, you can type @kbd{C-x h C-M-\}. | |
6bf7aab6 | 574 | |
93da5dff RS |
575 | @vindex c-default-style |
576 | You can also set the variable @code{c-default-style} to specify the | |
7ae8ad94 RS |
577 | default style for various major modes. Its value should be either the |
578 | style's name (a string) or an alist, in which each element specifies | |
579 | one major mode and which indentation style to use for it. For | |
580 | example, | |
6bf7aab6 DL |
581 | |
582 | @example | |
93da5dff RS |
583 | (setq c-default-style |
584 | '((java-mode . "java") (other . "gnu"))) | |
6bf7aab6 DL |
585 | @end example |
586 | ||
93da5dff RS |
587 | @noindent |
588 | specifies an explicit choice for Java mode, and the default @samp{gnu} | |
589 | style for the other C-like modes. This variable takes effect when you | |
e79c6b89 | 590 | select one of the C-like major modes; thus, if you specify a new |
93da5dff RS |
591 | default style for Java mode, you can make it take effect in an |
592 | existing Java mode buffer by typing @kbd{M-x java-mode} there. | |
6bf7aab6 | 593 | |
93da5dff RS |
594 | The @code{gnu} style specifies the formatting recommended by the GNU |
595 | Project for C; it is the default, so as to encourage use of our | |
596 | recommended style. | |
6bf7aab6 | 597 | |
0d103856 | 598 | @xref{Customizing Indentation,,, ccmode, the CC Mode Manual}, for |
93da5dff RS |
599 | more information on customizing indentation for C and related modes, |
600 | including how to override parts of an existing style and how to define | |
601 | your own styles. | |
6bf7aab6 | 602 | |
93da5dff RS |
603 | @node Parentheses |
604 | @section Commands for Editing with Parentheses | |
6bf7aab6 | 605 | |
93da5dff RS |
606 | @findex check-parens |
607 | @cindex unbalanced parentheses and quotes | |
608 | This section describes the commands and features that take advantage | |
609 | of the parenthesis structure in a program, or help you keep it | |
610 | balanced. | |
6bf7aab6 | 611 | |
93da5dff RS |
612 | When talking about these facilities, the term ``parenthesis'' also |
613 | includes braces, brackets, or whatever delimiters are defined to match | |
e79c6b89 RS |
614 | in pairs. The major mode controls which delimiters are significant, |
615 | through the syntax table (@pxref{Syntax}). In Lisp, only parentheses | |
616 | count; in C, these commands apply to braces and brackets too. | |
6bf7aab6 | 617 | |
93da5dff RS |
618 | You can use @kbd{M-x check-parens} to find any unbalanced |
619 | parentheses and unbalanced string quotes in the buffer. | |
6bf7aab6 | 620 | |
93da5dff RS |
621 | @menu |
622 | * Expressions:: Expressions with balanced parentheses. | |
623 | * Moving by Parens:: Commands for moving up, down and across | |
624 | in the structure of parentheses. | |
625 | * Matching:: Insertion of a close-delimiter flashes matching open. | |
626 | @end menu | |
6bf7aab6 | 627 | |
93da5dff RS |
628 | @node Expressions |
629 | @subsection Expressions with Balanced Parentheses | |
6bf7aab6 | 630 | |
93da5dff RS |
631 | @cindex sexp |
632 | @cindex expression | |
633 | @cindex balanced expression | |
634 | These commands deal with balanced expressions, also called | |
635 | @dfn{sexps}@footnote{The word ``sexp'' is used to refer to an | |
636 | expression in Lisp.}. | |
6bf7aab6 | 637 | |
93da5dff RS |
638 | @table @kbd |
639 | @item C-M-f | |
640 | Move forward over a balanced expression (@code{forward-sexp}). | |
641 | @item C-M-b | |
ea118de1 | 642 | Move backward over a balanced expression (@code{backward-sexp}). |
93da5dff RS |
643 | @item C-M-k |
644 | Kill balanced expression forward (@code{kill-sexp}). | |
93da5dff RS |
645 | @item C-M-t |
646 | Transpose expressions (@code{transpose-sexps}). | |
647 | @item C-M-@@ | |
649d1cbe | 648 | @itemx C-M-@key{SPC} |
93da5dff RS |
649 | Put mark after following expression (@code{mark-sexp}). |
650 | @end table | |
6bf7aab6 | 651 | |
93da5dff RS |
652 | Each programming language major mode customizes the definition of |
653 | balanced expressions to suit that language. Balanced expressions | |
654 | typically include symbols, numbers, and string constants, as well as | |
e79c6b89 | 655 | any pair of matching delimiters and their contents. Some languages |
93da5dff RS |
656 | have obscure forms of expression syntax that nobody has bothered to |
657 | implement in Emacs. | |
6bf7aab6 | 658 | |
93da5dff | 659 | @cindex Control-Meta |
e79c6b89 RS |
660 | By convention, the keys for these commands are all Control-Meta |
661 | characters. They usually act on expressions just as the corresponding | |
662 | Meta characters act on words. For instance, the command @kbd{C-M-b} | |
663 | moves backward over a balanced expression, just as @kbd{M-b} moves | |
664 | back over a word. | |
6bf7aab6 | 665 | |
93da5dff RS |
666 | @kindex C-M-f |
667 | @kindex C-M-b | |
668 | @findex forward-sexp | |
669 | @findex backward-sexp | |
670 | To move forward over a balanced expression, use @kbd{C-M-f} | |
671 | (@code{forward-sexp}). If the first significant character after point | |
672 | is an opening delimiter (@samp{(} in Lisp; @samp{(}, @samp{[} or | |
673 | @samp{@{} in C), @kbd{C-M-f} moves past the matching closing | |
674 | delimiter. If the character begins a symbol, string, or number, | |
675 | @kbd{C-M-f} moves over that. | |
6bf7aab6 | 676 | |
93da5dff RS |
677 | The command @kbd{C-M-b} (@code{backward-sexp}) moves backward over a |
678 | balanced expression. The detailed rules are like those above for | |
679 | @kbd{C-M-f}, but with directions reversed. If there are prefix | |
680 | characters (single-quote, backquote and comma, in Lisp) preceding the | |
681 | expression, @kbd{C-M-b} moves back over them as well. The balanced | |
682 | expression commands move across comments as if they were whitespace, | |
683 | in most modes. | |
6bf7aab6 | 684 | |
93da5dff RS |
685 | @kbd{C-M-f} or @kbd{C-M-b} with an argument repeats that operation the |
686 | specified number of times; with a negative argument, it moves in the | |
687 | opposite direction. | |
6bf7aab6 | 688 | |
93da5dff RS |
689 | @cindex killing expressions |
690 | @kindex C-M-k | |
691 | @findex kill-sexp | |
93da5dff | 692 | Killing a whole balanced expression can be done with @kbd{C-M-k} |
880b0421 RS |
693 | (@code{kill-sexp}). @kbd{C-M-k} kills the characters that @kbd{C-M-f} |
694 | would move over. | |
6bf7aab6 | 695 | |
93da5dff RS |
696 | @cindex transposition of expressions |
697 | @kindex C-M-t | |
698 | @findex transpose-sexps | |
699 | A somewhat random-sounding command which is nevertheless handy is | |
700 | @kbd{C-M-t} (@code{transpose-sexps}), which drags the previous | |
701 | balanced expression across the next one. An argument serves as a | |
e79c6b89 RS |
702 | repeat count, and a negative argument drags the previous balanced |
703 | expression backwards across those before it (thus canceling out the | |
704 | effect of @kbd{C-M-t} with a positive argument). An argument of zero, | |
705 | rather than doing nothing, transposes the balanced expressions ending | |
706 | at or after point and the mark. | |
6bf7aab6 | 707 | |
93da5dff | 708 | @kindex C-M-@@ |
649d1cbe | 709 | @kindex C-M-@key{SPC} |
93da5dff RS |
710 | @findex mark-sexp |
711 | To set the region around the next balanced expression in the buffer, | |
712 | use @kbd{C-M-@@} (@code{mark-sexp}), which sets mark at the same place | |
713 | that @kbd{C-M-f} would move to. @kbd{C-M-@@} takes arguments like | |
714 | @kbd{C-M-f}. In particular, a negative argument is useful for putting | |
715 | the mark at the beginning of the previous balanced expression. | |
649d1cbe | 716 | The alias @kbd{C-M-@key{SPC}} is equivalent to @kbd{C-M-@@}. |
93da5dff RS |
717 | |
718 | In languages that use infix operators, such as C, it is not possible | |
719 | to recognize all balanced expressions as such because there can be | |
720 | multiple possibilities at a given position. For example, C mode does | |
721 | not treat @samp{foo + bar} as a single expression, even though it | |
722 | @emph{is} one C expression; instead, it recognizes @samp{foo} as one | |
723 | expression and @samp{bar} as another, with the @samp{+} as punctuation | |
724 | between them. Both @samp{foo + bar} and @samp{foo} are legitimate | |
725 | choices for ``the expression following point'' when point is at the | |
e79c6b89 RS |
726 | @samp{f}, so the expression commands must perforce choose one or the |
727 | other to operate on. Note that @samp{(foo + bar)} is recognized as a | |
728 | single expression in C mode, because of the parentheses. | |
93da5dff RS |
729 | |
730 | @node Moving by Parens | |
731 | @subsection Moving in the Parenthesis Structure | |
732 | ||
733 | @cindex parenthetical groupings | |
734 | @cindex parentheses, moving across | |
735 | @cindex matching parenthesis and braces, moving to | |
736 | @cindex braces, moving across | |
737 | @cindex list commands | |
738 | The Emacs commands for handling parenthetical groupings see nothing | |
739 | except parentheses (or whatever characters must balance in the | |
740 | language you are working with), and the escape characters that might | |
741 | be used to quote those. They are mainly intended for editing | |
742 | programs, but can be useful for editing any text that has parentheses. | |
743 | They are sometimes called ``list'' commands because in Lisp these | |
744 | groupings are lists. | |
6bf7aab6 DL |
745 | |
746 | @table @kbd | |
93da5dff RS |
747 | @item C-M-n |
748 | Move forward over a parenthetical group (@code{forward-list}). | |
749 | @item C-M-p | |
ea118de1 | 750 | Move backward over a parenthetical group (@code{backward-list}). |
93da5dff RS |
751 | @item C-M-u |
752 | Move up in parenthesis structure (@code{backward-up-list}). | |
753 | @item C-M-d | |
754 | Move down in parenthesis structure (@code{down-list}). | |
6bf7aab6 DL |
755 | @end table |
756 | ||
93da5dff RS |
757 | @kindex C-M-n |
758 | @kindex C-M-p | |
759 | @findex forward-list | |
760 | @findex backward-list | |
761 | The ``list'' commands @kbd{C-M-n} (@code{forward-list}) and | |
762 | @kbd{C-M-p} (@code{backward-list}) move over one (or @var{n}) | |
763 | parenthetical groupings, skipping blithely over any amount of text | |
764 | that doesn't include meaningful parentheses (symbols, strings, etc.). | |
6bf7aab6 | 765 | |
93da5dff RS |
766 | @kindex C-M-u |
767 | @kindex C-M-d | |
768 | @findex backward-up-list | |
769 | @findex down-list | |
770 | @kbd{C-M-n} and @kbd{C-M-p} try to stay at the same level in the | |
771 | parenthesis structure. To move @emph{up} one (or @var{n}) levels, use | |
772 | @kbd{C-M-u} (@code{backward-up-list}). @kbd{C-M-u} moves backward up | |
773 | past one unmatched opening delimiter. A positive argument serves as a | |
774 | repeat count; a negative argument reverses the direction of motion, so | |
d2fab838 | 775 | that the command moves forward and up one or more levels. |
93da5dff RS |
776 | |
777 | To move @emph{down} in the parenthesis structure, use @kbd{C-M-d} | |
778 | (@code{down-list}). In Lisp mode, where @samp{(} is the only opening | |
779 | delimiter, this is nearly the same as searching for a @samp{(}. An | |
780 | argument specifies the number of levels to go down. | |
6bf7aab6 DL |
781 | |
782 | @node Matching | |
93da5dff | 783 | @subsection Automatic Display Of Matching Parentheses |
6bf7aab6 DL |
784 | @cindex matching parentheses |
785 | @cindex parentheses, displaying matches | |
786 | ||
787 | The Emacs parenthesis-matching feature is designed to show | |
93da5dff RS |
788 | automatically how parentheses (and other matching delimiters) match in |
789 | the text. Whenever you type a self-inserting character that is a | |
790 | closing delimiter, the cursor moves momentarily to the location of the | |
791 | matching opening delimiter, provided that is on the screen. If it is | |
e79c6b89 RS |
792 | not on the screen, Emacs displays some of the text near it in the echo |
793 | area. Either way, you can tell which grouping you are closing off. | |
93da5dff RS |
794 | |
795 | If the opening delimiter and closing delimiter are mismatched---such | |
796 | as in @samp{[x)}---a warning message is displayed in the echo area. | |
6bf7aab6 DL |
797 | |
798 | @vindex blink-matching-paren | |
799 | @vindex blink-matching-paren-distance | |
800 | @vindex blink-matching-delay | |
054af0fd SE |
801 | Three variables control parenthesis match display: |
802 | ||
803 | @code{blink-matching-paren} turns the feature on or off: @code{nil} | |
93da5dff | 804 | disables it, but the default is @code{t} to enable match display. |
f772775c RS |
805 | |
806 | @code{blink-matching-delay} says how many seconds to leave the | |
93da5dff | 807 | cursor on the matching opening delimiter, before bringing it back to |
f772775c RS |
808 | the real location of point; the default is 1, but on some systems it |
809 | is useful to specify a fraction of a second. | |
810 | ||
811 | @code{blink-matching-paren-distance} specifies how many characters | |
812 | back to search to find the matching opening delimiter. If the match | |
8b6f4c0a | 813 | is not found in that distance, scanning stops, and nothing is displayed. |
93da5dff | 814 | This is to prevent the scan for the matching delimiter from wasting |
f772775c | 815 | lots of time when there is no match. The default is 25600. |
6bf7aab6 DL |
816 | |
817 | @cindex Show Paren mode | |
79f9f655 | 818 | @cindex highlighting matching parentheses |
6bf7aab6 | 819 | @findex show-paren-mode |
93da5dff RS |
820 | Show Paren mode provides a more powerful kind of automatic matching. |
821 | Whenever point is after a closing delimiter, that delimiter and its | |
822 | matching opening delimiter are both highlighted; otherwise, if point | |
823 | is before an opening delimiter, the matching closing delimiter is | |
824 | highlighted. (There is no need to highlight the opening delimiter in | |
825 | that case, because the cursor appears on top of that character.) Use | |
826 | the command @kbd{M-x show-paren-mode} to enable or disable this mode. | |
79f9f655 EZ |
827 | |
828 | By default, @code{show-paren-mode} uses colors to highlight the | |
829 | parentheses. However, if your display doesn't support colors, you can | |
830 | customize the faces @code{show-paren-match-face} and | |
831 | @code{show-paren-mismatch-face} to use other attributes, such as bold or | |
832 | underline. @xref{Face Customization}. | |
6bf7aab6 DL |
833 | |
834 | @node Comments | |
835 | @section Manipulating Comments | |
836 | @cindex comments | |
837 | ||
838 | Because comments are such an important part of programming, Emacs | |
8f50b630 RS |
839 | provides special commands for editing and inserting comments. It can |
840 | also do spell checking on comments with Flyspell Prog mode | |
841 | (@pxref{Spelling}). | |
6bf7aab6 DL |
842 | |
843 | @menu | |
93da5dff RS |
844 | * Comment Commands:: Inserting, killing, and indenting comments. |
845 | * Multi-Line Comments:: Commands for adding and editing multi-line comments. | |
846 | * Options for Comments::Customizing the comment features. | |
6bf7aab6 DL |
847 | @end menu |
848 | ||
849 | @node Comment Commands | |
850 | @subsection Comment Commands | |
6bf7aab6 | 851 | @cindex indentation for comments |
6bf7aab6 | 852 | |
9234c238 RS |
853 | The comment commands in this table insert, kill and align comments. |
854 | They are described in this section and following sections. | |
6bf7aab6 | 855 | |
7ae8ad94 RS |
856 | @table @asis |
857 | @item @kbd{M-;} | |
9234c238 RS |
858 | Insert or realign comment on current line; alternatively, comment or |
859 | uncomment the region (@code{comment-dwim}). | |
7ae8ad94 | 860 | @item @kbd{C-u M-;} |
9234c238 | 861 | Kill comment on current line (@code{comment-kill}). |
7ae8ad94 | 862 | @item @kbd{C-x ;} |
47c1b5f4 | 863 | Set comment column (@code{comment-set-column}). |
7ae8ad94 RS |
864 | @item @kbd{C-M-j} |
865 | @itemx @kbd{M-j} | |
6bf7aab6 | 866 | Like @key{RET} followed by inserting and aligning a comment |
47c1b5f4 | 867 | (@code{comment-indent-new-line}). |
7ae8ad94 RS |
868 | @item @kbd{M-x comment-region} |
869 | @itemx @kbd{C-c C-c} (in C-like modes) | |
6bf7aab6 DL |
870 | Add or remove comment delimiters on all the lines in the region. |
871 | @end table | |
872 | ||
9234c238 RS |
873 | @kindex M-; |
874 | @findex comment-dwim | |
875 | The command to create or align a comment is @kbd{M-;} | |
876 | (@code{comment-dwim}). The word ``dwim'' is an acronym for ``Do What | |
877 | I Mean''; it indicates that this command can be used for many | |
878 | different jobs relating to comments, depending on the situation where | |
879 | you use it. | |
880 | ||
881 | If there is no comment already on the line, @kbd{M-;} inserts a new | |
882 | comment, aligned at a specific column called the @dfn{comment column}. | |
883 | The new comment begins with the string Emacs thinks comments should | |
884 | start with (the value of @code{comment-start}; see below). Point is | |
885 | after that string, so you can insert the text of the comment right | |
886 | away. If the major mode has specified a string to terminate comments, | |
887 | @kbd{M-;} inserts that too, to keep the syntax valid. | |
888 | ||
889 | If the text of the line extends past the comment column, then the | |
890 | comment start string is indented to a suitable boundary (usually, at | |
891 | least one space is inserted). | |
892 | ||
893 | You can also use @kbd{M-;} to align an existing comment. If a line | |
894 | already contains the comment-start string, @kbd{M-;} reindents it to | |
895 | the conventional alignment and moves point after it. (Exception: | |
896 | comments starting in column 0 are not moved.) Even when an existing | |
897 | comment is properly aligned, @kbd{M-;} is still useful for moving | |
898 | directly to the start of the text inside the comment. | |
899 | ||
900 | @findex comment-kill | |
901 | @kindex C-u M-; | |
902 | @kbd{C-u M-;} kills any comment on the current line, along with the | |
903 | whitespace before it. To reinsert the comment on another line, move | |
904 | to the end of that line, do @kbd{C-y}, and then do @kbd{M-;} to | |
905 | realign it. | |
906 | ||
907 | Note that @kbd{C-u M-;} is not a distinct key; it is @kbd{M-;} | |
908 | (@code{comment-dwim}) with a prefix argument. That command is | |
909 | programmed so that when it receives a prefix argument it calls | |
910 | @code{comment-kill}. However, @code{comment-kill} is a valid command | |
911 | in its own right, and you can bind it directly to a key if you wish. | |
912 | ||
913 | @kbd{M-;} does two other jobs when used with an active region in | |
914 | Transient Mark mode (@pxref{Transient Mark}). Then it either adds or | |
915 | removes comment delimiters on each line of the region. (If every line | |
916 | is a comment, it removes comment delimiters from each; otherwise, it | |
917 | adds comment delimiters to each.) If you are not using Transient Mark | |
918 | mode, then you should use the commands @code{comment-region} and | |
7ad1b919 | 919 | @code{uncomment-region} to do these jobs (@pxref{Multi-Line Comments}). |
9234c238 RS |
920 | A prefix argument used in these circumstances specifies how many |
921 | comment delimiters to add or how many to delete. | |
6bf7aab6 DL |
922 | |
923 | Some major modes have special rules for indenting certain kinds of | |
924 | comments in certain contexts. For example, in Lisp code, comments which | |
925 | start with two semicolons are indented as if they were lines of code, | |
926 | instead of at the comment column. Comments which start with three | |
927 | semicolons are supposed to start at the left margin. Emacs understands | |
928 | these conventions by indenting a double-semicolon comment using @key{TAB}, | |
929 | and by not changing the indentation of a triple-semicolon comment at all. | |
930 | ||
931 | @example | |
932 | ;; This function is just an example | |
933 | ;;; Here either two or three semicolons are appropriate. | |
934 | (defun foo (x) | |
935 | ;;; And now, the first part of the function: | |
936 | ;; The following line adds one. | |
937 | (1+ x)) ; This line adds one. | |
938 | @end example | |
939 | ||
940 | In C code, a comment preceded on its line by nothing but whitespace | |
941 | is indented like a line of code. | |
942 | ||
6bf7aab6 DL |
943 | @node Multi-Line Comments |
944 | @subsection Multiple Lines of Comments | |
945 | ||
946 | @kindex C-M-j | |
7ae8ad94 | 947 | @kindex M-j |
6bf7aab6 | 948 | @cindex blank lines in programs |
47c1b5f4 | 949 | @findex comment-indent-new-line |
6bf7aab6 | 950 | If you are typing a comment and wish to continue it on another line, |
7ae8ad94 RS |
951 | you can use the command @kbd{C-M-j} or @kbd{M-j} |
952 | (@code{comment-indent-new-line}). This terminates the comment you are | |
953 | typing, creates a new blank line afterward, and begins a new comment | |
954 | indented under the old one. When Auto Fill mode is on, going past the | |
955 | fill column while typing a comment causes the comment to be continued | |
956 | in just this fashion. If point is not at the end of the line when you | |
957 | type the command, the text on the rest of the line becomes part of the | |
958 | new comment line. | |
959 | ||
960 | @kindex C-c C-c (C mode) | |
6bf7aab6 DL |
961 | @findex comment-region |
962 | To turn existing lines into comment lines, use the @kbd{M-x | |
963 | comment-region} command. It adds comment delimiters to the lines that start | |
964 | in the region, thus commenting them out. With a negative argument, it | |
965 | does the opposite---it deletes comment delimiters from the lines in the | |
966 | region. | |
967 | ||
968 | With a positive argument, @code{comment-region} duplicates the last | |
969 | character of the comment start sequence it adds; the argument specifies | |
970 | how many copies of the character to insert. Thus, in Lisp mode, | |
971 | @kbd{C-u 2 M-x comment-region} adds @samp{;;} to each line. Duplicating | |
972 | the comment delimiter is a way of calling attention to the comment. It | |
973 | can also affect how the comment is indented. In Lisp, for proper | |
47c1b5f4 RS |
974 | indentation, you should use an argument of two or three, if between defuns; |
975 | if within a defun, it must be three. | |
6bf7aab6 | 976 | |
6bf7aab6 DL |
977 | @node Options for Comments |
978 | @subsection Options Controlling Comments | |
979 | ||
980 | @vindex comment-column | |
981 | @kindex C-x ; | |
47c1b5f4 | 982 | @findex comment-set-column |
7ae8ad94 RS |
983 | The @dfn{comment column}, the column at which Emacs tries to place |
984 | comments, is stored in the variable @code{comment-column}. You can | |
985 | set it to a number explicitly. Alternatively, the command @kbd{C-x ;} | |
986 | (@code{comment-set-column}) sets the comment column to the column | |
987 | point is at. @kbd{C-u C-x ;} sets the comment column to match the | |
988 | last comment before point in the buffer, and then does a @kbd{M-;} to | |
989 | align the current line's comment under the previous one. | |
6bf7aab6 DL |
990 | |
991 | The variable @code{comment-column} is per-buffer: setting the variable | |
992 | in the normal fashion affects only the current buffer, but there is a | |
993 | default value which you can change with @code{setq-default}. | |
994 | @xref{Locals}. Many major modes initialize this variable for the | |
995 | current buffer. | |
996 | ||
997 | @vindex comment-start-skip | |
998 | The comment commands recognize comments based on the regular | |
999 | expression that is the value of the variable @code{comment-start-skip}. | |
1000 | Make sure this regexp does not match the null string. It may match more | |
1001 | than the comment starting delimiter in the strictest sense of the word; | |
47c1b5f4 RS |
1002 | for example, in C mode the value of the variable is |
1003 | @c This stops M-q from breaking the line inside that @code. | |
7ae8ad94 | 1004 | @code{@w{"/\\*+ *\\|//+ *"}}, which matches extra stars and spaces |
47c1b5f4 | 1005 | after the @samp{/*} itself, and accepts C++ style comments also. |
6bf7aab6 DL |
1006 | (Note that @samp{\\} is needed in Lisp syntax to include a @samp{\} in |
1007 | the string, which is needed to deny the first star its special meaning | |
1008 | in regexp syntax. @xref{Regexps}.) | |
1009 | ||
1010 | @vindex comment-start | |
1011 | @vindex comment-end | |
1012 | When a comment command makes a new comment, it inserts the value of | |
1013 | @code{comment-start} to begin it. The value of @code{comment-end} is | |
1014 | inserted after point, so that it will follow the text that you will insert | |
1015 | into the comment. In C mode, @code{comment-start} has the value | |
1016 | @w{@code{"/* "}} and @code{comment-end} has the value @w{@code{" */"}}. | |
1017 | ||
9234c238 RS |
1018 | @vindex comment-padding |
1019 | The variable @code{comment-padding} specifies how many spaces | |
7ae8ad94 RS |
1020 | @code{comment-region} should insert on each line between the comment |
1021 | delimiter and the line's original text. The default is 1, to insert | |
1022 | one space. @code{nil} means 0. Alternatively, @code{comment-padding} | |
1023 | can hold the actual string to insert. | |
9234c238 | 1024 | |
6bf7aab6 DL |
1025 | @vindex comment-multi-line |
1026 | The variable @code{comment-multi-line} controls how @kbd{C-M-j} | |
7ae8ad94 RS |
1027 | (@code{indent-new-comment-line}) behaves when used inside a comment. |
1028 | Specifically, when @code{comment-multi-line} is @code{nil} (the | |
1029 | default value), the command inserts a comment terminator, begins a new | |
1030 | line, and finally inserts a comment starter. Otherwise it does not | |
1031 | insert the terminator and starter, so it effectively continues the | |
1032 | current comment across multiple lines. In languages that allow | |
1033 | multi-line comments, the choice of value for this variable is a matter | |
1034 | of taste. | |
6bf7aab6 | 1035 | |
4190ce5c | 1036 | @vindex comment-indent-function |
6bf7aab6 DL |
1037 | The variable @code{comment-indent-function} should contain a function |
1038 | that will be called to compute the indentation for a newly inserted | |
1039 | comment or for aligning an existing comment. It is set differently by | |
1040 | various major modes. The function is called with no arguments, but with | |
1041 | point at the beginning of the comment, or at the end of a line if a new | |
1042 | comment is to be inserted. It should return the column in which the | |
1043 | comment ought to start. For example, in Lisp mode, the indent hook | |
1044 | function bases its decision on how many semicolons begin an existing | |
1045 | comment, and on the code in the preceding lines. | |
1046 | ||
93da5dff RS |
1047 | @node Documentation |
1048 | @section Documentation Lookup | |
6bf7aab6 | 1049 | |
93da5dff RS |
1050 | Emacs provides several features you can use to look up the |
1051 | documentation of functions, variables and commands that you plan to | |
1052 | use in your program. | |
6bf7aab6 | 1053 | |
93da5dff RS |
1054 | @menu |
1055 | * Info Lookup:: Looking up library functions and commands | |
1056 | in Info files. | |
1057 | * Man Page:: Looking up man pages of library functions and commands. | |
1058 | * Lisp Doc:: Looking up Emacs Lisp functions, etc. | |
1059 | @end menu | |
6bf7aab6 | 1060 | |
93da5dff RS |
1061 | @node Info Lookup |
1062 | @subsection Info Documentation Lookup | |
85750656 | 1063 | |
93da5dff RS |
1064 | @findex info-lookup-symbol |
1065 | @findex info-lookup-file | |
d2f9ea87 | 1066 | @kindex C-h S |
93da5dff | 1067 | For C, Lisp, and other languages that have documentation in Info, |
d2f9ea87 | 1068 | you can use @kbd{C-h S} (@code{info-lookup-symbol}) to view the Info |
93da5dff RS |
1069 | documentation for a symbol. You specify the symbol with the |
1070 | minibuffer; the default is the symbol appearing in the buffer at | |
1071 | point. | |
6bf7aab6 | 1072 | |
93da5dff RS |
1073 | The major mode determines where to look for documentation for the |
1074 | symbol---which Info files to look in, and which indices to search. | |
1075 | You can also use @kbd{M-x info-lookup-file} to look for documentation | |
1076 | for a file name. | |
6bf7aab6 | 1077 | |
7ae8ad94 | 1078 | This feature currently supports the modes AWK, Autoconf, Bison, C, |
93da5dff RS |
1079 | Emacs Lisp, LaTeX, M4, Makefile, Octave, Perl, Scheme, and Texinfo, |
1080 | provided you have installed the relevant Info files, which are | |
1081 | typically available with the appropriate GNU package. | |
6bf7aab6 | 1082 | |
93da5dff RS |
1083 | @node Man Page |
1084 | @subsection Man Page Lookup | |
6bf7aab6 | 1085 | |
e79c6b89 RS |
1086 | @cindex manual page |
1087 | On Unix, the main form of on-line documentation was the @dfn{manual | |
1088 | page} or @dfn{man page}. In the GNU operating system, we hope to | |
1089 | replace man pages with better-organized manuals that you can browse | |
1090 | with Info (@pxref{Misc Help}). This process is not finished, so it is | |
1091 | still useful to read manual pages. | |
6bf7aab6 | 1092 | |
93da5dff | 1093 | @findex manual-entry |
e79c6b89 | 1094 | You can read the man page for an operating system command, library |
7ae8ad94 | 1095 | function, or system call, with the @kbd{M-x man} command. It |
e79c6b89 RS |
1096 | runs the @code{man} program to format the man page; if the system |
1097 | permits, it runs @code{man} asynchronously, so that you can keep on | |
1098 | editing while the page is being formatted. (On MS-DOS and MS-Windows | |
1099 | 3, you cannot edit while Emacs waits for @code{man} to finish.) The | |
1100 | result goes in a buffer named @samp{*Man @var{topic}*}. These buffers | |
1101 | use a special major mode, Man mode, that facilitates scrolling and | |
1102 | jumping to other manual pages. For details, type @kbd{C-h m} while in | |
1103 | a man page buffer. | |
6bf7aab6 | 1104 | |
93da5dff | 1105 | @cindex sections of manual pages |
e79c6b89 RS |
1106 | Each man page belongs to one of ten or more @dfn{sections}, each |
1107 | named by a digit or by a digit and a letter. Sometimes there are | |
1108 | multiple man pages with the same name in different sections. To read | |
1109 | a man page from a specific section, type | |
93da5dff RS |
1110 | @samp{@var{topic}(@var{section})} or @samp{@var{section} @var{topic}} |
1111 | when @kbd{M-x manual-entry} prompts for the topic. For example, to | |
1112 | read the man page for the C library function @code{chmod} (as opposed | |
e79c6b89 RS |
1113 | to a command of the same name), type @kbd{M-x manual-entry @key{RET} |
1114 | chmod(2) @key{RET}} (@code{chmod} is a system call, so it is in | |
1115 | section @samp{2}). | |
6bf7aab6 | 1116 | |
08220274 | 1117 | @vindex Man-switches |
93da5dff | 1118 | If you do not specify a section, the results depend on how the |
08220274 | 1119 | @code{man} program works on your system. Some of them display only |
93da5dff RS |
1120 | the first man page they find. Others display all man pages that have |
1121 | the specified name, so you can move between them with the @kbd{M-n} | |
08220274 EZ |
1122 | and @kbd{M-p} keys@footnote{On some systems, the @code{man} program |
1123 | accepts a @samp{-a} command-line option which tells it to display all | |
1124 | the man pages for the specified topic. If you want this behavior, you | |
1125 | can add this option to the value of the variable @code{Man-switches}.}. | |
1126 | The mode line shows how many manual pages are present in the Man buffer. | |
6bf7aab6 | 1127 | |
93da5dff | 1128 | @vindex Man-fontify-manpage-flag |
e79c6b89 RS |
1129 | By default, Emacs highlights the text in man pages. For a long man |
1130 | page, highlighting can take substantial time. You can turn off | |
1131 | highlighting of man pages by setting the variable | |
1132 | @code{Man-fontify-manpage-flag} to @code{nil}. | |
6bf7aab6 | 1133 | |
93da5dff RS |
1134 | @findex Man-fontify-manpage |
1135 | If you insert the text of a man page into an Emacs buffer in some | |
1136 | other fashion, you can use the command @kbd{M-x Man-fontify-manpage} to | |
1137 | perform the same conversions that @kbd{M-x manual-entry} does. | |
1138 | ||
1139 | @findex woman | |
1140 | @cindex manual pages, on MS-DOS/MS-Windows | |
1141 | An alternative way of reading manual pages is the @kbd{M-x woman} | |
1142 | command@footnote{The name of the command, @code{woman}, is an acronym | |
1143 | for ``w/o (without) man,'' since it doesn't use the @code{man} | |
1144 | program.}. Unlike @kbd{M-x man}, it does not run any external | |
1145 | programs to format and display the man pages; instead it does the job | |
1146 | in Emacs Lisp, so it works on systems such as MS-Windows, where the | |
ea118de1 | 1147 | @code{man} program (and other programs it uses) are not generally |
d2fab838 RS |
1148 | available. |
1149 | ||
1150 | @kbd{M-x woman} prompts for a name of a manual page, and provides | |
1151 | completion based on the list of manual pages that are installed on | |
1152 | your machine; the list of available manual pages is computed | |
1153 | automatically the first time you invoke @code{woman}. The word at | |
1154 | point in the current buffer is used to suggest the default for the | |
1155 | name the manual page. | |
93da5dff RS |
1156 | |
1157 | With a numeric argument, @kbd{M-x woman} recomputes the list of the | |
1158 | manual pages used for completion. This is useful if you add or delete | |
1159 | manual pages. | |
1160 | ||
1161 | If you type a name of a manual page and @kbd{M-x woman} finds that | |
1162 | several manual pages by the same name exist in different sections, it | |
1163 | pops up a window with possible candidates asking you to choose one of | |
1164 | them. | |
1165 | ||
1166 | @vindex woman-manpath | |
1167 | By default, @kbd{M-x woman} looks for manual pages in the | |
1168 | directories specified in the @code{MANPATH} environment variable. (If | |
1169 | @code{MANPATH} is not set, @code{woman} uses a suitable default value, | |
1170 | which can be customized.) More precisely, @code{woman} looks for | |
e79c6b89 | 1171 | subdirectories that match the shell wildcard pattern @file{man*} in each one |
93da5dff RS |
1172 | of these directories, and tries to find the manual pages in those |
1173 | subdirectories. When first invoked, @kbd{M-x woman} converts the | |
1174 | value of @code{MANPATH} to a list of directory names and stores that | |
1175 | list in the @code{woman-manpath} variable. Changing the value of this | |
1176 | variable is another way to control the list of directories used. | |
1177 | ||
1178 | @vindex woman-path | |
1179 | You can also augment the list of directories searched by | |
1180 | @code{woman} by setting the value of the @code{woman-path} variable. | |
1181 | This variable should hold a list of specific directories which | |
1182 | @code{woman} should search, in addition to those in | |
1183 | @code{woman-manpath}. Unlike @code{woman-manpath}, the directories in | |
1184 | @code{woman-path} are searched for the manual pages, not for | |
1185 | @file{man*} subdirectories. | |
1186 | ||
1187 | @findex woman-find-file | |
1188 | Occasionally, you might need to display manual pages that are not in | |
1189 | any of the directories listed by @code{woman-manpath} and | |
1190 | @code{woman-path}. The @kbd{M-x woman-find-file} command prompts for a | |
1191 | name of a manual page file, with completion, and then formats and | |
1192 | displays that file like @kbd{M-x woman} does. | |
1193 | ||
1194 | @vindex woman-dired-keys | |
1195 | The first time you invoke @kbd{M-x woman}, it defines the Dired | |
1196 | @kbd{W} key to run the @code{woman-find-file} command on the current | |
1197 | line's file. You can disable this by setting the variable | |
1198 | @code{woman-dired-keys} to @code{nil}. @xref{Dired}. In addition, | |
1199 | the Tar-mode @kbd{w} key is define to invoke @code{woman-find-file} on | |
1200 | the current line's archive member. | |
1201 | ||
1202 | For more information about setting up and using @kbd{M-x woman}, see | |
1203 | @ref{Top, WoMan, Browse UN*X Manual Pages WithOut Man, woman, The WoMan | |
1204 | Manual}. | |
1205 | ||
1206 | @node Lisp Doc | |
1207 | @subsection Emacs Lisp Documentation Lookup | |
1208 | ||
1209 | As you edit Lisp code to be run in Emacs, you can use the commands | |
1210 | @kbd{C-h f} (@code{describe-function}) and @kbd{C-h v} | |
1211 | (@code{describe-variable}) to view documentation of functions and | |
1212 | variables that you want to use. These commands use the minibuffer to | |
1213 | read the name of a function or variable to document, and display the | |
1214 | documentation in a window. Their default arguments are based on the | |
1215 | code in the neighborhood of point. For @kbd{C-h f}, the default is | |
1216 | the function called in the innermost list containing point. @kbd{C-h | |
1217 | v} uses the symbol name around or adjacent to point as its default. | |
1218 | ||
1219 | @cindex Eldoc mode | |
1220 | @findex eldoc-mode | |
1221 | A more automatic but less powerful method is Eldoc mode. This minor | |
1222 | mode constantly displays in the echo area the argument list for the | |
1223 | function being called at point. (In other words, it finds the | |
1224 | function call that point is contained in, and displays the argument | |
054af0fd SE |
1225 | list of that function.) If point is over a documented variable, it |
1226 | shows the variable's docstring. Eldoc mode applies in Emacs Lisp and | |
1227 | Lisp Interaction modes only. Use the command @kbd{M-x eldoc-mode} to | |
93da5dff | 1228 | enable or disable this feature. |
6bf7aab6 | 1229 | |
51ed0ea0 DL |
1230 | @node Hideshow |
1231 | @section Hideshow minor mode | |
1232 | ||
1233 | @findex hs-minor-mode | |
9234c238 | 1234 | Hideshow minor mode provides selective display of portions of a |
93da5dff RS |
1235 | program, known as @dfn{blocks}. You can use @kbd{M-x hs-minor-mode} |
1236 | to enable or disable this mode, or add @code{hs-minor-mode} to the | |
1237 | mode hook for certain major modes in order to enable it automatically | |
1238 | for those modes. | |
51ed0ea0 | 1239 | |
9234c238 RS |
1240 | Just what constitutes a block depends on the major mode. In C mode |
1241 | or C++ mode, they are delimited by braces, while in Lisp mode and | |
1242 | similar modes they are delimited by parentheses. Multi-line comments | |
1243 | also count as blocks. | |
51ed0ea0 DL |
1244 | |
1245 | @findex hs-hide-all | |
1246 | @findex hs-hide-block | |
1247 | @findex hs-show-all | |
1248 | @findex hs-show-block | |
1249 | @findex hs-show-region | |
1250 | @findex hs-hide-level | |
1251 | @findex hs-minor-mode | |
6401dc86 EZ |
1252 | @kindex C-c @@ C-h |
1253 | @kindex C-c @@ C-s | |
1254 | @kindex C-c @@ C-M-h | |
1255 | @kindex C-c @@ C-M-s | |
1256 | @kindex C-c @@ C-r | |
1257 | @kindex C-c @@ C-l | |
9234c238 RS |
1258 | @kindex S-Mouse-2 |
1259 | @table @kbd | |
6401dc86 | 1260 | @item C-c @@ C-h |
9234c238 | 1261 | Hide the current block (@code{hs-hide-block}). |
6401dc86 | 1262 | @item C-c @@ C-s |
9234c238 | 1263 | Show the current block (@code{hs-show-block}). |
6401dc86 | 1264 | @item C-c @@ C-c |
ea118de1 | 1265 | Either hide or show the current block (@code{hs-toggle-hiding}). |
9234c238 | 1266 | @item S-Mouse-2 |
ea118de1 | 1267 | Either hide or show the block you click on (@code{hs-mouse-toggle-hiding}). |
6401dc86 | 1268 | @item C-c @@ C-M-h |
9234c238 | 1269 | Hide all top-level blocks (@code{hs-hide-all}). |
6401dc86 | 1270 | @item C-c @@ C-M-s |
9234c238 | 1271 | Show everything in the buffer (@code{hs-show-all}). |
6401dc86 | 1272 | @item C-c @@ C-l |
9234c238 RS |
1273 | Hide all blocks @var{n} levels below this block |
1274 | (@code{hs-hide-level}). | |
1275 | @end table | |
51ed0ea0 DL |
1276 | |
1277 | @vindex hs-hide-comments-when-hiding-all | |
51ed0ea0 DL |
1278 | @vindex hs-isearch-open |
1279 | @vindex hs-special-modes-alist | |
19b2c4ca | 1280 | These variables exist for customizing Hideshow mode. |
9234c238 | 1281 | |
51ed0ea0 DL |
1282 | @table @code |
1283 | @item hs-hide-comments-when-hiding-all | |
9234c238 | 1284 | Non-@code{nil} says that @kbd{hs-hide-all} should hide comments too. |
d2fab838 | 1285 | |
51ed0ea0 DL |
1286 | @item hs-isearch-open |
1287 | Specifies what kind of hidden blocks to open in Isearch mode. | |
ea118de1 | 1288 | The value should be one of these four symbols: |
d2fab838 RS |
1289 | |
1290 | @table @code | |
9198a323 RS |
1291 | @item code |
1292 | Open only code blocks. | |
d2fab838 RS |
1293 | @item comment |
1294 | Open only comments. | |
1295 | @item t | |
9198a323 | 1296 | Open both code blocks and comments. |
d2fab838 | 1297 | @item nil |
9198a323 | 1298 | Open neither code blocks nor comments. |
d2fab838 RS |
1299 | @end table |
1300 | ||
51ed0ea0 | 1301 | @item hs-special-modes-alist |
e79c6b89 | 1302 | A list of elements, each specifying how to initialize Hideshow |
d2fab838 RS |
1303 | variables for one major mode. See the variable's documentation string |
1304 | for more information. | |
51ed0ea0 DL |
1305 | @end table |
1306 | ||
93da5dff RS |
1307 | @node Symbol Completion |
1308 | @section Completion for Symbol Names | |
1309 | @cindex completion (symbol names) | |
3b8b8888 | 1310 | |
e79c6b89 RS |
1311 | In Emacs, completion is something you normally do in the minibuffer. |
1312 | But one kind of completion is available in all buffers: completion for | |
1313 | symbol names. | |
3b8b8888 | 1314 | |
93da5dff | 1315 | @kindex M-TAB |
e79c6b89 RS |
1316 | The character @kbd{M-@key{TAB}} runs a command to complete the |
1317 | partial symbol before point against the set of meaningful symbol | |
1318 | names. This command inserts at point any additional characters that | |
1319 | it can determine from the partial name. | |
6bf7aab6 | 1320 | |
e79c6b89 RS |
1321 | If the partial name in the buffer has multiple possible completions |
1322 | that differ in the very next character, so that it is impossible to | |
1323 | complete even one more character, @kbd{M-@key{TAB}} displays a list of | |
1324 | all possible completions in another window. | |
6bf7aab6 | 1325 | |
93da5dff RS |
1326 | @cindex tags-based completion |
1327 | @cindex Info index completion | |
1328 | @findex complete-symbol | |
1329 | In most programming language major modes, @kbd{M-@key{TAB}} runs the | |
1330 | command @code{complete-symbol}, which provides two kinds of completion. | |
1331 | Normally it does completion based on a tags table (@pxref{Tags}); with a | |
1332 | numeric argument (regardless of the value), it does completion based on | |
1333 | the names listed in the Info file indexes for your language. Thus, to | |
1334 | complete the name of a symbol defined in your own program, use | |
1335 | @kbd{M-@key{TAB}} with no argument; to complete the name of a standard | |
1336 | library function, use @kbd{C-u M-@key{TAB}}. Of course, Info-based | |
1337 | completion works only if there is an Info file for the standard library | |
1338 | functions of your language, and only if it is installed at your site. | |
6bf7aab6 | 1339 | |
93da5dff RS |
1340 | @cindex Lisp symbol completion |
1341 | @cindex completion (Lisp symbols) | |
1342 | @findex lisp-complete-symbol | |
1343 | In Emacs-Lisp mode, the name space for completion normally consists of | |
1344 | nontrivial symbols present in Emacs---those that have function | |
1345 | definitions, values or properties. However, if there is an | |
1346 | open-parenthesis immediately before the beginning of the partial symbol, | |
1347 | only symbols with function definitions are considered as completions. | |
1348 | The command which implements this is @code{lisp-complete-symbol}. | |
6bf7aab6 | 1349 | |
93da5dff RS |
1350 | In Text mode and related modes, @kbd{M-@key{TAB}} completes words |
1351 | based on the spell-checker's dictionary. @xref{Spelling}. | |
6bf7aab6 | 1352 | |
93da5dff RS |
1353 | @node Glasses |
1354 | @section Glasses minor mode | |
1355 | @cindex Glasses mode | |
1356 | @cindex identifiers, making long ones readable | |
1357 | @cindex StudlyCaps, making them readable | |
1358 | @findex glasses-mode | |
6bf7aab6 | 1359 | |
93da5dff | 1360 | Glasses minor mode makes @samp{unreadableIdentifiersLikeThis} |
e79c6b89 RS |
1361 | readable by altering the way they display. It knows two different |
1362 | ways to do this: by displaying underscores between a lower-case letter | |
1363 | and the following capital letter, and by emboldening the capital | |
1364 | letters. It does not alter the buffer text, only the way they | |
1365 | display, so you can use it even on read-only buffers. You can use the | |
1366 | command @kbd{M-x glasses-mode} to enable or disable the mode in the | |
1367 | current buffer; you can also add @code{glasses-mode} to the mode hook | |
1368 | of the programming language major modes in which you normally want | |
177c0ea7 | 1369 | to use Glasses mode. |
6bf7aab6 | 1370 | |
93da5dff RS |
1371 | @node Misc for Programs |
1372 | @section Other Features Useful for Editing Programs | |
6bf7aab6 | 1373 | |
93da5dff | 1374 | A number of Emacs commands that aren't designed specifically for |
e79c6b89 | 1375 | editing programs are useful for that nonetheless. |
6bf7aab6 | 1376 | |
93da5dff RS |
1377 | The Emacs commands that operate on words, sentences and paragraphs |
1378 | are useful for editing code. Most symbols names contain words | |
1379 | (@pxref{Words}); sentences can be found in strings and comments | |
e79c6b89 | 1380 | (@pxref{Sentences}). Paragraphs in the strict sense can be found in |
93da5dff RS |
1381 | program code (in long comments), but the paragraph commands are useful |
1382 | in other places too, because programming language major modes define | |
1383 | paragraphs to begin and end at blank lines (@pxref{Paragraphs}). | |
1384 | Judicious use of blank lines to make the program clearer will also | |
1385 | provide useful chunks of text for the paragraph commands to work on. | |
1386 | Auto Fill mode, if enabled in a programming language major mode, | |
1387 | indents the new lines which it creates. | |
6bf7aab6 | 1388 | |
93da5dff RS |
1389 | The selective display feature is useful for looking at the overall |
1390 | structure of a function (@pxref{Selective Display}). This feature | |
1391 | hides the lines that are indented more than a specified amount. | |
1392 | Programming modes often support Outline minor mode (@pxref{Outline | |
1393 | Mode}). The Foldout package provides folding-editor features | |
1394 | (@pxref{Foldout}). | |
6bf7aab6 | 1395 | |
93da5dff RS |
1396 | The ``automatic typing'' features may be useful for writing programs. |
1397 | @xref{Top,,Autotyping, autotype, Autotyping}. | |
6bf7aab6 DL |
1398 | |
1399 | @node C Modes | |
1400 | @section C and Related Modes | |
1401 | @cindex C mode | |
1402 | @cindex Java mode | |
1403 | @cindex Pike mode | |
1404 | @cindex IDL mode | |
1405 | @cindex CORBA IDL mode | |
1406 | @cindex Objective C mode | |
1407 | @cindex C++ mode | |
7ae8ad94 | 1408 | @cindex AWK mode |
6bf7aab6 DL |
1409 | @cindex mode, Java |
1410 | @cindex mode, C | |
7ae8ad94 | 1411 | @cindex mode, C++ |
6bf7aab6 DL |
1412 | @cindex mode, Objective C |
1413 | @cindex mode, CORBA IDL | |
1414 | @cindex mode, Pike | |
7ae8ad94 | 1415 | @cindex mode, AWK |
6bf7aab6 | 1416 | |
9234c238 | 1417 | This section gives a brief description of the special features |
7ae8ad94 | 1418 | available in C, C++, Objective-C, Java, CORBA IDL, Pike and AWK modes. |
5d80fe1f EZ |
1419 | (These are called ``C mode and related modes.'') @xref{Top, , CC Mode, |
1420 | ccmode, CC Mode}, for a more extensive description of these modes | |
9234c238 | 1421 | and their special features. |
51ed0ea0 | 1422 | |
6bf7aab6 | 1423 | @menu |
7ae8ad94 RS |
1424 | * Motion in C:: Commands to move by C statements, etc. |
1425 | * Electric C:: Colon and other chars can automatically reindent. | |
1426 | * Hungry Delete:: A more powerful DEL command. | |
1427 | * Other C Commands:: Filling comments, viewing expansion of macros, | |
1428 | and other neat features. | |
6bf7aab6 DL |
1429 | @end menu |
1430 | ||
1431 | @node Motion in C | |
1432 | @subsection C Mode Motion Commands | |
1433 | ||
1434 | This section describes commands for moving point, in C mode and | |
1435 | related modes. | |
1436 | ||
1437 | @table @code | |
7ae8ad94 RS |
1438 | @item M-x c-beginning-of-defun |
1439 | @itemx M-x c-end-of-defun | |
1440 | @findex c-beginning-of-defun | |
1441 | @findex c-end-of-defun | |
1442 | Move point to the beginning or end of the current function or | |
1443 | top-level definition. These are found by searching for the least | |
1444 | enclosing braces. (By contrast, @code{beginning-of-defun} and | |
1445 | @code{end-of-defun} search for braces in column zero.) If you are | |
1446 | editing code where the opening brace of a function isn't placed in | |
1447 | column zero, you may wish to bind @code{C-M-a} and @code{C-M-e} to | |
1448 | these commands. @xref{Moving by Defuns}. | |
1449 | ||
6bf7aab6 DL |
1450 | @item C-c C-u |
1451 | @kindex C-c C-u @r{(C mode)} | |
1452 | @findex c-up-conditional | |
1453 | Move point back to the containing preprocessor conditional, leaving the | |
1454 | mark behind. A prefix argument acts as a repeat count. With a negative | |
1455 | argument, move point forward to the end of the containing | |
7ae8ad94 RS |
1456 | preprocessor conditional. |
1457 | ||
1458 | @samp{#elif} is equivalent to @samp{#else} followed by @samp{#if}, so | |
1459 | the function will stop at a @samp{#elif} when going backward, but not | |
1460 | when going forward. | |
6bf7aab6 DL |
1461 | |
1462 | @item C-c C-p | |
1463 | @kindex C-c C-p @r{(C mode)} | |
1464 | @findex c-backward-conditional | |
1465 | Move point back over a preprocessor conditional, leaving the mark | |
1466 | behind. A prefix argument acts as a repeat count. With a negative | |
1467 | argument, move forward. | |
1468 | ||
1469 | @item C-c C-n | |
1470 | @kindex C-c C-n @r{(C mode)} | |
1471 | @findex c-forward-conditional | |
1472 | Move point forward across a preprocessor conditional, leaving the mark | |
1473 | behind. A prefix argument acts as a repeat count. With a negative | |
1474 | argument, move backward. | |
1475 | ||
1476 | @item M-a | |
7ae8ad94 | 1477 | @kindex M-a (C mode) |
6bf7aab6 DL |
1478 | @findex c-beginning-of-statement |
1479 | Move point to the beginning of the innermost C statement | |
1480 | (@code{c-beginning-of-statement}). If point is already at the beginning | |
1481 | of a statement, move to the beginning of the preceding statement. With | |
1482 | prefix argument @var{n}, move back @var{n} @minus{} 1 statements. | |
1483 | ||
7ae8ad94 RS |
1484 | In comments or in strings which span more than one line, this command |
1485 | moves by sentences instead of statements. | |
6bf7aab6 DL |
1486 | |
1487 | @item M-e | |
7ae8ad94 | 1488 | @kindex M-e (C mode) |
6bf7aab6 | 1489 | @findex c-end-of-statement |
7ae8ad94 RS |
1490 | Move point to the end of the innermost C statement or sentence; like |
1491 | @kbd{M-a} except that it moves in the other direction | |
1492 | (@code{c-end-of-statement}). | |
6bf7aab6 DL |
1493 | |
1494 | @item M-x c-backward-into-nomenclature | |
1495 | @findex c-backward-into-nomenclature | |
1496 | Move point backward to beginning of a C++ nomenclature section or word. | |
1497 | With prefix argument @var{n}, move @var{n} times. If @var{n} is | |
1498 | negative, move forward. C++ nomenclature means a symbol name in the | |
1499 | style of NamingSymbolsWithMixedCaseAndNoUnderlines; each capital letter | |
1500 | begins a section or word. | |
1501 | ||
1502 | In the GNU project, we recommend using underscores to separate words | |
1503 | within an identifier in C or C++, rather than using case distinctions. | |
1504 | ||
1505 | @item M-x c-forward-into-nomenclature | |
1506 | @findex c-forward-into-nomenclature | |
1507 | Move point forward to end of a C++ nomenclature section or word. | |
1508 | With prefix argument @var{n}, move @var{n} times. | |
1509 | @end table | |
1510 | ||
1511 | @node Electric C | |
1512 | @subsection Electric C Characters | |
1513 | ||
1514 | In C mode and related modes, certain printing characters are | |
1515 | ``electric''---in addition to inserting themselves, they also reindent | |
1516 | the current line and may insert newlines. This feature is controlled by | |
1517 | the variable @code{c-auto-newline}. The ``electric'' characters are | |
1518 | @kbd{@{}, @kbd{@}}, @kbd{:}, @kbd{#}, @kbd{;}, @kbd{,}, @kbd{<}, | |
1519 | @kbd{>}, @kbd{/}, @kbd{*}, @kbd{(}, and @kbd{)}. | |
1520 | ||
1521 | Electric characters insert newlines only when the @dfn{auto-newline} | |
1522 | feature is enabled (indicated by @samp{/a} in the mode line after the | |
1523 | mode name). This feature is controlled by the variable | |
1524 | @code{c-auto-newline}. You can turn this feature on or off with the | |
1525 | command @kbd{C-c C-a}: | |
1526 | ||
1527 | @table @kbd | |
1528 | @item C-c C-a | |
1529 | @kindex C-c C-a @r{(C mode)} | |
1530 | @findex c-toggle-auto-state | |
1531 | Toggle the auto-newline feature (@code{c-toggle-auto-state}). With a | |
1532 | prefix argument, this command turns the auto-newline feature on if the | |
1533 | argument is positive, and off if it is negative. | |
1534 | @end table | |
1535 | ||
1536 | The colon character is electric because that is appropriate for a | |
1537 | single colon. But when you want to insert a double colon in C++, the | |
1538 | electric behavior of colon is inconvenient. You can insert a double | |
1539 | colon with no reindentation or newlines by typing @kbd{C-c :}: | |
1540 | ||
1541 | @table @kbd | |
1542 | @item C-c : | |
da8acb6b | 1543 | @ifinfo |
c668cdd0 EZ |
1544 | @c This uses ``colon'' instead of a literal `:' because Info cannot |
1545 | @c cope with a `:' in a menu | |
1546 | @kindex C-c @key{colon} @r{(C mode)} | |
da8acb6b EZ |
1547 | @end ifinfo |
1548 | @ifnotinfo | |
1549 | @kindex C-c : @r{(C mode)} | |
1550 | @end ifnotinfo | |
6bf7aab6 DL |
1551 | @findex c-scope-operator |
1552 | Insert a double colon scope operator at point, without reindenting the | |
1553 | line or adding any newlines (@code{c-scope-operator}). | |
1554 | @end table | |
1555 | ||
7ae8ad94 | 1556 | @vindex c-electric-pound-behavior |
6bf7aab6 DL |
1557 | The electric @kbd{#} key reindents the line if it appears to be the |
1558 | beginning of a preprocessor directive. This happens when the value of | |
1559 | @code{c-electric-pound-behavior} is @code{(alignleft)}. You can turn | |
1560 | this feature off by setting @code{c-electric-pound-behavior} to | |
1561 | @code{nil}. | |
1562 | ||
7ae8ad94 | 1563 | @vindex c-hanging-braces-alist |
6bf7aab6 DL |
1564 | The variable @code{c-hanging-braces-alist} controls the insertion of |
1565 | newlines before and after inserted braces. It is an association list | |
1566 | with elements of the following form: @code{(@var{syntactic-symbol} | |
1567 | . @var{nl-list})}. Most of the syntactic symbols that appear in | |
1568 | @code{c-offsets-alist} are meaningful here as well. | |
1569 | ||
1570 | The list @var{nl-list} may contain either of the symbols | |
1571 | @code{before} or @code{after}, or both; or it may be @code{nil}. When a | |
1572 | brace is inserted, the syntactic context it defines is looked up in | |
1573 | @code{c-hanging-braces-alist}; if it is found, the @var{nl-list} is used | |
1574 | to determine where newlines are inserted: either before the brace, | |
1575 | after, or both. If not found, the default is to insert a newline both | |
1576 | before and after braces. | |
1577 | ||
7ae8ad94 | 1578 | @vindex c-hanging-colons-alist |
6bf7aab6 DL |
1579 | The variable @code{c-hanging-colons-alist} controls the insertion of |
1580 | newlines before and after inserted colons. It is an association list | |
1581 | with elements of the following form: @code{(@var{syntactic-symbol} | |
1582 | . @var{nl-list})}. The list @var{nl-list} may contain either of the | |
1583 | symbols @code{before} or @code{after}, or both; or it may be @code{nil}. | |
1584 | ||
1585 | When a colon is inserted, the syntactic symbol it defines is looked | |
1586 | up in this list, and if found, the @var{nl-list} is used to determine | |
1587 | where newlines are inserted: either before the brace, after, or both. | |
1588 | If the syntactic symbol is not found in this list, no newlines are | |
1589 | inserted. | |
1590 | ||
7ae8ad94 | 1591 | @vindex c-cleanup-list |
6bf7aab6 DL |
1592 | Electric characters can also delete newlines automatically when the |
1593 | auto-newline feature is enabled. This feature makes auto-newline more | |
1594 | acceptable, by deleting the newlines in the most common cases where you | |
1595 | do not want them. Emacs can recognize several cases in which deleting a | |
1596 | newline might be desirable; by setting the variable | |
1597 | @code{c-cleanup-list}, you can specify @emph{which} of these cases that | |
1598 | should happen. The variable's value is a list of symbols, each | |
1599 | describing one case for possible deletion of a newline. Here are the | |
1600 | meaningful symbols, and their meanings: | |
1601 | ||
1602 | @table @code | |
1603 | @item brace-catch-brace | |
1604 | Clean up @samp{@} catch (@var{condition}) @{} constructs by placing the | |
1605 | entire construct on a single line. The clean-up occurs when you type | |
1606 | the @samp{@{}, if there is nothing between the braces aside from | |
1607 | @code{catch} and @var{condition}. | |
1608 | ||
1609 | @item brace-else-brace | |
1610 | Clean up @samp{@} else @{} constructs by placing the entire construct on | |
1611 | a single line. The clean-up occurs when you type the @samp{@{} after | |
1612 | the @code{else}, but only if there is nothing but white space between | |
1613 | the braces and the @code{else}. | |
1614 | ||
1615 | @item brace-elseif-brace | |
1616 | Clean up @samp{@} else if (@dots{}) @{} constructs by placing the entire | |
1617 | construct on a single line. The clean-up occurs when you type the | |
1618 | @samp{@{}, if there is nothing but white space between the @samp{@}} and | |
1619 | @samp{@{} aside from the keywords and the @code{if}-condition. | |
1620 | ||
1621 | @item empty-defun-braces | |
1622 | Clean up empty defun braces by placing the braces on the same | |
1623 | line. Clean-up occurs when you type the closing brace. | |
1624 | ||
1625 | @item defun-close-semi | |
1626 | Clean up the semicolon after a @code{struct} or similar type | |
1627 | declaration, by placing the semicolon on the same line as the closing | |
1628 | brace. Clean-up occurs when you type the semicolon. | |
1629 | ||
1630 | @item list-close-comma | |
1631 | Clean up commas following braces in array and aggregate | |
1632 | initializers. Clean-up occurs when you type the comma. | |
1633 | ||
1634 | @item scope-operator | |
1635 | Clean up double colons which may designate a C++ scope operator, by | |
1636 | placing the colons together. Clean-up occurs when you type the second | |
1637 | colon, but only when the two colons are separated by nothing but | |
1638 | whitespace. | |
1639 | @end table | |
1640 | ||
1641 | @node Hungry Delete | |
1642 | @subsection Hungry Delete Feature in C | |
7ae8ad94 | 1643 | @cindex hungry deletion (C Mode) |
6bf7aab6 DL |
1644 | |
1645 | When the @dfn{hungry-delete} feature is enabled (indicated by | |
1646 | @samp{/h} or @samp{/ah} in the mode line after the mode name), a single | |
1647 | @key{DEL} command deletes all preceding whitespace, not just one space. | |
1648 | To turn this feature on or off, use @kbd{C-c C-d}: | |
1649 | ||
1650 | @table @kbd | |
1651 | @item C-c C-d | |
1652 | @kindex C-c C-d @r{(C mode)} | |
1653 | @findex c-toggle-hungry-state | |
1654 | Toggle the hungry-delete feature (@code{c-toggle-hungry-state}). With a | |
1655 | prefix argument, this command turns the hungry-delete feature on if the | |
1656 | argument is positive, and off if it is negative. | |
1657 | ||
1658 | @item C-c C-t | |
1659 | @kindex C-c C-t @r{(C mode)} | |
1660 | @findex c-toggle-auto-hungry-state | |
1661 | Toggle the auto-newline and hungry-delete features, both at once | |
1662 | (@code{c-toggle-auto-hungry-state}). | |
1663 | @end table | |
1664 | ||
1665 | @vindex c-hungry-delete-key | |
1666 | The variable @code{c-hungry-delete-key} controls whether the | |
1667 | hungry-delete feature is enabled. | |
1668 | ||
1669 | @node Other C Commands | |
1670 | @subsection Other Commands for C Mode | |
1671 | ||
1672 | @table @kbd | |
7ae8ad94 RS |
1673 | @item M-x c-context-line-break |
1674 | @findex c-context-line-break | |
1675 | This command inserts a line break and indents the new line in a manner | |
1676 | appropriate to the context. In normal code, it does the work of | |
1677 | @kbd{C-j} (@code{newline-and-indent}), in a C preprocessor line it | |
1678 | additionally inserts a @samp{\} at the line break, and within comments | |
1679 | it's like @kbd{M-j} (@code{c-indent-new-comment-line}). | |
1680 | ||
1681 | @code{c-context-line-break} isn't bound to a key by default, but it | |
1682 | needs a binding to be useful. The following code will bind it to | |
1683 | @kbd{C-j}. | |
1684 | @example | |
1685 | (define-key c-mode-base-map "\C-j" 'c-context-line-break) | |
1686 | @end example | |
1687 | ||
6bf7aab6 | 1688 | @item C-M-h |
6bf7aab6 DL |
1689 | Put mark at the end of a function definition, and put point at the |
1690 | beginning (@code{c-mark-function}). | |
1691 | ||
1692 | @item M-q | |
1693 | @kindex M-q @r{(C mode)} | |
1694 | @findex c-fill-paragraph | |
1695 | Fill a paragraph, handling C and C++ comments (@code{c-fill-paragraph}). | |
1696 | If any part of the current line is a comment or within a comment, this | |
1697 | command fills the comment or the paragraph of it that point is in, | |
1698 | preserving the comment indentation and comment delimiters. | |
1699 | ||
1700 | @item C-c C-e | |
1701 | @cindex macro expansion in C | |
1702 | @cindex expansion of C macros | |
1703 | @findex c-macro-expand | |
1704 | @kindex C-c C-e @r{(C mode)} | |
1705 | Run the C preprocessor on the text in the region, and show the result, | |
1706 | which includes the expansion of all the macro calls | |
1707 | (@code{c-macro-expand}). The buffer text before the region is also | |
1708 | included in preprocessing, for the sake of macros defined there, but the | |
1709 | output from this part isn't shown. | |
1710 | ||
1711 | When you are debugging C code that uses macros, sometimes it is hard to | |
1712 | figure out precisely how the macros expand. With this command, you | |
1713 | don't have to figure it out; you can see the expansions. | |
1714 | ||
1715 | @item C-c C-\ | |
1716 | @findex c-backslash-region | |
1717 | @kindex C-c C-\ @r{(C mode)} | |
1718 | Insert or align @samp{\} characters at the ends of the lines of the | |
1719 | region (@code{c-backslash-region}). This is useful after writing or | |
1720 | editing a C macro definition. | |
1721 | ||
1722 | If a line already ends in @samp{\}, this command adjusts the amount of | |
1723 | whitespace before it. Otherwise, it inserts a new @samp{\}. However, | |
1724 | the last line in the region is treated specially; no @samp{\} is | |
1725 | inserted on that line, and any @samp{\} there is deleted. | |
1726 | ||
1727 | @item M-x cpp-highlight-buffer | |
1728 | @cindex preprocessor highlighting | |
1729 | @findex cpp-highlight-buffer | |
1730 | Highlight parts of the text according to its preprocessor conditionals. | |
1731 | This command displays another buffer named @samp{*CPP Edit*}, which | |
1732 | serves as a graphic menu for selecting how to display particular kinds | |
1733 | of conditionals and their contents. After changing various settings, | |
1734 | click on @samp{[A]pply these settings} (or go to that buffer and type | |
1735 | @kbd{a}) to rehighlight the C mode buffer accordingly. | |
1736 | ||
1737 | @item C-c C-s | |
1738 | @findex c-show-syntactic-information | |
1739 | @kindex C-c C-s @r{(C mode)} | |
1740 | Display the syntactic information about the current source line | |
054af0fd SE |
1741 | (@code{c-show-syntactic-information}). This information directs how |
1742 | the line is indented. | |
3b8b8888 DL |
1743 | |
1744 | @item M-x cwarn-mode | |
1745 | @itemx M-x global-cwarn-mode | |
1746 | @findex cwarn-mode | |
1747 | @findex global-cwarn-mode | |
7ae8ad94 | 1748 | @vindex global-cwarn-mode |
3b8b8888 DL |
1749 | @cindex CWarn mode |
1750 | @cindex suspicious constructions in C, C++ | |
9234c238 | 1751 | CWarn minor mode highlights certain suspicious C and C++ constructions: |
3b8b8888 DL |
1752 | |
1753 | @itemize @bullet{} | |
1754 | @item | |
9234c238 | 1755 | Assignments inside expressions. |
3b8b8888 DL |
1756 | @item |
1757 | Semicolon following immediately after @samp{if}, @samp{for}, and @samp{while} | |
1758 | (except after a @samp{do @dots{} while} statement); | |
1759 | @item | |
1760 | C++ functions with reference parameters. | |
1761 | @end itemize | |
1762 | ||
1763 | @noindent | |
9234c238 RS |
1764 | You can enable the mode for one buffer with the command @kbd{M-x |
1765 | cwarn-mode}, or for all suitable buffers with the command @kbd{M-x | |
1766 | global-cwarn-mode} or by customizing the variable | |
1767 | @code{global-cwarn-mode}. You must also enable Font Lock mode to make | |
1768 | it work. | |
3b8b8888 DL |
1769 | |
1770 | @item M-x hide-ifdef-mode | |
1771 | @findex hide-ifdef-mode | |
1772 | @cindex Hide-ifdef mode | |
1773 | Hide-ifdef minor mode hides selected code within @samp{#if} and | |
9234c238 RS |
1774 | @samp{#ifdef} preprocessor blocks. See the documentation string of |
1775 | @code{hide-ifdef-mode} for more information. | |
1776 | ||
1777 | @item M-x ff-find-related-file | |
1778 | @cindex related files | |
1779 | @findex ff-find-related-file | |
1780 | @vindex ff-related-file-alist | |
1781 | Find a file ``related'' in a special way to the file visited by the | |
1782 | current buffer. Typically this will be the header file corresponding | |
1783 | to a C/C++ source file, or vice versa. The variable | |
1784 | @code{ff-related-file-alist} specifies how to compute related file | |
1785 | names. | |
6bf7aab6 DL |
1786 | @end table |
1787 | ||
1788 | @node Fortran | |
1789 | @section Fortran Mode | |
1790 | @cindex Fortran mode | |
1791 | @cindex mode, Fortran | |
1792 | ||
1793 | Fortran mode provides special motion commands for Fortran statements and | |
1794 | subprograms, and indentation commands that understand Fortran conventions | |
1795 | of nesting, line numbers and continuation statements. Fortran mode has | |
1796 | its own Auto Fill mode that breaks long lines into proper Fortran | |
1797 | continuation lines. | |
1798 | ||
1799 | Special commands for comments are provided because Fortran comments | |
1800 | are unlike those of other languages. Built-in abbrevs optionally save | |
1801 | typing when you insert Fortran keywords. | |
1802 | ||
6bf7aab6 DL |
1803 | Use @kbd{M-x fortran-mode} to switch to this major mode. This command |
1804 | runs the hook @code{fortran-mode-hook} (@pxref{Hooks}). | |
1805 | ||
4946337d | 1806 | @cindex Fortran77 and Fortran90 |
138a8f12 DL |
1807 | @findex f90-mode |
1808 | @findex fortran-mode | |
5fe3b9bc | 1809 | Fortran mode is meant for editing Fortran77 ``fixed format'' source |
9234c238 RS |
1810 | code. For editing the modern Fortran90 ``free format'' source code, |
1811 | use F90 mode (@code{f90-mode}). Emacs normally uses Fortran mode for | |
1812 | files with extension @samp{.f}, @samp{.F} or @samp{.for}, and F90 mode | |
1813 | for the extension @samp{.f90}. GNU Fortran supports both kinds of | |
1814 | format. | |
138a8f12 | 1815 | |
6bf7aab6 DL |
1816 | @menu |
1817 | * Motion: Fortran Motion. Moving point by statements or subprograms. | |
1818 | * Indent: Fortran Indent. Indentation commands for Fortran. | |
1819 | * Comments: Fortran Comments. Inserting and aligning comments. | |
1820 | * Autofill: Fortran Autofill. Auto fill minor mode for Fortran. | |
1821 | * Columns: Fortran Columns. Measuring columns for valid Fortran. | |
1822 | * Abbrev: Fortran Abbrev. Built-in abbrevs for Fortran keywords. | |
6bf7aab6 DL |
1823 | @end menu |
1824 | ||
1825 | @node Fortran Motion | |
1826 | @subsection Motion Commands | |
1827 | ||
9234c238 RS |
1828 | In addition to the normal commands for moving by and operating on |
1829 | ``defuns'' (Fortran subprograms---functions and subroutines), Fortran | |
1830 | mode provides special commands to move by statements. | |
6bf7aab6 | 1831 | |
9234c238 | 1832 | @table @kbd |
6bf7aab6 | 1833 | @kindex C-c C-n @r{(Fortran mode)} |
6bf7aab6 | 1834 | @findex fortran-next-statement |
6bf7aab6 DL |
1835 | @item C-c C-n |
1836 | Move to beginning of current or next statement | |
1837 | (@code{fortran-next-statement}). | |
9234c238 RS |
1838 | |
1839 | @kindex C-c C-p @r{(Fortran mode)} | |
1840 | @findex fortran-previous-statement | |
6bf7aab6 DL |
1841 | @item C-c C-p |
1842 | Move to beginning of current or previous statement | |
1843 | (@code{fortran-previous-statement}). | |
1844 | @end table | |
1845 | ||
1846 | @node Fortran Indent | |
1847 | @subsection Fortran Indentation | |
1848 | ||
1849 | Special commands and features are needed for indenting Fortran code in | |
1850 | order to make sure various syntactic entities (line numbers, comment line | |
1851 | indicators and continuation line flags) appear in the columns that are | |
1852 | required for standard Fortran. | |
1853 | ||
1854 | @menu | |
85750656 | 1855 | * Commands: ForIndent Commands. Commands for indenting and filling Fortran. |
6bf7aab6 DL |
1856 | * Contline: ForIndent Cont. How continuation lines indent. |
1857 | * Numbers: ForIndent Num. How line numbers auto-indent. | |
1858 | * Conv: ForIndent Conv. Conventions you must obey to avoid trouble. | |
1859 | * Vars: ForIndent Vars. Variables controlling Fortran indent style. | |
1860 | @end menu | |
1861 | ||
1862 | @node ForIndent Commands | |
9234c238 | 1863 | @subsubsection Fortran Indentation and Filling Commands |
6bf7aab6 DL |
1864 | |
1865 | @table @kbd | |
6bf7aab6 | 1866 | @item C-M-j |
85750656 DL |
1867 | Break the current line and set up a continuation line |
1868 | (@code{fortran-split-line}). | |
6bf7aab6 | 1869 | @item M-^ |
85750656 | 1870 | Join this line to the previous line (@code{fortran-join-line}). |
6bf7aab6 DL |
1871 | @item C-M-q |
1872 | Indent all the lines of the subprogram point is in | |
1873 | (@code{fortran-indent-subprogram}). | |
85750656 DL |
1874 | @item M-q |
1875 | Fill a comment block or statement. | |
6bf7aab6 DL |
1876 | @end table |
1877 | ||
6bf7aab6 DL |
1878 | @kindex C-M-q @r{(Fortran mode)} |
1879 | @findex fortran-indent-subprogram | |
1880 | The key @kbd{C-M-q} runs @code{fortran-indent-subprogram}, a command | |
1881 | to reindent all the lines of the Fortran subprogram (function or | |
1882 | subroutine) containing point. | |
1883 | ||
1884 | @kindex C-M-j @r{(Fortran mode)} | |
1885 | @findex fortran-split-line | |
1886 | The key @kbd{C-M-j} runs @code{fortran-split-line}, which splits | |
1887 | a line in the appropriate fashion for Fortran. In a non-comment line, | |
1888 | the second half becomes a continuation line and is indented | |
1889 | accordingly. In a comment line, both halves become separate comment | |
1890 | lines. | |
1891 | ||
1892 | @kindex M-^ @r{(Fortran mode)} | |
138a8f12 DL |
1893 | @kindex C-c C-d @r{(Fortran mode)} |
1894 | @findex fortran-join-line | |
85750656 DL |
1895 | @kbd{M-^} or @kbd{C-c C-d} runs the command @code{fortran-join-line}, |
1896 | which joins a continuation line back to the previous line, roughly as | |
1897 | the inverse of @code{fortran-split-line}. The point must be on a | |
138a8f12 DL |
1898 | continuation line when this command is invoked. |
1899 | ||
85750656 | 1900 | @kindex M-q @r{(Fortran mode)} |
9234c238 RS |
1901 | @kbd{M-q} in Fortran mode fills the comment block or statement that |
1902 | point is in. This removes any excess statement continuations. | |
85750656 | 1903 | |
6bf7aab6 DL |
1904 | @node ForIndent Cont |
1905 | @subsubsection Continuation Lines | |
1906 | @cindex Fortran continuation lines | |
1907 | ||
1908 | @vindex fortran-continuation-string | |
1909 | Most modern Fortran compilers allow two ways of writing continuation | |
1910 | lines. If the first non-space character on a line is in column 5, then | |
1911 | that line is a continuation of the previous line. We call this | |
1912 | @dfn{fixed format}. (In GNU Emacs we always count columns from 0.) The | |
1913 | variable @code{fortran-continuation-string} specifies what character to | |
1914 | put on column 5. A line that starts with a tab character followed by | |
1915 | any digit except @samp{0} is also a continuation line. We call this | |
1916 | style of continuation @dfn{tab format}. | |
1917 | ||
1918 | @vindex indent-tabs-mode @r{(Fortran mode)} | |
1919 | Fortran mode can make either style of continuation line, but you | |
1920 | must specify which one you prefer. The value of the variable | |
1921 | @code{indent-tabs-mode} controls the choice: @code{nil} for fixed | |
1922 | format, and non-@code{nil} for tab format. You can tell which style | |
1923 | is presently in effect by the presence or absence of the string | |
1924 | @samp{Tab} in the mode line. | |
1925 | ||
1926 | If the text on a line starts with the conventional Fortran | |
1927 | continuation marker @samp{$}, or if it begins with any non-whitespace | |
1928 | character in column 5, Fortran mode treats it as a continuation line. | |
1929 | When you indent a continuation line with @key{TAB}, it converts the line | |
1930 | to the current continuation style. When you split a Fortran statement | |
1931 | with @kbd{C-M-j}, the continuation marker on the newline is created | |
1932 | according to the continuation style. | |
1933 | ||
1934 | The setting of continuation style affects several other aspects of | |
1935 | editing in Fortran mode. In fixed format mode, the minimum column | |
1936 | number for the body of a statement is 6. Lines inside of Fortran | |
1937 | blocks that are indented to larger column numbers always use only the | |
1938 | space character for whitespace. In tab format mode, the minimum | |
1939 | column number for the statement body is 8, and the whitespace before | |
1940 | column 8 must always consist of one tab character. | |
1941 | ||
1942 | @vindex fortran-tab-mode-default | |
1943 | @vindex fortran-analyze-depth | |
1944 | When you enter Fortran mode for an existing file, it tries to deduce the | |
1945 | proper continuation style automatically from the file contents. The first | |
1946 | line that begins with either a tab character or six spaces determines the | |
1947 | choice. The variable @code{fortran-analyze-depth} specifies how many lines | |
1948 | to consider (at the beginning of the file); if none of those lines | |
1949 | indicates a style, then the variable @code{fortran-tab-mode-default} | |
1950 | specifies the style. If it is @code{nil}, that specifies fixed format, and | |
1951 | non-@code{nil} specifies tab format. | |
1952 | ||
1953 | @node ForIndent Num | |
1954 | @subsubsection Line Numbers | |
1955 | ||
1956 | If a number is the first non-whitespace in the line, Fortran | |
1957 | indentation assumes it is a line number and moves it to columns 0 | |
1958 | through 4. (Columns always count from 0 in GNU Emacs.) | |
1959 | ||
1960 | @vindex fortran-line-number-indent | |
1961 | Line numbers of four digits or less are normally indented one space. | |
1962 | The variable @code{fortran-line-number-indent} controls this; it | |
1963 | specifies the maximum indentation a line number can have. Line numbers | |
ea118de1 SE |
1964 | are right-justified to end in column 4 unless that would require more |
1965 | than this maximum indentation. The default value of the variable is 1. | |
6bf7aab6 DL |
1966 | |
1967 | @vindex fortran-electric-line-number | |
1968 | Simply inserting a line number is enough to indent it according to | |
1969 | these rules. As each digit is inserted, the indentation is recomputed. | |
1970 | To turn off this feature, set the variable | |
ea118de1 SE |
1971 | @code{fortran-electric-line-number} to @code{nil}. |
1972 | ||
6bf7aab6 DL |
1973 | |
1974 | @node ForIndent Conv | |
1975 | @subsubsection Syntactic Conventions | |
1976 | ||
1977 | Fortran mode assumes that you follow certain conventions that simplify | |
1978 | the task of understanding a Fortran program well enough to indent it | |
1979 | properly: | |
1980 | ||
1981 | @itemize @bullet | |
1982 | @item | |
1983 | Two nested @samp{do} loops never share a @samp{continue} statement. | |
1984 | ||
1985 | @item | |
1986 | Fortran keywords such as @samp{if}, @samp{else}, @samp{then}, @samp{do} | |
1987 | and others are written without embedded whitespace or line breaks. | |
1988 | ||
1989 | Fortran compilers generally ignore whitespace outside of string | |
1990 | constants, but Fortran mode does not recognize these keywords if they | |
1991 | are not contiguous. Constructs such as @samp{else if} or @samp{end do} | |
1992 | are acceptable, but the second word should be on the same line as the | |
1993 | first and not on a continuation line. | |
1994 | @end itemize | |
1995 | ||
1996 | @noindent | |
1997 | If you fail to follow these conventions, the indentation commands may | |
1998 | indent some lines unaesthetically. However, a correct Fortran program | |
1999 | retains its meaning when reindented even if the conventions are not | |
2000 | followed. | |
2001 | ||
2002 | @node ForIndent Vars | |
2003 | @subsubsection Variables for Fortran Indentation | |
2004 | ||
2005 | @vindex fortran-do-indent | |
2006 | @vindex fortran-if-indent | |
2007 | @vindex fortran-structure-indent | |
2008 | @vindex fortran-continuation-indent | |
2009 | @vindex fortran-check-all-num@dots{} | |
2010 | @vindex fortran-minimum-statement-indent@dots{} | |
2011 | Several additional variables control how Fortran indentation works: | |
2012 | ||
2013 | @table @code | |
2014 | @item fortran-do-indent | |
2015 | Extra indentation within each level of @samp{do} statement (default 3). | |
2016 | ||
2017 | @item fortran-if-indent | |
2018 | Extra indentation within each level of @samp{if} statement (default 3). | |
2019 | This value is also used for extra indentation within each level of the | |
2020 | Fortran 90 @samp{where} statement. | |
2021 | ||
2022 | @item fortran-structure-indent | |
2023 | Extra indentation within each level of @samp{structure}, @samp{union}, or | |
2024 | @samp{map} statements (default 3). | |
2025 | ||
2026 | @item fortran-continuation-indent | |
2027 | Extra indentation for bodies of continuation lines (default 5). | |
2028 | ||
2029 | @item fortran-check-all-num-for-matching-do | |
2030 | If this is @code{nil}, indentation assumes that each @samp{do} statement | |
2031 | ends on a @samp{continue} statement. Therefore, when computing | |
2032 | indentation for a statement other than @samp{continue}, it can save time | |
2033 | by not checking for a @samp{do} statement ending there. If this is | |
2034 | non-@code{nil}, indenting any numbered statement must check for a | |
2035 | @samp{do} that ends there. The default is @code{nil}. | |
2036 | ||
2037 | @item fortran-blink-matching-if | |
2038 | If this is @code{t}, indenting an @samp{endif} statement moves the | |
2039 | cursor momentarily to the matching @samp{if} statement to show where it | |
2040 | is. The default is @code{nil}. | |
2041 | ||
2042 | @item fortran-minimum-statement-indent-fixed | |
2043 | Minimum indentation for fortran statements when using fixed format | |
2044 | continuation line style. Statement bodies are never indented less than | |
2045 | this much. The default is 6. | |
2046 | ||
2047 | @item fortran-minimum-statement-indent-tab | |
2048 | Minimum indentation for fortran statements for tab format continuation line | |
2049 | style. Statement bodies are never indented less than this much. The | |
2050 | default is 8. | |
2051 | @end table | |
2052 | ||
2053 | @node Fortran Comments | |
2054 | @subsection Fortran Comments | |
2055 | ||
2056 | The usual Emacs comment commands assume that a comment can follow a line | |
2057 | of code. In Fortran, the standard comment syntax requires an entire line | |
2058 | to be just a comment. Therefore, Fortran mode replaces the standard Emacs | |
2059 | comment commands and defines some new variables. | |
2060 | ||
85750656 DL |
2061 | Fortran mode can also handle the Fortran90 comment syntax where comments |
2062 | start with @samp{!} and can follow other text. Because only some Fortran77 | |
6bf7aab6 DL |
2063 | compilers accept this syntax, Fortran mode will not insert such comments |
2064 | unless you have said in advance to do so. To do this, set the variable | |
2065 | @code{comment-start} to @samp{"!"} (@pxref{Variables}). | |
2066 | ||
2067 | @table @kbd | |
2068 | @item M-; | |
054af0fd | 2069 | Align comment or insert new comment (@code{fortran-indent-comment}). |
6bf7aab6 DL |
2070 | |
2071 | @item C-x ; | |
2072 | Applies to nonstandard @samp{!} comments only. | |
2073 | ||
2074 | @item C-c ; | |
2075 | Turn all lines of the region into comments, or (with argument) turn them back | |
2076 | into real code (@code{fortran-comment-region}). | |
2077 | @end table | |
2078 | ||
2079 | @kbd{M-;} in Fortran mode is redefined as the command | |
054af0fd | 2080 | @code{fortran-indent-comment}. Like the usual @kbd{M-;} command, this |
6bf7aab6 DL |
2081 | recognizes any kind of existing comment and aligns its text appropriately; |
2082 | if there is no existing comment, a comment is inserted and aligned. But | |
2083 | inserting and aligning comments are not the same in Fortran mode as in | |
2084 | other modes. | |
2085 | ||
2086 | When a new comment must be inserted, if the current line is blank, a | |
2087 | full-line comment is inserted. On a non-blank line, a nonstandard @samp{!} | |
2088 | comment is inserted if you have said you want to use them. Otherwise a | |
2089 | full-line comment is inserted on a new line before the current line. | |
2090 | ||
2091 | Nonstandard @samp{!} comments are aligned like comments in other | |
2092 | languages, but full-line comments are different. In a standard full-line | |
2093 | comment, the comment delimiter itself must always appear in column zero. | |
2094 | What can be aligned is the text within the comment. You can choose from | |
2095 | three styles of alignment by setting the variable | |
2096 | @code{fortran-comment-indent-style} to one of these values: | |
2097 | ||
2098 | @vindex fortran-comment-indent-style | |
2099 | @vindex fortran-comment-line-extra-indent | |
2100 | @table @code | |
2101 | @item fixed | |
2102 | Align the text at a fixed column, which is the sum of | |
2103 | @code{fortran-comment-line-extra-indent} and the minimum statement | |
2104 | indentation. This is the default. | |
2105 | ||
2106 | The minimum statement indentation is | |
2107 | @code{fortran-minimum-statement-indent-fixed} for fixed format | |
2108 | continuation line style and @code{fortran-minimum-statement-indent-tab} | |
2109 | for tab format style. | |
2110 | ||
2111 | @item relative | |
2112 | Align the text as if it were a line of code, but with an additional | |
2113 | @code{fortran-comment-line-extra-indent} columns of indentation. | |
2114 | ||
2115 | @item nil | |
ea118de1 | 2116 | Don't move text in full-line comments automatically. |
6bf7aab6 DL |
2117 | @end table |
2118 | ||
2119 | @vindex fortran-comment-indent-char | |
2120 | In addition, you can specify the character to be used to indent within | |
2121 | full-line comments by setting the variable | |
2122 | @code{fortran-comment-indent-char} to the single-character string you want | |
2123 | to use. | |
2d588beb GM |
2124 | |
2125 | @vindex fortran-directive-re | |
2126 | Compiler directive lines, or preprocessor lines, have much the same | |
2127 | appearance as comment lines. It is important, though, that such lines | |
2128 | never be indented at all, no matter what the value of | |
2129 | @code{fortran-comment-indent-style}. The variable | |
2130 | @code{fortran-directive-re} is a regular expression that specifies which | |
2131 | lines are directives. Matching lines are never indented, and receive | |
2132 | distinctive font-locking. | |
6bf7aab6 DL |
2133 | |
2134 | @vindex comment-line-start | |
2135 | @vindex comment-line-start-skip | |
2136 | Fortran mode introduces two variables @code{comment-line-start} and | |
2137 | @code{comment-line-start-skip}, which play for full-line comments the same | |
2138 | roles played by @code{comment-start} and @code{comment-start-skip} for | |
2139 | ordinary text-following comments. Normally these are set properly by | |
2140 | Fortran mode, so you do not need to change them. | |
2141 | ||
2142 | The normal Emacs comment command @kbd{C-x ;} has not been redefined. If | |
2143 | you use @samp{!} comments, this command can be used with them. Otherwise | |
2144 | it is useless in Fortran mode. | |
2145 | ||
2146 | @kindex C-c ; @r{(Fortran mode)} | |
2147 | @findex fortran-comment-region | |
2148 | @vindex fortran-comment-region | |
2149 | The command @kbd{C-c ;} (@code{fortran-comment-region}) turns all the | |
2150 | lines of the region into comments by inserting the string @samp{C$$$} at | |
2151 | the front of each one. With a numeric argument, it turns the region | |
2152 | back into live code by deleting @samp{C$$$} from the front of each line | |
2153 | in it. The string used for these comments can be controlled by setting | |
2154 | the variable @code{fortran-comment-region}. Note that here we have an | |
2155 | example of a command and a variable with the same name; these two uses | |
2156 | of the name never conflict because in Lisp and in Emacs it is always | |
2157 | clear from the context which one is meant. | |
2158 | ||
2159 | @node Fortran Autofill | |
2160 | @subsection Fortran Auto Fill Mode | |
2161 | ||
2162 | Fortran Auto Fill mode is a minor mode which automatically splits | |
2163 | Fortran statements as you insert them when they become too wide. | |
2164 | Splitting a statement involves making continuation lines using | |
2165 | @code{fortran-continuation-string} (@pxref{ForIndent Cont}). This | |
2166 | splitting happens when you type @key{SPC}, @key{RET}, or @key{TAB}, and | |
2167 | also in the Fortran indentation commands. | |
2168 | ||
2169 | @findex fortran-auto-fill-mode | |
6daf3e15 RS |
2170 | @kbd{M-x fortran-auto-fill-mode} toggles Fortran Auto Fill mode, |
2171 | which is a variant of normal Auto Fill mode (@pxref{Filling}) designed | |
2172 | for Fortran programs. Fortran Auto Fill mode is a buffer-local minor | |
2173 | mode (@pxref{Minor Modes}). When Fortran Auto Fill mode is in effect, | |
2174 | the word @samp{Fill} appears in the mode line inside the parentheses. | |
6bf7aab6 DL |
2175 | |
2176 | @vindex fortran-break-before-delimiters | |
2177 | Fortran Auto Fill mode breaks lines at spaces or delimiters when the | |
2178 | lines get longer than the desired width (the value of @code{fill-column}). | |
2179 | The delimiters that Fortran Auto Fill mode may break at are @samp{,}, | |
2180 | @samp{'}, @samp{+}, @samp{-}, @samp{/}, @samp{*}, @samp{=}, and @samp{)}. | |
2181 | The line break comes after the delimiter if the variable | |
2182 | @code{fortran-break-before-delimiters} is @code{nil}. Otherwise (and by | |
2183 | default), the break comes before the delimiter. | |
2184 | ||
6daf3e15 | 2185 | To enable this mode permanently, add a hook function to |
6bf7aab6 DL |
2186 | @code{fortran-mode-hook} to execute @code{(fortran-auto-fill-mode 1)}. |
2187 | @xref{Hooks}. | |
2188 | ||
2189 | @node Fortran Columns | |
2190 | @subsection Checking Columns in Fortran | |
2191 | ||
2192 | @table @kbd | |
2193 | @item C-c C-r | |
2194 | Display a ``column ruler'' momentarily above the current line | |
2195 | (@code{fortran-column-ruler}). | |
2196 | @item C-c C-w | |
2197 | Split the current window horizontally temporarily so that it is 72 | |
9234c238 RS |
2198 | columns wide (@code{fortran-window-create-momentarily}). This may |
2199 | help you avoid making lines longer than the 72-character limit that | |
2200 | some Fortran compilers impose. | |
2201 | @item C-u C-c C-w | |
2202 | Split the current window horizontally so that it is 72 columns wide | |
2203 | (@code{fortran-window-create}). You can then continue editing. | |
2204 | @item M-x fortran-strip-sequence-nos | |
2205 | Delete all text in column 72 and beyond. | |
6bf7aab6 DL |
2206 | @end table |
2207 | ||
2208 | @kindex C-c C-r @r{(Fortran mode)} | |
2209 | @findex fortran-column-ruler | |
6bf7aab6 DL |
2210 | The command @kbd{C-c C-r} (@code{fortran-column-ruler}) shows a column |
2211 | ruler momentarily above the current line. The comment ruler is two lines | |
2212 | of text that show you the locations of columns with special significance in | |
2213 | Fortran programs. Square brackets show the limits of the columns for line | |
2214 | numbers, and curly brackets show the limits of the columns for the | |
2215 | statement body. Column numbers appear above them. | |
2216 | ||
2217 | Note that the column numbers count from zero, as always in GNU Emacs. | |
2218 | As a result, the numbers may be one less than those you are familiar | |
2219 | with; but the positions they indicate in the line are standard for | |
2220 | Fortran. | |
2221 | ||
9234c238 RS |
2222 | @vindex fortran-column-ruler-fixed |
2223 | @vindex fortran-column-ruler-tabs | |
ea118de1 SE |
2224 | The text used to display the column ruler depends on the value of the |
2225 | variable @code{indent-tabs-mode}. If @code{indent-tabs-mode} is | |
6bf7aab6 DL |
2226 | @code{nil}, then the value of the variable |
2227 | @code{fortran-column-ruler-fixed} is used as the column ruler. | |
ea118de1 SE |
2228 | Otherwise, the value of the variable @code{fortran-column-ruler-tab} is |
2229 | displayed. By changing these variables, you can change the column ruler | |
2230 | display. | |
6bf7aab6 | 2231 | |
9234c238 RS |
2232 | @kindex C-c C-w @r{(Fortran mode)} |
2233 | @findex fortran-window-create-momentarily | |
2234 | @kbd{C-c C-w} (@code{fortran-window-create-momentarily}) temporarily | |
2235 | splits the current window horizontally, making a window 72 columns | |
2236 | wide, so you can see which lines that is too long. Type a space to | |
2237 | restore the normal width. | |
2238 | ||
138a8f12 | 2239 | @kindex C-u C-c C-w @r{(Fortran mode)} |
6bf7aab6 | 2240 | @findex fortran-window-create |
9234c238 RS |
2241 | You can also split the window horizontally and continue editing with |
2242 | the split in place. To do this, use @kbd{C-u C-c C-w} (@code{M-x | |
2243 | fortran-window-create}). By editing in this window you can | |
2244 | immediately see when you make a line too wide to be correct Fortran. | |
6bf7aab6 | 2245 | |
9234c238 RS |
2246 | @findex fortran-strip-sequence-nos |
2247 | The command @kbd{M-x fortran-strip-sequence-nos} deletes all text in | |
2248 | column 72 and beyond, on all lines in the current buffer. This is the | |
2249 | easiest way to get rid of old sequence numbers. | |
138a8f12 | 2250 | |
6bf7aab6 DL |
2251 | @node Fortran Abbrev |
2252 | @subsection Fortran Keyword Abbrevs | |
2253 | ||
2254 | Fortran mode provides many built-in abbrevs for common keywords and | |
2255 | declarations. These are the same sort of abbrev that you can define | |
2256 | yourself. To use them, you must turn on Abbrev mode. @xref{Abbrevs}. | |
2257 | ||
2258 | The built-in abbrevs are unusual in one way: they all start with a | |
2259 | semicolon. You cannot normally use semicolon in an abbrev, but Fortran | |
2260 | mode makes this possible by changing the syntax of semicolon to ``word | |
2261 | constituent.'' | |
2262 | ||
2263 | For example, one built-in Fortran abbrev is @samp{;c} for | |
2264 | @samp{continue}. If you insert @samp{;c} and then insert a punctuation | |
2265 | character such as a space or a newline, the @samp{;c} expands automatically | |
2266 | to @samp{continue}, provided Abbrev mode is enabled.@refill | |
2267 | ||
2268 | Type @samp{;?} or @samp{;C-h} to display a list of all the built-in | |
2269 | Fortran abbrevs and what they stand for. | |
2270 | ||
6bf7aab6 DL |
2271 | @node Asm Mode |
2272 | @section Asm Mode | |
2273 | ||
2274 | @cindex Asm mode | |
9234c238 | 2275 | @cindex assembler mode |
6bf7aab6 DL |
2276 | Asm mode is a major mode for editing files of assembler code. It |
2277 | defines these commands: | |
2278 | ||
2279 | @table @kbd | |
2280 | @item @key{TAB} | |
2281 | @code{tab-to-tab-stop}. | |
2282 | @item C-j | |
2283 | Insert a newline and then indent using @code{tab-to-tab-stop}. | |
2284 | @item : | |
2285 | Insert a colon and then remove the indentation from before the label | |
2286 | preceding colon. Then do @code{tab-to-tab-stop}. | |
2287 | @item ; | |
2288 | Insert or align a comment. | |
2289 | @end table | |
2290 | ||
2291 | The variable @code{asm-comment-char} specifies which character | |
2292 | starts comments in assembler syntax. | |
ab5796a9 MB |
2293 | |
2294 | @ignore | |
2295 | arch-tag: c7ee7409-40a4-45c7-bfb7-ae7f2c74d0c0 | |
2296 | @end ignore |