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6bf7aab6 | 1 | @c This is part of the Emacs manual. |
40279251 GM |
2 | @c Copyright (C) 1985, 1986, 1987, 1993, 1994, 1995, 1997, 1999, 2000, |
3 | @c 2001, 2005 Free Software Foundation, Inc. | |
6bf7aab6 DL |
4 | @c See file emacs.texi for copying conditions. |
5 | @node Programs, Building, Text, Top | |
6 | @chapter Editing Programs | |
7 | @cindex Lisp editing | |
8 | @cindex C editing | |
9 | @cindex program editing | |
10 | ||
e79c6b89 RS |
11 | Emacs provides many features to facilitate editing programs. Some |
12 | of these features can | |
6bf7aab6 DL |
13 | |
14 | @itemize @bullet | |
15 | @item | |
93da5dff | 16 | Find or move over top-level definitions (@pxref{Defuns}). |
6bf7aab6 | 17 | @item |
93da5dff RS |
18 | Apply the usual indentation conventions of the language |
19 | (@pxref{Program Indent}). | |
6bf7aab6 | 20 | @item |
93da5dff | 21 | Balance parentheses (@pxref{Parentheses}). |
cf1c48d4 | 22 | @item |
ea118de1 SE |
23 | Insert, kill or align comments (@pxref{Comments}). |
24 | @item | |
cf1c48d4 | 25 | Highlight program syntax (@pxref{Font Lock}). |
6bf7aab6 DL |
26 | @end itemize |
27 | ||
e79c6b89 RS |
28 | This chapter describes these features and many more. |
29 | ||
6bf7aab6 DL |
30 | @menu |
31 | * Program Modes:: Major modes for editing programs. | |
93da5dff RS |
32 | * Defuns:: Commands to operate on major top-level parts |
33 | of a program. | |
6bf7aab6 | 34 | * Program Indent:: Adjusting indentation to show the nesting. |
93da5dff | 35 | * Parentheses:: Commands that operate on parentheses. |
c8b21b5e | 36 | * Comments:: Inserting, killing, and aligning comments. |
93da5dff | 37 | * Documentation:: Getting documentation of functions you plan to call. |
51ed0ea0 | 38 | * Hideshow:: Displaying blocks selectively. |
93da5dff | 39 | * Symbol Completion:: Completion on symbol names of your program or language. |
3b8b8888 | 40 | * Glasses:: Making identifiersLikeThis more readable. |
93da5dff | 41 | * Misc for Programs:: Other Emacs features useful for editing programs. |
79214ddf | 42 | * C Modes:: Special commands of C, C++, Objective-C, |
6bf7aab6 | 43 | Java, and Pike modes. |
51ed0ea0 DL |
44 | * Fortran:: Fortran mode and its special features. |
45 | * Asm Mode:: Asm mode and its special features. | |
6bf7aab6 DL |
46 | @end menu |
47 | ||
48 | @node Program Modes | |
49 | @section Major Modes for Programming Languages | |
6bf7aab6 | 50 | @cindex modes for programming languages |
cf1c48d4 RS |
51 | |
52 | Emacs has specialized major modes for various programming languages. | |
53 | @xref{Major Modes}. A programming language major mode typically | |
54 | specifies the syntax of expressions, the customary rules for | |
55 | indentation, how to do syntax highlighting for the language, and how | |
e79c6b89 RS |
56 | to find the beginning of a function definition. It often customizes |
57 | or provides facilities for compiling and debugging programs as well. | |
cf1c48d4 RS |
58 | |
59 | Ideally, Emacs should provide a major mode for each programming | |
60 | language that you might want to edit; if it doesn't have a mode for | |
61 | your favorite language, you can contribute one. But often the mode | |
62 | for one language can serve for other syntactically similar languages. | |
63 | The major mode for language @var{l} is called @code{@var{l}-mode}, | |
e79c6b89 | 64 | and you can select it by typing @kbd{M-x @var{l}-mode @key{RET}}. |
cf1c48d4 RS |
65 | @xref{Choosing Modes}. |
66 | ||
6bf7aab6 DL |
67 | @cindex Perl mode |
68 | @cindex Icon mode | |
6bf7aab6 DL |
69 | @cindex Makefile mode |
70 | @cindex Tcl mode | |
71 | @cindex CPerl mode | |
138a8f12 DL |
72 | @cindex DSSSL mode |
73 | @cindex Octave mode | |
74 | @cindex Metafont mode | |
75 | @cindex Modula2 mode | |
76 | @cindex Prolog mode | |
64e207c0 | 77 | @cindex Python mode |
138a8f12 DL |
78 | @cindex Simula mode |
79 | @cindex VHDL mode | |
80 | @cindex M4 mode | |
81 | @cindex Shell-script mode | |
3b8b8888 DL |
82 | @cindex Delphi mode |
83 | @cindex PostScript mode | |
8758a7da RS |
84 | @cindex Conf mode |
85 | @cindex DNS mode | |
cf1c48d4 RS |
86 | The existing programming language major modes include Lisp, Scheme (a |
87 | variant of Lisp) and the Scheme-based DSSSL expression language, Ada, | |
ea118de1 | 88 | ASM, AWK, C, C++, Delphi (Object Pascal), Fortran (free format and fixed |
cf1c48d4 RS |
89 | format), Icon, IDL (CORBA), IDLWAVE, Java, Metafont (@TeX{}'s |
90 | companion for font creation), Modula2, Objective-C, Octave, Pascal, | |
8758a7da RS |
91 | Perl, Pike, PostScript, Prolog, Python, Simula, Tcl, and VHDL. An |
92 | alternative mode for Perl is called CPerl mode. Modes are available for | |
93 | the scripting languages of the common GNU and Unix shells, VMS DCL, and | |
cf1c48d4 | 94 | MS-DOS/MS-Windows @samp{BAT} files. There are also major modes for |
8758a7da RS |
95 | editing makefiles, DNS master files, and various sorts of configuration |
96 | files. | |
6bf7aab6 DL |
97 | |
98 | @kindex DEL @r{(programming modes)} | |
4f7666dc | 99 | @findex c-electric-backspace |
93da5dff RS |
100 | In most programming languages, indentation should vary from line to |
101 | line to illustrate the structure of the program. So the major modes | |
e79c6b89 RS |
102 | for programming languages arrange for @key{TAB} to update the |
103 | indentation of the current line. They also rebind @key{DEL} to treat | |
104 | a tab as if it were the equivalent number of spaces; this lets you | |
105 | delete one column of indentation without worrying whether the | |
106 | whitespace consists of spaces or tabs. Use @kbd{C-b C-d} to delete a | |
107 | tab character before point, in these modes. | |
6bf7aab6 | 108 | |
cf1c48d4 | 109 | Separate manuals are available for the modes for Ada (@pxref{Top, , Ada |
7ae8ad94 | 110 | Mode, ada-mode, Ada Mode}), C/C++/Objective C/Java/Corba IDL/Pike/AWK |
cf1c48d4 RS |
111 | (@pxref{Top, , CC Mode, ccmode, CC Mode}) and the IDLWAVE modes |
112 | (@pxref{Top, , IDLWAVE, idlwave, IDLWAVE User Manual}). | |
f9fd7fbc | 113 | |
6bf7aab6 DL |
114 | @cindex mode hook |
115 | @vindex c-mode-hook | |
116 | @vindex lisp-mode-hook | |
117 | @vindex emacs-lisp-mode-hook | |
118 | @vindex lisp-interaction-mode-hook | |
119 | @vindex scheme-mode-hook | |
d2fab838 RS |
120 | Turning on a major mode runs a normal hook called the @dfn{mode |
121 | hook}, which is the value of a Lisp variable. Each major mode has a | |
122 | mode hook, and the hook's name is always made from the mode command's | |
123 | name by adding @samp{-hook}. For example, turning on C mode runs the | |
124 | hook @code{c-mode-hook}, while turning on Lisp mode runs the hook | |
125 | @code{lisp-mode-hook}. The purpose of the mode hook is to give you a | |
126 | place to set up customizations for that major mode. @xref{Hooks}. | |
6bf7aab6 | 127 | |
93da5dff RS |
128 | @node Defuns |
129 | @section Top-Level Definitions, or Defuns | |
6bf7aab6 | 130 | |
93da5dff RS |
131 | In Emacs, a major definition at the top level in the buffer is |
132 | called a @dfn{defun}. The name comes from Lisp, but in Emacs we use | |
133 | it for all languages. | |
6bf7aab6 | 134 | |
93da5dff RS |
135 | In most programming language modes, Emacs assumes that a defun is |
136 | any pair of parentheses (or braces, if the language uses braces this | |
137 | way) that starts at the left margin. For example, in C, the body of a | |
138 | function definition is normally a defun, because the open-brace that | |
139 | begins it is normally at the left margin. A variable's initializer | |
140 | can also count as a defun, if the open-brace that begins the | |
141 | initializer is at the left margin. | |
6bf7aab6 | 142 | |
93da5dff RS |
143 | However, some language modes provide their own code for recognizing |
144 | defuns in a way that suits the language syntax and conventions better. | |
6bf7aab6 | 145 | |
93da5dff RS |
146 | @menu |
147 | * Left Margin Paren:: An open-paren or similar opening delimiter | |
148 | starts a defun if it is at the left margin. | |
149 | * Moving by Defuns:: Commands to move over or mark a major definition. | |
150 | * Imenu:: Making buffer indexes as menus. | |
151 | * Which Function:: Which Function mode shows which function you are in. | |
152 | @end menu | |
6bf7aab6 | 153 | |
93da5dff RS |
154 | @node Left Margin Paren |
155 | @subsection Left Margin Convention | |
6bf7aab6 | 156 | |
93da5dff RS |
157 | @cindex open-parenthesis in leftmost column |
158 | @cindex ( in leftmost column | |
159 | In most major modes, Emacs assumes that any opening delimiter found | |
160 | at the left margin is the start of a top-level definition, or defun. | |
161 | Therefore, @strong{never put an opening delimiter at the left margin | |
162 | unless it should have that significance.} For instance, never put an | |
163 | open-parenthesis at the left margin in a Lisp file unless it is the | |
164 | start of a top-level list. Never put an open-brace or other opening | |
165 | delimiter at the beginning of a line of C code unless it is at top | |
166 | level. | |
167 | ||
168 | If you don't follow this convention, not only will you have trouble | |
169 | when you explicitly use the commands for motion by defuns; other | |
170 | features that use them will also give you trouble. This includes | |
171 | the indentation commands (@pxref{Program Indent}) and Font Lock | |
172 | mode (@pxref{Font Lock}). | |
173 | ||
174 | The most likely problem case is when you want an opening delimiter | |
175 | at the start of a line inside a string. To avoid trouble, put an | |
176 | escape character (@samp{\}, in C and Emacs Lisp, @samp{/} in some | |
177 | other Lisp dialects) before the opening delimiter. This will not | |
178 | affect the contents of the string, but will prevent that opening | |
179 | delimiter from starting a defun. Here's an example: | |
6bf7aab6 | 180 | |
93da5dff RS |
181 | @example |
182 | (insert "Foo: | |
183 | \(bar) | |
184 | ") | |
185 | @end example | |
6bf7aab6 | 186 | |
5b8fe684 RS |
187 | To help you catch violations of this convention, Font Lock mode |
188 | highlights confusing opening delimiters (those that ought to be | |
189 | quoted) in bold red. | |
190 | ||
93da5dff RS |
191 | In the earliest days, the original Emacs found defuns by moving |
192 | upward a level of parentheses or braces until there were no more | |
193 | levels to go up. This always required scanning all the way back to | |
194 | the beginning of the buffer, even for a small function. To speed up | |
195 | the operation, we changed Emacs to assume that any opening delimiter | |
196 | at the left margin is the start of a defun. This heuristic is nearly | |
197 | always right, and avoids the need to scan back to the beginning of the | |
198 | buffer. However, it mandates following the convention described | |
199 | above. | |
200 | ||
201 | @node Moving by Defuns | |
202 | @subsection Moving by Defuns | |
6bf7aab6 DL |
203 | @cindex defuns |
204 | ||
93da5dff RS |
205 | These commands move point or set up the region based on top-level |
206 | major definitions, also called @dfn{defuns}. | |
520c3f4c | 207 | |
6bf7aab6 DL |
208 | @table @kbd |
209 | @item C-M-a | |
210 | Move to beginning of current or preceding defun | |
211 | (@code{beginning-of-defun}). | |
212 | @item C-M-e | |
213 | Move to end of current or following defun (@code{end-of-defun}). | |
214 | @item C-M-h | |
215 | Put region around whole current or following defun (@code{mark-defun}). | |
216 | @end table | |
217 | ||
f772775c RS |
218 | @cindex move to beginning or end of function |
219 | @cindex function, move to beginning or end | |
220 | @kindex C-M-a | |
221 | @kindex C-M-e | |
222 | @kindex C-M-h | |
223 | @findex beginning-of-defun | |
224 | @findex end-of-defun | |
225 | @findex mark-defun | |
226 | The commands to move to the beginning and end of the current defun | |
227 | are @kbd{C-M-a} (@code{beginning-of-defun}) and @kbd{C-M-e} | |
228 | (@code{end-of-defun}). If you repeat one of these commands, or use a | |
229 | positive numeric argument, each repetition moves to the next defun in | |
230 | the direction of motion. | |
231 | ||
232 | @kbd{C-M-a} with a negative argument @minus{}@var{n} moves forward | |
233 | @var{n} times to the next beginning of a defun. This is not exactly | |
234 | the same place that @kbd{C-M-e} with argument @var{n} would move to; | |
235 | the end of this defun is not usually exactly the same place as the | |
93da5dff RS |
236 | beginning of the following defun. (Whitespace, comments, and perhaps |
237 | declarations can separate them.) Likewise, @kbd{C-M-e} with a | |
238 | negative argument moves back to an end of a defun, which is not quite | |
239 | the same as @kbd{C-M-a} with a positive argument. | |
f772775c | 240 | |
4946337d | 241 | @kindex C-M-h @r{(C mode)} |
6bf7aab6 | 242 | @findex c-mark-function |
93da5dff RS |
243 | To operate on the current defun, use @kbd{C-M-h} (@code{mark-defun}) |
244 | which puts point at the beginning and mark at the end of the current | |
5e6f9132 RS |
245 | defun. This is the easiest way to get ready to kill the defun in |
246 | order to move it to a different place in the file. If you use the | |
247 | command while point is between defuns, it uses the following defun. | |
64e207c0 RS |
248 | Successive uses of @kbd{C-M-h}, or using it in Transient Mark mode |
249 | when the mark is active, includes an additional defun in the region | |
250 | each time. | |
93da5dff RS |
251 | |
252 | In C mode, @kbd{C-M-h} runs the function @code{c-mark-function}, | |
253 | which is almost the same as @code{mark-defun}; the difference is that | |
254 | it backs up over the argument declarations, function name and returned | |
e79c6b89 RS |
255 | data type so that the entire C function is inside the region. This is |
256 | an example of how major modes adjust the standard key bindings so that | |
257 | they do their standard jobs in a way better fitting a particular | |
258 | language. Other major modes may replace any or all of these key | |
259 | bindings for that purpose. | |
6bf7aab6 | 260 | |
93da5dff RS |
261 | @node Imenu |
262 | @subsection Imenu | |
e79c6b89 RS |
263 | @cindex index of buffer definitions |
264 | @cindex buffer definitions index | |
93da5dff RS |
265 | @cindex tags |
266 | ||
269b7745 | 267 | The Imenu facility offers a way to find the major definitions in |
5e6f9132 RS |
268 | a file by name. It is also useful in text formatter major modes, |
269 | where it treats each chapter, section, etc., as a definition. | |
e79c6b89 | 270 | (@xref{Tags}, for a more powerful feature that handles multiple files |
5e6f9132 | 271 | together.) |
93da5dff RS |
272 | |
273 | @findex imenu | |
5e6f9132 | 274 | If you type @kbd{M-x imenu}, it reads the name of a definition using |
e79c6b89 RS |
275 | the minibuffer, then moves point to that definition. You can use |
276 | completion to specify the name; the command always displays the whole | |
277 | list of valid names. | |
d2fab838 | 278 | |
5e6f9132 | 279 | @findex imenu-add-menubar-index |
d2fab838 | 280 | Alternatively, you can bind the command @code{imenu} to a mouse |
e79c6b89 RS |
281 | click. Then it displays mouse menus for you to select a definition |
282 | name. You can also add the buffer's index to the menu bar by calling | |
283 | @code{imenu-add-menubar-index}. If you want to have this menu bar | |
284 | item available for all buffers in a certain major mode, you can do | |
285 | this by adding @code{imenu-add-menubar-index} to its mode hook. But | |
286 | if you have done that, you will have to wait each time you visit a | |
287 | file in that mode, while Emacs finds all the definitions in that | |
288 | buffer. | |
93da5dff RS |
289 | |
290 | @vindex imenu-auto-rescan | |
291 | When you change the contents of a buffer, if you add or delete | |
e79c6b89 | 292 | definitions, you can update the buffer's index based on the |
d2fab838 | 293 | new contents by invoking the @samp{*Rescan*} item in the menu. |
dcace646 EZ |
294 | Rescanning happens automatically if you set @code{imenu-auto-rescan} to |
295 | a non-@code{nil} value. There is no need to rescan because of small | |
e79c6b89 | 296 | changes in the text. |
93da5dff RS |
297 | |
298 | @vindex imenu-sort-function | |
d2fab838 | 299 | You can customize the way the menus are sorted by setting the |
e79c6b89 | 300 | variable @code{imenu-sort-function}. By default, names are ordered as |
5e6f9132 RS |
301 | they occur in the buffer; if you want alphabetic sorting, use the |
302 | symbol @code{imenu--sort-by-name} as the value. You can also | |
303 | define your own comparison function by writing Lisp code. | |
93da5dff RS |
304 | |
305 | Imenu provides the information to guide Which Function mode | |
306 | @ifnottex | |
307 | (@pxref{Which Function}). | |
308 | @end ifnottex | |
309 | @iftex | |
310 | (see below). | |
311 | @end iftex | |
312 | The Speedbar can also use it (@pxref{Speedbar}). | |
313 | ||
314 | @node Which Function | |
315 | @subsection Which Function Mode | |
af056954 | 316 | @cindex current function name in mode line |
93da5dff RS |
317 | |
318 | Which Function mode is a minor mode that displays the current | |
319 | function name in the mode line, updating it as you move around in a | |
320 | buffer. | |
321 | ||
322 | @findex which-function-mode | |
323 | @vindex which-func-modes | |
324 | To enable (or disable) Which Function mode, use the command @kbd{M-x | |
325 | which-function-mode}. This command is global; it applies to all | |
ea118de1 | 326 | buffers, both existing ones and those yet to be created. However, it |
6daf3e15 | 327 | takes effect only in certain major modes, those listed in the value of |
ea118de1 SE |
328 | @code{which-func-modes}. If the value is @code{t}, then Which Function |
329 | mode applies to all major modes that know how to support it---in other | |
330 | words, all the major modes that support Imenu. | |
6bf7aab6 DL |
331 | |
332 | @node Program Indent | |
333 | @section Indentation for Programs | |
334 | @cindex indentation for programs | |
335 | ||
336 | The best way to keep a program properly indented is to use Emacs to | |
337 | reindent it as you change it. Emacs has commands to indent properly | |
338 | either a single line, a specified number of lines, or all of the lines | |
339 | inside a single parenthetical grouping. | |
340 | ||
341 | @menu | |
342 | * Basic Indent:: Indenting a single line. | |
343 | * Multi-line Indent:: Commands to reindent many lines at once. | |
344 | * Lisp Indent:: Specifying how each Lisp function should be indented. | |
345 | * C Indent:: Extra features for indenting C and related modes. | |
346 | * Custom C Indent:: Controlling indentation style for C and related modes. | |
347 | @end menu | |
348 | ||
d2fab838 | 349 | @cindex pretty-printer |
6bf7aab6 DL |
350 | Emacs also provides a Lisp pretty-printer in the library @code{pp}. |
351 | This program reformats a Lisp object with indentation chosen to look nice. | |
352 | ||
353 | @node Basic Indent | |
354 | @subsection Basic Program Indentation Commands | |
355 | ||
d2fab838 RS |
356 | The basic indentation commands indent a single line according to the |
357 | usual conventions of the language you are editing. | |
cf1c48d4 | 358 | |
6bf7aab6 DL |
359 | @table @kbd |
360 | @item @key{TAB} | |
361 | Adjust indentation of current line. | |
362 | @item C-j | |
363 | Equivalent to @key{RET} followed by @key{TAB} (@code{newline-and-indent}). | |
d2fab838 | 364 | @item @key{LINEFEED} |
e79c6b89 | 365 | This key, if the keyboard has it, is another way to enter @kbd{C-j}. |
6bf7aab6 DL |
366 | @end table |
367 | ||
368 | @kindex TAB @r{(programming modes)} | |
4f7666dc RS |
369 | @findex c-indent-command |
370 | @findex indent-line-function | |
f772775c | 371 | @findex indent-for-tab-command |
6bf7aab6 DL |
372 | The basic indentation command is @key{TAB}, which gives the current line |
373 | the correct indentation as determined from the previous lines. The | |
cf1c48d4 | 374 | function that @key{TAB} runs depends on the major mode; it is |
054af0fd | 375 | @code{lisp-indent-line} |
4f7666dc | 376 | in Lisp mode, @code{c-indent-command} in C mode, etc. These functions |
cf1c48d4 RS |
377 | understand the syntax and conventions of different languages, but they all do |
378 | conceptually the same job: @key{TAB} in any programming-language major mode | |
6bf7aab6 | 379 | inserts or deletes whitespace at the beginning of the current line, |
cf1c48d4 RS |
380 | independent of where point is in the line. If point was inside the |
381 | whitespace at the beginning of the line, @key{TAB} puts it at the end of | |
382 | that whitespace; otherwise, @key{TAB} keeps point fixed with respect to | |
6bf7aab6 DL |
383 | the characters around it. |
384 | ||
64e207c0 | 385 | Use @kbd{C-q @key{TAB}} to insert a tab character at point. |
6bf7aab6 DL |
386 | |
387 | @kindex C-j | |
388 | @findex newline-and-indent | |
cf1c48d4 RS |
389 | When entering lines of new code, use @kbd{C-j} |
390 | (@code{newline-and-indent}), which is equivalent to a @key{RET} | |
391 | followed by a @key{TAB}. @kbd{C-j} at the end of a line creates a | |
392 | blank line and then gives it the appropriate indentation. | |
6bf7aab6 | 393 | |
64e207c0 RS |
394 | @key{TAB} indents a line that starts within a parenthetical grouping |
395 | under the preceding line within the grouping, or the text after the | |
396 | parenthesis. Therefore, if you manually give one of these lines a | |
397 | nonstandard indentation, the lines below will tend to follow it. This | |
398 | behavior is convenient in cases where you have overridden the standard | |
399 | result of @key{TAB} because you find it unaesthetic for a particular | |
400 | line. | |
6bf7aab6 DL |
401 | |
402 | Remember that an open-parenthesis, open-brace or other opening delimiter | |
403 | at the left margin is assumed by Emacs (including the indentation routines) | |
404 | to be the start of a function. Therefore, you must never have an opening | |
405 | delimiter in column zero that is not the beginning of a function, not even | |
406 | inside a string. This restriction is vital for making the indentation | |
93da5dff RS |
407 | commands fast; you must simply accept it. @xref{Left Margin Paren}, |
408 | for more information on this. | |
6bf7aab6 | 409 | |
5151db0c EZ |
410 | Normally, lines are indented with tabs and spaces. If you want Emacs |
411 | to use spaces only, see @ref{Just Spaces}. | |
412 | ||
6bf7aab6 DL |
413 | @node Multi-line Indent |
414 | @subsection Indenting Several Lines | |
415 | ||
93da5dff RS |
416 | When you wish to reindent several lines of code which have been |
417 | altered or moved to a different level in the parenthesis structure, | |
418 | you have several commands available. | |
6bf7aab6 DL |
419 | |
420 | @table @kbd | |
421 | @item C-M-q | |
6daf3e15 | 422 | Reindent all the lines within one parenthetical grouping (@code{indent-pp-sexp}). |
e79c6b89 RS |
423 | @item C-M-\ |
424 | Reindent all lines in the region (@code{indent-region}). | |
6bf7aab6 | 425 | @item C-u @key{TAB} |
93da5dff RS |
426 | Shift an entire parenthetical grouping rigidly sideways so that its |
427 | first line is properly indented. | |
5cc06e0b EZ |
428 | @item M-x indent-code-rigidly |
429 | Shift all the lines in the region rigidly sideways, but do not alter | |
430 | lines that start inside comments and strings. | |
6bf7aab6 DL |
431 | @end table |
432 | ||
433 | @kindex C-M-q | |
6daf3e15 | 434 | @findex indent-pp-sexp |
93da5dff RS |
435 | You can reindent the contents of a single parenthetical grouping by |
436 | positioning point before the beginning of it and typing @kbd{C-M-q} | |
054af0fd | 437 | (@code{indent-pp-sexp} in Lisp mode, @code{c-indent-exp} in C mode; also |
93da5dff | 438 | bound to other suitable commands in other modes). The indentation of |
6daf3e15 | 439 | the line where the grouping starts is not changed; therefore this |
93da5dff RS |
440 | changes only the relative indentation within the grouping, not its |
441 | overall indentation. To correct that as well, type @key{TAB} first. | |
6bf7aab6 | 442 | |
e79c6b89 RS |
443 | Another way to specify the range to be reindented is with the |
444 | region. The command @kbd{C-M-\} (@code{indent-region}) applies | |
445 | @key{TAB} to every line whose first character is between point and | |
446 | mark. | |
447 | ||
6bf7aab6 | 448 | @kindex C-u TAB |
93da5dff RS |
449 | If you like the relative indentation within a grouping, but not the |
450 | indentation of its first line, you can type @kbd{C-u @key{TAB}} to | |
24c7c69c RS |
451 | reindent the whole grouping as a rigid unit. (This works in Lisp |
452 | modes and C and related modes.) @key{TAB} with a numeric argument | |
453 | reindents the current line as usual, then reindents by the same amount | |
454 | all the lines in the parenthetical grouping starting on the current | |
455 | line. It is clever, though, and does not alter lines that start | |
7ae8ad94 RS |
456 | inside strings. Neither does it alter C preprocessor lines when in C |
457 | mode, but it does reindent any continuation lines that may be attached | |
458 | to them. | |
6bf7aab6 | 459 | |
5cc06e0b | 460 | @findex indent-code-rigidly |
e79c6b89 RS |
461 | You can also perform this operation on the region, using the command |
462 | @kbd{M-x indent-code-rigidly}. It rigidly shifts all the lines in the | |
463 | region sideways, like @code{indent-rigidly} does (@pxref{Indentation | |
464 | Commands}). It doesn't alter the indentation of lines that start | |
7ae8ad94 | 465 | inside a string, unless the region also starts inside that string. |
054af0fd | 466 | The prefix arg specifies the number of columns to indent. |
6bf7aab6 DL |
467 | |
468 | @node Lisp Indent | |
469 | @subsection Customizing Lisp Indentation | |
470 | @cindex customizing Lisp indentation | |
471 | ||
472 | The indentation pattern for a Lisp expression can depend on the function | |
473 | called by the expression. For each Lisp function, you can choose among | |
474 | several predefined patterns of indentation, or define an arbitrary one with | |
475 | a Lisp program. | |
476 | ||
477 | The standard pattern of indentation is as follows: the second line of the | |
478 | expression is indented under the first argument, if that is on the same | |
479 | line as the beginning of the expression; otherwise, the second line is | |
480 | indented underneath the function name. Each following line is indented | |
481 | under the previous line whose nesting depth is the same. | |
482 | ||
483 | @vindex lisp-indent-offset | |
484 | If the variable @code{lisp-indent-offset} is non-@code{nil}, it overrides | |
485 | the usual indentation pattern for the second line of an expression, so that | |
486 | such lines are always indented @code{lisp-indent-offset} more columns than | |
487 | the containing list. | |
488 | ||
489 | @vindex lisp-body-indent | |
d2fab838 | 490 | Certain functions override the standard pattern. Functions whose |
269b7745 | 491 | names start with @code{def} treat the second lines as the start of |
d2fab838 RS |
492 | a @dfn{body}, by indenting the second line @code{lisp-body-indent} |
493 | additional columns beyond the open-parenthesis that starts the | |
494 | expression. | |
6bf7aab6 | 495 | |
b771b258 | 496 | @cindex @code{lisp-indent-function} property |
d2fab838 | 497 | You can override the standard pattern in various ways for individual |
690a6d08 RS |
498 | functions, according to the @code{lisp-indent-function} property of |
499 | the function name. Normally you would use this for macro definitions | |
500 | and specify it using the @code{declare} construct (@pxref{Defining | |
501 | Macros,,, elisp, the Emacs Lisp Reference Manual}). | |
6bf7aab6 DL |
502 | |
503 | @node C Indent | |
504 | @subsection Commands for C Indentation | |
505 | ||
93da5dff | 506 | Here are special features for indentation in C mode and related modes: |
6bf7aab6 DL |
507 | |
508 | @table @code | |
509 | @item C-c C-q | |
510 | @kindex C-c C-q @r{(C mode)} | |
511 | @findex c-indent-defun | |
512 | Reindent the current top-level function definition or aggregate type | |
513 | declaration (@code{c-indent-defun}). | |
514 | ||
515 | @item C-M-q | |
516 | @kindex C-M-q @r{(C mode)} | |
517 | @findex c-indent-exp | |
518 | Reindent each line in the balanced expression that follows point | |
7ae8ad94 RS |
519 | (@code{c-indent-exp}). A prefix argument inhibits warning messages |
520 | about invalid syntax. | |
6bf7aab6 DL |
521 | |
522 | @item @key{TAB} | |
523 | @findex c-indent-command | |
524 | Reindent the current line, and/or in some cases insert a tab character | |
525 | (@code{c-indent-command}). | |
526 | ||
7ae8ad94 | 527 | @vindex c-tab-always-indent |
6bf7aab6 DL |
528 | If @code{c-tab-always-indent} is @code{t}, this command always reindents |
529 | the current line and does nothing else. This is the default. | |
530 | ||
531 | If that variable is @code{nil}, this command reindents the current line | |
532 | only if point is at the left margin or in the line's indentation; | |
533 | otherwise, it inserts a tab (or the equivalent number of spaces, | |
534 | if @code{indent-tabs-mode} is @code{nil}). | |
535 | ||
536 | Any other value (not @code{nil} or @code{t}) means always reindent the | |
7ae8ad94 | 537 | line, and also insert a tab if within a comment or a string. |
6bf7aab6 DL |
538 | @end table |
539 | ||
540 | To reindent the whole current buffer, type @kbd{C-x h C-M-\}. This | |
541 | first selects the whole buffer as the region, then reindents that | |
542 | region. | |
543 | ||
544 | To reindent the current block, use @kbd{C-M-u C-M-q}. This moves | |
545 | to the front of the block and then reindents it all. | |
546 | ||
547 | @node Custom C Indent | |
548 | @subsection Customizing C Indentation | |
93da5dff | 549 | @cindex style (for indentation) |
6bf7aab6 | 550 | |
7ae8ad94 RS |
551 | C mode and related modes use a flexible mechanism for customizing |
552 | indentation. C mode indents a source line in two steps: first it | |
553 | classifies the line syntactically according to its contents and | |
554 | context; second, it determines the indentation offset associated by | |
555 | your selected @dfn{style} with the syntactic construct and adds this | |
556 | onto the indentation of the @dfn{anchor statement}. | |
6bf7aab6 | 557 | |
93da5dff | 558 | @table @kbd |
7ae8ad94 RS |
559 | @item C-c . @key{RET} @var{style} @key{RET} |
560 | Select a predefined style @var{style} (@code{c-set-style}). | |
93da5dff | 561 | @end table |
6bf7aab6 | 562 | |
7ae8ad94 | 563 | A @dfn{style} is a named collection of customizations that can |
93da5dff RS |
564 | be used in C mode and the related modes. Emacs comes with several |
565 | predefined styles, including @code{gnu}, @code{k&r}, @code{bsd}, | |
566 | @code{stroustrup}, @code{linux}, @code{python}, @code{java}, | |
567 | @code{whitesmith}, @code{ellemtel}, @code{cc-mode}, and @code{user}. | |
568 | Some of these styles are primarily intended for one language, but any | |
569 | of them can be used with any of the languages supported by these | |
570 | modes. To find out what a style looks like, select it and reindent | |
571 | some code, e.g., by typing @key{C-M-q} at the start of a function | |
572 | definition. | |
6bf7aab6 | 573 | |
7ae8ad94 | 574 | @kindex C-c . @r{(C mode)} |
93da5dff | 575 | @findex c-set-style |
7ae8ad94 RS |
576 | To choose a style for the current buffer, use the command @kbd{C-c |
577 | .}. Specify a style name as an argument (case is not significant). | |
578 | This command affects the current buffer only, and it affects only | |
579 | future invocations of the indentation commands; it does not reindent | |
580 | the code in the buffer. To reindent the whole buffer in the new | |
581 | style, you can type @kbd{C-x h C-M-\}. | |
6bf7aab6 | 582 | |
93da5dff RS |
583 | @vindex c-default-style |
584 | You can also set the variable @code{c-default-style} to specify the | |
7ae8ad94 RS |
585 | default style for various major modes. Its value should be either the |
586 | style's name (a string) or an alist, in which each element specifies | |
587 | one major mode and which indentation style to use for it. For | |
588 | example, | |
6bf7aab6 DL |
589 | |
590 | @example | |
93da5dff RS |
591 | (setq c-default-style |
592 | '((java-mode . "java") (other . "gnu"))) | |
6bf7aab6 DL |
593 | @end example |
594 | ||
93da5dff RS |
595 | @noindent |
596 | specifies an explicit choice for Java mode, and the default @samp{gnu} | |
64e207c0 RS |
597 | style for the other C-like modes. (These settings are actually the |
598 | defaults.) This variable takes effect when you select one of the | |
599 | C-like major modes; thus, if you specify a new default style for Java | |
600 | mode, you can make it take effect in an existing Java mode buffer by | |
601 | typing @kbd{M-x java-mode} there. | |
6bf7aab6 | 602 | |
93da5dff RS |
603 | The @code{gnu} style specifies the formatting recommended by the GNU |
604 | Project for C; it is the default, so as to encourage use of our | |
605 | recommended style. | |
6bf7aab6 | 606 | |
0d103856 | 607 | @xref{Customizing Indentation,,, ccmode, the CC Mode Manual}, for |
93da5dff RS |
608 | more information on customizing indentation for C and related modes, |
609 | including how to override parts of an existing style and how to define | |
610 | your own styles. | |
6bf7aab6 | 611 | |
93da5dff RS |
612 | @node Parentheses |
613 | @section Commands for Editing with Parentheses | |
6bf7aab6 | 614 | |
93da5dff RS |
615 | @findex check-parens |
616 | @cindex unbalanced parentheses and quotes | |
617 | This section describes the commands and features that take advantage | |
618 | of the parenthesis structure in a program, or help you keep it | |
619 | balanced. | |
6bf7aab6 | 620 | |
93da5dff RS |
621 | When talking about these facilities, the term ``parenthesis'' also |
622 | includes braces, brackets, or whatever delimiters are defined to match | |
e79c6b89 RS |
623 | in pairs. The major mode controls which delimiters are significant, |
624 | through the syntax table (@pxref{Syntax}). In Lisp, only parentheses | |
625 | count; in C, these commands apply to braces and brackets too. | |
6bf7aab6 | 626 | |
93da5dff RS |
627 | You can use @kbd{M-x check-parens} to find any unbalanced |
628 | parentheses and unbalanced string quotes in the buffer. | |
6bf7aab6 | 629 | |
93da5dff RS |
630 | @menu |
631 | * Expressions:: Expressions with balanced parentheses. | |
632 | * Moving by Parens:: Commands for moving up, down and across | |
633 | in the structure of parentheses. | |
634 | * Matching:: Insertion of a close-delimiter flashes matching open. | |
635 | @end menu | |
6bf7aab6 | 636 | |
93da5dff RS |
637 | @node Expressions |
638 | @subsection Expressions with Balanced Parentheses | |
6bf7aab6 | 639 | |
93da5dff RS |
640 | @cindex sexp |
641 | @cindex expression | |
642 | @cindex balanced expression | |
643 | These commands deal with balanced expressions, also called | |
644 | @dfn{sexps}@footnote{The word ``sexp'' is used to refer to an | |
645 | expression in Lisp.}. | |
6bf7aab6 | 646 | |
93da5dff RS |
647 | @table @kbd |
648 | @item C-M-f | |
649 | Move forward over a balanced expression (@code{forward-sexp}). | |
650 | @item C-M-b | |
ea118de1 | 651 | Move backward over a balanced expression (@code{backward-sexp}). |
93da5dff RS |
652 | @item C-M-k |
653 | Kill balanced expression forward (@code{kill-sexp}). | |
93da5dff RS |
654 | @item C-M-t |
655 | Transpose expressions (@code{transpose-sexps}). | |
656 | @item C-M-@@ | |
649d1cbe | 657 | @itemx C-M-@key{SPC} |
93da5dff RS |
658 | Put mark after following expression (@code{mark-sexp}). |
659 | @end table | |
6bf7aab6 | 660 | |
93da5dff RS |
661 | Each programming language major mode customizes the definition of |
662 | balanced expressions to suit that language. Balanced expressions | |
663 | typically include symbols, numbers, and string constants, as well as | |
e79c6b89 | 664 | any pair of matching delimiters and their contents. Some languages |
93da5dff RS |
665 | have obscure forms of expression syntax that nobody has bothered to |
666 | implement in Emacs. | |
6bf7aab6 | 667 | |
93da5dff | 668 | @cindex Control-Meta |
e79c6b89 RS |
669 | By convention, the keys for these commands are all Control-Meta |
670 | characters. They usually act on expressions just as the corresponding | |
671 | Meta characters act on words. For instance, the command @kbd{C-M-b} | |
672 | moves backward over a balanced expression, just as @kbd{M-b} moves | |
673 | back over a word. | |
6bf7aab6 | 674 | |
93da5dff RS |
675 | @kindex C-M-f |
676 | @kindex C-M-b | |
677 | @findex forward-sexp | |
678 | @findex backward-sexp | |
679 | To move forward over a balanced expression, use @kbd{C-M-f} | |
680 | (@code{forward-sexp}). If the first significant character after point | |
681 | is an opening delimiter (@samp{(} in Lisp; @samp{(}, @samp{[} or | |
682 | @samp{@{} in C), @kbd{C-M-f} moves past the matching closing | |
683 | delimiter. If the character begins a symbol, string, or number, | |
684 | @kbd{C-M-f} moves over that. | |
6bf7aab6 | 685 | |
93da5dff RS |
686 | The command @kbd{C-M-b} (@code{backward-sexp}) moves backward over a |
687 | balanced expression. The detailed rules are like those above for | |
688 | @kbd{C-M-f}, but with directions reversed. If there are prefix | |
689 | characters (single-quote, backquote and comma, in Lisp) preceding the | |
690 | expression, @kbd{C-M-b} moves back over them as well. The balanced | |
691 | expression commands move across comments as if they were whitespace, | |
692 | in most modes. | |
6bf7aab6 | 693 | |
93da5dff RS |
694 | @kbd{C-M-f} or @kbd{C-M-b} with an argument repeats that operation the |
695 | specified number of times; with a negative argument, it moves in the | |
696 | opposite direction. | |
6bf7aab6 | 697 | |
93da5dff RS |
698 | @cindex killing expressions |
699 | @kindex C-M-k | |
700 | @findex kill-sexp | |
93da5dff | 701 | Killing a whole balanced expression can be done with @kbd{C-M-k} |
880b0421 RS |
702 | (@code{kill-sexp}). @kbd{C-M-k} kills the characters that @kbd{C-M-f} |
703 | would move over. | |
6bf7aab6 | 704 | |
93da5dff RS |
705 | @cindex transposition of expressions |
706 | @kindex C-M-t | |
707 | @findex transpose-sexps | |
708 | A somewhat random-sounding command which is nevertheless handy is | |
709 | @kbd{C-M-t} (@code{transpose-sexps}), which drags the previous | |
710 | balanced expression across the next one. An argument serves as a | |
e79c6b89 RS |
711 | repeat count, and a negative argument drags the previous balanced |
712 | expression backwards across those before it (thus canceling out the | |
713 | effect of @kbd{C-M-t} with a positive argument). An argument of zero, | |
714 | rather than doing nothing, transposes the balanced expressions ending | |
715 | at or after point and the mark. | |
6bf7aab6 | 716 | |
93da5dff | 717 | @kindex C-M-@@ |
649d1cbe | 718 | @kindex C-M-@key{SPC} |
93da5dff RS |
719 | @findex mark-sexp |
720 | To set the region around the next balanced expression in the buffer, | |
721 | use @kbd{C-M-@@} (@code{mark-sexp}), which sets mark at the same place | |
722 | that @kbd{C-M-f} would move to. @kbd{C-M-@@} takes arguments like | |
723 | @kbd{C-M-f}. In particular, a negative argument is useful for putting | |
64e207c0 RS |
724 | the mark at the beginning of the previous balanced expression. The |
725 | alias @kbd{C-M-@key{SPC}} is equivalent to @kbd{C-M-@@}. If you use | |
726 | this command repeatedly, or in Transient Mark mode whenever the mark | |
727 | is active, it extends the region by one sexp each time. | |
93da5dff RS |
728 | |
729 | In languages that use infix operators, such as C, it is not possible | |
730 | to recognize all balanced expressions as such because there can be | |
731 | multiple possibilities at a given position. For example, C mode does | |
732 | not treat @samp{foo + bar} as a single expression, even though it | |
733 | @emph{is} one C expression; instead, it recognizes @samp{foo} as one | |
734 | expression and @samp{bar} as another, with the @samp{+} as punctuation | |
735 | between them. Both @samp{foo + bar} and @samp{foo} are legitimate | |
736 | choices for ``the expression following point'' when point is at the | |
e79c6b89 RS |
737 | @samp{f}, so the expression commands must perforce choose one or the |
738 | other to operate on. Note that @samp{(foo + bar)} is recognized as a | |
739 | single expression in C mode, because of the parentheses. | |
93da5dff RS |
740 | |
741 | @node Moving by Parens | |
742 | @subsection Moving in the Parenthesis Structure | |
743 | ||
744 | @cindex parenthetical groupings | |
745 | @cindex parentheses, moving across | |
746 | @cindex matching parenthesis and braces, moving to | |
747 | @cindex braces, moving across | |
748 | @cindex list commands | |
749 | The Emacs commands for handling parenthetical groupings see nothing | |
750 | except parentheses (or whatever characters must balance in the | |
751 | language you are working with), and the escape characters that might | |
752 | be used to quote those. They are mainly intended for editing | |
753 | programs, but can be useful for editing any text that has parentheses. | |
754 | They are sometimes called ``list'' commands because in Lisp these | |
755 | groupings are lists. | |
6bf7aab6 DL |
756 | |
757 | @table @kbd | |
93da5dff RS |
758 | @item C-M-n |
759 | Move forward over a parenthetical group (@code{forward-list}). | |
760 | @item C-M-p | |
ea118de1 | 761 | Move backward over a parenthetical group (@code{backward-list}). |
93da5dff RS |
762 | @item C-M-u |
763 | Move up in parenthesis structure (@code{backward-up-list}). | |
764 | @item C-M-d | |
765 | Move down in parenthesis structure (@code{down-list}). | |
6bf7aab6 DL |
766 | @end table |
767 | ||
93da5dff RS |
768 | @kindex C-M-n |
769 | @kindex C-M-p | |
770 | @findex forward-list | |
771 | @findex backward-list | |
772 | The ``list'' commands @kbd{C-M-n} (@code{forward-list}) and | |
773 | @kbd{C-M-p} (@code{backward-list}) move over one (or @var{n}) | |
774 | parenthetical groupings, skipping blithely over any amount of text | |
775 | that doesn't include meaningful parentheses (symbols, strings, etc.). | |
6bf7aab6 | 776 | |
93da5dff RS |
777 | @kindex C-M-u |
778 | @kindex C-M-d | |
779 | @findex backward-up-list | |
780 | @findex down-list | |
781 | @kbd{C-M-n} and @kbd{C-M-p} try to stay at the same level in the | |
782 | parenthesis structure. To move @emph{up} one (or @var{n}) levels, use | |
783 | @kbd{C-M-u} (@code{backward-up-list}). @kbd{C-M-u} moves backward up | |
784 | past one unmatched opening delimiter. A positive argument serves as a | |
785 | repeat count; a negative argument reverses the direction of motion, so | |
d2fab838 | 786 | that the command moves forward and up one or more levels. |
93da5dff RS |
787 | |
788 | To move @emph{down} in the parenthesis structure, use @kbd{C-M-d} | |
789 | (@code{down-list}). In Lisp mode, where @samp{(} is the only opening | |
790 | delimiter, this is nearly the same as searching for a @samp{(}. An | |
791 | argument specifies the number of levels to go down. | |
6bf7aab6 DL |
792 | |
793 | @node Matching | |
93da5dff | 794 | @subsection Automatic Display Of Matching Parentheses |
6bf7aab6 DL |
795 | @cindex matching parentheses |
796 | @cindex parentheses, displaying matches | |
797 | ||
798 | The Emacs parenthesis-matching feature is designed to show | |
93da5dff RS |
799 | automatically how parentheses (and other matching delimiters) match in |
800 | the text. Whenever you type a self-inserting character that is a | |
801 | closing delimiter, the cursor moves momentarily to the location of the | |
802 | matching opening delimiter, provided that is on the screen. If it is | |
e79c6b89 RS |
803 | not on the screen, Emacs displays some of the text near it in the echo |
804 | area. Either way, you can tell which grouping you are closing off. | |
93da5dff RS |
805 | |
806 | If the opening delimiter and closing delimiter are mismatched---such | |
807 | as in @samp{[x)}---a warning message is displayed in the echo area. | |
6bf7aab6 DL |
808 | |
809 | @vindex blink-matching-paren | |
810 | @vindex blink-matching-paren-distance | |
811 | @vindex blink-matching-delay | |
054af0fd SE |
812 | Three variables control parenthesis match display: |
813 | ||
814 | @code{blink-matching-paren} turns the feature on or off: @code{nil} | |
93da5dff | 815 | disables it, but the default is @code{t} to enable match display. |
f772775c RS |
816 | |
817 | @code{blink-matching-delay} says how many seconds to leave the | |
93da5dff | 818 | cursor on the matching opening delimiter, before bringing it back to |
f772775c RS |
819 | the real location of point; the default is 1, but on some systems it |
820 | is useful to specify a fraction of a second. | |
821 | ||
822 | @code{blink-matching-paren-distance} specifies how many characters | |
823 | back to search to find the matching opening delimiter. If the match | |
8b6f4c0a | 824 | is not found in that distance, scanning stops, and nothing is displayed. |
93da5dff | 825 | This is to prevent the scan for the matching delimiter from wasting |
f772775c | 826 | lots of time when there is no match. The default is 25600. |
6bf7aab6 DL |
827 | |
828 | @cindex Show Paren mode | |
79f9f655 | 829 | @cindex highlighting matching parentheses |
6bf7aab6 | 830 | @findex show-paren-mode |
93da5dff RS |
831 | Show Paren mode provides a more powerful kind of automatic matching. |
832 | Whenever point is after a closing delimiter, that delimiter and its | |
833 | matching opening delimiter are both highlighted; otherwise, if point | |
834 | is before an opening delimiter, the matching closing delimiter is | |
835 | highlighted. (There is no need to highlight the opening delimiter in | |
836 | that case, because the cursor appears on top of that character.) Use | |
837 | the command @kbd{M-x show-paren-mode} to enable or disable this mode. | |
79f9f655 EZ |
838 | |
839 | By default, @code{show-paren-mode} uses colors to highlight the | |
840 | parentheses. However, if your display doesn't support colors, you can | |
841 | customize the faces @code{show-paren-match-face} and | |
842 | @code{show-paren-mismatch-face} to use other attributes, such as bold or | |
843 | underline. @xref{Face Customization}. | |
6bf7aab6 DL |
844 | |
845 | @node Comments | |
846 | @section Manipulating Comments | |
847 | @cindex comments | |
848 | ||
849 | Because comments are such an important part of programming, Emacs | |
8f50b630 RS |
850 | provides special commands for editing and inserting comments. It can |
851 | also do spell checking on comments with Flyspell Prog mode | |
852 | (@pxref{Spelling}). | |
6bf7aab6 DL |
853 | |
854 | @menu | |
93da5dff RS |
855 | * Comment Commands:: Inserting, killing, and indenting comments. |
856 | * Multi-Line Comments:: Commands for adding and editing multi-line comments. | |
857 | * Options for Comments::Customizing the comment features. | |
6bf7aab6 DL |
858 | @end menu |
859 | ||
860 | @node Comment Commands | |
861 | @subsection Comment Commands | |
6bf7aab6 | 862 | @cindex indentation for comments |
6bf7aab6 | 863 | |
9234c238 RS |
864 | The comment commands in this table insert, kill and align comments. |
865 | They are described in this section and following sections. | |
6bf7aab6 | 866 | |
7ae8ad94 RS |
867 | @table @asis |
868 | @item @kbd{M-;} | |
9234c238 RS |
869 | Insert or realign comment on current line; alternatively, comment or |
870 | uncomment the region (@code{comment-dwim}). | |
7ae8ad94 | 871 | @item @kbd{C-u M-;} |
9234c238 | 872 | Kill comment on current line (@code{comment-kill}). |
7ae8ad94 | 873 | @item @kbd{C-x ;} |
47c1b5f4 | 874 | Set comment column (@code{comment-set-column}). |
7ae8ad94 RS |
875 | @item @kbd{C-M-j} |
876 | @itemx @kbd{M-j} | |
6bf7aab6 | 877 | Like @key{RET} followed by inserting and aligning a comment |
47c1b5f4 | 878 | (@code{comment-indent-new-line}). |
7ae8ad94 RS |
879 | @item @kbd{M-x comment-region} |
880 | @itemx @kbd{C-c C-c} (in C-like modes) | |
6bf7aab6 DL |
881 | Add or remove comment delimiters on all the lines in the region. |
882 | @end table | |
883 | ||
9234c238 RS |
884 | @kindex M-; |
885 | @findex comment-dwim | |
886 | The command to create or align a comment is @kbd{M-;} | |
887 | (@code{comment-dwim}). The word ``dwim'' is an acronym for ``Do What | |
888 | I Mean''; it indicates that this command can be used for many | |
889 | different jobs relating to comments, depending on the situation where | |
890 | you use it. | |
891 | ||
892 | If there is no comment already on the line, @kbd{M-;} inserts a new | |
893 | comment, aligned at a specific column called the @dfn{comment column}. | |
894 | The new comment begins with the string Emacs thinks comments should | |
895 | start with (the value of @code{comment-start}; see below). Point is | |
896 | after that string, so you can insert the text of the comment right | |
897 | away. If the major mode has specified a string to terminate comments, | |
898 | @kbd{M-;} inserts that too, to keep the syntax valid. | |
899 | ||
900 | If the text of the line extends past the comment column, then the | |
901 | comment start string is indented to a suitable boundary (usually, at | |
902 | least one space is inserted). | |
903 | ||
904 | You can also use @kbd{M-;} to align an existing comment. If a line | |
905 | already contains the comment-start string, @kbd{M-;} reindents it to | |
906 | the conventional alignment and moves point after it. (Exception: | |
907 | comments starting in column 0 are not moved.) Even when an existing | |
908 | comment is properly aligned, @kbd{M-;} is still useful for moving | |
909 | directly to the start of the text inside the comment. | |
910 | ||
911 | @findex comment-kill | |
912 | @kindex C-u M-; | |
913 | @kbd{C-u M-;} kills any comment on the current line, along with the | |
914 | whitespace before it. To reinsert the comment on another line, move | |
915 | to the end of that line, do @kbd{C-y}, and then do @kbd{M-;} to | |
916 | realign it. | |
917 | ||
918 | Note that @kbd{C-u M-;} is not a distinct key; it is @kbd{M-;} | |
919 | (@code{comment-dwim}) with a prefix argument. That command is | |
920 | programmed so that when it receives a prefix argument it calls | |
921 | @code{comment-kill}. However, @code{comment-kill} is a valid command | |
922 | in its own right, and you can bind it directly to a key if you wish. | |
923 | ||
924 | @kbd{M-;} does two other jobs when used with an active region in | |
925 | Transient Mark mode (@pxref{Transient Mark}). Then it either adds or | |
926 | removes comment delimiters on each line of the region. (If every line | |
927 | is a comment, it removes comment delimiters from each; otherwise, it | |
928 | adds comment delimiters to each.) If you are not using Transient Mark | |
929 | mode, then you should use the commands @code{comment-region} and | |
7ad1b919 | 930 | @code{uncomment-region} to do these jobs (@pxref{Multi-Line Comments}). |
9234c238 RS |
931 | A prefix argument used in these circumstances specifies how many |
932 | comment delimiters to add or how many to delete. | |
6bf7aab6 DL |
933 | |
934 | Some major modes have special rules for indenting certain kinds of | |
935 | comments in certain contexts. For example, in Lisp code, comments which | |
936 | start with two semicolons are indented as if they were lines of code, | |
937 | instead of at the comment column. Comments which start with three | |
938 | semicolons are supposed to start at the left margin. Emacs understands | |
939 | these conventions by indenting a double-semicolon comment using @key{TAB}, | |
940 | and by not changing the indentation of a triple-semicolon comment at all. | |
941 | ||
942 | @example | |
943 | ;; This function is just an example | |
944 | ;;; Here either two or three semicolons are appropriate. | |
945 | (defun foo (x) | |
946 | ;;; And now, the first part of the function: | |
947 | ;; The following line adds one. | |
948 | (1+ x)) ; This line adds one. | |
949 | @end example | |
950 | ||
951 | In C code, a comment preceded on its line by nothing but whitespace | |
952 | is indented like a line of code. | |
953 | ||
6bf7aab6 DL |
954 | @node Multi-Line Comments |
955 | @subsection Multiple Lines of Comments | |
956 | ||
957 | @kindex C-M-j | |
7ae8ad94 | 958 | @kindex M-j |
6bf7aab6 | 959 | @cindex blank lines in programs |
47c1b5f4 | 960 | @findex comment-indent-new-line |
6bf7aab6 | 961 | If you are typing a comment and wish to continue it on another line, |
7ae8ad94 RS |
962 | you can use the command @kbd{C-M-j} or @kbd{M-j} |
963 | (@code{comment-indent-new-line}). This terminates the comment you are | |
964 | typing, creates a new blank line afterward, and begins a new comment | |
965 | indented under the old one. When Auto Fill mode is on, going past the | |
966 | fill column while typing a comment causes the comment to be continued | |
967 | in just this fashion. If point is not at the end of the line when you | |
968 | type the command, the text on the rest of the line becomes part of the | |
969 | new comment line. | |
970 | ||
971 | @kindex C-c C-c (C mode) | |
6bf7aab6 DL |
972 | @findex comment-region |
973 | To turn existing lines into comment lines, use the @kbd{M-x | |
974 | comment-region} command. It adds comment delimiters to the lines that start | |
975 | in the region, thus commenting them out. With a negative argument, it | |
976 | does the opposite---it deletes comment delimiters from the lines in the | |
977 | region. | |
978 | ||
979 | With a positive argument, @code{comment-region} duplicates the last | |
980 | character of the comment start sequence it adds; the argument specifies | |
981 | how many copies of the character to insert. Thus, in Lisp mode, | |
982 | @kbd{C-u 2 M-x comment-region} adds @samp{;;} to each line. Duplicating | |
983 | the comment delimiter is a way of calling attention to the comment. It | |
984 | can also affect how the comment is indented. In Lisp, for proper | |
47c1b5f4 RS |
985 | indentation, you should use an argument of two or three, if between defuns; |
986 | if within a defun, it must be three. | |
6bf7aab6 | 987 | |
6bf7aab6 DL |
988 | @node Options for Comments |
989 | @subsection Options Controlling Comments | |
990 | ||
991 | @vindex comment-column | |
992 | @kindex C-x ; | |
47c1b5f4 | 993 | @findex comment-set-column |
7ae8ad94 RS |
994 | The @dfn{comment column}, the column at which Emacs tries to place |
995 | comments, is stored in the variable @code{comment-column}. You can | |
996 | set it to a number explicitly. Alternatively, the command @kbd{C-x ;} | |
997 | (@code{comment-set-column}) sets the comment column to the column | |
998 | point is at. @kbd{C-u C-x ;} sets the comment column to match the | |
999 | last comment before point in the buffer, and then does a @kbd{M-;} to | |
1000 | align the current line's comment under the previous one. | |
6bf7aab6 DL |
1001 | |
1002 | The variable @code{comment-column} is per-buffer: setting the variable | |
1003 | in the normal fashion affects only the current buffer, but there is a | |
1004 | default value which you can change with @code{setq-default}. | |
1005 | @xref{Locals}. Many major modes initialize this variable for the | |
1006 | current buffer. | |
1007 | ||
1008 | @vindex comment-start-skip | |
1009 | The comment commands recognize comments based on the regular | |
1010 | expression that is the value of the variable @code{comment-start-skip}. | |
1011 | Make sure this regexp does not match the null string. It may match more | |
1012 | than the comment starting delimiter in the strictest sense of the word; | |
47c1b5f4 RS |
1013 | for example, in C mode the value of the variable is |
1014 | @c This stops M-q from breaking the line inside that @code. | |
7ae8ad94 | 1015 | @code{@w{"/\\*+ *\\|//+ *"}}, which matches extra stars and spaces |
47c1b5f4 | 1016 | after the @samp{/*} itself, and accepts C++ style comments also. |
6bf7aab6 DL |
1017 | (Note that @samp{\\} is needed in Lisp syntax to include a @samp{\} in |
1018 | the string, which is needed to deny the first star its special meaning | |
1019 | in regexp syntax. @xref{Regexps}.) | |
1020 | ||
1021 | @vindex comment-start | |
1022 | @vindex comment-end | |
1023 | When a comment command makes a new comment, it inserts the value of | |
1024 | @code{comment-start} to begin it. The value of @code{comment-end} is | |
1025 | inserted after point, so that it will follow the text that you will insert | |
1026 | into the comment. In C mode, @code{comment-start} has the value | |
1027 | @w{@code{"/* "}} and @code{comment-end} has the value @w{@code{" */"}}. | |
1028 | ||
9234c238 RS |
1029 | @vindex comment-padding |
1030 | The variable @code{comment-padding} specifies how many spaces | |
7ae8ad94 RS |
1031 | @code{comment-region} should insert on each line between the comment |
1032 | delimiter and the line's original text. The default is 1, to insert | |
1033 | one space. @code{nil} means 0. Alternatively, @code{comment-padding} | |
1034 | can hold the actual string to insert. | |
9234c238 | 1035 | |
6bf7aab6 DL |
1036 | @vindex comment-multi-line |
1037 | The variable @code{comment-multi-line} controls how @kbd{C-M-j} | |
7ae8ad94 RS |
1038 | (@code{indent-new-comment-line}) behaves when used inside a comment. |
1039 | Specifically, when @code{comment-multi-line} is @code{nil} (the | |
1040 | default value), the command inserts a comment terminator, begins a new | |
1041 | line, and finally inserts a comment starter. Otherwise it does not | |
1042 | insert the terminator and starter, so it effectively continues the | |
1043 | current comment across multiple lines. In languages that allow | |
1044 | multi-line comments, the choice of value for this variable is a matter | |
1045 | of taste. | |
6bf7aab6 | 1046 | |
4190ce5c | 1047 | @vindex comment-indent-function |
6bf7aab6 DL |
1048 | The variable @code{comment-indent-function} should contain a function |
1049 | that will be called to compute the indentation for a newly inserted | |
1050 | comment or for aligning an existing comment. It is set differently by | |
1051 | various major modes. The function is called with no arguments, but with | |
1052 | point at the beginning of the comment, or at the end of a line if a new | |
1053 | comment is to be inserted. It should return the column in which the | |
1054 | comment ought to start. For example, in Lisp mode, the indent hook | |
1055 | function bases its decision on how many semicolons begin an existing | |
1056 | comment, and on the code in the preceding lines. | |
1057 | ||
93da5dff RS |
1058 | @node Documentation |
1059 | @section Documentation Lookup | |
6bf7aab6 | 1060 | |
93da5dff RS |
1061 | Emacs provides several features you can use to look up the |
1062 | documentation of functions, variables and commands that you plan to | |
1063 | use in your program. | |
6bf7aab6 | 1064 | |
93da5dff RS |
1065 | @menu |
1066 | * Info Lookup:: Looking up library functions and commands | |
1067 | in Info files. | |
1068 | * Man Page:: Looking up man pages of library functions and commands. | |
1069 | * Lisp Doc:: Looking up Emacs Lisp functions, etc. | |
1070 | @end menu | |
6bf7aab6 | 1071 | |
93da5dff RS |
1072 | @node Info Lookup |
1073 | @subsection Info Documentation Lookup | |
85750656 | 1074 | |
93da5dff RS |
1075 | @findex info-lookup-symbol |
1076 | @findex info-lookup-file | |
d2f9ea87 | 1077 | @kindex C-h S |
93da5dff | 1078 | For C, Lisp, and other languages that have documentation in Info, |
d2f9ea87 | 1079 | you can use @kbd{C-h S} (@code{info-lookup-symbol}) to view the Info |
64e207c0 RS |
1080 | documentation for a symbol used in the program. You specify the |
1081 | symbol with the minibuffer; the default is the symbol appearing in the | |
1082 | buffer at point. For example, in C mode this looks for the symbol in | |
1083 | the C Library Manual. | |
6bf7aab6 | 1084 | |
93da5dff RS |
1085 | The major mode determines where to look for documentation for the |
1086 | symbol---which Info files to look in, and which indices to search. | |
1087 | You can also use @kbd{M-x info-lookup-file} to look for documentation | |
1088 | for a file name. | |
6bf7aab6 | 1089 | |
7ae8ad94 | 1090 | This feature currently supports the modes AWK, Autoconf, Bison, C, |
93da5dff RS |
1091 | Emacs Lisp, LaTeX, M4, Makefile, Octave, Perl, Scheme, and Texinfo, |
1092 | provided you have installed the relevant Info files, which are | |
1093 | typically available with the appropriate GNU package. | |
6bf7aab6 | 1094 | |
93da5dff RS |
1095 | @node Man Page |
1096 | @subsection Man Page Lookup | |
6bf7aab6 | 1097 | |
e79c6b89 RS |
1098 | @cindex manual page |
1099 | On Unix, the main form of on-line documentation was the @dfn{manual | |
1100 | page} or @dfn{man page}. In the GNU operating system, we hope to | |
1101 | replace man pages with better-organized manuals that you can browse | |
1102 | with Info (@pxref{Misc Help}). This process is not finished, so it is | |
1103 | still useful to read manual pages. | |
6bf7aab6 | 1104 | |
93da5dff | 1105 | @findex manual-entry |
e79c6b89 | 1106 | You can read the man page for an operating system command, library |
7ae8ad94 | 1107 | function, or system call, with the @kbd{M-x man} command. It |
e79c6b89 RS |
1108 | runs the @code{man} program to format the man page; if the system |
1109 | permits, it runs @code{man} asynchronously, so that you can keep on | |
1110 | editing while the page is being formatted. (On MS-DOS and MS-Windows | |
1111 | 3, you cannot edit while Emacs waits for @code{man} to finish.) The | |
1112 | result goes in a buffer named @samp{*Man @var{topic}*}. These buffers | |
1113 | use a special major mode, Man mode, that facilitates scrolling and | |
1114 | jumping to other manual pages. For details, type @kbd{C-h m} while in | |
1115 | a man page buffer. | |
6bf7aab6 | 1116 | |
93da5dff | 1117 | @cindex sections of manual pages |
e79c6b89 RS |
1118 | Each man page belongs to one of ten or more @dfn{sections}, each |
1119 | named by a digit or by a digit and a letter. Sometimes there are | |
1120 | multiple man pages with the same name in different sections. To read | |
1121 | a man page from a specific section, type | |
93da5dff RS |
1122 | @samp{@var{topic}(@var{section})} or @samp{@var{section} @var{topic}} |
1123 | when @kbd{M-x manual-entry} prompts for the topic. For example, to | |
1124 | read the man page for the C library function @code{chmod} (as opposed | |
e79c6b89 RS |
1125 | to a command of the same name), type @kbd{M-x manual-entry @key{RET} |
1126 | chmod(2) @key{RET}} (@code{chmod} is a system call, so it is in | |
1127 | section @samp{2}). | |
6bf7aab6 | 1128 | |
08220274 | 1129 | @vindex Man-switches |
93da5dff | 1130 | If you do not specify a section, the results depend on how the |
08220274 | 1131 | @code{man} program works on your system. Some of them display only |
93da5dff RS |
1132 | the first man page they find. Others display all man pages that have |
1133 | the specified name, so you can move between them with the @kbd{M-n} | |
08220274 EZ |
1134 | and @kbd{M-p} keys@footnote{On some systems, the @code{man} program |
1135 | accepts a @samp{-a} command-line option which tells it to display all | |
1136 | the man pages for the specified topic. If you want this behavior, you | |
1137 | can add this option to the value of the variable @code{Man-switches}.}. | |
1138 | The mode line shows how many manual pages are present in the Man buffer. | |
6bf7aab6 | 1139 | |
93da5dff | 1140 | @vindex Man-fontify-manpage-flag |
e79c6b89 RS |
1141 | By default, Emacs highlights the text in man pages. For a long man |
1142 | page, highlighting can take substantial time. You can turn off | |
1143 | highlighting of man pages by setting the variable | |
1144 | @code{Man-fontify-manpage-flag} to @code{nil}. | |
6bf7aab6 | 1145 | |
93da5dff RS |
1146 | @findex Man-fontify-manpage |
1147 | If you insert the text of a man page into an Emacs buffer in some | |
1148 | other fashion, you can use the command @kbd{M-x Man-fontify-manpage} to | |
1149 | perform the same conversions that @kbd{M-x manual-entry} does. | |
1150 | ||
1151 | @findex woman | |
1152 | @cindex manual pages, on MS-DOS/MS-Windows | |
1153 | An alternative way of reading manual pages is the @kbd{M-x woman} | |
1154 | command@footnote{The name of the command, @code{woman}, is an acronym | |
1155 | for ``w/o (without) man,'' since it doesn't use the @code{man} | |
1156 | program.}. Unlike @kbd{M-x man}, it does not run any external | |
1157 | programs to format and display the man pages; instead it does the job | |
1158 | in Emacs Lisp, so it works on systems such as MS-Windows, where the | |
ea118de1 | 1159 | @code{man} program (and other programs it uses) are not generally |
d2fab838 RS |
1160 | available. |
1161 | ||
1162 | @kbd{M-x woman} prompts for a name of a manual page, and provides | |
1163 | completion based on the list of manual pages that are installed on | |
1164 | your machine; the list of available manual pages is computed | |
1165 | automatically the first time you invoke @code{woman}. The word at | |
1166 | point in the current buffer is used to suggest the default for the | |
1167 | name the manual page. | |
93da5dff RS |
1168 | |
1169 | With a numeric argument, @kbd{M-x woman} recomputes the list of the | |
1170 | manual pages used for completion. This is useful if you add or delete | |
1171 | manual pages. | |
1172 | ||
1173 | If you type a name of a manual page and @kbd{M-x woman} finds that | |
1174 | several manual pages by the same name exist in different sections, it | |
1175 | pops up a window with possible candidates asking you to choose one of | |
1176 | them. | |
1177 | ||
1178 | @vindex woman-manpath | |
1179 | By default, @kbd{M-x woman} looks for manual pages in the | |
1180 | directories specified in the @code{MANPATH} environment variable. (If | |
1181 | @code{MANPATH} is not set, @code{woman} uses a suitable default value, | |
1182 | which can be customized.) More precisely, @code{woman} looks for | |
e79c6b89 | 1183 | subdirectories that match the shell wildcard pattern @file{man*} in each one |
93da5dff RS |
1184 | of these directories, and tries to find the manual pages in those |
1185 | subdirectories. When first invoked, @kbd{M-x woman} converts the | |
1186 | value of @code{MANPATH} to a list of directory names and stores that | |
1187 | list in the @code{woman-manpath} variable. Changing the value of this | |
1188 | variable is another way to control the list of directories used. | |
1189 | ||
1190 | @vindex woman-path | |
1191 | You can also augment the list of directories searched by | |
1192 | @code{woman} by setting the value of the @code{woman-path} variable. | |
1193 | This variable should hold a list of specific directories which | |
1194 | @code{woman} should search, in addition to those in | |
1195 | @code{woman-manpath}. Unlike @code{woman-manpath}, the directories in | |
1196 | @code{woman-path} are searched for the manual pages, not for | |
1197 | @file{man*} subdirectories. | |
1198 | ||
1199 | @findex woman-find-file | |
1200 | Occasionally, you might need to display manual pages that are not in | |
1201 | any of the directories listed by @code{woman-manpath} and | |
1202 | @code{woman-path}. The @kbd{M-x woman-find-file} command prompts for a | |
1203 | name of a manual page file, with completion, and then formats and | |
1204 | displays that file like @kbd{M-x woman} does. | |
1205 | ||
1206 | @vindex woman-dired-keys | |
1207 | The first time you invoke @kbd{M-x woman}, it defines the Dired | |
1208 | @kbd{W} key to run the @code{woman-find-file} command on the current | |
1209 | line's file. You can disable this by setting the variable | |
1210 | @code{woman-dired-keys} to @code{nil}. @xref{Dired}. In addition, | |
1211 | the Tar-mode @kbd{w} key is define to invoke @code{woman-find-file} on | |
1212 | the current line's archive member. | |
1213 | ||
1214 | For more information about setting up and using @kbd{M-x woman}, see | |
1215 | @ref{Top, WoMan, Browse UN*X Manual Pages WithOut Man, woman, The WoMan | |
1216 | Manual}. | |
1217 | ||
1218 | @node Lisp Doc | |
1219 | @subsection Emacs Lisp Documentation Lookup | |
1220 | ||
1221 | As you edit Lisp code to be run in Emacs, you can use the commands | |
1222 | @kbd{C-h f} (@code{describe-function}) and @kbd{C-h v} | |
1223 | (@code{describe-variable}) to view documentation of functions and | |
1224 | variables that you want to use. These commands use the minibuffer to | |
1225 | read the name of a function or variable to document, and display the | |
1226 | documentation in a window. Their default arguments are based on the | |
1227 | code in the neighborhood of point. For @kbd{C-h f}, the default is | |
1228 | the function called in the innermost list containing point. @kbd{C-h | |
1229 | v} uses the symbol name around or adjacent to point as its default. | |
1230 | ||
1231 | @cindex Eldoc mode | |
1232 | @findex eldoc-mode | |
1233 | A more automatic but less powerful method is Eldoc mode. This minor | |
1234 | mode constantly displays in the echo area the argument list for the | |
1235 | function being called at point. (In other words, it finds the | |
1236 | function call that point is contained in, and displays the argument | |
054af0fd | 1237 | list of that function.) If point is over a documented variable, it |
ea802fce LT |
1238 | shows the first line of the variable's docstring. Eldoc mode applies |
1239 | in Emacs Lisp and Lisp Interaction modes, and perhaps a few others | |
1240 | that provide special support for looking up doc strings. Use the | |
1241 | command @kbd{M-x eldoc-mode} to enable or disable this feature. | |
6bf7aab6 | 1242 | |
51ed0ea0 DL |
1243 | @node Hideshow |
1244 | @section Hideshow minor mode | |
1245 | ||
1246 | @findex hs-minor-mode | |
9234c238 | 1247 | Hideshow minor mode provides selective display of portions of a |
93da5dff RS |
1248 | program, known as @dfn{blocks}. You can use @kbd{M-x hs-minor-mode} |
1249 | to enable or disable this mode, or add @code{hs-minor-mode} to the | |
1250 | mode hook for certain major modes in order to enable it automatically | |
1251 | for those modes. | |
51ed0ea0 | 1252 | |
9234c238 RS |
1253 | Just what constitutes a block depends on the major mode. In C mode |
1254 | or C++ mode, they are delimited by braces, while in Lisp mode and | |
1255 | similar modes they are delimited by parentheses. Multi-line comments | |
1256 | also count as blocks. | |
51ed0ea0 DL |
1257 | |
1258 | @findex hs-hide-all | |
1259 | @findex hs-hide-block | |
1260 | @findex hs-show-all | |
1261 | @findex hs-show-block | |
1262 | @findex hs-show-region | |
1263 | @findex hs-hide-level | |
1264 | @findex hs-minor-mode | |
6401dc86 EZ |
1265 | @kindex C-c @@ C-h |
1266 | @kindex C-c @@ C-s | |
1267 | @kindex C-c @@ C-M-h | |
1268 | @kindex C-c @@ C-M-s | |
1269 | @kindex C-c @@ C-r | |
1270 | @kindex C-c @@ C-l | |
9234c238 RS |
1271 | @kindex S-Mouse-2 |
1272 | @table @kbd | |
6401dc86 | 1273 | @item C-c @@ C-h |
9234c238 | 1274 | Hide the current block (@code{hs-hide-block}). |
6401dc86 | 1275 | @item C-c @@ C-s |
9234c238 | 1276 | Show the current block (@code{hs-show-block}). |
6401dc86 | 1277 | @item C-c @@ C-c |
ea118de1 | 1278 | Either hide or show the current block (@code{hs-toggle-hiding}). |
9234c238 | 1279 | @item S-Mouse-2 |
ea118de1 | 1280 | Either hide or show the block you click on (@code{hs-mouse-toggle-hiding}). |
6401dc86 | 1281 | @item C-c @@ C-M-h |
9234c238 | 1282 | Hide all top-level blocks (@code{hs-hide-all}). |
6401dc86 | 1283 | @item C-c @@ C-M-s |
9234c238 | 1284 | Show everything in the buffer (@code{hs-show-all}). |
6401dc86 | 1285 | @item C-c @@ C-l |
9234c238 RS |
1286 | Hide all blocks @var{n} levels below this block |
1287 | (@code{hs-hide-level}). | |
1288 | @end table | |
51ed0ea0 DL |
1289 | |
1290 | @vindex hs-hide-comments-when-hiding-all | |
51ed0ea0 DL |
1291 | @vindex hs-isearch-open |
1292 | @vindex hs-special-modes-alist | |
19b2c4ca | 1293 | These variables exist for customizing Hideshow mode. |
9234c238 | 1294 | |
51ed0ea0 DL |
1295 | @table @code |
1296 | @item hs-hide-comments-when-hiding-all | |
9234c238 | 1297 | Non-@code{nil} says that @kbd{hs-hide-all} should hide comments too. |
d2fab838 | 1298 | |
51ed0ea0 DL |
1299 | @item hs-isearch-open |
1300 | Specifies what kind of hidden blocks to open in Isearch mode. | |
ea118de1 | 1301 | The value should be one of these four symbols: |
d2fab838 RS |
1302 | |
1303 | @table @code | |
9198a323 RS |
1304 | @item code |
1305 | Open only code blocks. | |
d2fab838 RS |
1306 | @item comment |
1307 | Open only comments. | |
1308 | @item t | |
9198a323 | 1309 | Open both code blocks and comments. |
d2fab838 | 1310 | @item nil |
9198a323 | 1311 | Open neither code blocks nor comments. |
d2fab838 RS |
1312 | @end table |
1313 | ||
51ed0ea0 | 1314 | @item hs-special-modes-alist |
e79c6b89 | 1315 | A list of elements, each specifying how to initialize Hideshow |
d2fab838 RS |
1316 | variables for one major mode. See the variable's documentation string |
1317 | for more information. | |
51ed0ea0 DL |
1318 | @end table |
1319 | ||
93da5dff RS |
1320 | @node Symbol Completion |
1321 | @section Completion for Symbol Names | |
1322 | @cindex completion (symbol names) | |
3b8b8888 | 1323 | |
e79c6b89 RS |
1324 | In Emacs, completion is something you normally do in the minibuffer. |
1325 | But one kind of completion is available in all buffers: completion for | |
1326 | symbol names. | |
3b8b8888 | 1327 | |
93da5dff | 1328 | @kindex M-TAB |
e79c6b89 RS |
1329 | The character @kbd{M-@key{TAB}} runs a command to complete the |
1330 | partial symbol before point against the set of meaningful symbol | |
1331 | names. This command inserts at point any additional characters that | |
64e207c0 | 1332 | it can determine from the partial name. (If your window manager |
7fb36547 RS |
1333 | defines @kbd{M-@key{TAB}} to switch windows, you can type |
1334 | @kbd{@key{ESC} @key{TAB}} or @kbd{C-M-i}.) | |
6bf7aab6 | 1335 | |
e79c6b89 RS |
1336 | If the partial name in the buffer has multiple possible completions |
1337 | that differ in the very next character, so that it is impossible to | |
1338 | complete even one more character, @kbd{M-@key{TAB}} displays a list of | |
1339 | all possible completions in another window. | |
6bf7aab6 | 1340 | |
93da5dff RS |
1341 | @cindex tags-based completion |
1342 | @cindex Info index completion | |
1343 | @findex complete-symbol | |
1344 | In most programming language major modes, @kbd{M-@key{TAB}} runs the | |
1345 | command @code{complete-symbol}, which provides two kinds of completion. | |
1346 | Normally it does completion based on a tags table (@pxref{Tags}); with a | |
1347 | numeric argument (regardless of the value), it does completion based on | |
1348 | the names listed in the Info file indexes for your language. Thus, to | |
1349 | complete the name of a symbol defined in your own program, use | |
1350 | @kbd{M-@key{TAB}} with no argument; to complete the name of a standard | |
1351 | library function, use @kbd{C-u M-@key{TAB}}. Of course, Info-based | |
1352 | completion works only if there is an Info file for the standard library | |
1353 | functions of your language, and only if it is installed at your site. | |
6bf7aab6 | 1354 | |
93da5dff RS |
1355 | @cindex Lisp symbol completion |
1356 | @cindex completion (Lisp symbols) | |
1357 | @findex lisp-complete-symbol | |
1358 | In Emacs-Lisp mode, the name space for completion normally consists of | |
1359 | nontrivial symbols present in Emacs---those that have function | |
1360 | definitions, values or properties. However, if there is an | |
1361 | open-parenthesis immediately before the beginning of the partial symbol, | |
1362 | only symbols with function definitions are considered as completions. | |
1363 | The command which implements this is @code{lisp-complete-symbol}. | |
6bf7aab6 | 1364 | |
93da5dff RS |
1365 | In Text mode and related modes, @kbd{M-@key{TAB}} completes words |
1366 | based on the spell-checker's dictionary. @xref{Spelling}. | |
6bf7aab6 | 1367 | |
93da5dff RS |
1368 | @node Glasses |
1369 | @section Glasses minor mode | |
1370 | @cindex Glasses mode | |
1371 | @cindex identifiers, making long ones readable | |
1372 | @cindex StudlyCaps, making them readable | |
1373 | @findex glasses-mode | |
6bf7aab6 | 1374 | |
93da5dff | 1375 | Glasses minor mode makes @samp{unreadableIdentifiersLikeThis} |
e79c6b89 RS |
1376 | readable by altering the way they display. It knows two different |
1377 | ways to do this: by displaying underscores between a lower-case letter | |
1378 | and the following capital letter, and by emboldening the capital | |
1379 | letters. It does not alter the buffer text, only the way they | |
1380 | display, so you can use it even on read-only buffers. You can use the | |
1381 | command @kbd{M-x glasses-mode} to enable or disable the mode in the | |
1382 | current buffer; you can also add @code{glasses-mode} to the mode hook | |
1383 | of the programming language major modes in which you normally want | |
177c0ea7 | 1384 | to use Glasses mode. |
6bf7aab6 | 1385 | |
93da5dff RS |
1386 | @node Misc for Programs |
1387 | @section Other Features Useful for Editing Programs | |
6bf7aab6 | 1388 | |
93da5dff | 1389 | A number of Emacs commands that aren't designed specifically for |
e79c6b89 | 1390 | editing programs are useful for that nonetheless. |
6bf7aab6 | 1391 | |
93da5dff RS |
1392 | The Emacs commands that operate on words, sentences and paragraphs |
1393 | are useful for editing code. Most symbols names contain words | |
1394 | (@pxref{Words}); sentences can be found in strings and comments | |
e79c6b89 | 1395 | (@pxref{Sentences}). Paragraphs in the strict sense can be found in |
93da5dff RS |
1396 | program code (in long comments), but the paragraph commands are useful |
1397 | in other places too, because programming language major modes define | |
1398 | paragraphs to begin and end at blank lines (@pxref{Paragraphs}). | |
1399 | Judicious use of blank lines to make the program clearer will also | |
1400 | provide useful chunks of text for the paragraph commands to work on. | |
1401 | Auto Fill mode, if enabled in a programming language major mode, | |
1402 | indents the new lines which it creates. | |
6bf7aab6 | 1403 | |
93da5dff RS |
1404 | The selective display feature is useful for looking at the overall |
1405 | structure of a function (@pxref{Selective Display}). This feature | |
1406 | hides the lines that are indented more than a specified amount. | |
1407 | Programming modes often support Outline minor mode (@pxref{Outline | |
1408 | Mode}). The Foldout package provides folding-editor features | |
1409 | (@pxref{Foldout}). | |
6bf7aab6 | 1410 | |
93da5dff RS |
1411 | The ``automatic typing'' features may be useful for writing programs. |
1412 | @xref{Top,,Autotyping, autotype, Autotyping}. | |
6bf7aab6 DL |
1413 | |
1414 | @node C Modes | |
1415 | @section C and Related Modes | |
1416 | @cindex C mode | |
1417 | @cindex Java mode | |
1418 | @cindex Pike mode | |
1419 | @cindex IDL mode | |
1420 | @cindex CORBA IDL mode | |
1421 | @cindex Objective C mode | |
1422 | @cindex C++ mode | |
7ae8ad94 | 1423 | @cindex AWK mode |
6bf7aab6 DL |
1424 | @cindex mode, Java |
1425 | @cindex mode, C | |
7ae8ad94 | 1426 | @cindex mode, C++ |
6bf7aab6 DL |
1427 | @cindex mode, Objective C |
1428 | @cindex mode, CORBA IDL | |
1429 | @cindex mode, Pike | |
7ae8ad94 | 1430 | @cindex mode, AWK |
6bf7aab6 | 1431 | |
9234c238 | 1432 | This section gives a brief description of the special features |
7ae8ad94 | 1433 | available in C, C++, Objective-C, Java, CORBA IDL, Pike and AWK modes. |
5d80fe1f EZ |
1434 | (These are called ``C mode and related modes.'') @xref{Top, , CC Mode, |
1435 | ccmode, CC Mode}, for a more extensive description of these modes | |
9234c238 | 1436 | and their special features. |
51ed0ea0 | 1437 | |
6bf7aab6 | 1438 | @menu |
7ae8ad94 RS |
1439 | * Motion in C:: Commands to move by C statements, etc. |
1440 | * Electric C:: Colon and other chars can automatically reindent. | |
1441 | * Hungry Delete:: A more powerful DEL command. | |
1442 | * Other C Commands:: Filling comments, viewing expansion of macros, | |
1443 | and other neat features. | |
6bf7aab6 DL |
1444 | @end menu |
1445 | ||
1446 | @node Motion in C | |
1447 | @subsection C Mode Motion Commands | |
1448 | ||
1449 | This section describes commands for moving point, in C mode and | |
1450 | related modes. | |
1451 | ||
1452 | @table @code | |
7ae8ad94 RS |
1453 | @item M-x c-beginning-of-defun |
1454 | @itemx M-x c-end-of-defun | |
1455 | @findex c-beginning-of-defun | |
1456 | @findex c-end-of-defun | |
1457 | Move point to the beginning or end of the current function or | |
1458 | top-level definition. These are found by searching for the least | |
1459 | enclosing braces. (By contrast, @code{beginning-of-defun} and | |
1460 | @code{end-of-defun} search for braces in column zero.) If you are | |
1461 | editing code where the opening brace of a function isn't placed in | |
1462 | column zero, you may wish to bind @code{C-M-a} and @code{C-M-e} to | |
1463 | these commands. @xref{Moving by Defuns}. | |
1464 | ||
6bf7aab6 DL |
1465 | @item C-c C-u |
1466 | @kindex C-c C-u @r{(C mode)} | |
1467 | @findex c-up-conditional | |
1468 | Move point back to the containing preprocessor conditional, leaving the | |
1469 | mark behind. A prefix argument acts as a repeat count. With a negative | |
1470 | argument, move point forward to the end of the containing | |
7ae8ad94 RS |
1471 | preprocessor conditional. |
1472 | ||
1473 | @samp{#elif} is equivalent to @samp{#else} followed by @samp{#if}, so | |
1474 | the function will stop at a @samp{#elif} when going backward, but not | |
1475 | when going forward. | |
6bf7aab6 DL |
1476 | |
1477 | @item C-c C-p | |
1478 | @kindex C-c C-p @r{(C mode)} | |
1479 | @findex c-backward-conditional | |
1480 | Move point back over a preprocessor conditional, leaving the mark | |
1481 | behind. A prefix argument acts as a repeat count. With a negative | |
1482 | argument, move forward. | |
1483 | ||
1484 | @item C-c C-n | |
1485 | @kindex C-c C-n @r{(C mode)} | |
1486 | @findex c-forward-conditional | |
1487 | Move point forward across a preprocessor conditional, leaving the mark | |
1488 | behind. A prefix argument acts as a repeat count. With a negative | |
1489 | argument, move backward. | |
1490 | ||
1491 | @item M-a | |
7ae8ad94 | 1492 | @kindex M-a (C mode) |
6bf7aab6 DL |
1493 | @findex c-beginning-of-statement |
1494 | Move point to the beginning of the innermost C statement | |
1495 | (@code{c-beginning-of-statement}). If point is already at the beginning | |
1496 | of a statement, move to the beginning of the preceding statement. With | |
1497 | prefix argument @var{n}, move back @var{n} @minus{} 1 statements. | |
1498 | ||
7ae8ad94 RS |
1499 | In comments or in strings which span more than one line, this command |
1500 | moves by sentences instead of statements. | |
6bf7aab6 DL |
1501 | |
1502 | @item M-e | |
7ae8ad94 | 1503 | @kindex M-e (C mode) |
6bf7aab6 | 1504 | @findex c-end-of-statement |
7ae8ad94 RS |
1505 | Move point to the end of the innermost C statement or sentence; like |
1506 | @kbd{M-a} except that it moves in the other direction | |
1507 | (@code{c-end-of-statement}). | |
6bf7aab6 DL |
1508 | |
1509 | @item M-x c-backward-into-nomenclature | |
1510 | @findex c-backward-into-nomenclature | |
1511 | Move point backward to beginning of a C++ nomenclature section or word. | |
1512 | With prefix argument @var{n}, move @var{n} times. If @var{n} is | |
1513 | negative, move forward. C++ nomenclature means a symbol name in the | |
1514 | style of NamingSymbolsWithMixedCaseAndNoUnderlines; each capital letter | |
1515 | begins a section or word. | |
1516 | ||
1517 | In the GNU project, we recommend using underscores to separate words | |
1518 | within an identifier in C or C++, rather than using case distinctions. | |
1519 | ||
1520 | @item M-x c-forward-into-nomenclature | |
1521 | @findex c-forward-into-nomenclature | |
1522 | Move point forward to end of a C++ nomenclature section or word. | |
1523 | With prefix argument @var{n}, move @var{n} times. | |
1524 | @end table | |
1525 | ||
1526 | @node Electric C | |
1527 | @subsection Electric C Characters | |
1528 | ||
1529 | In C mode and related modes, certain printing characters are | |
1530 | ``electric''---in addition to inserting themselves, they also reindent | |
64e207c0 RS |
1531 | the current line, and optionally also insert newlines. The |
1532 | ``electric'' characters are @kbd{@{}, @kbd{@}}, @kbd{:}, @kbd{#}, | |
1533 | @kbd{;}, @kbd{,}, @kbd{<}, @kbd{>}, @kbd{/}, @kbd{*}, @kbd{(}, and | |
1534 | @kbd{)}. | |
6bf7aab6 DL |
1535 | |
1536 | Electric characters insert newlines only when the @dfn{auto-newline} | |
1537 | feature is enabled (indicated by @samp{/a} in the mode line after the | |
1538 | mode name). This feature is controlled by the variable | |
1539 | @code{c-auto-newline}. You can turn this feature on or off with the | |
1540 | command @kbd{C-c C-a}: | |
1541 | ||
1542 | @table @kbd | |
1543 | @item C-c C-a | |
1544 | @kindex C-c C-a @r{(C mode)} | |
1545 | @findex c-toggle-auto-state | |
1546 | Toggle the auto-newline feature (@code{c-toggle-auto-state}). With a | |
1547 | prefix argument, this command turns the auto-newline feature on if the | |
1548 | argument is positive, and off if it is negative. | |
1549 | @end table | |
1550 | ||
1551 | The colon character is electric because that is appropriate for a | |
1552 | single colon. But when you want to insert a double colon in C++, the | |
1553 | electric behavior of colon is inconvenient. You can insert a double | |
1554 | colon with no reindentation or newlines by typing @kbd{C-c :}: | |
1555 | ||
1556 | @table @kbd | |
1557 | @item C-c : | |
da8acb6b | 1558 | @ifinfo |
c668cdd0 EZ |
1559 | @c This uses ``colon'' instead of a literal `:' because Info cannot |
1560 | @c cope with a `:' in a menu | |
1561 | @kindex C-c @key{colon} @r{(C mode)} | |
da8acb6b EZ |
1562 | @end ifinfo |
1563 | @ifnotinfo | |
1564 | @kindex C-c : @r{(C mode)} | |
1565 | @end ifnotinfo | |
6bf7aab6 DL |
1566 | @findex c-scope-operator |
1567 | Insert a double colon scope operator at point, without reindenting the | |
1568 | line or adding any newlines (@code{c-scope-operator}). | |
1569 | @end table | |
1570 | ||
7ae8ad94 | 1571 | @vindex c-electric-pound-behavior |
6bf7aab6 DL |
1572 | The electric @kbd{#} key reindents the line if it appears to be the |
1573 | beginning of a preprocessor directive. This happens when the value of | |
1574 | @code{c-electric-pound-behavior} is @code{(alignleft)}. You can turn | |
1575 | this feature off by setting @code{c-electric-pound-behavior} to | |
1576 | @code{nil}. | |
1577 | ||
7ae8ad94 | 1578 | @vindex c-hanging-braces-alist |
6bf7aab6 DL |
1579 | The variable @code{c-hanging-braces-alist} controls the insertion of |
1580 | newlines before and after inserted braces. It is an association list | |
1581 | with elements of the following form: @code{(@var{syntactic-symbol} | |
1582 | . @var{nl-list})}. Most of the syntactic symbols that appear in | |
1583 | @code{c-offsets-alist} are meaningful here as well. | |
1584 | ||
1585 | The list @var{nl-list} may contain either of the symbols | |
1586 | @code{before} or @code{after}, or both; or it may be @code{nil}. When a | |
1587 | brace is inserted, the syntactic context it defines is looked up in | |
1588 | @code{c-hanging-braces-alist}; if it is found, the @var{nl-list} is used | |
1589 | to determine where newlines are inserted: either before the brace, | |
1590 | after, or both. If not found, the default is to insert a newline both | |
1591 | before and after braces. | |
1592 | ||
7ae8ad94 | 1593 | @vindex c-hanging-colons-alist |
6bf7aab6 DL |
1594 | The variable @code{c-hanging-colons-alist} controls the insertion of |
1595 | newlines before and after inserted colons. It is an association list | |
1596 | with elements of the following form: @code{(@var{syntactic-symbol} | |
1597 | . @var{nl-list})}. The list @var{nl-list} may contain either of the | |
1598 | symbols @code{before} or @code{after}, or both; or it may be @code{nil}. | |
1599 | ||
1600 | When a colon is inserted, the syntactic symbol it defines is looked | |
1601 | up in this list, and if found, the @var{nl-list} is used to determine | |
1602 | where newlines are inserted: either before the brace, after, or both. | |
1603 | If the syntactic symbol is not found in this list, no newlines are | |
1604 | inserted. | |
1605 | ||
7ae8ad94 | 1606 | @vindex c-cleanup-list |
6bf7aab6 DL |
1607 | Electric characters can also delete newlines automatically when the |
1608 | auto-newline feature is enabled. This feature makes auto-newline more | |
1609 | acceptable, by deleting the newlines in the most common cases where you | |
1610 | do not want them. Emacs can recognize several cases in which deleting a | |
1611 | newline might be desirable; by setting the variable | |
1612 | @code{c-cleanup-list}, you can specify @emph{which} of these cases that | |
1613 | should happen. The variable's value is a list of symbols, each | |
1614 | describing one case for possible deletion of a newline. Here are the | |
1615 | meaningful symbols, and their meanings: | |
1616 | ||
1617 | @table @code | |
1618 | @item brace-catch-brace | |
1619 | Clean up @samp{@} catch (@var{condition}) @{} constructs by placing the | |
1620 | entire construct on a single line. The clean-up occurs when you type | |
1621 | the @samp{@{}, if there is nothing between the braces aside from | |
1622 | @code{catch} and @var{condition}. | |
1623 | ||
1624 | @item brace-else-brace | |
1625 | Clean up @samp{@} else @{} constructs by placing the entire construct on | |
1626 | a single line. The clean-up occurs when you type the @samp{@{} after | |
1627 | the @code{else}, but only if there is nothing but white space between | |
1628 | the braces and the @code{else}. | |
1629 | ||
1630 | @item brace-elseif-brace | |
1631 | Clean up @samp{@} else if (@dots{}) @{} constructs by placing the entire | |
1632 | construct on a single line. The clean-up occurs when you type the | |
1633 | @samp{@{}, if there is nothing but white space between the @samp{@}} and | |
1634 | @samp{@{} aside from the keywords and the @code{if}-condition. | |
1635 | ||
1636 | @item empty-defun-braces | |
1637 | Clean up empty defun braces by placing the braces on the same | |
1638 | line. Clean-up occurs when you type the closing brace. | |
1639 | ||
1640 | @item defun-close-semi | |
1641 | Clean up the semicolon after a @code{struct} or similar type | |
1642 | declaration, by placing the semicolon on the same line as the closing | |
1643 | brace. Clean-up occurs when you type the semicolon. | |
1644 | ||
1645 | @item list-close-comma | |
1646 | Clean up commas following braces in array and aggregate | |
1647 | initializers. Clean-up occurs when you type the comma. | |
1648 | ||
1649 | @item scope-operator | |
1650 | Clean up double colons which may designate a C++ scope operator, by | |
1651 | placing the colons together. Clean-up occurs when you type the second | |
1652 | colon, but only when the two colons are separated by nothing but | |
1653 | whitespace. | |
1654 | @end table | |
1655 | ||
1656 | @node Hungry Delete | |
1657 | @subsection Hungry Delete Feature in C | |
7ae8ad94 | 1658 | @cindex hungry deletion (C Mode) |
6bf7aab6 DL |
1659 | |
1660 | When the @dfn{hungry-delete} feature is enabled (indicated by | |
1661 | @samp{/h} or @samp{/ah} in the mode line after the mode name), a single | |
1662 | @key{DEL} command deletes all preceding whitespace, not just one space. | |
1663 | To turn this feature on or off, use @kbd{C-c C-d}: | |
1664 | ||
1665 | @table @kbd | |
1666 | @item C-c C-d | |
1667 | @kindex C-c C-d @r{(C mode)} | |
1668 | @findex c-toggle-hungry-state | |
1669 | Toggle the hungry-delete feature (@code{c-toggle-hungry-state}). With a | |
1670 | prefix argument, this command turns the hungry-delete feature on if the | |
1671 | argument is positive, and off if it is negative. | |
1672 | ||
1673 | @item C-c C-t | |
1674 | @kindex C-c C-t @r{(C mode)} | |
1675 | @findex c-toggle-auto-hungry-state | |
1676 | Toggle the auto-newline and hungry-delete features, both at once | |
1677 | (@code{c-toggle-auto-hungry-state}). | |
1678 | @end table | |
1679 | ||
1680 | @vindex c-hungry-delete-key | |
1681 | The variable @code{c-hungry-delete-key} controls whether the | |
1682 | hungry-delete feature is enabled. | |
1683 | ||
1684 | @node Other C Commands | |
1685 | @subsection Other Commands for C Mode | |
1686 | ||
1687 | @table @kbd | |
7ae8ad94 RS |
1688 | @item M-x c-context-line-break |
1689 | @findex c-context-line-break | |
1690 | This command inserts a line break and indents the new line in a manner | |
1691 | appropriate to the context. In normal code, it does the work of | |
1692 | @kbd{C-j} (@code{newline-and-indent}), in a C preprocessor line it | |
1693 | additionally inserts a @samp{\} at the line break, and within comments | |
1694 | it's like @kbd{M-j} (@code{c-indent-new-comment-line}). | |
1695 | ||
1696 | @code{c-context-line-break} isn't bound to a key by default, but it | |
1697 | needs a binding to be useful. The following code will bind it to | |
1698 | @kbd{C-j}. | |
1699 | @example | |
1700 | (define-key c-mode-base-map "\C-j" 'c-context-line-break) | |
1701 | @end example | |
1702 | ||
6bf7aab6 | 1703 | @item C-M-h |
6bf7aab6 DL |
1704 | Put mark at the end of a function definition, and put point at the |
1705 | beginning (@code{c-mark-function}). | |
1706 | ||
1707 | @item M-q | |
1708 | @kindex M-q @r{(C mode)} | |
1709 | @findex c-fill-paragraph | |
1710 | Fill a paragraph, handling C and C++ comments (@code{c-fill-paragraph}). | |
1711 | If any part of the current line is a comment or within a comment, this | |
1712 | command fills the comment or the paragraph of it that point is in, | |
1713 | preserving the comment indentation and comment delimiters. | |
1714 | ||
1715 | @item C-c C-e | |
1716 | @cindex macro expansion in C | |
1717 | @cindex expansion of C macros | |
1718 | @findex c-macro-expand | |
1719 | @kindex C-c C-e @r{(C mode)} | |
1720 | Run the C preprocessor on the text in the region, and show the result, | |
1721 | which includes the expansion of all the macro calls | |
1722 | (@code{c-macro-expand}). The buffer text before the region is also | |
1723 | included in preprocessing, for the sake of macros defined there, but the | |
1724 | output from this part isn't shown. | |
1725 | ||
1726 | When you are debugging C code that uses macros, sometimes it is hard to | |
1727 | figure out precisely how the macros expand. With this command, you | |
1728 | don't have to figure it out; you can see the expansions. | |
1729 | ||
1730 | @item C-c C-\ | |
1731 | @findex c-backslash-region | |
1732 | @kindex C-c C-\ @r{(C mode)} | |
1733 | Insert or align @samp{\} characters at the ends of the lines of the | |
1734 | region (@code{c-backslash-region}). This is useful after writing or | |
1735 | editing a C macro definition. | |
1736 | ||
1737 | If a line already ends in @samp{\}, this command adjusts the amount of | |
1738 | whitespace before it. Otherwise, it inserts a new @samp{\}. However, | |
1739 | the last line in the region is treated specially; no @samp{\} is | |
1740 | inserted on that line, and any @samp{\} there is deleted. | |
1741 | ||
1742 | @item M-x cpp-highlight-buffer | |
1743 | @cindex preprocessor highlighting | |
1744 | @findex cpp-highlight-buffer | |
1745 | Highlight parts of the text according to its preprocessor conditionals. | |
1746 | This command displays another buffer named @samp{*CPP Edit*}, which | |
1747 | serves as a graphic menu for selecting how to display particular kinds | |
1748 | of conditionals and their contents. After changing various settings, | |
1749 | click on @samp{[A]pply these settings} (or go to that buffer and type | |
1750 | @kbd{a}) to rehighlight the C mode buffer accordingly. | |
1751 | ||
1752 | @item C-c C-s | |
1753 | @findex c-show-syntactic-information | |
1754 | @kindex C-c C-s @r{(C mode)} | |
1755 | Display the syntactic information about the current source line | |
054af0fd SE |
1756 | (@code{c-show-syntactic-information}). This information directs how |
1757 | the line is indented. | |
3b8b8888 DL |
1758 | |
1759 | @item M-x cwarn-mode | |
1760 | @itemx M-x global-cwarn-mode | |
1761 | @findex cwarn-mode | |
1762 | @findex global-cwarn-mode | |
7ae8ad94 | 1763 | @vindex global-cwarn-mode |
3b8b8888 DL |
1764 | @cindex CWarn mode |
1765 | @cindex suspicious constructions in C, C++ | |
9234c238 | 1766 | CWarn minor mode highlights certain suspicious C and C++ constructions: |
3b8b8888 DL |
1767 | |
1768 | @itemize @bullet{} | |
1769 | @item | |
9234c238 | 1770 | Assignments inside expressions. |
3b8b8888 DL |
1771 | @item |
1772 | Semicolon following immediately after @samp{if}, @samp{for}, and @samp{while} | |
1773 | (except after a @samp{do @dots{} while} statement); | |
1774 | @item | |
1775 | C++ functions with reference parameters. | |
1776 | @end itemize | |
1777 | ||
1778 | @noindent | |
9234c238 RS |
1779 | You can enable the mode for one buffer with the command @kbd{M-x |
1780 | cwarn-mode}, or for all suitable buffers with the command @kbd{M-x | |
1781 | global-cwarn-mode} or by customizing the variable | |
1782 | @code{global-cwarn-mode}. You must also enable Font Lock mode to make | |
1783 | it work. | |
3b8b8888 DL |
1784 | |
1785 | @item M-x hide-ifdef-mode | |
1786 | @findex hide-ifdef-mode | |
1787 | @cindex Hide-ifdef mode | |
1788 | Hide-ifdef minor mode hides selected code within @samp{#if} and | |
9234c238 RS |
1789 | @samp{#ifdef} preprocessor blocks. See the documentation string of |
1790 | @code{hide-ifdef-mode} for more information. | |
1791 | ||
1792 | @item M-x ff-find-related-file | |
1793 | @cindex related files | |
1794 | @findex ff-find-related-file | |
1795 | @vindex ff-related-file-alist | |
1796 | Find a file ``related'' in a special way to the file visited by the | |
1797 | current buffer. Typically this will be the header file corresponding | |
1798 | to a C/C++ source file, or vice versa. The variable | |
1799 | @code{ff-related-file-alist} specifies how to compute related file | |
1800 | names. | |
6bf7aab6 DL |
1801 | @end table |
1802 | ||
1803 | @node Fortran | |
1804 | @section Fortran Mode | |
1805 | @cindex Fortran mode | |
1806 | @cindex mode, Fortran | |
1807 | ||
40279251 GM |
1808 | Fortran mode provides special motion commands for Fortran statements |
1809 | and subprograms, and indentation commands that understand Fortran | |
1810 | conventions of nesting, line numbers and continuation statements. | |
1811 | Fortran mode has support for Auto Fill mode that breaks long lines into | |
1812 | proper Fortran continuation lines. | |
6bf7aab6 DL |
1813 | |
1814 | Special commands for comments are provided because Fortran comments | |
1815 | are unlike those of other languages. Built-in abbrevs optionally save | |
1816 | typing when you insert Fortran keywords. | |
1817 | ||
6bf7aab6 DL |
1818 | Use @kbd{M-x fortran-mode} to switch to this major mode. This command |
1819 | runs the hook @code{fortran-mode-hook} (@pxref{Hooks}). | |
1820 | ||
4946337d | 1821 | @cindex Fortran77 and Fortran90 |
138a8f12 DL |
1822 | @findex f90-mode |
1823 | @findex fortran-mode | |
40279251 GM |
1824 | Fortran mode is meant for editing Fortran77 ``fixed format'' (and also |
1825 | ``tab format'') source code. For editing the modern Fortran90 or | |
1826 | Fortran95 ``free format'' source code, use F90 mode (@code{f90-mode}). | |
1827 | Emacs normally uses Fortran mode for files with extension @samp{.f}, | |
1828 | @samp{.F} or @samp{.for}, and F90 mode for the extension @samp{.f90} and | |
1829 | @samp{.f95}. GNU Fortran supports both kinds of format. | |
138a8f12 | 1830 | |
6bf7aab6 DL |
1831 | @menu |
1832 | * Motion: Fortran Motion. Moving point by statements or subprograms. | |
1833 | * Indent: Fortran Indent. Indentation commands for Fortran. | |
1834 | * Comments: Fortran Comments. Inserting and aligning comments. | |
40279251 | 1835 | * Autofill: Fortran Autofill. Auto fill support for Fortran. |
6bf7aab6 DL |
1836 | * Columns: Fortran Columns. Measuring columns for valid Fortran. |
1837 | * Abbrev: Fortran Abbrev. Built-in abbrevs for Fortran keywords. | |
6bf7aab6 DL |
1838 | @end menu |
1839 | ||
1840 | @node Fortran Motion | |
1841 | @subsection Motion Commands | |
1842 | ||
9234c238 | 1843 | In addition to the normal commands for moving by and operating on |
40279251 GM |
1844 | ``defuns'' (Fortran subprograms---functions and subroutines, as well as |
1845 | modules for F90 mode), Fortran mode provides special commands to move by | |
3718bcde | 1846 | statements and other program units. |
6bf7aab6 | 1847 | |
9234c238 | 1848 | @table @kbd |
6bf7aab6 | 1849 | @kindex C-c C-n @r{(Fortran mode)} |
6bf7aab6 | 1850 | @findex fortran-next-statement |
6be8476a | 1851 | @findex f90-next-statement |
6bf7aab6 | 1852 | @item C-c C-n |
6be8476a RS |
1853 | Move to the beginning of the next statement |
1854 | (@code{fortran-next-statement}/@code{f90-next-statement}). | |
9234c238 RS |
1855 | |
1856 | @kindex C-c C-p @r{(Fortran mode)} | |
1857 | @findex fortran-previous-statement | |
6be8476a | 1858 | @findex f90-previous-statement |
6bf7aab6 | 1859 | @item C-c C-p |
6be8476a RS |
1860 | Move to the beginning of the previous statement |
1861 | (@code{fortran-previous-statement}/@code{f90-previous-statement}). | |
1862 | If there is no previous statement (i.e. if called from the first | |
1863 | statement in the buffer), move to the start of the buffer. | |
1864 | ||
1865 | @kindex C-c C-e @r{(F90 mode)} | |
1866 | @findex f90-next-block | |
1867 | @item C-c C-e | |
1868 | Move point forward to the start of the next code block | |
1869 | (@code{f90-next-block}). A code block is a subroutine, | |
1870 | @code{if}--@code{endif} statement, and so forth. This command exists | |
1871 | for F90 mode only, not Fortran mode. With a numeric argument, this | |
1872 | moves forward that many blocks. | |
1873 | ||
1874 | @kindex C-c C-a @r{(F90 mode)} | |
1875 | @findex f90-previous-block | |
1876 | @item C-c C-a | |
1877 | Move point backward to the previous code block | |
1878 | (@code{f90-previous-block}). This is like @code{f90-next-block}, but | |
1879 | moves backwards. | |
1880 | ||
3718bcde | 1881 | @kindex C-M-n @r{(Fortran mode)} |
3718bcde | 1882 | @findex fortran-end-of-block |
6be8476a RS |
1883 | @findex f90-end-of-block |
1884 | @item C-M-n | |
ba0243c6 GM |
1885 | Move to the end of the current code block |
1886 | (@code{fortran-end-of-block}/@code{f90-end-of-block}). With a numeric | |
1887 | agument, move forward that number of blocks. The mark is set before | |
1888 | moving point. The F90 mode version of this command checks for | |
1889 | consistency of block types and labels (if present), but it does not | |
1890 | check the outermost block since that may be incomplete. | |
3718bcde GM |
1891 | |
1892 | @kindex C-M-p @r{(Fortran mode)} | |
3718bcde | 1893 | @findex fortran-beginning-of-block |
6be8476a RS |
1894 | @findex f90-beginning-of-block |
1895 | @item C-M-p | |
1896 | Move to the start of the current code block | |
ba0243c6 | 1897 | (@code{fortran-beginning-of-block}/@code{f90-beginning-of-block}). This |
3718bcde | 1898 | is like @code{fortran-end-of-block}, but moves backwards. |
6bf7aab6 DL |
1899 | @end table |
1900 | ||
1901 | @node Fortran Indent | |
1902 | @subsection Fortran Indentation | |
1903 | ||
1904 | Special commands and features are needed for indenting Fortran code in | |
1905 | order to make sure various syntactic entities (line numbers, comment line | |
1906 | indicators and continuation line flags) appear in the columns that are | |
40279251 | 1907 | required for standard, fixed (or tab) format Fortran. |
6bf7aab6 DL |
1908 | |
1909 | @menu | |
85750656 | 1910 | * Commands: ForIndent Commands. Commands for indenting and filling Fortran. |
6bf7aab6 DL |
1911 | * Contline: ForIndent Cont. How continuation lines indent. |
1912 | * Numbers: ForIndent Num. How line numbers auto-indent. | |
1913 | * Conv: ForIndent Conv. Conventions you must obey to avoid trouble. | |
1914 | * Vars: ForIndent Vars. Variables controlling Fortran indent style. | |
1915 | @end menu | |
1916 | ||
1917 | @node ForIndent Commands | |
9234c238 | 1918 | @subsubsection Fortran Indentation and Filling Commands |
6bf7aab6 DL |
1919 | |
1920 | @table @kbd | |
6bf7aab6 | 1921 | @item C-M-j |
40279251 | 1922 | Break the current line at point and set up a continuation line |
85750656 | 1923 | (@code{fortran-split-line}). |
6bf7aab6 | 1924 | @item M-^ |
85750656 | 1925 | Join this line to the previous line (@code{fortran-join-line}). |
6bf7aab6 DL |
1926 | @item C-M-q |
1927 | Indent all the lines of the subprogram point is in | |
1928 | (@code{fortran-indent-subprogram}). | |
85750656 DL |
1929 | @item M-q |
1930 | Fill a comment block or statement. | |
6bf7aab6 DL |
1931 | @end table |
1932 | ||
6bf7aab6 DL |
1933 | @kindex C-M-q @r{(Fortran mode)} |
1934 | @findex fortran-indent-subprogram | |
1935 | The key @kbd{C-M-q} runs @code{fortran-indent-subprogram}, a command | |
1936 | to reindent all the lines of the Fortran subprogram (function or | |
1937 | subroutine) containing point. | |
1938 | ||
1939 | @kindex C-M-j @r{(Fortran mode)} | |
1940 | @findex fortran-split-line | |
1941 | The key @kbd{C-M-j} runs @code{fortran-split-line}, which splits | |
1942 | a line in the appropriate fashion for Fortran. In a non-comment line, | |
1943 | the second half becomes a continuation line and is indented | |
1944 | accordingly. In a comment line, both halves become separate comment | |
1945 | lines. | |
1946 | ||
1947 | @kindex M-^ @r{(Fortran mode)} | |
138a8f12 DL |
1948 | @kindex C-c C-d @r{(Fortran mode)} |
1949 | @findex fortran-join-line | |
85750656 DL |
1950 | @kbd{M-^} or @kbd{C-c C-d} runs the command @code{fortran-join-line}, |
1951 | which joins a continuation line back to the previous line, roughly as | |
1952 | the inverse of @code{fortran-split-line}. The point must be on a | |
138a8f12 DL |
1953 | continuation line when this command is invoked. |
1954 | ||
85750656 | 1955 | @kindex M-q @r{(Fortran mode)} |
9234c238 RS |
1956 | @kbd{M-q} in Fortran mode fills the comment block or statement that |
1957 | point is in. This removes any excess statement continuations. | |
85750656 | 1958 | |
6bf7aab6 DL |
1959 | @node ForIndent Cont |
1960 | @subsubsection Continuation Lines | |
1961 | @cindex Fortran continuation lines | |
1962 | ||
1963 | @vindex fortran-continuation-string | |
40279251 GM |
1964 | Most Fortran77 compilers allow two ways of writing continuation lines. |
1965 | If the first non-space character on a line is in column 5, then that | |
1966 | line is a continuation of the previous line. We call this @dfn{fixed | |
1967 | format}. (In GNU Emacs we always count columns from 0; but note that | |
1968 | the Fortran standard counts from 1.) The variable | |
1969 | @code{fortran-continuation-string} specifies what character to put in | |
1970 | column 5. A line that starts with a tab character followed by any digit | |
1971 | except @samp{0} is also a continuation line. We call this style of | |
1972 | continuation @dfn{tab format}. (Fortran90 introduced ``free format'', | |
1973 | with another style of continuation lines). | |
6bf7aab6 DL |
1974 | |
1975 | @vindex indent-tabs-mode @r{(Fortran mode)} | |
40279251 GM |
1976 | @vindex fortran-analyze-depth |
1977 | @vindex fortran-tab-mode-default | |
40279251 GM |
1978 | Fortran mode can use either style of continuation line. When you |
1979 | enter Fortran mode, it tries to deduce the proper continuation style | |
1980 | automatically from the buffer contents. It does this by scanning up to | |
1981 | @code{fortran-analyze-depth} (default 100) lines from the start of the | |
1982 | buffer. The first line that begins with either a tab character or six | |
1983 | spaces determines the choice. If the scan fails (for example, if the | |
1984 | buffer is new and therefore empty), the value of | |
1985 | @code{fortran-tab-mode-default} (@code{nil} for fixed format, and | |
10787f7a RS |
1986 | non-@code{nil} for tab format) is used. @samp{/t} in the mode line |
1987 | indicates tab format is selected. Fortran mode sets the value of | |
1988 | @code{indent-tabs-mode} accordingly (@pxref{Just Spaces}). | |
40279251 | 1989 | |
40279251 | 1990 | If the text on a line starts with the Fortran continuation marker |
10787f7a | 1991 | @samp{$}, or if it begins with any non-whitespace character in column |
40279251 GM |
1992 | 5, Fortran mode treats it as a continuation line. When you indent a |
1993 | continuation line with @key{TAB}, it converts the line to the current | |
1994 | continuation style. When you split a Fortran statement with | |
1995 | @kbd{C-M-j}, the continuation marker on the newline is created according | |
1996 | to the continuation style. | |
6bf7aab6 DL |
1997 | |
1998 | The setting of continuation style affects several other aspects of | |
1999 | editing in Fortran mode. In fixed format mode, the minimum column | |
2000 | number for the body of a statement is 6. Lines inside of Fortran | |
2001 | blocks that are indented to larger column numbers always use only the | |
2002 | space character for whitespace. In tab format mode, the minimum | |
2003 | column number for the statement body is 8, and the whitespace before | |
2004 | column 8 must always consist of one tab character. | |
2005 | ||
6bf7aab6 DL |
2006 | @node ForIndent Num |
2007 | @subsubsection Line Numbers | |
2008 | ||
2009 | If a number is the first non-whitespace in the line, Fortran | |
2010 | indentation assumes it is a line number and moves it to columns 0 | |
2011 | through 4. (Columns always count from 0 in GNU Emacs.) | |
2012 | ||
2013 | @vindex fortran-line-number-indent | |
2014 | Line numbers of four digits or less are normally indented one space. | |
2015 | The variable @code{fortran-line-number-indent} controls this; it | |
40279251 GM |
2016 | specifies the maximum indentation a line number can have. The default |
2017 | value of the variable is 1. Fortran mode tries to prevent line number | |
2018 | digits passing column 4, reducing the indentation below the specified | |
2019 | maximum if necessary. If @code{fortran-line-number-indent} has the | |
2020 | value 5, line numbers are right-justified to end in column 4. | |
6bf7aab6 DL |
2021 | |
2022 | @vindex fortran-electric-line-number | |
2023 | Simply inserting a line number is enough to indent it according to | |
2024 | these rules. As each digit is inserted, the indentation is recomputed. | |
2025 | To turn off this feature, set the variable | |
ea802fce | 2026 | @code{fortran-electric-line-number} to @code{nil}. |
ea118de1 | 2027 | |
6bf7aab6 DL |
2028 | |
2029 | @node ForIndent Conv | |
2030 | @subsubsection Syntactic Conventions | |
2031 | ||
2032 | Fortran mode assumes that you follow certain conventions that simplify | |
2033 | the task of understanding a Fortran program well enough to indent it | |
2034 | properly: | |
2035 | ||
2036 | @itemize @bullet | |
2037 | @item | |
2038 | Two nested @samp{do} loops never share a @samp{continue} statement. | |
2039 | ||
2040 | @item | |
2041 | Fortran keywords such as @samp{if}, @samp{else}, @samp{then}, @samp{do} | |
2042 | and others are written without embedded whitespace or line breaks. | |
2043 | ||
2044 | Fortran compilers generally ignore whitespace outside of string | |
2045 | constants, but Fortran mode does not recognize these keywords if they | |
2046 | are not contiguous. Constructs such as @samp{else if} or @samp{end do} | |
2047 | are acceptable, but the second word should be on the same line as the | |
2048 | first and not on a continuation line. | |
2049 | @end itemize | |
2050 | ||
2051 | @noindent | |
2052 | If you fail to follow these conventions, the indentation commands may | |
2053 | indent some lines unaesthetically. However, a correct Fortran program | |
2054 | retains its meaning when reindented even if the conventions are not | |
2055 | followed. | |
2056 | ||
2057 | @node ForIndent Vars | |
2058 | @subsubsection Variables for Fortran Indentation | |
2059 | ||
2060 | @vindex fortran-do-indent | |
2061 | @vindex fortran-if-indent | |
2062 | @vindex fortran-structure-indent | |
2063 | @vindex fortran-continuation-indent | |
2064 | @vindex fortran-check-all-num@dots{} | |
2065 | @vindex fortran-minimum-statement-indent@dots{} | |
2066 | Several additional variables control how Fortran indentation works: | |
2067 | ||
2068 | @table @code | |
2069 | @item fortran-do-indent | |
2070 | Extra indentation within each level of @samp{do} statement (default 3). | |
2071 | ||
2072 | @item fortran-if-indent | |
6351cad9 GM |
2073 | Extra indentation within each level of @samp{if}, @samp{select case}, or |
2074 | @samp{where} statements (default 3). | |
6bf7aab6 DL |
2075 | |
2076 | @item fortran-structure-indent | |
40279251 GM |
2077 | Extra indentation within each level of @samp{structure}, @samp{union}, |
2078 | @samp{map}, or @samp{interface} statements (default 3). | |
6bf7aab6 DL |
2079 | |
2080 | @item fortran-continuation-indent | |
2081 | Extra indentation for bodies of continuation lines (default 5). | |
2082 | ||
2083 | @item fortran-check-all-num-for-matching-do | |
40279251 GM |
2084 | In Fortran77, a numbered @samp{do} statement is ended by any statement |
2085 | with a matching line number. It is common (but not compulsory) to use a | |
2086 | @samp{continue} statement for this purpose. If this variable has a | |
2087 | non-@code{nil} value, indenting any numbered statement must check for a | |
2088 | @samp{do} that ends there. If you always end @samp{do} statements with | |
2089 | a @samp{continue} line (or if you use the more modern @samp{enddo}), | |
2090 | then you can speed up indentation by setting this variable to | |
2091 | @code{nil}. The default is @code{nil}. | |
6bf7aab6 DL |
2092 | |
2093 | @item fortran-blink-matching-if | |
40279251 GM |
2094 | If this is @code{t}, indenting an @samp{endif} (or @samp{enddo} |
2095 | statement moves the cursor momentarily to the matching @samp{if} (or | |
2096 | @samp{do}) statement to show where it is. The default is @code{nil}. | |
6bf7aab6 DL |
2097 | |
2098 | @item fortran-minimum-statement-indent-fixed | |
40279251 | 2099 | Minimum indentation for Fortran statements when using fixed format |
6bf7aab6 DL |
2100 | continuation line style. Statement bodies are never indented less than |
2101 | this much. The default is 6. | |
2102 | ||
2103 | @item fortran-minimum-statement-indent-tab | |
40279251 | 2104 | Minimum indentation for Fortran statements for tab format continuation line |
6bf7aab6 DL |
2105 | style. Statement bodies are never indented less than this much. The |
2106 | default is 8. | |
2107 | @end table | |
2108 | ||
40279251 | 2109 | The variables controlling the indentation of comments are described in |
10787f7a | 2110 | the following section. |
40279251 | 2111 | |
6bf7aab6 DL |
2112 | @node Fortran Comments |
2113 | @subsection Fortran Comments | |
2114 | ||
40279251 GM |
2115 | The usual Emacs comment commands assume that a comment can follow a |
2116 | line of code. In Fortran77, the standard comment syntax requires an | |
2117 | entire line to be just a comment. Therefore, Fortran mode replaces the | |
2118 | standard Emacs comment commands and defines some new variables. | |
6bf7aab6 | 2119 | |
40279251 | 2120 | @vindex fortran-comment-line-start |
85750656 DL |
2121 | Fortran mode can also handle the Fortran90 comment syntax where comments |
2122 | start with @samp{!} and can follow other text. Because only some Fortran77 | |
6bf7aab6 DL |
2123 | compilers accept this syntax, Fortran mode will not insert such comments |
2124 | unless you have said in advance to do so. To do this, set the variable | |
40279251 | 2125 | @code{fortran-comment-line-start} to @samp{"!"}. |
6bf7aab6 DL |
2126 | |
2127 | @table @kbd | |
2128 | @item M-; | |
054af0fd | 2129 | Align comment or insert new comment (@code{fortran-indent-comment}). |
6bf7aab6 DL |
2130 | |
2131 | @item C-x ; | |
2132 | Applies to nonstandard @samp{!} comments only. | |
2133 | ||
2134 | @item C-c ; | |
2135 | Turn all lines of the region into comments, or (with argument) turn them back | |
2136 | into real code (@code{fortran-comment-region}). | |
2137 | @end table | |
2138 | ||
40279251 | 2139 | @findex fortran-indent-comment |
6bf7aab6 | 2140 | @kbd{M-;} in Fortran mode is redefined as the command |
054af0fd | 2141 | @code{fortran-indent-comment}. Like the usual @kbd{M-;} command, this |
6bf7aab6 DL |
2142 | recognizes any kind of existing comment and aligns its text appropriately; |
2143 | if there is no existing comment, a comment is inserted and aligned. But | |
2144 | inserting and aligning comments are not the same in Fortran mode as in | |
2145 | other modes. | |
2146 | ||
2147 | When a new comment must be inserted, if the current line is blank, a | |
2148 | full-line comment is inserted. On a non-blank line, a nonstandard @samp{!} | |
2149 | comment is inserted if you have said you want to use them. Otherwise a | |
2150 | full-line comment is inserted on a new line before the current line. | |
2151 | ||
2152 | Nonstandard @samp{!} comments are aligned like comments in other | |
2153 | languages, but full-line comments are different. In a standard full-line | |
2154 | comment, the comment delimiter itself must always appear in column zero. | |
2155 | What can be aligned is the text within the comment. You can choose from | |
2156 | three styles of alignment by setting the variable | |
2157 | @code{fortran-comment-indent-style} to one of these values: | |
2158 | ||
2159 | @vindex fortran-comment-indent-style | |
2160 | @vindex fortran-comment-line-extra-indent | |
2161 | @table @code | |
2162 | @item fixed | |
2163 | Align the text at a fixed column, which is the sum of | |
2164 | @code{fortran-comment-line-extra-indent} and the minimum statement | |
2165 | indentation. This is the default. | |
2166 | ||
2167 | The minimum statement indentation is | |
2168 | @code{fortran-minimum-statement-indent-fixed} for fixed format | |
2169 | continuation line style and @code{fortran-minimum-statement-indent-tab} | |
2170 | for tab format style. | |
2171 | ||
2172 | @item relative | |
2173 | Align the text as if it were a line of code, but with an additional | |
2174 | @code{fortran-comment-line-extra-indent} columns of indentation. | |
2175 | ||
2176 | @item nil | |
ea118de1 | 2177 | Don't move text in full-line comments automatically. |
6bf7aab6 DL |
2178 | @end table |
2179 | ||
2180 | @vindex fortran-comment-indent-char | |
2181 | In addition, you can specify the character to be used to indent within | |
2182 | full-line comments by setting the variable | |
2183 | @code{fortran-comment-indent-char} to the single-character string you want | |
2184 | to use. | |
2d588beb GM |
2185 | |
2186 | @vindex fortran-directive-re | |
2187 | Compiler directive lines, or preprocessor lines, have much the same | |
2188 | appearance as comment lines. It is important, though, that such lines | |
2189 | never be indented at all, no matter what the value of | |
2190 | @code{fortran-comment-indent-style}. The variable | |
2191 | @code{fortran-directive-re} is a regular expression that specifies which | |
2192 | lines are directives. Matching lines are never indented, and receive | |
2193 | distinctive font-locking. | |
6bf7aab6 | 2194 | |
6bf7aab6 DL |
2195 | The normal Emacs comment command @kbd{C-x ;} has not been redefined. If |
2196 | you use @samp{!} comments, this command can be used with them. Otherwise | |
2197 | it is useless in Fortran mode. | |
2198 | ||
2199 | @kindex C-c ; @r{(Fortran mode)} | |
2200 | @findex fortran-comment-region | |
2201 | @vindex fortran-comment-region | |
2202 | The command @kbd{C-c ;} (@code{fortran-comment-region}) turns all the | |
2203 | lines of the region into comments by inserting the string @samp{C$$$} at | |
2204 | the front of each one. With a numeric argument, it turns the region | |
2205 | back into live code by deleting @samp{C$$$} from the front of each line | |
2206 | in it. The string used for these comments can be controlled by setting | |
2207 | the variable @code{fortran-comment-region}. Note that here we have an | |
2208 | example of a command and a variable with the same name; these two uses | |
2209 | of the name never conflict because in Lisp and in Emacs it is always | |
2210 | clear from the context which one is meant. | |
2211 | ||
2212 | @node Fortran Autofill | |
40279251 GM |
2213 | @subsection Auto Fill in Fortran Mode |
2214 | ||
2215 | Fortran mode has specialized support for Auto Fill mode, which is a | |
2216 | minor mode that automatically splits statements as you insert them when | |
2217 | they become too wide. Splitting a statement involves making | |
2218 | continuation lines using @code{fortran-continuation-string} | |
2219 | (@pxref{ForIndent Cont}). This splitting happens when you type | |
2220 | @key{SPC}, @key{RET}, or @key{TAB}, and also in the Fortran indentation | |
2221 | commands. You activate Auto Fill in Fortran mode in the normal way | |
2222 | (@pxref{Auto Fill}). | |
6bf7aab6 DL |
2223 | |
2224 | @vindex fortran-break-before-delimiters | |
40279251 GM |
2225 | Auto Fill breaks lines at spaces or delimiters when the lines get |
2226 | longer than the desired width (the value of @code{fill-column}). The | |
10787f7a | 2227 | delimiters (besides whitespace) that Auto Fill can break at are |
40279251 | 2228 | @samp{+}, @samp{-}, @samp{/}, @samp{*}, @samp{=}, @samp{<}, @samp{>}, |
10787f7a RS |
2229 | and @samp{,}. The line break comes after the delimiter if the |
2230 | variable @code{fortran-break-before-delimiters} is @code{nil}. | |
2231 | Otherwise (and by default), the break comes before the delimiter. | |
6bf7aab6 | 2232 | |
40279251 GM |
2233 | To enable Auto Fill in all Fortran buffers, add |
2234 | @code{turn-on-auto-fill} to @code{fortran-mode-hook}. @xref{Hooks}. | |
6bf7aab6 DL |
2235 | |
2236 | @node Fortran Columns | |
2237 | @subsection Checking Columns in Fortran | |
2238 | ||
2239 | @table @kbd | |
2240 | @item C-c C-r | |
2241 | Display a ``column ruler'' momentarily above the current line | |
2242 | (@code{fortran-column-ruler}). | |
2243 | @item C-c C-w | |
2244 | Split the current window horizontally temporarily so that it is 72 | |
9234c238 RS |
2245 | columns wide (@code{fortran-window-create-momentarily}). This may |
2246 | help you avoid making lines longer than the 72-character limit that | |
2247 | some Fortran compilers impose. | |
2248 | @item C-u C-c C-w | |
2249 | Split the current window horizontally so that it is 72 columns wide | |
2250 | (@code{fortran-window-create}). You can then continue editing. | |
2251 | @item M-x fortran-strip-sequence-nos | |
2252 | Delete all text in column 72 and beyond. | |
6bf7aab6 DL |
2253 | @end table |
2254 | ||
2255 | @kindex C-c C-r @r{(Fortran mode)} | |
2256 | @findex fortran-column-ruler | |
6bf7aab6 DL |
2257 | The command @kbd{C-c C-r} (@code{fortran-column-ruler}) shows a column |
2258 | ruler momentarily above the current line. The comment ruler is two lines | |
2259 | of text that show you the locations of columns with special significance in | |
2260 | Fortran programs. Square brackets show the limits of the columns for line | |
2261 | numbers, and curly brackets show the limits of the columns for the | |
2262 | statement body. Column numbers appear above them. | |
2263 | ||
2264 | Note that the column numbers count from zero, as always in GNU Emacs. | |
2265 | As a result, the numbers may be one less than those you are familiar | |
2266 | with; but the positions they indicate in the line are standard for | |
2267 | Fortran. | |
2268 | ||
9234c238 RS |
2269 | @vindex fortran-column-ruler-fixed |
2270 | @vindex fortran-column-ruler-tabs | |
ea118de1 SE |
2271 | The text used to display the column ruler depends on the value of the |
2272 | variable @code{indent-tabs-mode}. If @code{indent-tabs-mode} is | |
6bf7aab6 DL |
2273 | @code{nil}, then the value of the variable |
2274 | @code{fortran-column-ruler-fixed} is used as the column ruler. | |
ea118de1 SE |
2275 | Otherwise, the value of the variable @code{fortran-column-ruler-tab} is |
2276 | displayed. By changing these variables, you can change the column ruler | |
2277 | display. | |
6bf7aab6 | 2278 | |
9234c238 RS |
2279 | @kindex C-c C-w @r{(Fortran mode)} |
2280 | @findex fortran-window-create-momentarily | |
2281 | @kbd{C-c C-w} (@code{fortran-window-create-momentarily}) temporarily | |
2282 | splits the current window horizontally, making a window 72 columns | |
40279251 | 2283 | wide, so you can see any lines that are too long. Type a space to |
9234c238 RS |
2284 | restore the normal width. |
2285 | ||
138a8f12 | 2286 | @kindex C-u C-c C-w @r{(Fortran mode)} |
6bf7aab6 | 2287 | @findex fortran-window-create |
9234c238 RS |
2288 | You can also split the window horizontally and continue editing with |
2289 | the split in place. To do this, use @kbd{C-u C-c C-w} (@code{M-x | |
2290 | fortran-window-create}). By editing in this window you can | |
2291 | immediately see when you make a line too wide to be correct Fortran. | |
6bf7aab6 | 2292 | |
9234c238 RS |
2293 | @findex fortran-strip-sequence-nos |
2294 | The command @kbd{M-x fortran-strip-sequence-nos} deletes all text in | |
2295 | column 72 and beyond, on all lines in the current buffer. This is the | |
2296 | easiest way to get rid of old sequence numbers. | |
138a8f12 | 2297 | |
6bf7aab6 DL |
2298 | @node Fortran Abbrev |
2299 | @subsection Fortran Keyword Abbrevs | |
2300 | ||
2301 | Fortran mode provides many built-in abbrevs for common keywords and | |
2302 | declarations. These are the same sort of abbrev that you can define | |
2303 | yourself. To use them, you must turn on Abbrev mode. @xref{Abbrevs}. | |
2304 | ||
2305 | The built-in abbrevs are unusual in one way: they all start with a | |
2306 | semicolon. You cannot normally use semicolon in an abbrev, but Fortran | |
2307 | mode makes this possible by changing the syntax of semicolon to ``word | |
2308 | constituent.'' | |
2309 | ||
2310 | For example, one built-in Fortran abbrev is @samp{;c} for | |
2311 | @samp{continue}. If you insert @samp{;c} and then insert a punctuation | |
2312 | character such as a space or a newline, the @samp{;c} expands automatically | |
2313 | to @samp{continue}, provided Abbrev mode is enabled.@refill | |
2314 | ||
2315 | Type @samp{;?} or @samp{;C-h} to display a list of all the built-in | |
2316 | Fortran abbrevs and what they stand for. | |
2317 | ||
6bf7aab6 DL |
2318 | @node Asm Mode |
2319 | @section Asm Mode | |
2320 | ||
2321 | @cindex Asm mode | |
9234c238 | 2322 | @cindex assembler mode |
6bf7aab6 DL |
2323 | Asm mode is a major mode for editing files of assembler code. It |
2324 | defines these commands: | |
2325 | ||
2326 | @table @kbd | |
2327 | @item @key{TAB} | |
2328 | @code{tab-to-tab-stop}. | |
2329 | @item C-j | |
2330 | Insert a newline and then indent using @code{tab-to-tab-stop}. | |
2331 | @item : | |
2332 | Insert a colon and then remove the indentation from before the label | |
2333 | preceding colon. Then do @code{tab-to-tab-stop}. | |
2334 | @item ; | |
2335 | Insert or align a comment. | |
2336 | @end table | |
2337 | ||
2338 | The variable @code{asm-comment-char} specifies which character | |
2339 | starts comments in assembler syntax. | |
ab5796a9 MB |
2340 | |
2341 | @ignore | |
2342 | arch-tag: c7ee7409-40a4-45c7-bfb7-ae7f2c74d0c0 | |
2343 | @end ignore |