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1 \input texinfo
2 @c Notes to self regarding line handling:
3 @c
4 @c Empty lines are often significant before @end directives; avoid them.
5 @c
6 @c Empty lines before and after @example directives are significant in
7 @c info output but not in TeX. Empty lines inside @example directives
8 @c are significant.
9
10 @c Conventions for formatting examples:
11 @c o If the example contains empty lines then put the surrounding empty
12 @c lines inside the @example directives. Put them outside otherwise.
13 @c o Use @group inside the example only if it shows indentation where
14 @c the relation between lines inside is relevant.
15 @c o Format line number columns like this:
16 @c 1: foo
17 @c 2: bar
18 @c ^ one space
19 @c ^^ two columns, right alignment
20 @c o Check line lengths in TeX output; they can typically be no longer
21 @c than 70 chars, 60 if the paragraph is indented.
22
23 @comment TBD: Document the finer details of statement anchoring?
24
25 @comment !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
26 @comment %**start of header (This is for running Texinfo on a region)
27 @comment !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
28
29
30 @comment !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
31 @comment How to make the various output formats:
32 @comment (Thanks to Robert Chassell for supplying this information.)
33 @comment Note that Texinfo 4.7 (or later) is needed.
34 @comment !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
35 @ignore
36 In each of the following pairs of commands, the first generates a
37 version with cross references pointing to the GNU Emacs manuals,
38 the second with them pointing to the XEmacs manuals.
39 ## Info output
40 makeinfo cc-mode.texi
41 makeinfo -DXEMACS cc-mode.texi
42
43 ## DVI output
44 ## You may need to set up the environment variable TEXINPUTS so
45 ## that tex can find the file texinfo.tex - See the tex
46 ## manpage.
47 texi2dvi cc-mode.texi
48 texi2dvi -t "@set XEMACS " cc-mode.texi
49
50 ## HTML output. (The --no-split parameter is optional)
51 makeinfo --html --no-split cc-mode.texi
52 makeinfo --html --no-split -DXEMACS cc-mode.texi
53
54 ## Plain text output
55 makeinfo --fill-column=70 --no-split --paragraph-indent=0 \
56 --no-headers --output=cc-mode.txt cc-mode.texi
57 makeinfo --fill-column=70 --no-split --paragraph-indent=0 \
58 --no-headers --output=cc-mode.txt -DXEMACS cc-mode.texi
59
60 ## DocBook output
61 makeinfo --docbook --no-split --paragraph-indent=0 \
62 cc-mode.texi
63 makeinfo --docbook --no-split --paragraph-indent=0 \
64 -DXEMACS cc-mode.texi
65
66 ## XML output
67 makeinfo --xml --no-split --paragraph-indent=0 \
68 cc-mode.texi
69 makeinfo --xml --no-split --paragraph-indent=0 \
70 -DXEMACS cc-mode.texi
71
72 #### (You must be in the same directory as the viewed file.)
73
74 ## View DVI output
75 xdvi cc-mode.dvi &
76
77 ## View HTML output
78 mozilla cc-mode.html
79 @end ignore
80
81 @comment No overfull hbox marks in the dvi file.
82 @finalout
83
84 @setfilename ../info/ccmode
85 @settitle CC Mode Manual
86 @footnotestyle end
87
88 @c The following four macros generate the filenames and titles of the
89 @c main (X)Emacs manual and the Elisp/Lispref manual. Leave the
90 @c Texinfo variable `XEMACS' unset to generate a GNU Emacs version, set it
91 @c to generate an XEmacs version, e.g. with
92 @c "makeinfo -DXEMACS cc-mode.texi".
93 @ifset XEMACS
94 @macro emacsman
95 xemacs
96 @end macro
97 @macro emacsmantitle
98 XEmacs User's Manual
99 @end macro
100 @macro lispref
101 lispref
102 @end macro
103 @macro lispreftitle
104 XEmacs Lisp Reference Manual
105 @end macro
106 @end ifset
107
108 @ifclear XEMACS
109 @macro emacsman
110 emacs
111 @end macro
112 @macro emacsmantitle
113 GNU Emacs Manual
114 @end macro
115 @macro lispref
116 elisp
117 @end macro
118 @macro lispreftitle
119 GNU Emacs Lisp Reference Manual
120 @end macro
121 @end ifclear
122
123
124 @macro ccmode
125 CC Mode
126 @end macro
127
128 @comment !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
129 @comment @setchapternewpage odd !! we don't want blank pages !!
130 @comment %**end of header (This is for running Texinfo on a region)
131 @comment !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
132
133
134 @comment !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
135 @comment
136 @comment Texinfo manual for CC Mode
137 @comment Generated from the original README file by Krishna Padmasola
138 @comment <krishna@earth-gw.njit.edu>
139 @comment
140 @comment Authors:
141 @comment Barry A. Warsaw
142 @comment Martin Stjernholm
143 @comment Alan Mackenzie
144 @comment
145 @comment Maintained by Martin Stjernholm and Alan Mackenzie <bug-cc-mode@gnu.org>
146 @comment
147 @comment !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
148
149 @comment Define an index for syntactic symbols.
150 @ifnottex @c In texi2dvi, the @defindex would create an empty cc-mode.ss
151 @c For Info, unlike tex, @syncodeindex needs a matching @defindex.
152 @defindex ss
153 @end ifnottex
154
155 @comment Combine key, syntactic symbol and concept indices into one.
156 @syncodeindex ss cp
157 @syncodeindex ky cp
158
159 @copying
160 This manual is for CC Mode in Emacs.
161
162 Copyright @copyright{} 1995, 1996, 1997, 1998, 1999, 2000, 2001, 2002,
163 2003, 2004, 2005, 2006 Free Software Foundation, Inc.
164
165 @quotation
166 Permission is granted to copy, distribute and/or modify this document
167 under the terms of the GNU Free Documentation License, Version 1.2 or
168 any later version published by the Free Software Foundation; with the
169 Invariant Sections being ``The GNU Manifesto'', ``Distribution'' and
170 ``GNU GENERAL PUBLIC LICENSE'', with the Front-Cover texts being ``A GNU
171 Manual'', and with the Back-Cover Texts as in (a) below. A copy of the
172 license is included in the section entitled ``GNU Free Documentation
173 License'' in the Emacs manual.
174
175 (a) The FSF's Back-Cover Text is: ``You have freedom to copy and modify
176 this GNU Manual, like GNU software. Copies published by the Free
177 Software Foundation raise funds for GNU development.''
178
179 This document is part of a collection distributed under the GNU Free
180 Documentation License. If you want to distribute this document
181 separately from the collection, you can do so by adding a copy of the
182 license to the document, as described in section 6 of the license.
183 @end quotation
184 @end copying
185
186 @comment Info directory entry for use by install-info. The indentation
187 @comment here is by request from the FSF folks.
188 @dircategory Emacs
189 @direntry
190 * CC Mode: (ccmode). Emacs mode for editing C, C++, Objective-C,
191 Java, Pike, AWK, and CORBA IDL code.
192 @end direntry
193
194 @comment !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
195 @comment TeX title page
196 @comment !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
197
198 @titlepage
199 @sp 10
200
201 @center @titlefont{CC Mode 5.31}
202 @sp 2
203 @center @subtitlefont{A GNU Emacs mode for editing C and C-like languages}
204 @sp 2
205 @center Barry A. Warsaw, Martin Stjernholm, Alan Mackenzie
206
207 @page
208 @vskip 0pt plus 1filll
209 @insertcopying
210
211 This manual was generated from $Revision: 1.36 $ of $RCSfile: cc-mode.texi,v $, which can be
212 downloaded from
213 @url{http://cvs.savannah.gnu.org/viewcvs/emacs/emacs/man/cc-mode.texi}.
214 @end titlepage
215
216 @comment !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
217 @comment The Top node contains the master menu for the Info file.
218 @comment This appears only in the Info file, not the printed manual.
219 @comment !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
220
221 @node Top, Introduction, (dir), (dir)
222 @comment node-name, next, previous, up
223
224 @ifinfo
225 @top @ccmode{}
226
227 @ccmode{} is a GNU Emacs mode for editing files containing C, C++,
228 Objective-C, Java, CORBA IDL (and the variants PSDL and CIDL), Pike
229 and AWK code. It provides syntax-based indentation, font locking, and
230 has several handy commands and some minor modes to make the editing
231 easier. It does not provide tools to look up and navigate between
232 functions, classes etc - there are other packages for that.
233 @end ifinfo
234
235 @comment !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
236 @comment !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
237
238 @menu
239 * Introduction::
240 * Overview::
241 * Getting Started::
242 * Commands::
243 * Font Locking::
244 * Config Basics::
245 * Custom Filling and Breaking::
246 * Custom Auto-newlines::
247 * Clean-ups::
248 * Indentation Engine Basics::
249 * Customizing Indentation::
250 * Custom Macros::
251 * Odds and Ends::
252 * Sample .emacs File::
253 * Performance Issues::
254 * Limitations and Known Bugs::
255 * FAQ::
256 * Updating CC Mode::
257 * Mailing Lists and Bug Reports::
258 * Command and Function Index::
259 * Variable Index::
260 * Concept and Key Index::
261
262 @detailmenu
263 --- The Detailed Node Listing ---
264
265 Commands
266
267 * Indentation Commands::
268 * Comment Commands::
269 * Movement Commands::
270 * Filling and Breaking::
271 * Minor Modes::
272 * Electric Keys::
273 * Auto-newlines::
274 * Hungry WS Deletion::
275 * Subword Movement::
276 * Other Commands::
277
278 Font Locking
279
280 * Font Locking Preliminaries::
281 * Faces::
282 * Doc Comments::
283 * AWK Mode Font Locking::
284
285 Configuration Basics
286
287 * CC Hooks::
288 * Style Variables::
289 * Styles::
290
291 Styles
292
293 * Built-in Styles::
294 * Choosing a Style::
295 * Adding Styles::
296 * File Styles::
297
298 Customizing Auto-newlines
299
300 * Hanging Braces::
301 * Hanging Colons::
302 * Hanging Semicolons and Commas::
303
304 Hanging Braces
305
306 * Custom Braces::
307
308 Indentation Engine Basics
309
310 * Syntactic Analysis::
311 * Syntactic Symbols::
312 * Indentation Calculation::
313
314 Syntactic Symbols
315
316 * Function Symbols::
317 * Class Symbols::
318 * Conditional Construct Symbols::
319 * Switch Statement Symbols::
320 * Brace List Symbols::
321 * External Scope Symbols::
322 * Paren List Symbols::
323 * Literal Symbols::
324 * Multiline Macro Symbols::
325 * Objective-C Method Symbols::
326 * Anonymous Class Symbol::
327 * Statement Block Symbols::
328 * K&R Symbols::
329
330 Customizing Indentation
331
332 * c-offsets-alist::
333 * Interactive Customization::
334 * Line-Up Functions::
335 * Custom Line-Up::
336 * Other Indentation::
337
338 Line-Up Functions
339
340 * Brace/Paren Line-Up::
341 * List Line-Up::
342 * Operator Line-Up::
343 * Comment Line-Up::
344 * Misc Line-Up::
345
346 @end detailmenu
347 @end menu
348
349 @comment !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
350 @node Introduction, Overview, Top, Top
351 @comment node-name, next, previous, up
352 @chapter Introduction
353 @comment !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
354
355 @cindex BOCM
356 @cindex history
357 @cindex awk-mode.el
358 @cindex c-mode.el
359 @cindex c++-mode.el
360
361 Welcome to @ccmode{}, a GNU Emacs mode for editing files containing C,
362 C++, Objective-C, Java, CORBA IDL (and the variants CORBA PSDL and
363 CIDL), Pike and AWK code. This incarnation of the mode is descended
364 from @file{c-mode.el} (also called ``Boring Old C Mode'' or BOCM
365 @t{:-)}, @file{c++-mode.el} version 2, which Barry Warsaw had been
366 maintaining since 1992, and @file{awk-mode.el}, a long neglected mode
367 in the (X)Emacs base.
368
369 Late in 1997, Martin Stjernholm joined Barry on the @ccmode{}
370 Maintainers Team, and implemented the Pike support. In 2000 Martin
371 took over as the sole maintainer. In 2001 Alan Mackenzie joined the
372 team, implementing AWK support in version 5.30. @ccmode{} did not
373 originally contain the font lock support for its languages --- that
374 was added in version 5.30.
375
376 This manual describes @ccmode{}
377 @comment The following line must appear on its own, so that the
378 version 5.31.
379 @comment Release.py script can update the version number automatically
380
381 @ccmode{} supports the editing of K&R and ANSI C, C++, Objective-C,
382 Java, CORBA's Interface Definition Language, Pike@footnote{A C-like
383 scripting language with its roots in the LPC language used in some MUD
384 engines. See @uref{http://pike.ida.liu.se/}.} and AWK files. In this
385 way, you can easily set up consistent font locking and coding styles for
386 use in editing all of these languages, although AWK is not yet as
387 uniformly integrated as the other languages.
388
389 @findex c-mode
390 @findex c++-mode
391 @findex objc-mode
392 @findex java-mode
393 @findex idl-mode
394 @findex pike-mode
395 @findex awk-mode
396 Note that the name of this package is ``@ccmode{}'', but there is no top
397 level @code{cc-mode} entry point. All of the variables, commands, and
398 functions in @ccmode{} are prefixed with @code{c-@var{thing}}, and
399 @code{c-mode}, @code{c++-mode}, @code{objc-mode}, @code{java-mode},
400 @code{idl-mode}, @code{pike-mode}, and @code{awk-mode} entry points are
401 provided. This package is intended to be a replacement for
402 @file{c-mode.el}, @file{c++-mode.el} and @file{awk-mode.el}.
403
404 A special word of thanks goes to Krishna Padmasola for his work in
405 converting the original @file{README} file to Texinfo format. I'd
406 also like to thank all the @ccmode{} victims who help enormously
407 during the early beta stages of @ccmode{}'s development.
408
409 @comment !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
410 @node Overview, Getting Started, Introduction, Top
411 @comment node-name, next, previous, up@cindex organization of the manual
412 @chapter Overview of the Manual
413 @comment !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
414
415 @noindent
416 The manual starts with several introductory chapters (including this
417 one).
418
419 @noindent
420 The next chunk of the manual describes the day to day @emph{use} of
421 @ccmode{} (as contrasted with how to customize it).
422
423 @itemize @bullet
424 @item
425 The chapter ``Commands'' describes in detail how to use (nearly) all
426 of @ccmode{}'s features. There are extensive cross-references from
427 here to the corresponding sections later in the manual which tell you
428 how to customize these features.
429
430 @item
431 ``Font Locking'' describes how ``syntax highlighting'' is applied to
432 your buffers. It is mainly background information and can be skipped
433 over at a first reading.
434 @end itemize
435
436 @noindent
437 The next chunk of the manual describes how to @emph{customize}
438 @ccmode{}. Typically, an overview of a topic is given at the chapter
439 level, then the sections and subsections describe the material in
440 increasing detail.
441
442 @itemize @bullet
443 @item
444 The chapter ``Configuration Basics'' tells you @emph{how} to write
445 customizations - whether in hooks, in styles, in both, or in neither,
446 depending on your needs. It describes the @ccmode{} style system and
447 lists the standard styles that @ccmode{} supplies.
448
449 @item
450 The next few chapters describe in detail how to customize the various
451 features of @ccmode{}.
452
453 @item
454 Finally, there is a sample @file{.emacs} fragment, which might help you
455 in creating your own customization.
456 @end itemize
457
458 @noindent
459 The manual ends with ``this and that'', things that don't fit cleanly
460 into any of the previous chunks.
461
462 @itemize @bullet
463 @item
464 Two chapters discuss the performance of @ccmode{} and known
465 bugs/limitations.
466
467 @item
468 The FAQ contains a list of common problems and questions.
469
470 @item
471 The next two chapters tell you how to get in touch with the @ccmode{}
472 project - whether for updating @ccmode{} or submitting bug reports.
473 @end itemize
474
475 @noindent
476 Finally, there are the customary indices.
477
478 @comment !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
479 @node Getting Started, Commands, Overview, Top
480 @comment node-name, next, previous, up
481 @chapter Getting Started
482 @comment !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
483
484 If you got this version of @ccmode{} with Emacs or XEmacs, it should
485 work just fine right out of the box. Note however that you might not
486 have the latest @ccmode{} release and might want to upgrade your copy
487 (see below).
488
489 You should probably start by reading the entire chapter
490 @ref{Commands} to get an overview of @ccmode{}'s capabilities.
491
492 After trying out some commands, you may dislike some aspects of
493 @ccmode{}'s default configuration. Here is an outline of how to
494 change some of the settings that newcomers to @ccmode{} most often
495 want to change:
496
497 @table @asis
498 @item c-basic-offset
499 This Lisp variable holds an integer, the number of columns @ccmode{}
500 indents nested code. To set this value to 6, customize
501 @code{c-basic-offset} or put this into your @file{.emacs}:
502
503 @example
504 (setq c-basic-offset 6)
505 @end example
506
507 @item The (indentation) style
508 The basic ``shape'' of indentation created by @ccmode{}---by default,
509 this is @code{gnu} style (except for Java and AWK buffers). A list of
510 the availables styles and their descriptions can be found in
511 @ref{Built-in Styles}. A complete specification of the @ccmode{}
512 style system, including how to create your own style, can be found in
513 the chapter @ref{Styles}. To set your style to @code{linux}, either
514 customize @code{c-default-style} or put this into your @file{.emacs}:
515
516 @example
517 (setq c-default-style '((java-mode . "java")
518 (awk-mode . "awk")
519 (other . "linux")))
520 @end example
521
522 @item Electric Indentation
523 Normally, when you type ``punctuation'' characters such as @samp{;} or
524 @samp{@{}, @ccmode{} instantly reindents the current line. This can
525 be disconcerting until you get used to it. To disable @dfn{electric
526 indentation} in the current buffer, type @kbd{C-c C-l}. Type the same
527 thing to enable it again. To have electric indentation disabled by
528 default, put the following into your @file{.emacs} file@footnote{There
529 is no ``easy customization'' facility for making this change.}:
530
531 @example
532 (setq-default c-electric-flag nil)
533 @end example
534
535 @noindent
536 Details of of this and other similar ``Minor Modes'' appear in the
537 section @ref{Minor Modes}.
538
539 @item Making the @key{RET} key indent the new line
540 The standard Emacs binding for @key{RET} just adds a new line. If you
541 want it to reindent the new line as well, rebind the key. Note that
542 the action of rebinding will fail if the pertinent keymap doesn't yet
543 exist---we thus need to delay the action until after @ccmode{} has
544 been loaded. Put the following code into your @file{.emacs}:
545
546 @example
547 (defun my-make-CR-do-indent ()
548 (define-key c-mode-base-map "\C-m" 'c-context-line-break))
549 (add-hook 'c-initialization-hook 'my-make-CR-do-indent)
550 @end example
551
552 @noindent
553 This example demonstrates the use of a very powerful @ccmode{} (and
554 Emacs) facility, the hook. The use of @ccmode{}'s hooks is described
555 in @ref{CC Hooks}.
556 @end table
557
558 All these settings should occur in your @file{.emacs} @emph{before}
559 any @ccmode{} buffers get loaded---in particular, before any call of
560 @code{desktop-read}.
561
562 As you get to know the mode better, you may want to make more
563 ambitious changes to your configuration. For this, you should start
564 reading the chapter @ref{Config Basics}.
565
566 If you are upgrading an existing @ccmode{} installation, please see
567 the @file{README} file for installation details. In particular, if
568 you are going to be editing AWK files, @file{README} describes how to
569 configure your (X)Emacs so that @ccmode{} will supersede the obsolete
570 @code{awk-mode.el} which might have been supplied with your (X)Emacs.
571 @ccmode{} might not work with older versions of Emacs or XEmacs. See
572 the @ccmode{} release notes at @uref{http://cc-mode.sourceforge.net}
573 for the latest information on Emacs version and package compatibility
574 (@pxref{Updating CC Mode}).
575
576 @deffn Command c-version
577 @findex version (c-)
578 You can find out what version of @ccmode{} you are using by visiting a C
579 file and entering @kbd{M-x c-version RET}. You should see this message in
580 the echo area:
581
582 @example
583 Using CC Mode version 5.XX
584 @end example
585
586 @noindent
587 where @samp{XX} is the minor release number.
588 @end deffn
589
590 @comment !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
591 @node Commands, Font Locking, Getting Started, Top
592 @comment node-name, next, previous, up
593 @chapter Commands
594 @comment !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
595
596 This chapter specifies all of CC Mode's commands, and thus contains
597 nearly everything you need to know to @emph{use} @ccmode{} (as
598 contrasted with configuring it). @dfn{Commands} here means both
599 control key sequences and @dfn{electric keys}, these being characters
600 such as @samp{;} which, as well as inserting themselves into the
601 buffer, also do other things.
602
603 You might well want to review
604 @ifset XEMACS
605 @ref{Lists,,,@emacsman{}, @emacsmantitle{}},
606 @end ifset
607 @ifclear XEMACS
608 @ref{Moving by Parens,,,@emacsman{}, @emacsmantitle{}},
609 @end ifclear
610 which describes commands for moving around brace and parenthesis
611 structures.
612
613
614 @menu
615 * Indentation Commands::
616 * Comment Commands::
617 * Movement Commands::
618 * Filling and Breaking::
619 * Minor Modes::
620 * Electric Keys::
621 * Auto-newlines::
622 * Hungry WS Deletion::
623 * Subword Movement::
624 * Other Commands::
625 @end menu
626
627 @comment !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
628 @node Indentation Commands, Comment Commands, Commands, Commands
629 @comment node-name, next, previous,up
630 @section Indentation Commands
631 @cindex indentation
632 @comment !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
633
634 The following commands reindent C constructs. Note that when you
635 change your coding style, either interactively or through some other
636 means, your file does @emph{not} automatically get reindented. You
637 will need to execute one of the following commands to see the effects
638 of your changes.
639
640 @cindex GNU indent program
641 Also, variables like @code{c-hanging-*} and @code{c-cleanup-list}
642 (@pxref{Custom Auto-newlines}) only affect how on-the-fly code is
643 formatted. Changing the ``hanginess'' of a brace and then
644 reindenting, will not move the brace to a different line. For this,
645 you're better off getting an external program like GNU @code{indent},
646 which will rearrange brace location, amongst other things.
647
648 Preprocessor directives are handled as syntactic whitespace from other
649 code, i.e. they can be interspersed anywhere without affecting the
650 indentation of the surrounding code, just like comments.
651
652 The code inside macro definitions is, by default, still analyzed
653 syntactically so that you get relative indentation there just as you'd
654 get if the same code was outside a macro. However, since there is no
655 hint about the syntactic context, i.e. whether the macro expands to an
656 expression, to some statements, or perhaps to whole functions, the
657 syntactic recognition can be wrong. @ccmode{} manages to figure it
658 out correctly most of the time, though.
659
660 Reindenting large sections of code can take a long time. When
661 @ccmode{} reindents a region of code, it is essentially equivalent to
662 hitting @key{TAB} on every line of the region.
663
664 These commands indent code:
665
666 @table @asis
667 @item @kbd{@key{TAB}} (@code{c-indent-command})
668 @kindex TAB
669 @findex c-indent-command
670 @findex indent-command (c-)
671 This command indents the current line. That is all you need to know
672 about it for normal use.
673
674 @code{c-indent-command} does different things, depending on the
675 settting of @code{c-syntactic-indentation} (@pxref{Indentation Engine
676 Basics}):
677
678 @itemize @bullet
679 @item
680 When it's non-@code{nil} (which it normally is), the command indents
681 the line according to its syntactic context. With a prefix argument
682 (@kbd{C-u @key{TAB}}), it will re-indent the entire
683 expression@footnote{this is only useful for a line starting with a
684 comment opener or an opening brace, parenthesis, or string quote.}
685 that begins at the line's left margin.
686
687 @item
688 When it's @code{nil}, the command indents the line by an extra
689 @code{c-basic-offset} columns. A prefix argument acts as a
690 multiplier. A bare prefix (@kbd{C-u @key{TAB}} is equivalent to -1,
691 removing @code{c-basic-offset} columns from the indentation.
692 @end itemize
693
694 The precise behavior is modified by several variables: With
695 @code{c-tab-always-indent}, you can make @key{TAB} insert whitespace
696 in some circumstances---@code{c-insert-tab-function} then defines
697 precisely what sort of ``whitespace'' this will be. Set the standard
698 Emacs variable @code{indent-tabs-mode} to @code{t} if you want real
699 @samp{tab} characters to be used in the indentation, to @code{nil} if
700 you want only spaces. @xref{Just Spaces,,, @emacsman{},
701 @emacsmantitle{}}.
702
703 @defopt c-tab-always-indent
704 @vindex tab-always-indent (c-)
705 @cindex literal
706 This variable modifies how @key{TAB} operates.
707 @itemize @bullet
708 @item
709 When it is @code{t} (the default), @key{TAB} simply indents the
710 current line.
711 @item
712 When it is @code{nil}, @key{TAB} (re)indents the line only if point is
713 to the left of the first non-whitespace character on the line.
714 Otherwise it inserts some whitespace (a tab or an equivalent number of
715 spaces - see below) at point.
716 @item
717 With some other value, the line is reindented. Additionally, if point
718 is within a string or comment, some whitespace is inserted.
719 @end itemize
720 @end defopt
721
722 @defopt c-insert-tab-function
723 @vindex insert-tab-function (c-)
724 @findex tab-to-tab-stop
725 When ``some whitespace'' is inserted as described above, what actually
726 happens is that the function stored in @code{c-insert-tab-function} is
727 called. Normally, this is @code{insert-tab}, which inserts a real tab
728 character or the equivalent number of spaces (depending on
729 @code{indent-tabs-mode}). Some people, however, set
730 @code{c-insert-tab-function} to @code{tab-to-tab-stop} so as to get
731 hard tab stops when indenting.
732 @end defopt
733 @end table
734
735 @noindent
736 The kind of indentation the next five commands do depends on the
737 setting of @code{c-syntactic-indentation} (@pxref{Indentation Engine
738 Basics}):
739 @itemize @bullet
740 @item
741 when it is non-@code{nil} (the default), the commands indent lines
742 according to their syntactic context;
743 @item
744 when it is @code{nil}, they just indent each line the same amount as
745 the previous non-blank line. The commands that indent a region aren't
746 very useful in this case.
747 @end itemize
748
749 @table @asis
750 @item @kbd{C-j} (@code{newline-and-indent})
751 @kindex C-j
752 @findex newline-and-indent
753 Inserts a newline and indents the new blank line, ready to start
754 typing. This is a standard (X)Emacs command.
755
756 @item @kbd{C-M-q} (@code{c-indent-exp})
757 @kindex C-M-q
758 @findex c-indent-exp
759 @findex indent-exp (c-)
760 Indents an entire balanced brace or parenthesis expression. Note that
761 point must be on the opening brace or parenthesis of the expression
762 you want to indent.
763
764 @item @kbd{C-c C-q} (@code{c-indent-defun})
765 @kindex C-c C-q
766 @findex c-indent-defun
767 @findex indent-defun (c-)
768 Indents the entire top-level function, class or macro definition
769 encompassing point. It leaves point unchanged. This function can't be
770 used to reindent a nested brace construct, such as a nested class or
771 function, or a Java method. The top-level construct being reindented
772 must be complete, i.e. it must have both a beginning brace and an ending
773 brace.
774
775 @item @kbd{C-M-\} (@code{indent-region})
776 @kindex C-M-\
777 @findex indent-region
778 Indents an arbitrary region of code. This is a standard Emacs command,
779 tailored for C code in a @ccmode{} buffer. Note, of course, that point
780 and mark must delineate the region you want to indent.
781
782 @item @kbd{C-M-h} (@code{c-mark-function})
783 @kindex C-M-h
784 @findex c-mark-function
785 @findex mark-function (c-)
786 While not strictly an indentation command, this is useful for marking
787 the current top-level function or class definition as the current
788 region. As with @code{c-indent-defun}, this command operates on
789 top-level constructs, and can't be used to mark say, a Java method.
790 @end table
791
792 These variables are also useful when indenting code:
793
794 @defopt indent-tabs-mode
795 This is a standard Emacs variable that controls how line indentation
796 is composed. When it's non-@code{nil}, tabs can be used in a line's
797 indentation, otherwise only spaces are used.
798 @end defopt
799
800 @defopt c-progress-interval
801 @vindex progress-interval (c-)
802 When indenting large regions of code, this variable controls how often a
803 progress message is displayed. Set this variable to @code{nil} to
804 inhibit the progress messages, or set it to an integer which is how
805 often (in seconds) progress messages are to be displayed.
806 @end defopt
807
808 @comment !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
809 @node Comment Commands, Movement Commands, Indentation Commands, Commands
810 @comment node-name, next, previous, up
811 @section Comment Commands
812 @cindex comments (insertion of)
813 @comment !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
814
815 @table @asis
816 @item @kbd{C-c C-c} (@code{comment-region})
817 @kindex C-c C-c
818 @findex comment-region
819 This command comments out the lines that start in the region. With a
820 negative argument, it does the opposite - it deletes the comment
821 delimiters from these lines. @xref{Multi-Line Comments,,, emacs, GNU
822 Emacs Manual}, for fuller details. @code{comment-region} isn't
823 actually part of @ccmode{} - it is given a @ccmode{} binding for
824 convenience.
825
826 @item @kbd{M-;} (@code{comment-dwim} or @code{indent-for-comment} @footnote{The name of this command varies between (X)Emacs versions.})
827 @kindex M-;
828 @findex comment-dwim
829 @findex indent-for-comment
830 Insert a comment at the end of the current line, if none is there
831 already. Then reindent the comment according to @code{comment-column}
832 @ifclear XEMACS
833 (@pxref{Options for Comments,,, emacs, GNU Emacs Manual})
834 @end ifclear
835 @ifset XEMACS
836 (@pxref{Comments,,, xemacs, XEmacs User's Manual})
837 @end ifset
838 and the variables below. Finally, position the point after the
839 comment starter. @kbd{C-u M-;} kills any comment on the current line,
840 together with any whitespace before it. This is a standard Emacs
841 command, but @ccmode{} enhances it a bit with two variables:
842
843 @defopt c-indent-comment-alist
844 @vindex indent-comment-alist (c-)
845 @vindex comment-column
846 This style variable allows you to vary the column that @kbd{M-;} puts
847 the comment at, depending on what sort of code is on the line, and
848 possibly the indentation of any similar comment on the preceding line.
849 It is an association list that maps different types of lines to
850 actions describing how they should be handled. If a certain line type
851 isn't present on the list then the line is indented to the column
852 specified by @code{comment-column}.
853
854 See the documentation string for for a full description of this
855 variable (use @kbd{C-h v c-indent-comment-alist}).
856 @end defopt
857
858 @defopt c-indent-comments-syntactically-p
859 @vindex indent-comments-syntactically-p (c-)
860 Normally, when this style variable is @code{nil}, @kbd{M-;} will
861 indent comment-only lines according to @code{c-indent-comment-alist},
862 just as it does with lines where other code precede the comments.
863 However, if you want it to act just like @key{TAB} for comment-only
864 lines you can get that by setting
865 @code{c-indent-comments-syntactically-p} to non-@code{nil}.
866
867 If @code{c-indent-comments-syntactically-p} is non-@code{nil} then
868 @code{c-indent-comment-alist} won't be consulted at all for comment-only
869 lines.
870 @end defopt
871 @end table
872
873 @comment !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
874 @node Movement Commands, Filling and Breaking, Comment Commands, Commands
875 @comment node-name, next, previous, up
876 @section Movement Commands
877 @cindex movement
878 @comment !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
879
880 @ccmode{} contains some useful commands for moving around in C code.
881
882 @table @asis
883 @item @kbd{M-x c-beginning-of-defun}
884 @itemx @kbd{M-x c-end-of-defun}
885 @findex c-beginning-of-defun
886 @findex c-end-of-defun
887 @findex beginning-of-defun (c-)
888 @findex end-of-defun (c-)
889 @findex beginning-of-defun
890 @findex end-of-defun
891 Move to the start or end of the current top-level definition. This is
892 the outermost brace pair which encloses point, together with the
893 function header or similar preamble which precedes the opening brace.
894 These functions are analogous to the Emacs built-in commands
895 @code{beginning-of-defun} and @code{end-of-defun}, except they
896 eliminate the constraint that the top-level opening brace of the defun
897 must be in column zero. See @ref{Defuns,,,@emacsman{},
898 @emacsmantitle{}}, for more information.
899
900 Depending on the coding style you're using, you might prefer these two
901 commands to the standard Emacs ones. If so, consider binding them to
902 @kbd{C-M-a} and @kbd{C-M-e}. @xref{Sample .emacs File}. This
903 customization won't affect the special bindings for these key
904 sequences in force in AWK Mode. For backwards compatibility reasons,
905 the default bindings for @kbd{C-M-a} and @kbd{C-M-e} remain in effect.
906
907 @item @kbd{C-M-a} (AWK Mode) (@code{c-awk-beginning-of-defun})
908 @itemx @kbd{C-M-e} (AWK Mode) (@code{c-awk-end-of-defun})
909 @kindex C-M-a (AWK Mode)
910 @kindex C-M-e (AWK Mode)
911 @findex c-awk-beginning-of-defun
912 @findex awk-beginning-of-defun (c-)
913 @findex c-awk-end-of-defun
914 @findex awk-end-of-defun (c-)
915 Move back to the beginning or forward to the end of the current AWK
916 defun. These functions are bound to @kbd{C-M-a} and @kbd{C-M-e} by
917 default in AWK Mode. They can take prefix-arguments, their
918 functionality being entirely equivalent to @code{beginning-of-defun}
919 and @code{end-of-defun}.
920
921 AWK Mode @dfn{defuns} are either pattern/action pairs (either of which
922 might be implicit) or user defined functions. Having the @samp{@{} and
923 @samp{@}} (if there are any) in column zero, as is suggested for some
924 modes, is neither necessary nor helpful in AWK mode.
925
926 @item @kbd{M-a} (@code{c-beginning-of-statement})
927 @itemx @kbd{M-e} (@code{c-end-of-statement})
928 @kindex M-a
929 @kindex M-e
930 @findex c-beginning-of-statement
931 @findex c-end-of-statement
932 @findex beginning-of-statement (c-)
933 @findex end-of-statement (c-)
934 Move to the beginning or end of the innermost C statement. If point
935 is already there, move to the next beginning or end of a statement,
936 even if that means moving into a block. (Use @kbd{C-M-b} or
937 @kbd{C-M-f} to move over a balanced block.) A prefix argument @var{n}
938 means move over @var{n} statements.
939
940 If point is within or next to a comment or a string which spans more
941 than one line, these commands move by sentences instead of statements.
942
943 When called from a program, these functions take three optional
944 arguments: the repetition count, a buffer position limit which is the
945 farthest back to search for the syntactic context, and a flag saying
946 whether to do sentence motion in or near comments and multiline
947 strings.
948
949 @item @kbd{C-c C-u} (@code{c-up-conditional})
950 @kindex C-c C-u
951 @findex c-up-conditional
952 @findex up-conditional (c-)
953 Move back to the containing preprocessor conditional, leaving the mark
954 behind. A prefix argument acts as a repeat count. With a negative
955 argument, move forward to the end of the containing preprocessor
956 conditional.
957
958 @samp{#elif} is treated like @samp{#else} followed by @samp{#if}, so the
959 function stops at them when going backward, but not when going
960 forward.
961
962 This key sequence is not bound in AWK Mode, which doesn't have
963 preprocessor statements.
964
965 @item @kbd{M-x c-up-conditional-with-else}
966 @findex c-up-conditional-with-else
967 @findex up-conditional-with-else (c-)
968 A variety of @code{c-up-conditional} that also stops at @samp{#else}
969 lines. Normally those lines are ignored.
970
971 @item @kbd{M-x c-down-conditional}
972 @findex c-down-conditional
973 @findex down-conditional (c-)
974 Move forward into the next nested preprocessor conditional, leaving
975 the mark behind. A prefix argument acts as a repeat count. With a
976 negative argument, move backward into the previous nested preprocessor
977 conditional.
978
979 @samp{#elif} is treated like @samp{#else} followed by @samp{#if}, so the
980 function stops at them when going forward, but not when going backward.
981
982 @item @kbd{M-x c-down-conditional-with-else}
983 @findex c-down-conditional-with-else
984 @findex down-conditional-with-else (c-)
985 A variety of @code{c-down-conditional} that also stops at @samp{#else}
986 lines. Normally those lines are ignored.
987
988 @item @kbd{C-c C-p} (@code{c-backward-conditional})
989 @itemx @kbd{C-c C-n} (@code{c-forward-conditional})
990 @kindex C-c C-p
991 @kindex C-c C-n
992 @findex c-backward-conditional
993 @findex c-forward-conditional
994 @findex backward-conditional (c-)
995 @findex forward-conditional (c-)
996 Move backward or forward across a preprocessor conditional, leaving
997 the mark behind. A prefix argument acts as a repeat count. With a
998 negative argument, move in the opposite direction.
999
1000 These key sequences are not bound in AWK Mode, which doesn't have
1001 preprocessor statements.
1002
1003 @item @kbd{M-x c-backward-into-nomenclature}
1004 @itemx @kbd{M-x c-forward-into-nomenclature}
1005 @findex c-backward-into-nomenclature
1006 @findex c-forward-into-nomenclature
1007 @findex backward-into-nomenclature (c-)
1008 @findex forward-into-nomenclature (c-)
1009 A popular programming style, especially for object-oriented languages
1010 such as C++ is to write symbols in a mixed case format, where the
1011 first letter of each word is capitalized, and not separated by
1012 underscores. E.g. @samp{SymbolsWithMixedCaseAndNoUnderlines}.
1013
1014 These commands move backward or forward to the beginning of the next
1015 capitalized word. With prefix argument @var{n}, move @var{n} times.
1016 If @var{n} is negative, move in the opposite direction.
1017
1018 Note that these two commands have been superseded by
1019 @code{c-subword-mode}, which you should use instead. @xref{Subword
1020 Movement}. They might be removed from a future release of @ccmode{}.
1021 @end table
1022
1023 @comment !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
1024 @node Filling and Breaking, Minor Modes, Movement Commands, Commands
1025 @comment node-name, next, previous, up
1026 @section Filling and Line Breaking Commands
1027 @cindex text filling
1028 @cindex line breaking
1029 @cindex comment handling
1030 @comment !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
1031
1032 Since there's a lot of normal text in comments and string literals,
1033 @ccmode{} provides features to edit these like in text mode. The goal
1034 is to do it seamlessly, i.e. you can use auto fill mode, sentence and
1035 paragraph movement, paragraph filling, adaptive filling etc. wherever
1036 there's a piece of normal text without having to think much about it.
1037 @ccmode{} keeps the indentation, fixes suitable comment line prefixes,
1038 and so on.
1039
1040 You can configure the exact way comments get filled and broken, and
1041 where Emacs does auto-filling (see @pxref{Custom Filling and
1042 Breaking}). Typically, the style system (@pxref{Styles}) will have
1043 set this up for you, so you probably won't have to bother.
1044
1045 @findex auto-fill-mode
1046 @cindex Auto Fill mode
1047 @cindex paragraph filling
1048 Line breaks are by default handled (almost) the same regardless of
1049 whether they are made by auto fill mode (@pxref{Auto Fill,,,
1050 @emacsman{}, @emacsmantitle{}}), by paragraph filling (e.g. with
1051 @kbd{M-q}), or explicitly with @kbd{M-j} or similar methods. In
1052 string literals, the new line gets the same indentation as the
1053 previous nonempty line.@footnote{You can change this default by
1054 setting the @code{string} syntactic symbol (@pxref{Syntactic Symbols}
1055 and @pxref{Customizing Indentation})}.
1056
1057 @table @asis
1058 @item @kbd{M-q} (@code{c-fill-paragraph})
1059 @kindex M-q
1060 @findex c-fill-paragraph
1061 @findex fill-paragraph (c-)
1062 @cindex Javadoc markup
1063 @cindex Pike autodoc markup
1064 This command fills multiline string literals and both block
1065 and line style comments. In Java buffers, the Javadoc markup words
1066 are recognized as paragraph starters. The line oriented Pike autodoc
1067 markup words are recognized in the same way in Pike mode.
1068
1069 The formatting of the starters (@code{/*}) and enders (@code{*/}) of
1070 block comments are kept as they were before the filling. I.e., if
1071 either the starter or ender were on a line of its own, then it stays
1072 on its own line; conversely, if the delimiter has comment text on its
1073 line, it keeps at least one word of that text with it on the line.
1074
1075 This command is the replacement for @code{fill-paragraph} in @ccmode{}
1076 buffers.
1077
1078 @item @kbd{M-j} (@code{c-indent-new-comment-line})
1079 @kindex M-j
1080 @findex c-indent-new-comment-line
1081 @findex indent-new-comment-line (c-)
1082 This breaks the current line at point and indents the new line. If
1083 point was in a comment, the new line gets the proper comment line
1084 prefix. If point was inside a macro, a backslash is inserted before
1085 the line break. It is the replacement for
1086 @code{indent-new-comment-line}.
1087
1088 @item @kbd{M-x c-context-line-break}
1089 @findex c-context-line-break
1090 @findex context-line-break (c-)
1091 Insert a line break suitable to the context: If the point is inside a
1092 comment, the new line gets the suitable indentation and comment line
1093 prefix like @code{c-indent-new-comment-line}. In normal code it's
1094 indented like @code{newline-and-indent} would do. In macros it acts
1095 like @code{newline-and-indent} but additionally inserts and optionally
1096 aligns the line ending backslash so that the macro remains unbroken.
1097 @xref{Custom Macros}, for details about the backslash alignment.
1098
1099 This function is not bound to a key by default, but it's intended to be
1100 used on the @kbd{RET} key. If you like the behavior of
1101 @code{newline-and-indent} on @kbd{RET}, you should consider switching to
1102 this function. @xref{Sample .emacs File}.
1103
1104 @item @kbd{M-x c-context-open-line}
1105 @findex c-context-open-line
1106 @findex context-open-line (c-)
1107 This is to @kbd{C-o} (@kbd{M-x open-line}) as
1108 @code{c-context-line-break} is to @kbd{RET}. I.e. it works just like
1109 @code{c-context-line-break} but leaves the point before the inserted
1110 line break.
1111 @end table
1112
1113
1114 @comment !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
1115 @node Minor Modes, Electric Keys, Filling and Breaking, Commands
1116 @comment node-name, next, previous, up
1117 @section Minor Modes
1118 @cindex Minor Modes
1119 @comment !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
1120
1121 @ccmode{} contains several minor-mode-like features that you might
1122 find useful while writing new code or editing old code:
1123
1124 @table @asis
1125 @item electric mode
1126 When this is enabled, certain visible characters cause reformatting as
1127 they are typed. This is normally helpful, but can be a nuisance when
1128 editing chaotically formatted code. It can also be disconcerting,
1129 especially for users who are new to @ccmode{}.
1130 @item auto-newline mode
1131 This automatically inserts newlines where you'd probably want to type
1132 them yourself, e.g. after typing @samp{@}}s. Its action is suppressed
1133 when electric mode is disabled.
1134 @item hungry-delete mode
1135 This lets you delete a contiguous block of whitespace with a single
1136 key - for example, the newline and indentation just inserted by
1137 auto-newline when you want to back up and write a comment after the
1138 last statement.
1139 @item subword mode
1140 This mode makes basic word movement commands like @kbd{M-f}
1141 (@code{forward-word}) and @kbd{M-b} (@code{backward-word}) treat the
1142 parts of sillycapsed symbols as different words.
1143 E.g. @samp{NSGraphicsContext} is treated as three words @samp{NS},
1144 @samp{Graphics}, and @samp{Context}.
1145 @item syntactic-indentation mode
1146 When this is enabled (which it normally is), indentation commands such
1147 as @kbd{C-j} indent lines of code according to their syntactic
1148 structure. Otherwise, a line is simply indented to the same level as
1149 the previous one and @kbd{@key{TAB}} adjusts the indentation in steps
1150 of `c-basic-offset'.
1151 @end table
1152
1153 Full details on how these minor modes work are at @ref{Electric Keys},
1154 @ref{Auto-newlines}, @ref{Hungry WS Deletion}, @ref{Subword Movement},
1155 and @ref{Indentation Engine Basics}.
1156
1157 You can toggle each of these minor modes on and off, and you can
1158 configure @ccmode{} so that it starts up with your favourite
1159 combination of them (@pxref{Sample .emacs File}). By default, when
1160 you initialize a buffer, electric mode and syntactic-indentation mode
1161 are enabled but the other two modes are disabled.
1162
1163 @ccmode{} displays the current state of the first four of these minor
1164 modes on the modeline by appending letters to the major mode's name,
1165 one letter for each enabled minor mode - @samp{l} for electric mode,
1166 @samp{a} for auto-newline mode, @samp{h} for hungry delete mode, and
1167 @samp{w} for subword mode. If all these modes were enabled, you'd see
1168 @samp{C/lahw}@footnote{The @samp{C} would be replaced with the name of
1169 the language in question for the other languages @ccmode{} supports.}.
1170
1171 Here are the commands to toggle these modes:
1172
1173 @table @asis
1174 @item @kbd{C-c C-l} (@code{c-toggle-electric-state})
1175 @kindex C-c C-l
1176 @findex c-toggle-electric-state
1177 @findex toggle-electric-state (c-)
1178 Toggle electric minor mode. When the command turns the mode off, it
1179 also suppresses auto-newline mode.
1180
1181 @item @kbd{C-c C-a} (@code{c-toggle-auto-newline})
1182 @kindex C-c C-a
1183 @findex c-toggle-auto-newline
1184 @findex toggle-auto-newline (c-)
1185 Toggle auto-newline minor mode. When the command turns the mode on,
1186 it also enables electric minor mode.
1187
1188 @item @kbd{M-x c-toggle-hungry-state}@footnote{Prior to @ccmode{} 5.31, this command was bound to @kbd{C-c C-d}.}
1189 @findex c-toggle-hungry-state
1190 @findex toggle-hungry-state (c-)
1191 Toggle hungry-delete minor mode.
1192
1193 @item @kbd{M-x c-toggle-auto-hungry-state}@footnote{Prior to @ccmode{} 5.31, this command was bound to @kbd{C-c C-t}.}
1194 @findex c-toggle-auto-hungry-state
1195 @findex toggle-auto-hungry-state (c-)
1196 Toggle both auto-newline and hungry delete minor modes.
1197
1198 @item @kbd{C-c C-w} (@code{M-x c-subword-mode})
1199 @kindex C-c C-w
1200 @findex c-subword-mode
1201 @findex subword-mode (c-)
1202 Toggle subword mode.
1203
1204 @item @kbd{M-x c-toggle-syntactic-indentation}
1205 @findex c-toggle-syntactic-indentation
1206 @findex toggle-syntactic-indentation (c-)
1207 Toggle syntactic-indentation mode.
1208 @end table
1209
1210 Common to all the toggle functions above is that if they are called
1211 programmatically, they take an optional numerical argument. A
1212 positive value will turn on the minor mode (or both of them in the
1213 case of @code{c-toggle-auto-hungry-state}) and a negative value will
1214 turn it (or them) off.
1215
1216
1217 @comment !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
1218 @node Electric Keys, Auto-newlines, Minor Modes, Commands
1219 @comment node-name, next, previous, up
1220 @section Electric Keys and Keywords
1221 @cindex electric characters
1222 @comment !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
1223
1224 Most punctuation keys provide @dfn{electric} behavior - as well as
1225 inserting themselves they perform some other action, such as
1226 reindenting the line. This reindentation saves you from having to
1227 reindent a line manually after typing, say, a @samp{@}}. A few
1228 keywords, such as @code{else}, also trigger electric action.
1229
1230 You can inhibit the electric behaviour described here by disabling
1231 electric minor mode (@pxref{Minor Modes}).
1232
1233 Common to all these keys is that they only behave electrically when
1234 used in normal code (as contrasted with getting typed in a string
1235 literal or comment). Those which cause re-indentation do so only when
1236 @code{c-syntactic-indentation} has a non-@code{nil} value (which it
1237 does by default).
1238
1239 These keys and keywords are:
1240 @c ACM, 2004/8/24: c-electric-pound doesn't check c-s-i: this is more
1241 @c like a bug in the code than a bug in this document. It'll get
1242 @c fixed in the code sometime.
1243
1244 @table @kbd
1245 @item #
1246 @kindex #
1247 @findex c-electric-pound
1248 @findex electric-pound (c-)
1249 @vindex c-electric-pound-behavior
1250 @vindex electric-pound-behavior (c-)
1251 Pound (bound to @code{c-electric-pound}) is electric when typed as the
1252 first non-whitespace character on a line and not within a macro
1253 definition. In this case, the variable @code{c-electric-pound-behavior}
1254 is consulted for the electric behavior. This variable takes a list
1255 value, although the only element currently defined is @code{alignleft},
1256 which tells this command to force the @samp{#} character into column
1257 zero. This is useful for entering preprocessor macro definitions.
1258
1259 Pound is not electric in AWK buffers, where @samp{#} starts a comment,
1260 and is bound to @code{self-insert-command} like any typical printable
1261 character.
1262 @c ACM, 2004/8/24: Change this (and the code) to do AWK comment
1263 @c reindentation.
1264
1265 @item *
1266 @kindex *
1267 @itemx /
1268 @kindex /
1269 @findex c-electric-star
1270 @findex electric-star (c-)
1271 @findex c-electric-slash
1272 @findex electric-slash (c-)
1273 A star (bound to @code{c-electric-star}) or a slash
1274 (@code{c-electric-slash}) causes reindentation when you type it as the
1275 second component of a C style block comment opener (@samp{/*}) or a
1276 C++ line comment opener (@samp{//}) respectively, but only if the
1277 comment opener is the first thing on the line (i.e. there's only
1278 whitespace before it).
1279
1280 Additionally, you can configure @ccmode{} so that typing a slash at
1281 the start of a line within a block comment will terminate the
1282 comment. You don't need to have electric minor mode enabled to get
1283 this behaviour. @xref{Clean-ups}.
1284
1285 In AWK mode, @samp{*} and @samp{/} do not delimit comments and are not
1286 electric.
1287
1288 @item <
1289 @kindex <
1290 @itemx >
1291 @kindex >
1292 @findex c-electric-lt-gt
1293 @findex electric-lt-gt (c-)
1294 A less-than or greater-than sign (bound to @code{c-electric-lt-gt}) is
1295 electric in two circumstances: when it is an angle bracket in a C++
1296 @samp{template} declaration (and similar constructs in other
1297 languages) and when it is the second of two @kbd{<} or @kbd{>}
1298 characters in a C++ style stream operator. In either case, the line
1299 is reindented. Angle brackets in C @samp{#include} directives are not
1300 electric.
1301
1302 @item (
1303 @kindex (
1304 @itemx )
1305 @kindex )
1306 @findex c-electric-paren
1307 @findex electric-paren (c-)
1308 The normal parenthesis characters @samp{(} and @samp{)} (bound to
1309 @code{c-electric-paren}) reindent the current line. This is useful
1310 for getting the closing parenthesis of an argument list aligned
1311 automatically.
1312
1313 You can also configure @ccmode{} to insert a space automatically
1314 between a function name and the @samp{(} you've just typed, and to
1315 remove it automatically after typing @samp{)}, should the argument
1316 list be empty. You don't need to have electric minor mode enabled to
1317 get these actions. @xref{Clean-ups}.
1318
1319 @item @{
1320 @kindex @{
1321 @itemx @}
1322 @kindex @}
1323 @findex c-electric-brace
1324 @findex electric-brace (c-)
1325 Typing a brace (bound to @code{c-electric-brace}) reindents the
1326 current line. Also, one or more newlines might be inserted if
1327 auto-newline minor mode is enabled. @xref{Auto-newlines}.
1328 Additionally, you can configure @ccmode{} to compact excess whitespace
1329 inserted by auto-newline mode in certain circumstances.
1330 @xref{Clean-ups}.
1331
1332 @item :
1333 @kindex :
1334 @findex c-electric-colon
1335 @findex electric-colon (c-)
1336 Typing a colon (bound to @code{c-electric-colon}) reindents the
1337 current line. Additionally, one or more newlines might be inserted if
1338 auto-newline minor mode is enabled. @xref{Auto-newlines}. If you
1339 type a second colon immediately after such an auto-newline, by default
1340 the whitespace between the two colons is removed, leaving a C++ scope
1341 operator. @xref{Clean-ups}.
1342
1343 If you prefer, you can insert @samp{::} in a single operation,
1344 avoiding all these spurious reindentations, newlines, and clean-ups.
1345 @xref{Other Commands}.
1346
1347 @item ;
1348 @kindex ;
1349 @itemx ,
1350 @kindex ,
1351 @findex c-electric-semi&comma
1352 @findex electric-semi&comma (c-)
1353 Typing a semicolon or comma (bound to @code{c-electric-semi&comma})
1354 reindents the current line. Also, a newline might be inserted if
1355 auto-newline minor mode is enabled. @xref{Auto-newlines}.
1356 Additionally, you can configure @ccmode{} so that when auto-newline
1357 has inserted whitespace after a @samp{@}}, it will be removed again
1358 when you type a semicolon or comma just after it. @xref{Clean-ups}.
1359
1360 @end table
1361
1362 @deffn Command c-electric-continued-statement
1363 @findex electric-continued-statement (c-)
1364
1365 Certain keywords are electric, causing reindentation when they are
1366 preceded only by whitespace on the line. The keywords are those that
1367 continue an earlier statement instead of starting a new one:
1368 @code{else}, @code{while}, @code{catch} (only in C++ and Java) and
1369 @code{finally} (only in Java).
1370
1371 An example:
1372
1373 @example
1374 @group
1375 for (i = 0; i < 17; i++)
1376 if (a[i])
1377 res += a[i]->offset;
1378 else
1379 @end group
1380 @end example
1381
1382 Here, the @code{else} should be indented like the preceding @code{if},
1383 since it continues that statement. @ccmode{} will automatically
1384 reindent it after the @code{else} has been typed in full, since only
1385 then is it possible to decide whether it's a new statement or a
1386 continuation of the preceding @code{if}.
1387
1388 @vindex abbrev-mode
1389 @findex abbrev-mode
1390 @cindex Abbrev mode
1391 @ccmode{} uses Abbrev mode (@pxref{Abbrevs,,, @emacsman{}, @emacsmantitle{}})
1392 to accomplish this. It's therefore turned on by default in all language
1393 modes except IDL mode, since CORBA IDL doesn't have any statements.
1394 @end deffn
1395
1396
1397 @comment !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
1398 @node Auto-newlines, Hungry WS Deletion, Electric Keys, Commands
1399 @comment node-name, next, previous, up
1400 @section Auto-newline Insertion
1401 @cindex auto-newline
1402 @comment !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
1403
1404 When you have @dfn{Auto-newline minor mode} enabled (@pxref{Minor
1405 Modes}), @ccmode{} inserts newlines for you automatically (in certain
1406 syntactic contexts) when you type a left or right brace, a colon, a
1407 semicolon, or a comma. Sometimes a newline appears before the
1408 character you type, sometimes after it, sometimes both.
1409
1410 Auto-newline only triggers when the following conditions hold:
1411
1412 @itemize @bullet
1413 @item
1414 Auto-newline minor mode is enabled, as evidenced by the indicator
1415 @samp{a} after the mode name on the modeline (e.g. @samp{C/a} or
1416 @samp{C/la}).
1417
1418 @item
1419 The character was typed at the end of a line, or with only whitespace
1420 after it, and possibly a @samp{\} escaping the newline.
1421
1422 @item
1423 The character is not on its own line already. (This applies only to
1424 insertion of a newline @emph{before} the character.)
1425
1426 @item
1427 @cindex literal
1428 @cindex syntactic whitespace
1429 The character was not typed inside of a literal @footnote{A
1430 @dfn{literal} is defined as any comment, string, or preprocessor macro
1431 definition. These constructs are also known as @dfn{syntactic
1432 whitespace} since they are usually ignored when scanning C code.}.
1433
1434 @item
1435 No numeric argument was supplied to the command (i.e. it was typed as
1436 normal, with no @kbd{C-u} prefix).
1437 @end itemize
1438
1439 You can configure the precise circumstances in which newlines get
1440 inserted (see @pxref{Custom Auto-newlines}). Typically, the style
1441 system (@pxref{Styles}) will have set this up for you, so you probably
1442 won't have to bother.
1443
1444 Sometimes @ccmode{} inserts an auto-newline where you don't want one,
1445 such as after a @samp{@}} when you're about to type a @samp{;}.
1446 Hungry deletion can help here (@pxref{Hungry WS Deletion}), or you can
1447 activate an appropriate @dfn{clean-up}, which will remove the excess
1448 whitespace after you've typed the @samp{;}. See @ref{Clean-ups} for a
1449 full description. See also @ref{Electric Keys} for a summary of
1450 clean-ups listed by key.
1451
1452
1453 @comment !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
1454 @node Hungry WS Deletion, Subword Movement, Auto-newlines, Commands
1455 @comment node-name, next, previous, up
1456 @section Hungry Deletion of Whitespace
1457 @cindex hungry-deletion
1458 @comment !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
1459
1460 If you want to delete an entire block of whitespace at point, you can
1461 use @dfn{hungry deletion}. This deletes all the contiguous whitespace
1462 either before point or after point in a single operation.
1463 ``Whitespace'' here includes tabs and newlines, but not comments or
1464 preprocessor commands. Hungry deletion can markedly cut down on the
1465 number of times you have to hit deletion keys when, for example,
1466 you've made a mistake on the preceding line and have already pressed
1467 @kbd{C-j}.
1468
1469 Hungry deletion is a simple feature that some people find extremely
1470 useful. In fact, you might find yourself wanting it in @strong{all}
1471 your editing modes!
1472
1473 Loosely speaking, in what follows, @dfn{@key{DEL}} means ``the
1474 backspace key'' and @dfn{@key{DELETE}} means ``the forward delete
1475 key''. This is discussed in more detail below.
1476
1477 There are two different ways you can use hungry deletion:
1478
1479 @table @asis
1480 @item Using @dfn{Hungry Delete Mode} with @kbd{@key{DEL}} and @kbd{C-d}
1481 Here you toggle Hungry Delete minor mode with @kbd{M-x
1482 c-toggle-hungry-state}@footnote{Prior to @ccmode{} 5.31, this command
1483 was bound to @kbd{C-c C-d}. @kbd{C-c C-d} is now the default binding
1484 for @code{c-hungry-delete-forward}.} (@pxref{Minor Modes}.) This
1485 makes @kbd{@key{DEL}} and @kbd{C-d} do backwards and forward hungry
1486 deletion.
1487
1488 @table @asis
1489 @item @kbd{@key{DEL}} (@code{c-electric-backspace})
1490 @kindex DEL
1491 @findex c-electric-backspace
1492 @findex electric-backspace (c-)
1493 This command is run by default when you hit the @kbd{DEL} key. When
1494 hungry delete mode is enabled, it deletes any amount of whitespace in
1495 the backwards direction. Otherwise, or when used with a prefix
1496 argument or in a literal (@pxref{Auto-newlines}), the command just
1497 deletes backwards in the usual way. (More precisely, it calls the
1498 function contained in the variable @code{c-backspace-function},
1499 passing it the prefix argument, if any.)
1500
1501 @item @code{c-backspace-function}
1502 @vindex c-backspace-function
1503 @vindex backspace-function (c-)
1504 @findex backward-delete-char-untabify
1505 Hook that gets called by @code{c-electric-backspace} when it doesn't
1506 do an ``electric'' deletion of the preceding whitespace. The default
1507 value is @code{backward-delete-char-untabify}
1508 (@pxref{Deletion,,,@lispref{}, @lispreftitle{}}, the function which
1509 deletes a single character.
1510
1511 @item @kbd{C-d} (@code{c-electric-delete-forward})
1512 @kindex C-d
1513 @findex c-electric-delete-forward
1514 @findex electric-delete-forward (c-)
1515 This function, which is bound to @kbd{C-d} by default, works just like
1516 @code{c-electric-backspace} but in the forward direction. When it
1517 doesn't do an ``electric'' deletion of the following whitespace, it
1518 just does @code{delete-char}, more or less. (Strictly speaking, it
1519 calls the function in @code{c-delete-function} with the prefix
1520 argument.)
1521
1522 @item @code{c-delete-function}
1523 @vindex c-delete-function
1524 @vindex delete-function (c-)
1525 @findex delete-char
1526 Hook that gets called by @code{c-electric-delete-forward} when it
1527 doesn't do an ``electric'' deletion of the following whitespace. The
1528 default value is @code{delete-char}.
1529 @end table
1530
1531 @item Using Distinct Bindings
1532 The other (newer and recommended) way to use hungry deletion is to
1533 perform @code{c-hungry-delete-backwards} and
1534 @code{c-hungry-delete-forward} directly through their key sequences
1535 rather than using the minor mode toggling.
1536
1537 @table @asis
1538 @item @kbd{C-c C-@key{DEL}}, or @kbd{C-c @key{DEL}} (@code{c-hungry-delete-backwards})@footnote{This command was formerly known as @code{c-hungry-backspace}.}
1539 @kindex C-c C-<backspace>
1540 @kindex C-c <backspace>
1541 @kindex C-c C-DEL
1542 @kindex C-c DEL
1543 @findex c-hungry-delete-backwards
1544 @findex hungry-delete-backwards (c-)
1545 Delete any amount of whitespace in the backwards direction (regardless
1546 whether hungry-delete mode is enabled or not). This command is bound
1547 to both @kbd{C-c C-@key{DEL}} and @kbd{C-c @key{DEL}}, since the more
1548 natural one, @kbd{C-c C-@key{DEL}}, is sometimes difficult to type at
1549 a character terminal.
1550
1551 @item @kbd{C-c C-d}, @kbd{C-c C-@key{DELETE}}, or @kbd{C-c @key{DELETE}} (@code{c-hungry-delete-forward})
1552 @kindex C-c C-d
1553 @kindex C-c C-<DELETE>
1554 @kindex C-c <DELETE>
1555 @findex c-hungry-delete-forward
1556 @findex hungry-delete-forward (c-)
1557 Delete any amount of whitespace in the forward direction (regardless
1558 whether hungry-delete mode is enabled or not). This command is bound
1559 to both @kbd{C-c C-@key{DELETE}} and @kbd{C-c @key{DELETE}} for the
1560 same reason as for @key{DEL} above.
1561 @end table
1562 @end table
1563
1564 @kindex <delete>
1565 @kindex <backspace>
1566
1567 When we talk about @kbd{@key{DEL}}, and @kbd{@key{DELETE}} above, we
1568 actually do so without connecting them to the physical keys commonly
1569 known as @key{Backspace} and @key{Delete}. The default bindings to
1570 those two keys depends on the flavor of (X)Emacs you are using.
1571
1572 @findex c-electric-delete
1573 @findex electric-delete (c-)
1574 @findex c-hungry-delete
1575 @findex hungry-delete (c-)
1576 @vindex delete-key-deletes-forward
1577 In XEmacs 20.3 and beyond, the @key{Backspace} key is bound to
1578 @code{c-electric-backspace} and the @key{Delete} key is bound to
1579 @code{c-electric-delete}. You control the direction it deletes in by
1580 setting the variable @code{delete-key-deletes-forward}, a standard
1581 XEmacs variable.
1582 @c This variable is encapsulated by XEmacs's (defsubst delete-forward-p ...).
1583 When this variable is non-@code{nil}, @code{c-electric-delete} will do
1584 forward deletion with @code{c-electric-delete-forward}, otherwise it
1585 does backward deletion with @code{c-electric-backspace}. Similarly,
1586 @kbd{C-c @key{Delete}} and @kbd{C-c C-@key{Delete}} are bound to
1587 @code{c-hungry-delete} which is controlled in the same way by
1588 @code{delete-key-deletes-forward}.
1589
1590 @findex normal-erase-is-backspace-mode
1591
1592 Emacs 21 and later automatically binds @key{Backspace} and
1593 @key{Delete} to @kbd{DEL} and @kbd{C-d} according to your environment,
1594 and @ccmode{} extends those bindings to @kbd{C-c C-@key{Backspace}}
1595 etc. If you need to change the bindings through
1596 @code{normal-erase-is-backspace-mode} then @ccmode{} will also adapt
1597 its extended bindings accordingly.
1598
1599 In earlier (X)Emacs versions, @ccmode{} doesn't bind either
1600 @key{Backspace} or @key{Delete} directly. Only the key codes
1601 @kbd{DEL} and @kbd{C-d} are bound, and it's up to the default bindings
1602 to map the physical keys to them. You might need to modify this
1603 yourself if the defaults are unsuitable.
1604
1605 Getting your @key{Backspace} and @key{Delete} keys properly set up can
1606 sometimes be tricky. The information in @ref{DEL Does Not
1607 Delete,,,emacs, GNU Emacs Manual}, might be helpful if you're having
1608 trouble with this in GNU Emacs.
1609
1610
1611 @comment !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
1612 @node Subword Movement, Other Commands, Hungry WS Deletion, Commands
1613 @comment node-name, next, previous, up
1614 @section Subword Movement and Editing
1615 @comment !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
1616
1617 @cindex nomenclature
1618 @cindex subword
1619 In spite of the GNU Coding Standards, it is popular to name a symbol
1620 by mixing uppercase and lowercase letters, e.g. @samp{GtkWidget},
1621 @samp{EmacsFrameClass}, or @samp{NSGraphicsContext}. Here we call
1622 these mixed case symbols @dfn{nomenclatures}. Also, each capitalized
1623 (or completely uppercase) part of a nomenclature is called a
1624 @dfn{subword}. Here are some examples:
1625
1626 @multitable {@samp{NSGraphicsContext}} {@samp{NS}, @samp{Graphics}, and @samp{Context}}
1627 @headitem Nomenclature
1628 @tab Subwords
1629 @item @samp{GtkWindow}
1630 @tab @samp{Gtk} and @samp{Window}
1631 @item @samp{EmacsFrameClass}
1632 @tab @samp{Emacs}, @samp{Frame}, and @samp{Class}
1633 @item @samp{NSGraphicsContext}
1634 @tab @samp{NS}, @samp{Graphics}, and @samp{Context}
1635 @end multitable
1636
1637 The subword minor mode replaces the basic word oriented movement and
1638 editing commands with variants that recognize subwords in a
1639 nomenclature and treat them as separate words:
1640
1641 @findex c-forward-subword
1642 @findex forward-subword (c-)
1643 @findex c-backward-subword
1644 @findex backward-subword (c-)
1645 @findex c-mark-subword
1646 @findex mark-subword (c-)
1647 @findex c-kill-subword
1648 @findex kill-subword (c-)
1649 @findex c-backward-kill-subword
1650 @findex backward-kill-subword (c-)
1651 @findex c-transpose-subwords
1652 @findex transpose-subwords (c-)
1653 @findex c-capitalize-subword
1654 @findex capitalize-subword (c-)
1655 @findex c-upcase-subword
1656 @findex upcase-subword (c-)
1657 @findex c-downcase-subword
1658 @findex downcase-subword (c-)
1659 @multitable @columnfractions .20 .40 .40
1660 @headitem Key @tab Word oriented command @tab Subword oriented command
1661 @item @kbd{M-f} @tab @code{forward-word} @tab @code{c-forward-subword}
1662 @item @kbd{M-b} @tab @code{backward-word} @tab @code{c-backward-subword}
1663 @item @kbd{M-@@} @tab @code{mark-word} @tab @code{c-mark-subword}
1664 @item @kbd{M-d} @tab @code{kill-word} @tab @code{c-kill-subword}
1665 @item @kbd{M-DEL} @tab @code{backward-kill-word} @tab @code{c-backward-kill-subword}
1666 @item @kbd{M-t} @tab @code{transpose-words} @tab @code{c-transpose-subwords}
1667 @item @kbd{M-c} @tab @code{capitalize-word} @tab @code{c-capitalize-subword}
1668 @item @kbd{M-u} @tab @code{upcase-word} @tab @code{c-upcase-subword}
1669 @item @kbd{M-l} @tab @code{downcase-word} @tab @code{c-downcase-subword}
1670 @end multitable
1671
1672 Note that if you have changed the key bindings for the word oriented
1673 commands in your @file{.emacs} or a similar place, the keys you have
1674 configured are also used for the corresponding subword oriented
1675 commands.
1676
1677 Type @kbd{C-c C-w} to toggle subword mode on and off. To make the
1678 mode turn on automatically, put the following code in your
1679 @file{.emacs}:
1680
1681 @example
1682 (add-hook 'c-mode-common-hook
1683 (lambda () (c-subword-mode 1)))
1684 @end example
1685
1686 As a bonus, you can also use @code{c-subword-mode} in non-@ccmode{}
1687 buffers by typing @kbd{M-x c-subword-mode}.
1688
1689 @comment !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
1690 @node Other Commands, , Subword Movement, Commands
1691 @comment node-name, next, previous, up
1692 @section Other Commands
1693 @comment !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
1694
1695 Here are the various other commands that didn't fit anywhere else:
1696
1697 @table @asis
1698 @item @kbd{C-c :} (@code{c-scope-operator})
1699 @kindex C-c :
1700 @findex c-scope-operator
1701 @findex scope-operator (c-)
1702 In C++, it is also sometimes desirable to insert the double-colon scope
1703 operator without performing the electric behavior of colon insertion.
1704 @kbd{C-c :} does just this.
1705
1706 @item @kbd{C-c C-\} (@code{c-backslash-region})
1707 @kindex C-c C-\
1708 @findex c-backslash-region
1709 @findex backslash-region (c-)
1710 This function inserts and aligns or deletes end-of-line backslashes in
1711 the current region. These are typically used in multi-line macros.
1712
1713 With no prefix argument, it inserts any missing backslashes and aligns
1714 them according to the @code{c-backslash-column} and
1715 @code{c-backslash-max-column} variables. With a prefix argument, it
1716 deletes any backslashes.
1717
1718 The function does not modify blank lines at the start of the region. If
1719 the region ends at the start of a line, it always deletes the backslash
1720 (if any) at the end of the previous line.
1721
1722 To customize the precise workings of this command, @ref{Custom Macros}.
1723 @end table
1724
1725 @noindent
1726 The recommended line breaking function, @code{c-context-line-break}
1727 (@pxref{Filling and Breaking}), is especially nice if you edit
1728 multiline macros frequently. When used inside a macro, it
1729 automatically inserts and adjusts the mandatory backslash at the end
1730 of the line to keep the macro together, and it leaves the point at the
1731 right indentation column for the code. Thus you can write code inside
1732 macros almost exactly as you can elsewhere, without having to bother
1733 with the trailing backslashes.
1734
1735 @table @asis
1736 @item @kbd{C-c C-e} (@code{c-macro-expand})
1737 @kindex C-c C-e
1738 @findex c-macro-expand
1739 @findex macro-expand (c-)
1740 This command expands C, C++, Objective C or Pike macros in the region,
1741 using an appropriate external preprocessor program. Normally it
1742 displays its output in a temporary buffer, but if you give it a prefix
1743 arg (with @kbd{C-u C-c C-e}) it will overwrite the original region
1744 with the expansion.
1745
1746 The command does not work in any of the other modes, and the key
1747 sequence is not bound in these other modes.
1748
1749 @code{c-macro-expand} isn't actually part of @ccmode{}, even though it
1750 is bound to a @ccmode{} key sequence. If you need help setting it up
1751 or have other problems with it, you can either read its source code or
1752 ask for help in the standard (X)Emacs forums.
1753 @end table
1754
1755 @comment !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
1756 @node Font Locking, Config Basics, Commands, Top
1757 @comment node-name, next, previous, up
1758 @chapter Font Locking
1759 @cindex font locking
1760 @comment !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
1761
1762 @cindex Font Lock mode
1763
1764 @ccmode{} provides font locking for its supported languages by
1765 supplying patterns for use with Font Lock mode. This means that you
1766 get distinct faces on the various syntactic parts such as comments,
1767 strings, keywords and types, which is very helpful in telling them
1768 apart at a glance and discovering syntactic errors. @xref{Font
1769 Lock,,, emacs, GNU Emacs Manual}, for ways to enable font locking in
1770 @ccmode{} buffers.
1771
1772 @strong{Please note:} The font locking in AWK mode is currently not
1773 integrated with the rest of @ccmode{}. Only the last section of this
1774 chapter, @ref{AWK Mode Font Locking}, applies to AWK. The other
1775 sections apply to the other languages.
1776
1777 @menu
1778 * Font Locking Preliminaries::
1779 * Faces::
1780 * Doc Comments::
1781 * AWK Mode Font Locking::
1782 @end menu
1783
1784
1785 @comment !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
1786 @node Font Locking Preliminaries, Faces, Font Locking, Font Locking
1787 @comment node-name, next, previous, up
1788 @section Font Locking Preliminaries
1789 @comment !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
1790
1791 The font locking for most of the @ccmode{} languages were provided
1792 directly by the Font Lock package prior to version 5.30 of @ccmode{}.
1793 In the transition to @ccmode{} the patterns have been reworked
1794 completely and are applied uniformly across all the languages except AWK
1795 mode, just like the indentation rules (although each language still has
1796 some peculiarities of its own, of course). Since the languages
1797 previously had completely separate font locking patterns, this means
1798 that it's a bit different in most languages now.
1799
1800 The main goal for the font locking in @ccmode{} is accuracy, to provide
1801 a dependable aid in recognizing the various constructs. Some, like
1802 strings and comments, are easy to recognize while others, like
1803 declarations and types, can be very tricky. @ccmode{} can go to great
1804 lengths to recognize declarations and casts correctly, especially when
1805 the types aren't recognized by standard patterns. This is a fairly
1806 demanding analysis which can be slow on older hardware, and it can
1807 therefore be disabled by choosing a lower decoration level with the
1808 variable @code{font-lock-maximum-decoration} (@pxref{Font Lock,,,
1809 emacs, GNU Emacs Manual}).
1810
1811 @vindex font-lock-maximum-decoration
1812
1813 The decoration levels are used as follows:
1814
1815 @enumerate
1816 @comment 1
1817 @item
1818 Minimal font locking: Fontify only comments, strings and preprocessor
1819 directives (in the languages that use cpp).
1820
1821 @comment 2
1822 @item
1823 Fast font locking: In addition to level 1, fontify keywords, simple
1824 types and declarations that are easy to recognize. The variables
1825 @code{*-font-lock-extra-types} (where @samp{*} is the name of the
1826 language) are used to recognize types (see below). Documentation
1827 comments like Javadoc are fontified according to
1828 @code{c-doc-comment-style} (@pxref{Doc Comments}).
1829
1830 Use this if you think the font locking is too slow. It's the closest
1831 corresponding level to level 3 in the old font lock patterns.
1832
1833 @comment 3
1834 @item
1835 Accurate font locking: Like level 2 but uses a different approach that
1836 can recognize types and declarations much more accurately. The
1837 @code{*-font-lock-extra-types} variables are still used, but user
1838 defined types are recognized correctly anyway in most cases. Therefore
1839 those variables should be fairly restrictive and not contain patterns
1840 that are uncertain.
1841
1842 @cindex Lazy Lock mode
1843 @cindex Just-in-time Lock mode
1844
1845 This level is designed for fairly modern hardware and a font lock
1846 support mode like Lazy Lock or Just-in-time Lock mode that only
1847 fontifies the parts that are actually shown. Fontifying the whole
1848 buffer at once can easily get bothersomely slow even on contemporary
1849 hardware.
1850 @c ACM, 2005/8/28: There should be a page in the (X)Emacs manual
1851 @c describing these support modes. There wasn't in the
1852 @c fourteenth edition of the Emacs manual (released with Emacs 21.3).
1853 @c There might be one in the Emacs CVS for 22.1.
1854 @end enumerate
1855
1856 @cindex user defined types
1857 @cindex types, user defined
1858
1859 Since user defined types are hard to recognize you can provide
1860 additional regexps to match those you use:
1861
1862 @defopt c-font-lock-extra-types
1863 @defoptx c++-font-lock-extra-types
1864 @defoptx objc-font-lock-extra-types
1865 @defoptx java-font-lock-extra-types
1866 @defoptx idl-font-lock-extra-types
1867 @defoptx pike-font-lock-extra-types
1868 For each language there's a variable @code{*-font-lock-extra-types},
1869 where @samp{*} stands for the language in question. It contains a list
1870 of regexps that matches identifiers that should be recognized as types,
1871 e.g. @samp{\\sw+_t} to recognize all identifiers ending with @samp{_t}
1872 as is customary in C code. Each regexp should not match more than a
1873 single identifier.
1874
1875 The default values contain regexps for many types in standard runtime
1876 libraries that are otherwise difficult to recognize, and patterns for
1877 standard type naming conventions like the @samp{_t} suffix in C and C++.
1878 Java, Objective-C and Pike have as a convention to start class names
1879 with capitals, so there are patterns for that in those languages.
1880
1881 Despite the names of these variables, they are not only used for
1882 fontification but in other places as well where @ccmode{} needs to
1883 recognize types.
1884 @end defopt
1885
1886
1887 @comment !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
1888 @node Faces, Doc Comments, Font Locking Preliminaries, Font Locking
1889 @comment node-name, next, previous, up
1890 @section Faces
1891 @cindex faces
1892 @comment !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
1893
1894 @ccmode{} attempts to use the standard faces for programming languages
1895 in accordance with their intended purposes as far as possible. No extra
1896 faces are currently provided, with the exception of a replacement face
1897 @code{c-invalid-face} for emacsen that don't provide
1898 @code{font-lock-warning-face}.
1899
1900 @itemize @bullet
1901 @item
1902 @vindex font-lock-comment-face
1903 Normal comments are fontified in @code{font-lock-comment-face}.
1904
1905 @item
1906 @vindex font-lock-doc-face
1907 @vindex font-lock-doc-string-face
1908 @vindex font-lock-comment-face
1909 Comments that are recognized as documentation (@pxref{Doc Comments})
1910 get @code{font-lock-doc-face} (Emacs) or
1911 @code{font-lock-doc-string-face} (XEmacs) if those faces exist. If
1912 they don't then @code{font-lock-comment-face} is used.
1913
1914 @item
1915 @vindex font-lock-string-face
1916 String and character literals are fontified in
1917 @code{font-lock-string-face}.
1918
1919 @item
1920 @vindex font-lock-keyword-face
1921 Keywords are fontified with @code{font-lock-keyword-face}.
1922
1923 @item
1924 @vindex font-lock-function-name-face
1925 @code{font-lock-function-name-face} is used for function names in
1926 declarations and definitions, and classes in those contexts. It's also
1927 used for preprocessor defines with arguments.
1928
1929 @item
1930 @vindex font-lock-variable-name-face
1931 Variables in declarations and definitions, and other identifiers in such
1932 variable contexts, get @code{font-lock-variable-name-face}. It's also
1933 used for preprocessor defines without arguments.
1934
1935 @item
1936 @vindex font-lock-constant-face
1937 @vindex font-lock-reference-face
1938 Builtin constants are fontified in @code{font-lock-constant-face} if it
1939 exists, @code{font-lock-reference-face} otherwise. As opposed to the
1940 preceding two faces, this is used on the names in expressions, and it's
1941 not used in declarations, even if there happen to be a @samp{const} in
1942 them somewhere.
1943
1944 @item
1945 @vindex font-lock-type-face
1946 @code{font-lock-type-face} is put on types (both predefined and user
1947 defined) and classes in type contexts.
1948
1949 @item
1950 @vindex font-lock-constant-face
1951 @vindex font-lock-reference-face
1952 Label identifiers get @code{font-lock-constant-face} if it exists,
1953 @code{font-lock-reference-face} otherwise.
1954
1955 @item
1956 Name qualifiers and identifiers for scope constructs are fontified like
1957 labels.
1958
1959 @item
1960 Special markup inside documentation comments are also fontified like
1961 labels.
1962
1963 @item
1964 @vindex font-lock-preprocessor-face
1965 @vindex font-lock-builtin-face
1966 @vindex font-lock-reference-face
1967 Preprocessor directives get @code{font-lock-preprocessor-face} if it
1968 exists (i.e. XEmacs). In Emacs they get @code{font-lock-builtin-face}
1969 or @code{font-lock-reference-face}, for lack of a closer equivalent.
1970
1971 @item
1972 @vindex font-lock-warning-face
1973 @vindex c-invalid-face
1974 @vindex invalid-face (c-)
1975 Some kinds of syntactic errors are fontified with
1976 @code{font-lock-warning-face} in Emacs. In older XEmacs versions
1977 there's no corresponding standard face, so there a special
1978 @code{c-invalid-face} is used, which is defined to stand out sharply by
1979 default.
1980
1981 Note that it's not used for @samp{#error} or @samp{#warning} directives,
1982 since those aren't syntactic errors in themselves.
1983 @end itemize
1984
1985
1986 @comment !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
1987 @node Doc Comments, AWK Mode Font Locking, Faces, Font Locking
1988 @comment node-name, next, previous, up
1989 @section Documentation Comments
1990 @cindex documentation comments
1991 @comment !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
1992
1993 There are various tools to supply documentation in the source as
1994 specially structured comments, e.g. the standard Javadoc tool in Java.
1995 @ccmode{} provides an extensible mechanism to fontify such comments and
1996 the special markup inside them.
1997
1998 @defopt c-doc-comment-style
1999 @vindex doc-comment-style (c-)
2000 This is a style variable that specifies which documentation comment
2001 style to recognize, e.g. @code{javadoc} for Javadoc comments.
2002
2003 The value may also be a list of styles, in which case all of them are
2004 recognized simultaneously (presumably with markup cues that don't
2005 conflict).
2006
2007 The value may also be an association list to specify different comment
2008 styles for different languages. The symbol for the major mode is then
2009 looked up in the alist, and the value of that element is interpreted as
2010 above if found. If it isn't found then the symbol `other' is looked up
2011 and its value is used instead.
2012
2013 The default value for @code{c-doc-comment-style} is
2014 @w{@code{((java-mode . javadoc) (pike-mode . autodoc) (c-mode . gtkdoc))}}.
2015
2016 Note that @ccmode{} uses this variable to set other variables that
2017 handle fontification etc. That's done at mode initialization or when
2018 you switch to a style which sets this variable. Thus, if you change it
2019 in some other way, e.g. interactively in a CC Mode buffer, you will need
2020 to do @kbd{M-x java-mode} (or whatever mode you're currently using) to
2021 reinitialize.
2022
2023 @findex c-setup-doc-comment-style
2024 @findex setup-doc-comment-style (c-)
2025 Note also that when @ccmode{} starts up, the other variables are
2026 modified before the mode hooks are run. If you change this variable in
2027 a mode hook, you'll have to call @code{c-setup-doc-comment-style}
2028 afterwards to redo that work.
2029 @end defopt
2030
2031 @ccmode{} currently provides handing of the following doc comment
2032 styles:
2033
2034 @table @code
2035 @item javadoc
2036 @cindex Javadoc markup
2037 Javadoc comments, the standard tool in Java.
2038
2039 @item autodoc
2040 @cindex Pike autodoc markup
2041 For Pike autodoc markup, the standard in Pike.
2042
2043 @item gtkdoc
2044 @cindex GtkDoc markup
2045 For GtkDoc markup, widely used in the Gnome community.
2046 @end table
2047
2048 The above is by no means complete. If you'd like to see support for
2049 other doc comment styles, please let us know (@pxref{Mailing Lists and
2050 Bug Reports}).
2051
2052 You can also write your own doc comment fontification support to use
2053 with @code{c-doc-comment-style}: Supply a variable or function
2054 @code{*-font-lock-keywords} where @samp{*} is the name you want to use
2055 in @code{c-doc-comment-style}. If it's a variable, it's prepended to
2056 @code{font-lock-keywords}. If it's a function, it's called at mode
2057 initialization and the result is prepended. For an example, see
2058 @code{javadoc-font-lock-keywords} in @file{cc-fonts.el}.
2059
2060 If you add support for another doc comment style, please consider
2061 contributing it - send a note to @email{bug-cc-mode@@gnu.org}.
2062
2063
2064 @comment !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
2065 @node AWK Mode Font Locking, , Doc Comments, Font Locking
2066 @comment node-name, next, previous, up
2067 @section AWK Mode Font Locking
2068 @comment !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
2069
2070 The general appearance of font-locking in AWK mode is much like in any
2071 other programming mode. @xref{Faces For Font Lock,,,elisp, GNU Emacs
2072 Lisp Reference Manual}.
2073
2074 The following faces are, however, used in a non-standard fashion in
2075 AWK mode:
2076
2077 @table @asis
2078 @item @code{font-lock-variable-name-face}
2079 This face was intended for variable declarations. Since variables are
2080 not declared in AWK, this face is used instead for AWK system
2081 variables (such as @code{NF}) and ``Special File Names'' (such as
2082 @code{"/dev/stderr"}).
2083
2084 @item @code{font-lock-builtin-face} (Emacs)/@code{font-lock-preprocessor-face} (XEmacs)
2085 This face is normally used for preprocessor directives in @ccmode{}.
2086 There are no such things in AWK, so this face is used instead for
2087 standard functions (such as @code{match}).
2088
2089 @item @code{font-lock-string-face}
2090 As well as being used for strings, including localizable strings,
2091 (delimited by @samp{"} and @samp{_"}), this face is also used for AWK
2092 regular expressions (delimited by @samp{/}).
2093
2094 @item @code{font-lock-warning-face} (Emacs)/@code{c-invalid-face} (XEmacs)
2095 This face highlights the following syntactically invalid AWK
2096 constructs:
2097
2098 @itemize @bullet
2099 @item
2100 An unterminated string or regular expression. Here the opening
2101 delimiter (@samp{"} or @samp{/} or @samp{_"}) is displayed in
2102 @code{font-lock-warning-face}. This is most noticeable when typing in a
2103 new string/regular expression into a buffer, when the warning-face
2104 serves as a continual reminder to terminate the construct.
2105
2106 AWK mode fontifies unterminated strings/regular expressions
2107 differently from other modes: Only the text up to the end of the line
2108 is fontified as a string (escaped newlines being handled correctly),
2109 rather than the text up to the next string quote.
2110
2111 @item
2112 A space between the function name and opening parenthesis when calling
2113 a user function. The last character of the function name and the
2114 opening parenthesis are highlighted. This font-locking rule will
2115 spuriously highlight a valid concatenation expression where an
2116 identifier precedes a parenthesised expression. Unfortunately.
2117
2118 @item
2119 Whitespace following the @samp{\} in what otherwise looks like an
2120 escaped newline. The @samp{\} is highlighted.
2121 @end itemize
2122 @end table
2123
2124
2125 @comment !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
2126 @node Config Basics, Custom Filling and Breaking, Font Locking, Top
2127 @comment node-name, next, previous, up
2128 @chapter Configuration Basics
2129 @comment !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
2130
2131 @cindex Emacs Initiliazation File
2132 @cindex Configuration
2133 You configure @ccmode{} by setting Lisp variables and calling (and
2134 perhaps writing) Lisp functions@footnote{DON'T PANIC!!! This isn't
2135 difficult.}, which is usually done by adding code to an Emacs
2136 initialization file. This file might be @file{site-start.el} or
2137 @file{.emacs} or @file{init.el} or @file{default.el} or perhaps some
2138 other file. @xref{Init File,,,@emacsman{}, @emacsmantitle{}}. For
2139 the sake of conciseness, we just call this file ``your @file{.emacs}''
2140 throughout the rest of the manual.
2141
2142 Several of these variables (currently 16), are known collectively as
2143 @dfn{style variables}. @ccmode{} provides a special mechanism, known
2144 as @dfn{styles} to make it easier to set these variables as a group,
2145 to ``inherit'' settings from one style into another, and so on. Style
2146 variables remain ordinary Lisp variables, whose values can be read and
2147 changed independently of the style system. @xref{Style Variables}.
2148
2149 There are several ways you can write the code, depending on the
2150 precise effect you want---they are described further down on this page.
2151 If you are new to @ccmode{}, we suggest you begin with the simplest
2152 method, ``Top-level commands or the customization interface''.
2153
2154 If you make conflicting settings in several of these ways, the way
2155 that takes precedence is the one that appears latest in this list:
2156 @itemize @asis
2157 @item
2158 @table @asis
2159 @item Style
2160 @itemx Top-level command or ``customization interface''
2161 @itemx Hook
2162 @itemx File Style
2163 @end table
2164 @end itemize
2165
2166 Here is a summary of the different ways of writing your configuration
2167 settings:
2168
2169 @table @asis
2170 @item Top-level commands or the ``customization interface''
2171 Most simply, you can write @code{setq} and similar commands at the top
2172 level of your @file{.emacs} file. When you load a @ccmode{} buffer,
2173 it initializes its configuration from these global values (at least,
2174 for those settings you have given values to), so it makes sense to
2175 have these @code{setq} commands run @emph{before} @ccmode{} is first
2176 initialized---in particular, before any call to @code{desktop-read}
2177 (@pxref{Saving Emacs Sessions,,, emacs, GNU Emacs Manual}). For
2178 example, you might set c-basic-offset thus:
2179
2180 @example
2181 (setq c-basic-offset 4)
2182 @end example
2183
2184 You can use the more user friendly Customization interface instead,
2185 but this manual does not cover in detail how that works. To do this,
2186 start by typing @kbd{M-x customize-group @key{RET} c @key{RET}}.
2187 @xref{Easy Customization,,,@emacsman{}, @emacsmantitle{}}.
2188 @c The following note really belongs in the Emacs manual.
2189 Emacs normally writes the customizations at the end of your
2190 @file{.emacs} file. If you use @code{desktop-read}, you should edit
2191 your @file{.emacs} to place the call to @code{desktop-read} @emph{after}
2192 the customizations.
2193
2194 The first initialization of @ccmode{} puts a snapshot of the
2195 configuration settings into the special style @code{user}.
2196 @xref{Built-in Styles}.
2197
2198 For basic use of Emacs, either of these ways of configuring is
2199 adequate. However, the settings are then the same in all @ccmode{}
2200 buffers and it can be clumsy to communicate them between programmers.
2201 For more flexibility, you'll want to use one (or both) of @ccmode{}'s
2202 more sophisticated facilities, hooks and styles.
2203
2204 @item Hooks
2205 An Emacs @dfn{hook} is a place to put Lisp functions that you want
2206 Emacs to execute later in specific circumstances.
2207 @xref{Hooks,,,@lispref{}, @lispreftitle{}}. @ccmode{} supplies a main
2208 hook and a language-specific hook for each language it supports - any
2209 functions you put onto these hooks get executed as the last part of a
2210 buffer's initialization. Typically you put most of your customization
2211 within the main hook, and use the language-specific hooks to vary the
2212 customization settings between language modes. For example, if you
2213 wanted different (non-standard) values of @code{c-basic-offset} in C
2214 Mode and Java Mode buffers, you could do it like this:
2215
2216 @example
2217 @group
2218 (defun my-c-mode-hook ()
2219 (setq c-basic-offset 3))
2220 (add-hook 'c-mode-hook 'my-c-mode-hook)
2221
2222 (defun my-java-mode-hook ()
2223 (setq c-basic-offset 6))
2224 (add-hook 'java-mode-hook 'my-java-mode-hook)
2225 @end group
2226 @end example
2227
2228 See @ref{CC Hooks} for more details on the use of @ccmode{} hooks.
2229
2230 @item Styles
2231 A @ccmode{} @dfn{style} is a coherent collection of customizations
2232 with a name. At any time, exactly one style is active in each
2233 @ccmode{} buffer, either the one you have selected or a default.
2234 @ccmode{} is delivered with several existing styles. Additionally,
2235 you can create your own styles, possibly based on these existing
2236 styles. If you worked in a programming team called the ``Free
2237 Group'', which had its own coding standards, you might well have this
2238 in your @file{.emacs} file:
2239
2240 @example
2241 (setq c-default-style '((java-mode . "java")
2242 (awk-mode . "awk")
2243 (other . "free-group-style")))
2244 @end example
2245
2246 See @ref{Styles} for fuller details on using @ccmode{} styles and how
2247 to create them.
2248
2249 @item File Styles
2250 A @dfn{file style} is a rarely used variant of the ``style'' mechanism
2251 described above, which applies to an individual source file. To use
2252 it, you set certain Emacs local variables in a special block at the
2253 end of the source file. @xref{File Styles}.
2254
2255 @item Hooks with Styles
2256 For ultimate flexibility, you can use hooks and styles together. For
2257 example, if your team were developing a product which required a
2258 Linux driver, you'd probably want to use the ``linux'' style for the
2259 driver, and your own team's style for the rest of the code. You
2260 could achieve this with code like this in your @file{.emacs}:
2261
2262 @example
2263 @group
2264 (defun my-c-mode-hook ()
2265 (c-set-style
2266 (if (and (buffer-file-name)
2267 (string-match "/usr/src/linux" (buffer-file-name)))
2268 "linux"
2269 "free-group-style")))
2270 (add-hook 'c-mode-hook 'my-c-mode-hook)
2271 @end group
2272 @end example
2273
2274 In a programming team, a hook is a also a good place for each member
2275 to put his own personal preferences. For example, you might be the
2276 only person in your team who likes Auto-newline minor mode. You could
2277 have it enabled by default by placing the following in your
2278 @file{.emacs}:
2279
2280 @example
2281 @group
2282 (defun my-turn-on-auto-newline ()
2283 (c-toggle-auto-newline 1))
2284 (add-hook 'c-mode-common-hook 'my-turn-on-auto-newline)
2285 @end group
2286 @end example
2287 @end table
2288
2289 @menu
2290 * CC Hooks::
2291 * Style Variables::
2292 * Styles::
2293 @end menu
2294
2295 @comment !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
2296 @node CC Hooks, Style Variables, Config Basics, Config Basics
2297 @comment node-name, next, previous, up
2298 @section Hooks
2299 @cindex mode hooks
2300 @comment !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
2301 @c The node name is "CC Hooks" rather than "Hooks" because of a bug in
2302 @c some older versions of Info, e.g. the info.el in GNU Emacs 21.3.
2303 @c If you go to "Config Basics" and hit <CR> on the xref to "CC
2304 @c Hooks" the function Info-follow-reference searches for "*Note: CC
2305 @c Hooks" from the beginning of the page. If this node were instead
2306 @c named "Hooks", that search would spuriously find "*Note:
2307 @c Hooks(elisp)" and go to the wrong node.
2308
2309 @ccmode{} provides several hooks that you can use to customize the
2310 mode for your coding style. The main hook is
2311 @code{c-mode-common-hook}; typically, you'll put the bulk of your
2312 customizations here. In addition, each language mode has its own
2313 hook, allowing you to fine tune your settings individually for the
2314 different @ccmode{} languages, and there is a package initialization
2315 hook. Finally, there is @code{c-special-indent-hook}, which enables
2316 you to solve anomalous indentation problems. It is described in
2317 @ref{Other Indentation}, not here. All these hooks adhere to the
2318 standard Emacs conventions.
2319
2320 When you open a buffer, @ccmode{} first initializes it with the
2321 currently active style (@pxref{Styles}). Then it calls
2322 @code{c-mode-common-hook}, and finally it calls the language-specific
2323 hook. Thus, any style settings done in these hooks will override
2324 those set by @code{c-default-style}.
2325
2326 @defvar c-initialization-hook
2327 @vindex initialization-hook (c-)
2328 Hook run only once per Emacs session, when @ccmode{} is initialized.
2329 This is a good place to change key bindings (or add new ones) in any
2330 of the @ccmode{} key maps. @xref{Sample .emacs File}.
2331 @end defvar
2332
2333 @defvar c-mode-common-hook
2334 @vindex mode-common-hook (c-)
2335 Common hook across all languages. It's run immediately before the
2336 language specific hook.
2337 @end defvar
2338
2339 @defvar c-mode-hook
2340 @defvarx c++-mode-hook
2341 @defvarx objc-mode-hook
2342 @defvarx java-mode-hook
2343 @defvarx idl-mode-hook
2344 @defvarx pike-mode-hook
2345 @defvarx awk-mode-hook
2346 The language specific mode hooks. The appropriate one is run as the
2347 last thing when you enter that language mode.
2348 @end defvar
2349
2350 Although these hooks are variables defined in @ccmode{}, you can give
2351 them values before @ccmode{}'s code is loaded - indeed, this is the
2352 only way to use @code{c-initialization-hook}. Their values aren't
2353 overwritten when @ccmode{} gets loaded.
2354
2355 Here's a simplified example of what you can add to your @file{.emacs}
2356 file to do things whenever any @ccmode{} language is edited. See the
2357 Emacs manuals for more information on customizing Emacs via hooks.
2358 @xref{Sample .emacs File}, for a more complete sample @file{.emacs}
2359 file.
2360
2361 @example
2362 (defun my-c-mode-common-hook ()
2363 ;; my customizations for all of c-mode and related modes
2364 (no-case-fold-search)
2365 )
2366 (add-hook 'c-mode-common-hook 'my-c-mode-common-hook)
2367 @end example
2368
2369 @comment !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
2370 @node Style Variables, Styles, CC Hooks, Config Basics
2371 @comment node-name, next, previous, up
2372 @section Style Variables
2373 @cindex styles
2374 @comment !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
2375
2376 @cindex style variables
2377 The variables that @ccmode{}'s style system control are called
2378 @dfn{style variables}. Note that style variables are ordinary Lisp
2379 variables, which the style system initializes; you can change their
2380 values at any time (e.g. in a hook function). The style system can
2381 also also set other variables, to some extent. @xref{Styles}.
2382
2383 @dfn{Style variables} are handled specially in several ways:
2384
2385 @itemize @bullet
2386 @item
2387 Style variables are by default buffer-local variables. However, they
2388 can instead be made global by setting
2389 @code{c-style-variables-are-local-p} to @code{nil} before @ccmode{} is
2390 initialized.
2391
2392 @item
2393 @vindex c-old-style-variable-behavior
2394 @vindex old-style-variable-behavior (c-)
2395 The default global binding of any style variable (with two exceptions
2396 - see below) is the special symbol @code{set-from-style}. When the
2397 style system initializes a buffer-local copy of a style variable for a
2398 @ccmode{} buffer, if its global binding is still that symbol then it
2399 will be set from the current style. Otherwise it will retain its
2400 global default@footnote{This is a big change from versions of
2401 @ccmode{} earlier than 5.26, where such settings would get overridden
2402 by the style system unless special precautions were taken. That was
2403 changed since it was counterintuitive and confusing, especially to
2404 novice users. If your configuration depends on the old overriding
2405 behavior, you can set the variable
2406 @code{c-old-style-variable-behavior} to non-@code{nil}.}. This
2407 ``otherwise'' happens, for example, when you've set the variable with
2408 @code{setq} at the top level of your @file{.emacs} (@pxref{Config
2409 Basics}).
2410
2411 @item
2412 The style variable @code{c-offsets-alist} (@pxref{c-offsets-alist}) is
2413 an association list with an element for each syntactic symbol. It's
2414 handled a little differently from the other style variables. It's
2415 default global binding is the empty list @code{nil}, rather than
2416 @code{set-from-style}. Before the style system is initialized, you
2417 can add individual elements to @code{c-offsets-alist} by calling
2418 @code{c-set-offset}(@pxref{c-offsets-alist}) just like you would set
2419 other style variables with @code{setq}. Those elements will then
2420 prevail when the style system later initializes a buffer-local copy of
2421 @code{c-offsets-alist}.
2422
2423 @item
2424 The style variable @code{c-special-indent-hook} is also handled in a
2425 special way. Styles can only add functions to this hook, not remove
2426 them, so any global settings you put on it are always
2427 preserved@footnote{This did not change in version 5.26.}. The value
2428 you give this variable in a style definition can be either a function
2429 or a list of functions.
2430
2431 @item
2432 The global bindings of the style variables get captured in the special
2433 @code{user} style when the style system is first initialized.
2434 @xref{Built-in Styles}, for details.
2435 @end itemize
2436
2437 The style variables are:@*
2438 @code{c-indent-comment-alist},
2439 @code{c-indent-comments-syntactically-p} (@pxref{Indentation
2440 Commands});@*
2441 @code{c-doc-comment-style} (@pxref{Doc Comments});@*
2442 @code{c-block-comment-prefix}, @code{c-comment-prefix-regexp}
2443 (@pxref{Custom Filling and Breaking});@*
2444 @code{c-hanging-braces-alist} (@pxref{Hanging Braces});@*
2445 @code{c-hanging-colons-alist} (@pxref{Hanging Colons});@*
2446 @code{c-hanging-semi&comma-criteria} (@pxref{Hanging Semicolons and
2447 Commas});@*
2448 @code{c-cleanup-list} (@pxref{Clean-ups});@*
2449 @code{c-basic-offset} (@pxref{Customizing Indentation});@*
2450 @code{c-offsets-alist} (@pxref{c-offsets-alist});@*
2451 @code{c-comment-only-line-offset} (@pxref{Comment Line-Up});@*
2452 @code{c-special-indent-hook}, @code{c-label-minimum-indentation}
2453 (@pxref{Other Indentation});@*
2454 @code{c-backslash-column}, @code{c-backslash-max-column}
2455 (@pxref{Custom Macros}).
2456
2457 @comment !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
2458 @node Styles, , Style Variables, Config Basics
2459 @comment node-name, next, previous, up
2460 @section Styles
2461 @cindex styles
2462 @comment !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
2463
2464 Most people only need to edit code formatted in just a few well-defined
2465 and consistent styles. For example, their organization might impose a
2466 ``blessed'' style that all its programmers must conform to. Similarly,
2467 people who work on GNU software will have to use the GNU coding style.
2468 Some shops are more lenient, allowing a variety of coding styles, and as
2469 programmers come and go, there could be a number of styles in use. For
2470 this reason, @ccmode{} makes it convenient for you to set up logical
2471 groupings of customizations called @dfn{styles}, associate a single name
2472 for any particular style, and pretty easily start editing new or
2473 existing code using these styles.
2474
2475 @menu
2476 * Built-in Styles::
2477 * Choosing a Style::
2478 * Adding Styles::
2479 * File Styles::
2480 @end menu
2481
2482
2483 @comment !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
2484 @node Built-in Styles, Choosing a Style, Styles, Styles
2485 @comment node-name, next, previous, up
2486 @subsection Built-in Styles
2487 @cindex styles, built-in
2488 @comment !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
2489
2490 If you're lucky, one of @ccmode{}'s built-in styles might be just
2491 what you're looking for. These are:
2492
2493 @table @code
2494 @item gnu
2495 @cindex GNU style
2496 Coding style blessed by the Free Software Foundation
2497 for C code in GNU programs.
2498
2499 @item k&r
2500 @cindex K&R style
2501 The classic Kernighan and Ritchie style for C code.
2502
2503 @item bsd
2504 @cindex BSD style
2505 Also known as ``Allman style'' after Eric Allman.
2506
2507 @item whitesmith
2508 @cindex Whitesmith style
2509 Popularized by the examples that came with Whitesmiths C, an early
2510 commercial C compiler.
2511
2512 @item stroustrup
2513 @cindex Stroustrup style
2514 The classic Stroustrup style for C++ code.
2515
2516 @item ellemtel
2517 @cindex Ellemtel style
2518 Popular C++ coding standards as defined by ``Programming in C++, Rules
2519 and Recommendations,'' Erik Nyquist and Mats Henricson,
2520 Ellemtel@footnote{This document is available at
2521 @uref{http://www.doc.ic.ac.uk/lab/cplus/c++.rules/} among other
2522 places.}.
2523 @c N.B. This URL was still valid at 2005/8/28 (ACM).
2524
2525 @item linux
2526 @cindex Linux style
2527 C coding standard for Linux (the kernel).
2528
2529 @item python
2530 @cindex Python style
2531 C coding standard for Python extension modules@footnote{Python is a
2532 high level scripting language with a C/C++ foreign function interface.
2533 For more information, see @uref{http://www.python.org/}.}.
2534
2535 @item java
2536 @cindex Java style
2537 The style for editing Java code. Note that the default
2538 value for @code{c-default-style} installs this style when you enter
2539 @code{java-mode}.
2540
2541 @item awk
2542 @cindex AWK style
2543 The style for editing AWK code. Note that the default value for
2544 @code{c-default-style} installs this style when you enter
2545 @code{awk-mode}.
2546
2547 @item user
2548 @cindex User style
2549 This is a special style created by you. It consists of the factory
2550 defaults for all the style variables as modified by the customizations
2551 you do either with the Customization interface or by writing
2552 @code{setq}s and @code{c-set-offset}s at the top level of your
2553 @file{.emacs} file (@pxref{Config Basics}). The style system creates
2554 this style as part of its initialization and doesn't modify it
2555 afterwards.
2556 @end table
2557
2558
2559 @comment !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
2560 @node Choosing a Style, Adding Styles, Built-in Styles, Styles
2561 @comment node-name, next, previous, up
2562 @subsection Choosing a Style
2563 @comment !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
2564
2565 Use @kbd{C-c .} to choose a style interactively:
2566
2567 @deffn Command c-set-style style-name
2568 @findex set-style (c-)
2569 @kindex C-c .
2570 Switch to the specified style in the current buffer. Use
2571 interactively like this:
2572
2573 @example
2574 @kbd{C-c . @var{style-name} @key{RET}}
2575 @end example
2576
2577 You can use the @key{TAB} in the normal way to do completion on the
2578 style name. Note that all style names are case insensitive, even the
2579 ones you define yourself.
2580
2581 Setting a style in this way does @emph{not} automatically reindent your
2582 file. For commands that you can use to view the effect of your changes,
2583 see @ref{Indentation Commands} and @ref{Filling and Breaking}.
2584 @end deffn
2585
2586 The default style in all newly created buffers is @code{gnu}, except
2587 in Java and AWK modes where it's @code{java} and @code{awk}.
2588
2589 Remember that if you set a style variable with the Customization
2590 interface or at the top level of your @file{.emacs} file before the
2591 style system is initialised (@pxref{Config Basics}), this setting will
2592 override the one that the style system would have given the variable.
2593
2594 @defopt c-default-style
2595 @vindex default-style (c-)
2596 This variable specifies which style to install by default in new
2597 buffers. It takes either a style name string, or an association list
2598 of major mode symbols to style names:
2599
2600 @enumerate
2601 @item
2602 When @code{c-default-style} is a string, it must be an existing style
2603 name. This style is then used for all modes.
2604
2605 @item
2606 When @code{c-default-style} is an association list, the mode language
2607 is looked up to find a style name string.
2608
2609 @item
2610 If @code{c-default-style} is an association list where the mode
2611 language mode isn't found then the special symbol @samp{other} is
2612 looked up. If it's found then the associated style is used.
2613
2614 @item
2615 If @samp{other} is not found then the @samp{gnu} style is used.
2616 @end enumerate
2617
2618 In all cases, the style described in @code{c-default-style} is installed
2619 @emph{before} the language hooks are run, so you can always override
2620 this setting by including an explicit call to @code{c-set-style} in your
2621 language mode hook, or in @code{c-mode-common-hook}.
2622
2623 The standard value of @code{c-default-style} is @w{@code{((java-mode
2624 . "java") (awk-mode . "awk") (other . "gnu"))}}.
2625 @end defopt
2626
2627 @defvar c-indentation-style
2628 @vindex indentation-style (c-)
2629 This variable always contains the buffer's current style name, as a
2630 string.
2631 @end defvar
2632
2633
2634 @comment !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
2635 @node Adding Styles, File Styles, Choosing a Style, Styles
2636 @comment node-name, next, previous, up
2637 @subsection Adding and Amending Styles
2638 @comment !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
2639
2640 If none of the built-in styles is appropriate, you'll probably want to
2641 create a new @dfn{style definition}, possibly based on an existing
2642 style. To do this, put the new style's settings into a list with the
2643 following format - the list can then be passed as an argument to the
2644 function @code{c-add-style}. You can see an example of a style
2645 definition in @ref{Sample .emacs File}.
2646
2647 @cindex style definition
2648 @c @defvr {List} style definition
2649 @table @asis
2650 @item Structure of a Style Definition List
2651 ([@var{base-style}] [(@var{variable} . @var{value}) @dots{}])
2652
2653 Optional @var{base-style}, if present, must be a string which is the
2654 name of the @dfn{base style} from which this style inherits. At most
2655 one @var{base-style} is allowed in a style definition. If
2656 @var{base-style} is not specified, the style inherits from the table
2657 of factory default values@footnote{This table is stored internally in
2658 the variable c-fallback-style.} instead. All styles eventually
2659 inherit from this internal table. Style loops generate errors. The
2660 list of pre-existing styles can be seen in @ref{Built-in Styles}.
2661
2662 The dotted pairs (@var{variable} . @var{value}) each consist of a
2663 variable and the value it is to be set to when the style is later
2664 activated.@footnote{Note that if the variable has been given a value
2665 by the Customization interface or a @code{setq} at the top level of
2666 your @file{.emacs}, this value will override the one the style system
2667 tries to give it. @xref{Config Basics}.} The variable can be either a
2668 @ccmode{} style variable or an arbitrary Emacs variable. In the
2669 latter case, it is @emph{not} made buffer-local by the @ccmode{} style
2670 system.
2671 @c @end defvr
2672
2673 Two variables are treated specially in the dotted pair list:
2674
2675 @table @code
2676 @item c-offsets-alist
2677 The value is in turn a list of dotted pairs of the form
2678
2679 @example
2680 (@r{@var{syntactic-symbol}} . @r{@var{offset}})
2681 @end example
2682
2683 as described in @ref{c-offsets-alist}. These are passed to
2684 @code{c-set-offset} so there is no need to set every syntactic symbol
2685 in your style, only those that are different from the inherited style.
2686
2687 @item c-special-indent-hook
2688 The value is added to @code{c-special-indent-hook} using
2689 @code{add-hook}, so any functions already on it are kept. If the value
2690 is a list, each element of the list is added with @code{add-hook}.
2691 @end table
2692 @end table
2693
2694 Styles are kept in the @code{c-style-alist} variable, but you
2695 should never modify this variable directly. Instead, @ccmode{}
2696 provides the function @code{c-add-style} for this purpose.
2697
2698 @defun c-add-style stylename description &optional set-p
2699 @findex add-style (c-)
2700 Add or update a style called @var{stylename}, a string.
2701 @var{description} is the new style definition in the form described
2702 above. If @var{stylename} already exists in @code{c-style-alist} then
2703 it is replaced by @var{description}. (Note, this replacement is
2704 total. The old style is @emph{not} merged into the new one.)
2705 Otherwise, a new style is added.
2706
2707 If the optional @var{set-p} is non-@code{nil} then the new style is
2708 applied to the current buffer as well. The use of this facility is
2709 deprecated and it might be removed from @ccmode{} in a future release.
2710 You should use @code{c-set-style} instead.
2711
2712 The sample @file{.emacs} file provides a concrete example of how a new
2713 style can be added and automatically set. @xref{Sample .emacs File}.
2714 @end defun
2715
2716 @defvar c-style-alist
2717 @vindex style-alist (c-)
2718 This is the variable that holds the definitions for the styles. It
2719 should not be changed directly; use @code{c-add-style} instead.
2720 @end defvar
2721
2722
2723 @comment !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
2724 @node File Styles, , Adding Styles, Styles
2725 @comment node-name, next, previous, up
2726 @subsection File Styles
2727 @cindex styles, file local
2728 @comment !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
2729
2730 @cindex file local variables
2731
2732 The Emacs manual describes how you can customize certain variables on a
2733 per-file basis by including a @dfn{file local variable} block at the end
2734 of the file (@pxref{File Variables,, Local Variables in Files, @emacsman{},
2735 @emacsmantitle{}}).
2736
2737 So far, you've only seen a functional interface for setting styles in
2738 @ccmode{}, and this can't be used here. @ccmode{} fills the gap by
2739 providing two variables for use in a file's local variable list.
2740 Don't use them anywhere else! These allow you to customize the style
2741 on a per-file basis:
2742
2743 @defvar c-file-style
2744 @vindex file-style (c-)
2745 Set this variable to a style name string in the Local Variables list.
2746 From now on, when you visit the file, @ccmode{} will automatically set
2747 the file's style to this one using @code{c-set-style}.
2748 @end defvar
2749
2750 @defvar c-file-offsets
2751 @vindex file-offsets (c-)
2752 Set this variable (in the Local Variables list) to an association list
2753 of the same format as @code{c-offsets-alist}. From now on, when you
2754 visit the file, @ccmode{} will automatically institute these offsets
2755 using @code{c-set-offset}.
2756 @end defvar
2757
2758 Note that file style settings (i.e. @code{c-file-style}) are applied
2759 before file offset settings
2760 (i.e. @code{c-file-offsets})@footnote{Also, if either of these are set
2761 in a file's local variable section, all the style variable values are
2762 made local to that buffer, even if
2763 @code{c-style-variables-are-local-p} is @code{nil}. Since this
2764 variable is virtually always non-@code{nil} anyhow, you're unlikely to
2765 notice this effect.}.
2766
2767 If you set any variables, including style variables, by the file local
2768 variables mechanism, these settings take priority over all other
2769 settings, even those in your mode hooks (@pxref{CC Hooks}). If you
2770 use @code{c-file-style} or @code{c-file-offsets} and also explicitly
2771 set a style variable in a local variable block, the explicit setting
2772 will take priority.
2773
2774 @comment !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
2775 @node Custom Filling and Breaking, Custom Auto-newlines, Config Basics, Top
2776 @comment node-name, next, previous, up
2777 @chapter Customizing Filling and Line Breaking
2778 @comment !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
2779
2780 Since there's a lot of normal text in comments and string literals,
2781 @ccmode{} provides features to edit these like in text mode. It does
2782 this by hooking in on the different line breaking functions and tuning
2783 relevant variables as necessary.
2784
2785 @vindex c-comment-prefix-regexp
2786 @vindex comment-prefix-regexp (c-)
2787 @cindex comment line prefix
2788 @vindex comment-start
2789 @vindex comment-end
2790 @vindex comment-start-skip
2791 @vindex paragraph-start
2792 @vindex paragraph-separate
2793 @vindex paragraph-ignore-fill-prefix
2794 @vindex adaptive-fill-mode
2795 @vindex adaptive-fill-regexp
2796 @vindex adaptive-fill-first-line-regexp
2797 To make Emacs recognize comments and treat text in them as normal
2798 paragraphs, @ccmode{} makes several standard
2799 variables@footnote{@code{comment-start}, @code{comment-end},
2800 @code{comment-start-skip}, @code{paragraph-start},
2801 @code{paragraph-separate}, @code{paragraph-ignore-fill-prefix},
2802 @code{adaptive-fill-mode}, @code{adaptive-fill-regexp}, and
2803 @code{adaptive-fill-first-line-regexp}.} buffer-local and modifies them
2804 according to the language syntax and the comment line prefix.
2805
2806 @defopt c-comment-prefix-regexp
2807 @vindex comment-prefix-regexp (c-)
2808 This style variable contains the regexp used to recognize the
2809 @dfn{comment line prefix}, which is the line decoration that starts
2810 every line in a comment. The variable is either the comment line
2811 prefix itself, or (more usually) an association list with different
2812 values for different languages. The symbol for the major mode is
2813 looked up in the alist to get the regexp for the language, and if it
2814 isn't found then the special symbol @samp{other} is looked up instead.
2815
2816 When a comment line gets divided by @kbd{M-j} or the like, @ccmode{}
2817 inserts the comment line prefix from a neighbouring line at the start
2818 of the new line. The default value of c-comment-prefix-regexp is
2819 @samp{//+\\|\\**}, which matches C++ style line comments like
2820
2821 @example
2822 // blah blah
2823 @end example
2824
2825 @noindent
2826 with two or more slashes in front of them, and the second and
2827 subsequent lines of C style block comments like
2828
2829 @example
2830 @group
2831 /*
2832 * blah blah
2833 */
2834 @end group
2835 @end example
2836
2837 @noindent
2838 with zero or more stars at the beginning of every line. If you change
2839 this variable, please make sure it still matches the comment starter
2840 (i.e. @code{//}) of line comments @emph{and} the line prefix inside
2841 block comments.
2842
2843 @findex c-setup-paragraph-variables
2844 @findex setup-paragraph-variables (c-)
2845 Also note that since @ccmode{} uses the value of
2846 @code{c-comment-prefix-regexp} to set up several other variables at
2847 mode initialization, there won't be any effect if you just change it
2848 inside a @ccmode{} buffer. You need to call the command
2849 @code{c-setup-paragraph-variables} too, to update those other
2850 variables. That's also the case if you modify
2851 @code{c-comment-prefix-regexp} in a mode hook, since @ccmode{} will
2852 already have set up these variables before calling the hook.
2853 @end defopt
2854
2855 In comments, @ccmode{} uses @code{c-comment-prefix-regexp} to adapt
2856 the line prefix from the other lines in the comment.
2857
2858 @vindex adaptive-fill-mode
2859 @cindex Adaptive Fill mode
2860 @ccmode{} uses adaptive fill mode (@pxref{Adaptive Fill,,, emacs, GNU
2861 Emacs Manual}) to make Emacs correctly keep the line prefix when
2862 filling paragraphs. That also makes Emacs preserve the text
2863 indentation @emph{inside} the comment line prefix. E.g. in the
2864 following comment, both paragraphs will be filled with the left
2865 margins of the texts kept intact:
2866
2867 @example
2868 @group
2869 /* Make a balanced b-tree of the nodes in the incoming
2870 * stream. But, to quote the famous words of Donald E.
2871 * Knuth,
2872 *
2873 * Beware of bugs in the above code; I have only
2874 * proved it correct, not tried it.
2875 */
2876 @end group
2877 @end example
2878
2879 @findex c-setup-filladapt
2880 @findex setup-filladapt (c-)
2881 @findex filladapt-mode
2882 @vindex filladapt-mode
2883 @cindex Filladapt mode
2884 It's also possible to use other adaptive filling packages, notably Kyle
2885 E. Jones' Filladapt package@footnote{It's available from
2886 @uref{http://www.wonderworks.com/}. As of version 2.12, it does however
2887 lack a feature that makes it work suboptimally when
2888 @code{c-comment-prefix-regexp} matches the empty string (which it does
2889 by default). A patch for that is available from
2890 @uref{http://cc-mode.sourceforge.net/,, the CC Mode web site}.},
2891 @c 2005/11/22: The above is still believed to be the case.
2892 which handles things like bulleted lists nicely. There's a convenience
2893 function @code{c-setup-filladapt} that tunes the relevant variables in
2894 Filladapt for use in @ccmode{}. Call it from a mode hook, e.g. with
2895 something like this in your @file{.emacs}:
2896
2897 @example
2898 (defun my-c-mode-common-hook ()
2899 (c-setup-filladapt)
2900 (filladapt-mode 1))
2901 (add-hook 'c-mode-common-hook 'my-c-mode-common-hook)
2902 @end example
2903
2904 @defopt c-block-comment-prefix
2905 @vindex block-comment-prefix (c-)
2906 @vindex c-comment-continuation-stars
2907 @vindex comment-continuation-stars (c-)
2908 Normally the comment line prefix inserted for a new line inside a
2909 comment is deduced from other lines in it. However there's one
2910 situation when there's no hint about what the prefix should look like,
2911 namely when a block comment is broken for the first time. This style
2912 variable@footnote{In versions before 5.26, this variable was called
2913 @code{c-comment-continuation-stars}. As a compatibility measure,
2914 @ccmode{} still uses the value on that variable if it's set.} is used
2915 then as the comment prefix. It defaults to @samp{*
2916 }@footnote{Actually, this default setting of
2917 @code{c-block-comment-prefix} typically gets overriden by the default
2918 style @code{gnu}, which sets it to blank. You can see the line
2919 splitting effect described here by setting a different style,
2920 e.g. @code{k&r} @xref{Choosing a Style}.}, which makes a comment
2921
2922 @example
2923 /* Got O(n^2) here, which is a Bad Thing. */
2924 @end example
2925
2926 @noindent
2927 break into
2928
2929 @example
2930 @group
2931 /* Got O(n^2) here, which
2932 * is a Bad Thing. */
2933 @end group
2934 @end example
2935
2936 Note that it won't work to adjust the indentation by putting leading
2937 spaces in @code{c-block-comment-prefix}, since @ccmode{} still uses the
2938 normal indentation engine to indent the line. Thus, the right way to
2939 fix the indentation is by customizing the @code{c} syntactic symbol. It
2940 defaults to @code{c-lineup-C-comments}, which handles the indentation of
2941 most common comment styles, see @ref{Line-Up Functions}.
2942 @end defopt
2943
2944 @defopt c-ignore-auto-fill
2945 @vindex ignore-auto-fill (c-)
2946 When auto fill mode is enabled, @ccmode{} can selectively ignore it
2947 depending on the context the line break would occur in, e.g. to never
2948 break a line automatically inside a string literal. This variable
2949 takes a list of symbols for the different contexts where auto-filling
2950 never should occur:
2951
2952 @table @code
2953 @item string
2954 Inside a string or character literal.
2955 @item c
2956 Inside a C style block comment.
2957 @item c++
2958 Inside a C++ style line comment.
2959 @item cpp
2960 Inside a preprocessor directive.
2961 @item code
2962 Anywhere else, i.e. in normal code.
2963 @end table
2964
2965 By default, @code{c-ignore-auto-fill} is set to @code{(string cpp
2966 code)}, which means that when auto-fill mode is activated,
2967 auto-filling only occurs in comments. In literals, it's often
2968 desirable to have explicit control over newlines. In preprocessor
2969 directives, the necessary @samp{\} escape character before the newline
2970 is not automatically inserted, so an automatic line break would
2971 produce invalid code. In normal code, line breaks are normally
2972 dictated by some logical structure in the code rather than the last
2973 whitespace character, so automatic line breaks there will produce poor
2974 results in the current implementation.
2975 @end defopt
2976
2977 @vindex comment-multi-line
2978 If inside a comment and @code{comment-multi-line} (@pxref{Auto Fill,,,
2979 @emacsman{}, @emacsmantitle{}} is non-@code{nil}, the indentation and
2980 line prefix are preserved. If inside a comment and
2981 @code{comment-multi-line} is @code{nil}, a new comment of the same
2982 type is started on the next line and indented as appropriate for
2983 comments.
2984
2985 Note that @ccmode{} sets @code{comment-multi-line} to @code{t} at
2986 startup. The reason is that @kbd{M-j} could otherwise produce sequences
2987 of single line block comments for texts that should logically be treated
2988 as one comment, and the rest of the paragraph handling code
2989 (e.g. @kbd{M-q} and @kbd{M-a}) can't cope with that, which would lead to
2990 inconsistent behavior.
2991
2992 @comment !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
2993 @node Custom Auto-newlines, Clean-ups, Custom Filling and Breaking, Top
2994 @comment node-name, next, previous, up
2995 @chapter Customizing Auto-newlines
2996 @comment !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
2997
2998 @ccmode{} determines whether to insert auto-newlines in two basically
2999 different ways, depending on the character just typed:
3000
3001 @table @asis
3002 @item Braces and Colons
3003 @ccmode{} first determines the syntactic context of the brace or colon
3004 (@pxref{Syntactic Symbols}), then looks for a corresponding element in
3005 an alist. This element specifies where to put newlines - this is any
3006 combination of before and after the brace or colon. If no alist
3007 element is found, newlines are inserted both before and after a brace,
3008 but none are inserted around a colon. See @ref{Hanging Braces} and
3009 @ref{Hanging Colons}.
3010
3011 @item Semicolons and Commas
3012 The variable @code{c-hanging-semi&comma-criteria} contains a list of
3013 functions which determine whether to insert a newline after a newly
3014 typed semicolon or comma. @xref{Hanging Semicolons and Commas}.
3015 @end table
3016
3017 The names of these configuration variables contain @samp{hanging}
3018 because they let you @dfn{hang} the pertinent characters. A character
3019 which introduces a C construct is said to @dfn{hang on the right} when
3020 it appears at the end of a line after other code, being separated by a
3021 line break from the construct it introduces, like the opening brace in:
3022
3023 @example
3024 @group
3025 while (i < MAX) @{
3026 total += entry[i];
3027 entry [i++] = 0;
3028 @}
3029 @end group
3030 @end example
3031
3032 @noindent
3033 A character @dfn{hangs on the left} when it appears at the start of
3034 the line after the construct it closes off, like the above closing
3035 brace.
3036
3037 The next chapter, ``Clean-ups'', describes how to configure @ccmode{}
3038 to remove these automatically added newlines in certain specific
3039 circumstances. @xref{Clean-ups}.
3040
3041 @menu
3042 * Hanging Braces::
3043 * Hanging Colons::
3044 * Hanging Semicolons and Commas::
3045 @end menu
3046
3047
3048 @comment !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
3049 @node Hanging Braces, Hanging Colons, Custom Auto-newlines, Custom Auto-newlines
3050 @comment node-name, next, previous, up
3051 @section Hanging Braces
3052 @cindex hanging braces
3053 @comment !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
3054
3055 To specify which kinds of braces you want auto-newlines put around,
3056 you set the style variable @code{c-hanging-braces-alist}. Its
3057 structure and semantics are described in this section. Details of how
3058 to set it up, and its relationship to CC Mode's style system are given
3059 in @ref{Style Variables}.
3060
3061 Say you wanted an auto-newline after (but not before) the following
3062 @samp{@{}:
3063
3064 @example
3065 if (foo < 17) @{
3066 @end example
3067
3068 @noindent
3069 First you need to find the @dfn{syntactic context} of the brace---type
3070 a @key{RET} before the brace to get it on a line of its
3071 own@footnote{Also insert a @samp{\} at the end of the previous line if
3072 you're in AWK Mode.}, then type @kbd{C-c C-s}. That will tell you
3073 something like:
3074
3075 @example
3076 ((substatement-open 1061))
3077 @end example
3078
3079 @noindent
3080 So here you need to put the entry @code{(substatement-open . (after))}
3081 into @code{c-hanging-braces-alist}.
3082
3083 If you don't want any auto-newlines for a particular syntactic symbol,
3084 put this into @code{c-hanging-braces-alist}:
3085
3086 @example
3087 (brace-entry-open)
3088 @end example
3089
3090 If some brace syntactic symbol is not in @code{c-hanging-brace-alist},
3091 its entry is taken by default as @code{(before after)}---insert a
3092 newline both before and after the brace. In place of a
3093 ``before/after'' list you can specify a function in this alist---this
3094 is useful when the auto newlines depend on the code around the brace.
3095
3096 @defopt c-hanging-braces-alist
3097 @vindex hanging-braces-alist (c-)
3098
3099 This variable is an association list which maps syntactic symbols to
3100 lists of places to insert a newline. @xref{Association
3101 Lists,,,@lispref{}, @lispreftitle{}}. The key of each element is the
3102 syntactic symbol, the associated value is either @code{nil}, a list,
3103 or a function.
3104
3105 @table @asis
3106 @item The Key - the syntactic symbol
3107 The syntactic symbols that are useful as keys in this list are
3108 @code{brace-list-intro}, @code{statement-cont},
3109 @code{inexpr-class-open}, @code{inexpr-class-close}, and all the
3110 @code{*-open} and @code{*-close} symbols. @xref{Syntactic Symbols},
3111 for a more detailed description of these syntactic symbols, except for
3112 @code{inexpr-class-open} and @code{inexpr-class-close}, which aren't
3113 actual syntactic symbols. Elements with any other value as a key get
3114 ignored.
3115
3116 The braces of anonymous inner classes in Java are given the special
3117 symbols @code{inexpr-class-open} and @code{inexpr-class-close}, so that
3118 they can be distinguished from the braces of normal classes@footnote{The
3119 braces of anonymous classes produce a combination of
3120 @code{inexpr-class}, and @code{class-open} or @code{class-close} in
3121 normal indentation analysis.}.
3122
3123 Note that the aggregate constructs in Pike mode, @samp{(@{}, @samp{@})},
3124 @samp{([}, @samp{])}, and @samp{(<}, @samp{>)}, do not count as brace
3125 lists in this regard, even though they do for normal indentation
3126 purposes. It's currently not possible to set automatic newlines on
3127 these constructs.
3128
3129 @item The associated value - the ``ACTION'' list or function
3130 The value associated with each syntactic symbol in this association
3131 list is called an @var{action}, which can be either a list or a
3132 function which returns a list. @xref{Custom Braces}, for how to use
3133 a function as a brace hanging @var{action}.
3134
3135 The list @var{action} (or the list returned by @var{action} when it's
3136 a function) contains some combination of the symbols @code{before} and
3137 @code{after}, directing @ccmode{} where to put newlines in
3138 relationship to the brace being inserted. Thus, if the list contains
3139 only the symbol @code{after}, then the brace hangs on the right side
3140 of the line, as in:
3141
3142 @example
3143 // here, open braces always `hang'
3144 void spam( int i ) @{
3145 if( i == 7 ) @{
3146 dosomething(i);
3147 @}
3148 @}
3149 @end example
3150
3151 When the list contains both @code{after} and @code{before}, the braces
3152 will appear on a line by themselves, as shown by the close braces in
3153 the above example. The list can also be empty, in which case newlines
3154 are added neither before nor after the brace.
3155 @end table
3156
3157 If a syntactic symbol is missing entirely from
3158 @code{c-hanging-braces-alist}, it's treated in the same way as an
3159 @var{action} with a list containing @code{before} and @code{after}, so
3160 that braces by default end up on their own line.
3161
3162 For example, the default value of @code{c-hanging-braces-alist} is:
3163
3164 @example
3165 ((brace-list-open)
3166 (brace-entry-open)
3167 (statement-cont)
3168 (substatement-open after)
3169 (block-close . c-snug-do-while)
3170 (extern-lang-open after)
3171 (namespace-open after)
3172 (module-open after)
3173 (composition-open after)
3174 (inexpr-class-open after)
3175 (inexpr-class-close before))
3176 @end example
3177
3178 @noindent which says that @code{brace-list-open},
3179 @code{brace-entry-open} and @code{statement-cont}@footnote{Brace lists
3180 inside statements, such as initializers for static array variables
3181 inside functions in C, are recognized as @code{statement-cont}. All
3182 normal substatement blocks are recognized with other symbols.} braces
3183 should both hang on the right side and allow subsequent text to follow
3184 on the same line as the brace. Also, @code{substatement-open},
3185 @code{extern-lang-open}, and @code{inexpr-class-open} braces should hang
3186 on the right side, but subsequent text should follow on the next line.
3187 The opposite holds for @code{inexpr-class-close} braces; they won't
3188 hang, but the following text continues on the same line. Here, in the
3189 @code{block-close} entry, you also see an example of using a function as
3190 an @var{action}. In all other cases, braces are put on a line by
3191 themselves.
3192 @end defopt
3193
3194 @menu
3195 * Custom Braces::
3196 @end menu
3197
3198 @comment !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
3199 @node Custom Braces, , Hanging Braces, Hanging Braces
3200 @comment node-name, next, previous, up
3201 @subsection Custom Brace Hanging
3202 @comment !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
3203
3204 @vindex c-hanging-braces-alist
3205 @vindex hanging-braces-alist (c-)
3206 @cindex action functions
3207 Syntactic symbols aren't the only place where you can customize
3208 @ccmode{} with the lisp equivalent of callback functions. Remember
3209 that @var{action}s are usually a list containing some combination of
3210 the symbols @code{before} and @code{after} (@pxref{Hanging Braces}).
3211 For more flexibility, you can instead specify brace ``hanginess'' by
3212 giving a synctactic symbol an @dfn{action function} in
3213 @code{c-hanging-braces-alist}; this function determines the
3214 ``hanginess'' of a brace, usually by looking at the code near it.
3215
3216 @cindex customization, brace hanging
3217 An action function is called with two arguments: the syntactic symbol
3218 for the brace (e.g. @code{substatement-open}), and the buffer position
3219 where the brace has been inserted. Point is undefined on entry to an
3220 action function, but the function must preserve it (e.g. by using
3221 @code{save-excursion}). The return value should be a list containing
3222 some combination of @code{before} and @code{after}, including neither
3223 of them (i.e. @code{nil}).
3224
3225 @defvar c-syntactic-context
3226 @vindex syntactic-context (c-)
3227 During the call to the indentation or brace hanging @var{action}
3228 function, this variable is bound to the full syntactic analysis list.
3229 This might be, for example, @samp{((block-close 73))}. Don't ever
3230 give @code{c-syntactic-context} a value yourself---this would disrupt
3231 the proper functioning of @ccmode{}.
3232
3233 This variable is also bound in three other circumstances:
3234 (i)@tie{}when calling a c-hanging-semi&comma-criteria function
3235 (@pxref{Hanging Semicolons and Commas}; (ii)@tie{}when calling a
3236 line-up function (@pxref{Custom Line-Up}; (iii)@tie{}when calling a
3237 c-special-indent-hook function (@pxref{Other Indentation}).
3238 @end defvar
3239
3240 As an example, @ccmode{} itself uses this feature to dynamically
3241 determine the hanginess of braces which close ``do-while''
3242 constructs:
3243
3244 @example
3245 void do_list( int count, char** atleast_one_string )
3246 @{
3247 int i=0;
3248 do @{
3249 handle_string( atleast_one_string[i] );
3250 i++;
3251 @} while( i < count );
3252 @}
3253 @end example
3254
3255 @ccmode{} assigns the @code{block-close} syntactic symbol to the
3256 brace that closes the @code{do} construct, and normally we'd like the
3257 line that follows a @code{block-close} brace to begin on a separate
3258 line. However, with ``do-while'' constructs, we want the
3259 @code{while} clause to follow the closing brace. To do this, we
3260 associate the @code{block-close} symbol with the @var{action} function
3261 @code{c-snug-do-while}:
3262
3263 @example
3264 (defun c-snug-do-while (syntax pos)
3265 "Dynamically calculate brace hanginess for do-while statements."
3266 (save-excursion
3267 (let (langelem)
3268 (if (and (eq syntax 'block-close)
3269 (setq langelem (assq 'block-close c-syntactic-context))
3270 (progn (goto-char (cdr langelem))
3271 (if (= (following-char) ?@{)
3272 (forward-sexp -1))
3273 (looking-at "\\<do\\>[^_]")))
3274 '(before)
3275 '(before after)))))
3276 @end example
3277
3278 @findex c-snug-do-while
3279 @findex snug-do-while (c-)
3280 This function simply looks to see if the brace closes a ``do-while''
3281 clause and if so, returns the list @samp{(before)} indicating
3282 that a newline should be inserted before the brace, but not after it.
3283 In all other cases, it returns the list @samp{(before after)} so
3284 that the brace appears on a line by itself.
3285
3286 @comment !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
3287 @node Hanging Colons, Hanging Semicolons and Commas, Hanging Braces, Custom Auto-newlines
3288 @comment node-name, next, previous, up
3289 @section Hanging Colons
3290 @cindex hanging colons
3291 @comment !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
3292
3293 @cindex customization, colon hanging
3294 @vindex c-hanging-colons-alist
3295 @vindex hanging-colons-alist (c-)
3296
3297 Using a mechanism similar to brace hanging (@pxref{Hanging Braces}),
3298 colons can also be made to hang using the style variable
3299 @code{c-hanging-colons-alist} - When a colon is typed, @ccmode
3300 determines its syntactic context, looks this up in the alist
3301 @code{c-changing-colons-alist} and inserts up to two newlines
3302 accordingly. Here, however, If @ccmode fails to find an entry for a
3303 syntactic symbol in the alist, no newlines are inserted around the
3304 newly typed colon.
3305
3306 @defopt c-hanging-colons-alist
3307 @vindex hanging-colons-alist (c-)
3308
3309 @table @asis
3310 @item The Key - the syntactic symbol
3311 The syntactic symbols appropriate as keys in this association list
3312 are: @code{case-label}, @code{label}, @code{access-label},
3313 @code{member-init-intro}, and @code{inher-intro}. @xref{Syntactic
3314 Symbols}. Elements with any other value as a key get ignored.
3315
3316 @item The associate value - the ``ACTION'' list
3317 The @var{action} here is simply a list containing a combination of the
3318 symbols @code{before} and @code{after}. Unlike in
3319 @code{c-hanging-braces-alist}, functions as @var{actions} are not
3320 supported - there doesn't seem to be any need for them.
3321 @end table
3322 @end defopt
3323
3324 In C++, double-colons are used as a scope operator but because these
3325 colons always appear right next to each other, newlines before and after
3326 them are controlled by a different mechanism, called @dfn{clean-ups} in
3327 @ccmode{}. @xref{Clean-ups}, for details.
3328
3329 @comment !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
3330 @node Hanging Semicolons and Commas, , Hanging Colons, Custom Auto-newlines
3331 @comment node-name, next, previous, up
3332 @section Hanging Semicolons and Commas
3333 @cindex hanging semicolons
3334 @cindex hanging commas
3335 @cindex customization, semicolon newlines
3336 @cindex customization, comma newlines
3337 @comment !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
3338
3339 @defopt c-hanging-semi&comma-criteria
3340 @vindex hanging-semi&comma-criteria (c-)
3341 This style variable takes a list of functions; these get called when
3342 you type a semicolon or comma. The functions are called in order
3343 without arguments. When these functions are entered, point is just
3344 after the newly inserted @samp{;} or @samp{,} and they must preserve
3345 point (e.g., by using @code{save-excursion}). During the call, the
3346 variable @code{c-syntactic-context} is bound to the syntactic context
3347 of the current line@footnote{This was first introduced in @ccmode{}
3348 5.31.} @pxref{Custom Braces}. These functions don't insert newlines
3349 themselves, rather they direct @ccmode{} whether or not to do so.
3350 They should return one of the following values:
3351
3352 @table @code
3353 @item t
3354 A newline is to be inserted after the @samp{;} or @samp{,}, and no
3355 more functions from the list are to be called.
3356 @item stop
3357 No more functions from the list are to be called, and no newline is to
3358 be inserted.
3359 @item nil
3360 No determination has been made, and the next function in the list is
3361 to be called.
3362 @end table
3363
3364 Note that auto-newlines are never inserted @emph{before} a semicolon
3365 or comma. If every function in the list is called without a
3366 determination being made, then no newline is added.
3367
3368 In AWK mode, this variable is set by default to @code{nil}. In the
3369 other modes, the default value is a list containing a single function,
3370 @code{c-semi&comma-inside-parenlist}. This inserts newlines after all
3371 semicolons, apart from those separating @code{for}-clause statements.
3372 @end defopt
3373
3374 @defun c-semi&comma-no-newlines-before-nonblanks
3375 @findex semi&comma-no-newlines-before-nonblanks (c-)
3376 This is an example of a criteria function, provided by @ccmode{}. It
3377 prevents newlines from being inserted after semicolons when there is a
3378 non-blank following line. Otherwise, it makes no determination. To
3379 use, add this function to the front of the
3380 @code{c-hanging-semi&comma-criteria} list.
3381
3382 @example
3383 (defun c-semi&comma-no-newlines-before-nonblanks ()
3384 (save-excursion
3385 (if (and (eq last-command-char ?\;)
3386 (zerop (forward-line 1))
3387 (not (looking-at "^[ \t]*$")))
3388 'stop
3389 nil)))
3390 @end example
3391 @end defun
3392
3393 @defun c-semi&comma-inside-parenlist
3394 @findex semi&comma-inside-parenlist (c-)
3395 @defunx c-semi&comma-no-newlines-for-oneline-inliners
3396 @findex semi&comma-no-newlines-for-oneline-inliners (c-)
3397 The function @code{c-semi&comma-inside-parenlist} is what prevents
3398 newlines from being inserted inside the parenthesis list of @code{for}
3399 statements. In addition to
3400 @code{c-semi&comma-no-newlines-before-nonblanks} described above,
3401 @ccmode{} also comes with the criteria function
3402 @code{c-semi&comma-no-newlines-for-oneline-inliners}, which suppresses
3403 newlines after semicolons inside one-line inline method definitions
3404 (e.g. in C++ or Java).
3405 @end defun
3406
3407
3408 @comment !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
3409 @node Clean-ups, Indentation Engine Basics, Custom Auto-newlines, Top
3410 @comment node-name, next, previous, up
3411 @chapter Clean-ups
3412 @cindex clean-ups
3413 @comment !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
3414
3415 @dfn{Clean-ups} are mechanisms which remove (or exceptionally, add)
3416 whitespace in specific circumstances and are complementary to colon
3417 and brace hanging. You enable a clean-up by adding its symbol into
3418 @code{c-cleanup-list}.
3419
3420 On the surface, it would seem that clean-ups overlap the functionality
3421 provided by the @code{c-hanging-*-alist} variables. Clean-ups,
3422 however, are used to adjust code ``after-the-fact'', i.e. to adjust
3423 the whitespace in constructs later than when they were typed.
3424
3425 Most of the clean-ups remove automatically inserted newlines, and are
3426 only active when auto-newline minor mode is turned on. Others will
3427 work all the time. Note that clean-ups are only performed when there
3428 is nothing but whitespace appearing between the individual components
3429 of the construct, and (apart from @code{comment-close-slash}) when the
3430 construct does not occur within a literal (@pxref{Auto-newlines}).
3431
3432 @defopt c-cleanup-list
3433 @vindex cleanup-list (c-)
3434 @cindex literal
3435
3436 You configure @ccmode{}'s clean-ups by setting the style variable
3437 @code{c-cleanup-list}, which is a list of clean-up symbols. By
3438 default, @ccmode{} cleans up only the @code{scope-operator} construct,
3439 which is necessary for proper C++ support.
3440 @end defopt
3441
3442 These are the clean-ups that are only active when electric and
3443 auto-newline minor modes are enabled:
3444
3445 @c TBD: Would like to use some sort of @deffoo here; @table indents a
3446 @c bit too much in dvi output.
3447 @table @code
3448 @item brace-else-brace
3449 Clean up @samp{@} else @{} constructs by placing the entire construct on
3450 a single line. Clean up occurs when the open brace after the
3451 @samp{else} is typed. So for example, this:
3452
3453 @example
3454 @group
3455 void spam(int i)
3456 @{
3457 if( i==7 ) @{
3458 dosomething();
3459 @}
3460 else
3461 @{
3462 @end group
3463 @end example
3464
3465 @noindent
3466 appears like this after the last open brace is typed:
3467
3468 @example
3469 @group
3470 void spam(int i)
3471 @{
3472 if( i==7 ) @{
3473 dosomething();
3474 @} else @{
3475 @end group
3476 @end example
3477
3478 @item brace-elseif-brace
3479 Similar to the @code{brace-else-brace} clean-up, but this cleans up
3480 @samp{@} else if (...) @{} constructs. For example:
3481
3482 @example
3483 @group
3484 void spam(int i)
3485 @{
3486 if( i==7 ) @{
3487 dosomething();
3488 @}
3489 else if( i==3 )
3490 @{
3491 @end group
3492 @end example
3493
3494 @noindent
3495 appears like this after the last open parenthesis is typed:
3496
3497 @example
3498 @group
3499 void spam(int i)
3500 @{
3501 if( i==7 ) @{
3502 dosomething();
3503 @} else if(
3504 @end group
3505 @end example
3506
3507 @noindent
3508 and like this after the last open brace is typed:
3509
3510 @example
3511 @group
3512 void spam(int i)
3513 @{
3514 if( i==7 ) @{
3515 dosomething();
3516 @} else if( i==3 ) @{
3517 @end group
3518 @end example
3519
3520 @item brace-catch-brace
3521 Analogous to @code{brace-elseif-brace}, but cleans up @samp{@} catch
3522 (...) @{} in C++ and Java mode.
3523
3524 @item empty-defun-braces
3525 Clean up braces following a top-level function or class definition that
3526 contains no body. Clean up occurs when the closing brace is typed.
3527 Thus the following:
3528
3529 @example
3530 @group
3531 class Spam
3532 @{
3533 @}
3534 @end group
3535 @end example
3536
3537 @noindent
3538 is transformed into this when the close brace is typed:
3539
3540 @example
3541 @group
3542 class Spam
3543 @{@}
3544 @end group
3545 @end example
3546
3547 @item defun-close-semi
3548 Clean up the terminating semicolon on top-level function or class
3549 definitions when they follow a close brace. Clean up occurs when the
3550 semicolon is typed. So for example, the following:
3551
3552 @example
3553 @group
3554 class Spam
3555 @{
3556 ...
3557 @}
3558 ;
3559 @end group
3560 @end example
3561
3562 @noindent
3563 is transformed into this when the semicolon is typed:
3564
3565 @example
3566 @group
3567 class Spam
3568 @{
3569 ...
3570 @};
3571 @end group
3572 @end example
3573
3574 @item list-close-comma
3575 Clean up commas following braces in array and aggregate initializers.
3576 Clean up occurs when the comma is typed. The space before the comma
3577 is zapped just like the space before the semicolon in
3578 @code{defun-close-semi}.
3579
3580 @item scope-operator
3581 Clean up double colons which might designate a C++ scope operator split
3582 across multiple lines@footnote{Certain C++ constructs introduce
3583 ambiguous situations, so @code{scope-operator} clean-ups might not
3584 always be correct. This usually only occurs when scoped identifiers
3585 appear in switch label tags.}. Clean up occurs when the second colon is
3586 typed. You will always want @code{scope-operator} in the
3587 @code{c-cleanup-list} when you are editing C++ code.
3588
3589 @item one-liner-defun
3590 Clean up a single line of code enclosed by defun braces by removing
3591 the whitespace before and after the code. The clean-up happens when
3592 the closing brace is typed. If the variable
3593 @code{c-max-one-liner-length} is set, the cleanup is only done if the
3594 resulting line would be no longer than the value of that variable.
3595
3596 For example, consider this AWK code:
3597
3598 @example
3599 @group
3600 BEGIN @{
3601 FS = "\t" # use <TAB> as a field separator
3602 @}
3603 @end group
3604 @end example
3605
3606 @noindent
3607 It gets compacted to the following when the closing brace is typed:
3608
3609 @example
3610 @group
3611 BEGIN @{FS = "\t"@} # use <TAB> as a field separator
3612 @end group
3613 @end example
3614
3615 @defopt c-max-one-liner-length
3616 @vindex max-one-liner-length (c-)
3617 The maximum length of the resulting line for which the clean-up
3618 @code{one-liner-defun} will be triggered. This length is that of the entire
3619 line, including any leading whitespace and any trailing comment. Its
3620 default value is 80. If the value is zero or @code{nil}, no limit
3621 applies.
3622 @end defopt
3623 @end table
3624
3625 The following clean-ups are always active when they occur on
3626 @code{c-cleanup-list}, regardless of whether Electric minor mode or
3627 Auto-newline minor mode are enabled:
3628
3629 @table @code
3630 @item space-before-funcall
3631 Insert a space between the function name and the opening parenthesis
3632 of a function call. This produces function calls in the style
3633 mandated by the GNU coding standards, e.g. @samp{signal@tie{}(SIGINT,
3634 SIG_IGN)} and @samp{abort@tie{}()}. Clean up occurs when the opening
3635 parenthesis is typed. This clean-up should never be active in AWK
3636 Mode, since such a space is syntactically invalid for user defined
3637 functions.
3638
3639 @item compact-empty-funcall
3640 Clean up any space between the function name and the opening parenthesis
3641 of a function call that has no arguments. This is typically used
3642 together with @code{space-before-funcall} if you prefer the GNU function
3643 call style for functions with arguments but think it looks ugly when
3644 it's only an empty parenthesis pair. I.e. you will get @samp{signal
3645 (SIGINT, SIG_IGN)}, but @samp{abort()}. Clean up occurs when the
3646 closing parenthesis is typed.
3647
3648 @item comment-close-slash
3649 When inside a block comment, terminate the comment when you type a
3650 slash at the beginning of a line (i.e. immediately after the comment
3651 prefix). This clean-up removes whitespace preceding the slash and if
3652 needed, inserts a star to complete the token @samp{*/}.
3653 @end table
3654
3655
3656 @comment !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
3657 @node Indentation Engine Basics, Customizing Indentation, Clean-ups, Top
3658 @comment node-name, next, previous, up
3659 @chapter Indentation Engine Basics
3660 @comment !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
3661
3662 This chapter will briefly cover how @ccmode{} indents lines of code.
3663 It is helpful to understand the indentation model being used so that
3664 you will know how to customize @ccmode{} for your personal coding
3665 style. All the details are in @ref{Customizing Indentation}.
3666
3667 @ccmode{} has an indentation engine that provides a flexible and
3668 general mechanism for customizing indentation. When @ccmode{} indents
3669 a line of code, it separates its calculations into two steps:
3670
3671 @enumerate
3672 @item
3673 @cindex syntactic symbol
3674 @cindex anchor position
3675 It analyzes the line to determine its @dfn{syntactic symbol(s)} (the
3676 kind of language construct it's looking at) and its @dfn{anchor
3677 position} (the position earlier in the file that @ccmode{} will indent
3678 the line relative to). The anchor position might be the location of
3679 an opening brace in the previous line, for example. @xref{Syntactic
3680 Analysis}.
3681 @item
3682 @cindex offsets
3683 @cindex indentation offset specifications
3684 It looks up the syntactic symbol(s) in the configuration to get the
3685 corresponding @dfn{offset(s)}. The symbol @code{+}, which means
3686 ``indent this line one more level'' is a typical offset. @ccmode{}
3687 then applies these offset(s) to the anchor position, giving the
3688 indentation for the line. The different sorts of offsets are
3689 described in @ref{c-offsets-alist}.
3690 @end enumerate
3691
3692 In exceptional circumstances, the syntax directed indentation
3693 described here may be a nuisance rather than a help. You can disable
3694 it by setting @code{c-syntactic-indentation} to @code{nil}. (To set
3695 the variable interactively, @ref{Minor Modes}).
3696
3697 @defopt c-syntactic-indentation
3698 @vindex syntactic-indentation (c-)
3699 When this is non-@code{nil} (which it is by default), the indentation
3700 of code is done according to its syntactic structure. When it's
3701 @code{nil}, every line is just indented to the same level as the
3702 previous one, and @kbd{TAB} (@code{c-indent-command}) adjusts the
3703 indentation in steps of @code{c-basic-offset}. The current style
3704 (@pxref{Config Basics}) then has no effect on indentation, nor do any
3705 of the variables associated with indentation, not even
3706 @code{c-special-indent-hook}.
3707 @end defopt
3708
3709 @menu
3710 * Syntactic Analysis::
3711 * Syntactic Symbols::
3712 * Indentation Calculation::
3713 @end menu
3714
3715
3716 @comment !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
3717 @node Syntactic Analysis, Syntactic Symbols, Indentation Engine Basics, Indentation Engine Basics
3718 @comment node-name, next, previous, up
3719 @section Syntactic Analysis
3720 @cindex syntactic analysis
3721 @comment !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
3722
3723 @cindex syntactic element
3724 @cindex syntactic context
3725 The first thing @ccmode{} does when indenting a line of code, is to
3726 analyze the line, determining the @dfn{syntactic context} of the
3727 (first) construct on that line. It's a list of @dfn{syntactic
3728 elements}, where each syntactic element in turn is a list@footnote{In
3729 @ccmode 5.28 and earlier, a syntactic element was a dotted pair; the
3730 cons was the syntactic symbol and the cdr was the anchor position.
3731 For compatibility's sake, the parameter passed to a line-up function
3732 still has this dotted pair form (@pxref{Custom Line-Up}).} Here is a
3733 brief and typical example:
3734
3735 @example
3736 ((defun-block-intro 1959))
3737 @end example
3738
3739 @cindex syntactic symbol
3740 @noindent
3741 The first thing inside each syntactic element is always a
3742 @dfn{syntactic symbol}. It describes the kind of construct that was
3743 recognized, e.g. @code{statement}, @code{substatement},
3744 @code{class-open}, @code{class-close}, etc. @xref{Syntactic Symbols},
3745 for a complete list of currently recognized syntactic symbols and
3746 their semantics. The remaining entries are various data associated
3747 with the recognized construct - there might be zero or more.
3748
3749 @cindex anchor position
3750 Conceptually, a line of code is always indented relative to some
3751 position higher up in the buffer (typically the indentation of the
3752 previous line). That position is the @dfn{anchor position} in the
3753 syntactic element. If there is an entry after the syntactic symbol in
3754 the syntactic element list then it's either nil or that anchor position.
3755
3756 Here is an example. Suppose we had the following code as the only thing
3757 in a C++ buffer @footnote{The line numbers in this and future examples
3758 don't actually appear in the buffer, of course!}:
3759
3760 @example
3761 1: void swap( int& a, int& b )
3762 2: @{
3763 3: int tmp = a;
3764 4: a = b;
3765 5: b = tmp;
3766 6: @}
3767 @end example
3768
3769 @noindent
3770 We can use @kbd{C-c C-s} (@code{c-show-syntactic-information}) to
3771 report what the syntactic analysis is for the current line:
3772
3773 @table @asis
3774 @item @kbd{C-c C-s} (@code{c-show-syntactic-information})
3775 @kindex C-c C-s
3776 @findex c-show-syntactic-information
3777 @findex show-syntactic-information (c-)
3778 This command calculates the syntactic analysis of the current line and
3779 displays it in the minibuffer. The command also highlights the anchor
3780 position(s).
3781 @end table
3782
3783 Running this command on line 4 of this example, we'd see in the echo
3784 area@footnote{With a universal argument (i.e. @kbd{C-u C-c C-s}) the
3785 analysis is inserted into the buffer as a comment on the current
3786 line.}:
3787
3788 @example
3789 ((statement 35))
3790 @end example
3791
3792 @noindent
3793 and the @samp{i} of @code{int} on line 3 would be highlighted. This
3794 tells us that the line is a statement and it is indented relative to
3795 buffer position 35, the highlighted position. If you were to move
3796 point to line 3 and hit @kbd{C-c C-s}, you would see:
3797
3798 @example
3799 ((defun-block-intro 29))
3800 @end example
3801
3802 @noindent
3803 This indicates that the @samp{int} line is the first statement in a top
3804 level function block, and is indented relative to buffer position 29,
3805 which is the brace just after the function header.
3806
3807 Here's another example:
3808
3809 @example
3810 1: int add( int val, int incr, int doit )
3811 2: @{
3812 3: if( doit )
3813 4: @{
3814 5: return( val + incr );
3815 6: @}
3816 7: return( val );
3817 8: @}
3818 @end example
3819
3820 @noindent
3821 Hitting @kbd{C-c C-s} on line 4 gives us:
3822
3823 @example
3824 ((substatement-open 46))
3825 @end example
3826
3827 @cindex substatement
3828 @cindex substatement block
3829 @noindent
3830 which tells us that this is a brace that @emph{opens} a substatement
3831 block. @footnote{A @dfn{substatement} is the line after a
3832 conditional statement, such as @code{if}, @code{else}, @code{while},
3833 @code{do}, @code{switch}, etc. A @dfn{substatement
3834 block} is a brace block following one of these conditional statements.}
3835
3836 @cindex comment-only line
3837 Syntactic contexts can contain more than one element, and syntactic
3838 elements need not have anchor positions. The most common example of
3839 this is a @dfn{comment-only line}:
3840
3841 @example
3842 1: void draw_list( List<Drawables>& drawables )
3843 2: @{
3844 3: // call the virtual draw() method on each element in list
3845 4: for( int i=0; i < drawables.count(), ++i )
3846 5: @{
3847 6: drawables[i].draw();
3848 7: @}
3849 8: @}
3850 @end example
3851
3852 @noindent
3853 Hitting @kbd{C-c C-s} on line 3 of this example gives:
3854
3855 @example
3856 ((comment-intro) (defun-block-intro 46))
3857 @end example
3858
3859 @noindent
3860 and you can see that the syntactic context contains two syntactic
3861 elements. Notice that the first element, @samp{(comment-intro)}, has no
3862 anchor position.
3863
3864
3865 @comment !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
3866 @node Syntactic Symbols, Indentation Calculation, Syntactic Analysis, Indentation Engine Basics
3867 @comment node-name, next, previous, up
3868 @section Syntactic Symbols
3869 @comment !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
3870
3871 @cindex syntactic symbols, brief list
3872 @vindex c-offsets-alist
3873 @vindex offsets-alist (c-)
3874 This section is a complete list of the syntactic symbols which appear
3875 in the @code{c-offsets-alist} style variable, along with brief
3876 descriptions. The previous section (@pxref{Syntactic Analysis})
3877 states what syntactic symbols are and how the indentation engine uses
3878 them.
3879
3880 More detailed descriptions of these symbols, together with snippets of
3881 source code to which they apply, appear in the examples in the
3882 subsections below. Note that, in the interests of brevity, the anchor
3883 position associated with most syntactic symbols is @emph{not}
3884 specified. In cases of doubt, type @kbd{C-c C-s} on a pertinent
3885 line---this highlights the anchor position.
3886
3887 @ssindex -open symbols
3888 @ssindex -close symbols
3889 @ssindex -block-intro symbols
3890 The syntactic symbols which indicate brace constructs follow a general
3891 naming convention. When a line begins with an open or close brace,
3892 its syntactic symbol will contain the suffix @code{-open} or
3893 @code{-close} respectively. The first line within the brace block
3894 construct will contain the suffix @code{-block-intro}.
3895
3896 @ssindex -intro symbols
3897 @ssindex -cont symbols
3898 In constructs which can span several lines, a distinction is usually
3899 made between the first line that introduces the construct and the
3900 lines that continue it. The syntactic symbols that indicate these
3901 lines will contain the suffixes @code{-intro} or @code{-cont}
3902 respectively.
3903
3904 The best way to understand how all this works is by looking at some
3905 examples. Remember that you can see the syntax of any source code
3906 line by using @kbd{C-c C-s}.
3907
3908 @table @code
3909 @item string
3910 Inside a multiline string. @ref{Literal Symbols}.
3911 @item c
3912 Inside a multiline C style block comment. @ref{Literal Symbols}.
3913 @item defun-open
3914 Brace that opens a top-level function definition. @ref{Function
3915 Symbols}.
3916 @item defun-close
3917 Brace that closes a top-level function definition. @ref{Function
3918 Symbols}.
3919 @item defun-block-intro
3920 The first line in a top-level defun. @ref{Function Symbols}.
3921 @item class-open
3922 Brace that opens a class definition. @ref{Class Symbols}.
3923 @item class-close
3924 Brace that closes a class definition. @ref{Class Symbols}.
3925 @item inline-open
3926 Brace that opens an in-class inline method. @ref{Class Symbols}.
3927 @item inline-close
3928 Brace that closes an in-class inline method. @ref{Class Symbols}.
3929 @item func-decl-cont
3930 The region between a function definition's argument list and the
3931 function opening brace (excluding K&R argument declarations). In C,
3932 you cannot put anything but whitespace and comments in this region,
3933 however in C++ and Java, @code{throws} declarations and other things
3934 can appear here. @ref{Literal Symbols}. @c @emph{FIXME!!! Can it not
3935 @c go somewhere better?}
3936 @item knr-argdecl-intro
3937 First line of a K&R C argument declaration. @ref{K&R Symbols}.
3938 @item knr-argdecl
3939 Subsequent lines in a K&R C argument declaration. @ref{K&R Symbols}.
3940 @item topmost-intro
3941 The first line in a ``topmost'' definition. @ref{Function Symbols}.
3942 @item topmost-intro-cont
3943 Topmost definition continuation lines. This is only used in the parts
3944 that aren't covered by other symbols such as @code{func-decl-cont} and
3945 @code{knr-argdecl}. @ref{Function Symbols}.
3946 @item member-init-intro
3947 First line in a member initialization list. @ref{Class Symbols}.
3948 @item member-init-cont
3949 Subsequent member initialization list lines. @ref{Class Symbols}.
3950 @item inher-intro
3951 First line of a multiple inheritance list. @ref{Class Symbols}.
3952 @item inher-cont
3953 Subsequent multiple inheritance lines. @ref{Class Symbols}.
3954 @item block-open
3955 Statement block open brace. @ref{Literal Symbols}.
3956 @item block-close
3957 Statement block close brace. @ref{Conditional Construct Symbols}.
3958 @item brace-list-open
3959 Open brace of an enum or static array list. @ref{Brace List Symbols}.
3960 @item brace-list-close
3961 Close brace of an enum or static array list. @ref{Brace List Symbols}.
3962 @item brace-list-intro
3963 First line in an enum or static array list. @ref{Brace List Symbols}.
3964 @item brace-list-entry
3965 Subsequent lines in an enum or static array list. @ref{Brace List
3966 Symbols}.
3967 @item brace-entry-open
3968 Subsequent lines in an enum or static array list where the line begins
3969 with an open brace. @ref{Brace List Symbols}.
3970 @item statement
3971 A statement. @ref{Function Symbols}.
3972 @item statement-cont
3973 A continuation of a statement. @ref{Function Symbols}.
3974 @item statement-block-intro
3975 The first line in a new statement block. @ref{Conditional Construct
3976 Symbols}.
3977 @item statement-case-intro
3978 The first line in a case block. @ref{Switch Statement Symbols}.
3979 @item statement-case-open
3980 The first line in a case block that starts with a brace. @ref{Switch
3981 Statement Symbols}.
3982 @item substatement
3983 The first line after a conditional or loop construct.
3984 @ref{Conditional Construct Symbols}.
3985 @item substatement-open
3986 The brace that opens a substatement block. @ref{Conditional Construct
3987 Symbols}.
3988 @item substatement-label
3989 The first line after a conditional or loop construct if it's a label.
3990 @ref{Conditional Construct Symbols}.
3991 @item case-label
3992 A label in a @code{switch} block. @ref{Switch Statement Symbols}.
3993 @item access-label
3994 C++ access control label. @ref{Class Symbols}.
3995 @item label
3996 Any other label. @ref{Literal Symbols}.
3997 @item do-while-closure
3998 The @code{while} line that ends a @code{do}-@code{while} construct.
3999 @ref{Conditional Construct Symbols}.
4000 @item else-clause
4001 The @code{else} line of an @code{if}-@code{else} construct.
4002 @ref{Conditional Construct Symbols}.
4003 @item catch-clause
4004 The @code{catch} or @code{finally} (in Java) line of a
4005 @code{try}-@code{catch} construct. @ref{Conditional Construct
4006 Symbols}.
4007 @item comment-intro
4008 A line containing only a comment introduction. @ref{Literal Symbols}.
4009 @item arglist-intro
4010 The first line in an argument list. @ref{Paren List Symbols}.
4011 @item arglist-cont
4012 Subsequent argument list lines when no arguments follow on the same
4013 line as the arglist opening paren. @ref{Paren List Symbols}.
4014 @item arglist-cont-nonempty
4015 Subsequent argument list lines when at least one argument follows on
4016 the same line as the arglist opening paren. @ref{Paren List Symbols}.
4017 @item arglist-close
4018 The solo close paren of an argument list. @ref{Paren List Symbols}.
4019 @item stream-op
4020 Lines continuing a stream operator (C++ only). @ref{Literal
4021 Symbols}. @c @emph{FIXME!!! Can this not be moved somewhere better?}
4022 @item inclass
4023 The line is nested inside a class definition. @ref{Class Symbols}.
4024 @item cpp-macro
4025 The start of a preprocessor macro definition. @ref{Literal Symbols}.
4026 @item cpp-define-intro
4027 The first line inside a multiline preproprocessor macro if
4028 @code{c-syntactic-indentation-in-macros} is set. @ref{Multiline Macro
4029 Symbols}.
4030 @item cpp-macro-cont
4031 All lines inside multiline preprocessor macros if
4032 @code{c-syntactic-indentation-in-macros} is @code{nil}.
4033 @ref{Multiline Macro Symbols}.
4034 @item friend
4035 A C++ friend declaration. @ref{Class Symbols}.
4036 @item objc-method-intro
4037 The first line of an Objective-C method definition. @ref{Objective-C
4038 Method Symbols}.
4039 @item objc-method-args-cont
4040 Lines continuing an Objective-C method definition. @ref{Objective-C
4041 Method Symbols}.
4042 @item objc-method-call-cont
4043 Lines continuing an Objective-C method call. @ref{Objective-C Method
4044 Symbols}.
4045 @item extern-lang-open
4046 Brace that opens an @code{extern} block (e.g. @code{extern "C"
4047 @{...@}}). @ref{External Scope Symbols}.
4048 @item extern-lang-close
4049 Brace that closes an @code{extern} block. @ref{External Scope
4050 Symbols}.
4051 @item inextern-lang
4052 Analogous to @code{inclass} syntactic symbol, but used inside
4053 @code{extern} blocks. @ref{External Scope Symbols}.
4054 @item namespace-open
4055 @itemx namespace-close
4056 @itemx innamespace
4057 These are analogous to the three @code{extern-lang} symbols above, but
4058 are returned for C++ namespace blocks. @ref{External Scope Symbols}.
4059 @item module-open
4060 @itemx module-close
4061 @itemx inmodule
4062 Analogous to the above, but for CORBA IDL @code{module} blocks.
4063 @ref{External Scope Symbols}.
4064 @item composition-open
4065 @itemx composition-close
4066 @itemx incomposition
4067 Analogous to the above, but for CORBA CIDL @code{composition} blocks.
4068 @ref{External Scope Symbols}.
4069 @item template-args-cont
4070 C++ template argument list continuations. @ref{Class Symbols}.
4071 @item inlambda
4072 Analogous to @code{inclass} syntactic symbol, but used inside lambda
4073 (i.e. anonymous) functions. Only used in Pike mode. @ref{Statement
4074 Block Symbols}.
4075 @item lambda-intro-cont
4076 Lines continuing the header of a lambda function, i.e. between the
4077 @code{lambda} keyword and the function body. Only used in Pike mode.
4078 @ref{Statement Block Symbols}.
4079 @item inexpr-statement
4080 A statement block inside an expression. The gcc C and C++ extension
4081 for this is recognized. It's also used for the special functions that
4082 take a statement block as an argument in Pike. @ref{Statement Block
4083 Symbols}.
4084 @item inexpr-class
4085 A class definition inside an expression. This is used for anonymous
4086 classes in Java. It's also used for anonymous array initializers in
4087 Java. @ref{Anonymous Class Symbol}.
4088 @end table
4089
4090 @menu
4091 * Function Symbols::
4092 * Class Symbols::
4093 * Conditional Construct Symbols::
4094 * Switch Statement Symbols::
4095 * Brace List Symbols::
4096 * External Scope Symbols::
4097 * Paren List Symbols::
4098 * Literal Symbols::
4099 * Multiline Macro Symbols::
4100 * Objective-C Method Symbols::
4101 * Anonymous Class Symbol::
4102 * Statement Block Symbols::
4103 * K&R Symbols::
4104 @end menu
4105
4106 @comment !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
4107 @node Function Symbols, Class Symbols, Syntactic Symbols, Syntactic Symbols
4108 @comment node-name, next, previous, up
4109 @subsection Function Symbols
4110 @comment !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
4111
4112 This example shows a typical function declaration.
4113
4114 @example
4115 1: void
4116 2: swap( int& a, int& b )
4117 3: @{
4118 4: int tmp = a;
4119 5: a = b;
4120 6: b = tmp;
4121 7: int ignored =
4122 8: a + b;
4123 9: @}
4124 @end example
4125
4126 @ssindex topmost-intro
4127 @ssindex topmost-intro-cont
4128 @ssindex defun-open
4129 @ssindex defun-close
4130 @ssindex defun-block-intro
4131 Line 1 shows a @code{topmost-intro} since it is the first line that
4132 introduces a top-level construct. Line 2 is a continuation of the
4133 top-level construct introduction so it has the syntax
4134 @code{topmost-intro-cont}. Line 3 shows a @code{defun-open} since it is
4135 the brace that opens a top-level function definition. Line 9 is the
4136 corresponding
4137 @code{defun-close} since it contains the brace that closes the top-level
4138 function definition. Line 4 is a @code{defun-block-intro}, i.e. it is
4139 the first line of a brace-block, enclosed in a
4140 top-level function definition.
4141
4142 @ssindex statement
4143 @ssindex statement-cont
4144 Lines 5, 6, and 7 are all given @code{statement} syntax since there
4145 isn't much special about them. Note however that line 8 is given
4146 @code{statement-cont} syntax since it continues the statement begun
4147 on the previous line.
4148
4149 @comment !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
4150 @node Class Symbols, Conditional Construct Symbols, Function Symbols, Syntactic Symbols
4151 @comment node-name, next, previous, up
4152 @subsection Class related Symbols
4153 @comment !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
4154
4155 Here's an example which illustrates some C++ class syntactic symbols:
4156
4157 @example
4158 1: class Bass
4159 2: : public Guitar,
4160 3: public Amplifiable
4161 4: @{
4162 5: public:
4163 6: Bass()
4164 7: : eString( new BassString( 0.105 )),
4165 8: aString( new BassString( 0.085 )),
4166 9: dString( new BassString( 0.065 )),
4167 10: gString( new BassString( 0.045 ))
4168 11: @{
4169 12: eString.tune( 'E' );
4170 13: aString.tune( 'A' );
4171 14: dString.tune( 'D' );
4172 15: gString.tune( 'G' );
4173 16: @}
4174 17: friend class Luthier;
4175 18: @};
4176 @end example
4177
4178 @ssindex class-open
4179 @ssindex class-close
4180 As in the previous example, line 1 has the @code{topmost-intro} syntax.
4181 Here however, the brace that opens a C++ class definition on line 4 is
4182 assigned the @code{class-open} syntax. Note that in C++, classes,
4183 structs, and unions are essentially equivalent syntactically (and are
4184 very similar semantically), so replacing the @code{class} keyword in the
4185 example above with @code{struct} or @code{union} would still result in a
4186 syntax of @code{class-open} for line 4 @footnote{This is the case even
4187 for C and Objective-C. For consistency, structs in all supported
4188 languages are syntactically equivalent to classes. Note however that
4189 the keyword @code{class} is meaningless in C and Objective-C.}.
4190 Similarly, line 18 is assigned @code{class-close} syntax.
4191
4192 @ssindex inher-intro
4193 @ssindex inher-cont
4194 Line 2 introduces the inheritance list for the class so it is assigned
4195 the @code{inher-intro} syntax, and line 3, which continues the
4196 inheritance list is given @code{inher-cont} syntax.
4197
4198 @ssindex access-label
4199 @ssindex inclass
4200 Hitting @kbd{C-c C-s} on line 5 shows the following analysis:
4201
4202 @example
4203 ((inclass 58) (access-label 58))
4204 @end example
4205
4206 @noindent
4207 The primary syntactic symbol for this line is @code{access-label} as
4208 this a label keyword that specifies access protection in C++. However,
4209 because this line is also a top-level construct inside a class
4210 definition, the analysis actually shows two syntactic symbols. The
4211 other syntactic symbol assigned to this line is @code{inclass}.
4212 Similarly, line 6 is given both @code{inclass} and @code{topmost-intro}
4213 syntax:
4214
4215 @example
4216 ((inclass 58) (topmost-intro 60))
4217 @end example
4218
4219 @ssindex member-init-intro
4220 @ssindex member-init-cont
4221 Line 7 introduces a C++ member initialization list and as such is given
4222 @code{member-init-intro} syntax. Note that in this case it is
4223 @emph{not} assigned @code{inclass} since this is not considered a
4224 top-level construct. Lines 8 through 10 are all assigned
4225 @code{member-init-cont} since they continue the member initialization
4226 list started on line 7.
4227
4228 @cindex in-class inline methods
4229 @ssindex inline-open
4230 @ssindex inline-close
4231 Line 11's analysis is a bit more complicated:
4232
4233 @example
4234 ((inclass 58) (inline-open))
4235 @end example
4236
4237 This line is assigned a syntax of both @code{inline-open} and
4238 @code{inclass} because it opens an @dfn{in-class} C++ inline method
4239 definition. This is distinct from, but related to, the C++ notion of an
4240 inline function in that its definition occurs inside an enclosing class
4241 definition, which in C++ implies that the function should be inlined.
4242 However, if the definition of the @code{Bass} constructor appeared
4243 outside the class definition, the construct would be given the
4244 @code{defun-open} syntax, even if the keyword @code{inline} appeared
4245 before the method name, as in:
4246
4247 @example
4248 1: class Bass
4249 2: : public Guitar,
4250 3: public Amplifiable
4251 4: @{
4252 5: public:
4253 6: Bass();
4254 7: @};
4255 8:
4256 9: inline
4257 10: Bass::Bass()
4258 11: : eString( new BassString( 0.105 )),
4259 12: aString( new BassString( 0.085 )),
4260 13: dString( new BassString( 0.065 )),
4261 14: gString( new BassString( 0.045 ))
4262 15: @{
4263 16: eString.tune( 'E' );
4264 17: aString.tune( 'A' );
4265 18: dString.tune( 'D' );
4266 19: gString.tune( 'G' );
4267 20: @}
4268 @end example
4269
4270 @ssindex friend
4271 Returning to the previous example, line 16 is given @code{inline-close}
4272 syntax, while line 12 is given @code{defun-block-open} syntax, and lines
4273 13 through 15 are all given @code{statement} syntax. Line 17 is
4274 interesting in that its syntactic analysis list contains three
4275 elements:
4276
4277 @example
4278 ((inclass 58) (topmost-intro 380) (friend))
4279 @end example
4280
4281 The @code{friend} and @code{inline-open} syntactic symbols are
4282 modifiers that do not have anchor positions.
4283
4284 @ssindex template-args-cont
4285 Template definitions introduce yet another syntactic symbol:
4286
4287 @example
4288 1: ThingManager <int,
4289 2: Framework::Callback *,
4290 3: Mutex> framework_callbacks;
4291 @end example
4292
4293 Here, line 1 is analyzed as a @code{topmost-intro}, but lines 2 and 3
4294 are both analyzed as @code{template-args-cont} lines.
4295
4296 @comment !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
4297 @node Conditional Construct Symbols, Switch Statement Symbols, Class Symbols, Syntactic Symbols
4298 @comment node-name, next, previous, up
4299 @subsection Conditional Construct Symbols
4300 @comment !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
4301
4302 Here is a (totally contrived) example which illustrates how syntax is
4303 assigned to various conditional constructs:
4304
4305 @example
4306 1: void spam( int index )
4307 2: @{
4308 3: for( int i=0; i<index; i++ )
4309 4: @{
4310 5: if( i == 10 )
4311 6: do_something_special();
4312 7: else
4313 8: silly_label:
4314 9: do_something( i );
4315 10: @}
4316 11: do @{
4317 12: another_thing( i-- );
4318 13: @}
4319 14: while( i > 0 );
4320 15: @}
4321 @end example
4322
4323 Only the lines that illustrate new syntactic symbols will be discussed.
4324
4325 @ssindex substatement-open
4326 @ssindex statement-block-intro
4327 @ssindex block-close
4328 Line 4 has a brace which opens a conditional's substatement block. It
4329 is thus assigned @code{substatement-open} syntax, and since line 5 is
4330 the first line in the substatement block, it is assigned
4331 @code{statement-block-intro} syntax. Line 10 contains the brace
4332 that closes the inner substatement block, and is therefore given the
4333 syntax @code{block-close}@footnote{@code{block-open} is used only for
4334 ``free-standing'' blocks, and is somewhat rare (@pxref{Literal
4335 Symbols} for an example.)}. Line 13 is treated the same way.
4336
4337 @ssindex substatement
4338 Lines 6 and 9 are also substatements of conditionals, but since they
4339 don't start blocks they are given @code{substatement} syntax
4340 instead of @code{substatement-open}.
4341
4342 @ssindex substatement-label
4343 Line 8 contains a label, which is normally given @code{label} syntax.
4344 This one is however a bit special since it's between a conditional and
4345 its substatement. It's analyzed as @code{substatement-label} to let you
4346 handle this rather odd case differently from normal labels.
4347
4348 @ssindex else-clause
4349 @ssindex catch-clause
4350 Line 7 start with an @code{else} that matches the @code{if} statement on
4351 line 5. It is therefore given the @code{else-clause} syntax and is
4352 anchored on the matching @code{if}. The @code{try}-@code{catch}
4353 constructs in C++ and Java are treated this way too, except that
4354 @code{catch} and (in Java) @code{finally}, are marked with
4355 @code{catch-clause}.
4356
4357 @ssindex do-while-closure
4358 The @code{while} construct on line 14 that closes a @code{do}
4359 conditional is given the special syntax @code{do-while-closure} if it
4360 appears on a line by itself. Note that if the @code{while} appeared on
4361 the same line as the preceding close brace, that line would still have
4362 @code{block-close} syntax.
4363
4364 @comment !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
4365 @node Switch Statement Symbols, Brace List Symbols, Conditional Construct Symbols, Syntactic Symbols
4366 @comment node-name, next, previous, up
4367 @subsection Switch Statement Symbols
4368 @comment !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
4369
4370 Switch statements have their own set of syntactic symbols. Here's an
4371 example:
4372
4373 @example
4374 1: void spam( enum Ingredient i )
4375 2: @{
4376 3: switch( i ) @{
4377 4: case Ham:
4378 5: be_a_pig();
4379 6: break;
4380 7: case Salt:
4381 8: drink_some_water();
4382 9: break;
4383 10: default:
4384 11: @{
4385 12: what_is_it();
4386 13: break;
4387 14: @}
4388 15: @}
4389 14: @}
4390 @end example
4391
4392 @ssindex case-label
4393 @ssindex statement-case-intro
4394 @ssindex statement-case-open
4395 Here, lines 4, 7, and 10 are all assigned @code{case-label} syntax,
4396 while lines 5 and 8 are assigned @code{statement-case-intro}. Line 11
4397 is treated slightly differently since it contains a brace that opens a
4398 block --- it is given @code{statement-case-open} syntax.
4399
4400 @comment !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
4401 @node Brace List Symbols, External Scope Symbols, Switch Statement Symbols, Syntactic Symbols
4402 @comment node-name, next, previous, up
4403 @subsection Brace List Symbols
4404 @comment !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
4405
4406 @cindex brace lists
4407 There are a set of syntactic symbols that are used to recognize
4408 constructs inside of brace lists. A brace list is defined as an
4409 @code{enum} or aggregate initializer list, such as might statically
4410 initialize an array of structs. The three special aggregate constructs
4411 in Pike, @code{(@{ @})}, @code{([ ])} and @code{(< >)}, are treated as
4412 brace lists too. An example:
4413
4414 @example
4415 1: static char* ingredients[] =
4416 2: @{
4417 3: "Ham",
4418 4: "Salt",
4419 5: NULL
4420 6: @};
4421 @end example
4422
4423 @ssindex brace-list-open
4424 @ssindex brace-list-intro
4425 @ssindex brace-list-close
4426 @ssindex brace-list-entry
4427 Following convention, line 2 in this example is assigned
4428 @code{brace-list-open} syntax, and line 3 is assigned
4429 @code{brace-list-intro} syntax. Likewise, line 6 is assigned
4430 @code{brace-list-close} syntax. Lines 4 and 5 however, are assigned
4431 @code{brace-list-entry} syntax, as would all subsequent lines in this
4432 initializer list.
4433
4434 @ssindex brace-entry-open
4435 Your static initializer might be initializing nested structures, for
4436 example:
4437
4438 @example
4439 1: struct intpairs[] =
4440 2: @{
4441 3: @{ 1, 2 @},
4442 4: @{
4443 5: 3,
4444 6: 4
4445 7: @}
4446 8: @{ 1,
4447 9: 2 @},
4448 10: @{ 3, 4 @}
4449 11: @};
4450 @end example
4451
4452 Here, you've already seen the analysis of lines 1, 2, 3, and 11. On
4453 line 4, things get interesting; this line is assigned
4454 @code{brace-entry-open} syntactic symbol because it's a bracelist entry
4455 line that starts with an open brace. Lines 5 and 6 (and line 9) are
4456 pretty standard, and line 7 is a @code{brace-list-close} as you'd
4457 expect. Once again, line 8 is assigned as @code{brace-entry-open} as is
4458 line 10.
4459
4460 @comment !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
4461 @node External Scope Symbols, Paren List Symbols, Brace List Symbols, Syntactic Symbols
4462 @comment node-name, next, previous, up
4463 @subsection External Scope Symbols
4464 @comment !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
4465
4466 External language definition blocks also have their own syntactic
4467 symbols. In this example:
4468
4469 @example
4470 1: extern "C"
4471 2: @{
4472 3: int thing_one( int );
4473 4: int thing_two( double );
4474 5: @}
4475 @end example
4476
4477 @ssindex extern-lang-open
4478 @ssindex extern-lang-close
4479 @ssindex inextern-lang
4480 @ssindex inclass
4481 @noindent
4482 line 2 is given the @code{extern-lang-open} syntax, while line 5 is given
4483 the @code{extern-lang-close} syntax. The analysis for line 3 yields:
4484
4485 @example
4486 ((inextern-lang) (topmost-intro 14))
4487 @end example
4488
4489 @noindent
4490 where @code{inextern-lang} is a modifier similar in purpose to
4491 @code{inclass}.
4492
4493 There are various other top level blocks like @code{extern}, and they
4494 are all treated in the same way except that the symbols are named after
4495 the keyword that introduces the block. E.g. C++ namespace blocks get
4496 the three symbols @code{namespace-open}, @code{namespace-close} and
4497 @code{innamespace}. The currently recognized top level blocks are:
4498
4499 @table @asis
4500 @item @code{extern-lang-open}, @code{extern-lang-close}, @code{inextern-lang}
4501 @code{extern} blocks in C and C++.@footnote{These should logically be
4502 named @code{extern-open}, @code{extern-close} and @code{inextern}, but
4503 that isn't the case for historical reasons.}
4504
4505 @item @code{namespace-open}, @code{namespace-close}, @code{innamespace}
4506 @ssindex namespace-open
4507 @ssindex namespace-close
4508 @ssindex innamespace
4509 @code{namespace} blocks in C++.
4510
4511 @item @code{module-open}, @code{module-close}, @code{inmodule}
4512 @ssindex module-open
4513 @ssindex module-close
4514 @ssindex inmodule
4515 @code{module} blocks in CORBA IDL.
4516
4517 @item @code{composition-open}, @code{composition-close}, @code{incomposition}
4518 @ssindex composition-open
4519 @ssindex composition-close
4520 @ssindex incomposition
4521 @code{composition} blocks in CORBA CIDL.
4522 @end table
4523
4524 @comment !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
4525 @node Paren List Symbols, Literal Symbols, External Scope Symbols, Syntactic Symbols
4526 @comment node-name, next, previous, up
4527 @subsection Parenthesis (Argument) List Symbols
4528 @comment !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
4529
4530 A number of syntactic symbols are associated with parenthesis lists,
4531 a.k.a argument lists, as found in function declarations and function
4532 calls. This example illustrates these:
4533
4534 @example
4535 1: void a_function( int line1,
4536 2: int line2 );
4537 3:
4538 4: void a_longer_function(
4539 5: int line1,
4540 6: int line2
4541 7: );
4542 8:
4543 9: void call_them( int line1, int line2 )
4544 10: @{
4545 11: a_function(
4546 12: line1,
4547 13: line2
4548 14: );
4549 15:
4550 16: a_longer_function( line1,
4551 17: line2 );
4552 18: @}
4553 @end example
4554
4555 @ssindex arglist-intro
4556 @ssindex arglist-close
4557 Lines 5 and 12 are assigned @code{arglist-intro} syntax since they are
4558 the first line following the open parenthesis, and lines 7 and 14 are
4559 assigned @code{arglist-close} syntax since they contain the parenthesis
4560 that closes the argument list.
4561
4562 @ssindex arglist-cont-nonempty
4563 @ssindex arglist-cont
4564 Lines that continue argument lists can be assigned one of two syntactic
4565 symbols. For example, Lines 2 and 17
4566 are assigned @code{arglist-cont-nonempty} syntax. What this means
4567 is that they continue an argument list, but that the line containing the
4568 parenthesis that opens the list is @emph{not empty} following the open
4569 parenthesis. Contrast this against lines 6 and 13 which are assigned
4570 @code{arglist-cont} syntax. This is because the parenthesis that opens
4571 their argument lists is the last character on that line.
4572
4573 Syntactic elements with @code{arglist-intro},
4574 @code{arglist-cont-nonempty}, and @code{arglist-close} contain two
4575 buffer positions: the anchor position (the beginning of the
4576 declaration or statement) and the position of the open parenthesis.
4577 The latter position can be used in a line-up function (@pxref{Line-Up
4578 Functions}).
4579
4580 Note that there is no @code{arglist-open} syntax. This is because any
4581 parenthesis that opens an argument list, appearing on a separate line,
4582 is assigned the @code{statement-cont} syntax instead.
4583
4584 @comment !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
4585 @node Literal Symbols, Multiline Macro Symbols, Paren List Symbols, Syntactic Symbols
4586 @comment node-name, next, previous, up
4587 @subsection Comment String Label and Macro Symbols
4588 @comment !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
4589
4590 A few miscellaneous syntactic symbols that haven't been previously
4591 covered are illustrated by this C++ example:
4592
4593 @example
4594 1: void Bass::play( int volume )
4595 2: const
4596 3: @{
4597 4: /* this line starts a multiline
4598 5: * comment. This line should get `c' syntax */
4599 6:
4600 7: char* a_multiline_string = "This line starts a multiline \
4601 8: string. This line should get `string' syntax.";
4602 9:
4603 10: note:
4604 11: @{
4605 12: #ifdef LOCK
4606 13: Lock acquire();
4607 14: #endif // LOCK
4608 15: slap_pop();
4609 16: cout << "I played "
4610 17: << "a note\n";
4611 18: @}
4612 19: @}
4613 @end example
4614
4615 The lines to note in this example include:
4616
4617 @itemize @bullet
4618 @item
4619 @ssindex func-decl-cont
4620 Line 2 is assigned the @code{func-decl-cont} syntax.
4621
4622 @item
4623 @ssindex comment-intro
4624 Line 4 is assigned both @code{defun-block-intro} @emph{and}
4625 @code{comment-intro} syntax. A syntactic element with
4626 @code{comment-intro} has no anchor point --- It is always accompanied
4627 by another syntactic element which does have one.
4628
4629 @item
4630 @ssindex c
4631 Line 5 is assigned @code{c} syntax.
4632
4633 @item
4634 @cindex syntactic whitespace
4635 Line 6 which, even though it contains nothing but whitespace, is
4636 assigned @code{defun-block-intro}. Note that the appearance of the
4637 comment on lines 4 and 5 do not cause line 6 to be assigned
4638 @code{statement} syntax because comments are considered to be
4639 @dfn{syntactic whitespace}, which are ignored when analyzing
4640 code.
4641
4642 @item
4643 @ssindex string
4644 Line 8 is assigned @code{string} syntax.
4645
4646 @item
4647 @ssindex label
4648 Line 10 is assigned @code{label} syntax.
4649
4650 @item
4651 @ssindex block-open
4652 Line 11 is assigned @code{block-open} as well as @code{statement}
4653 syntax. A @code{block-open} syntactic element doesn't have an anchor
4654 position, since it always appears with another syntactic element which
4655 does have one.
4656
4657 @item
4658 @ssindex cpp-macro
4659 Lines 12 and 14 are assigned @code{cpp-macro} syntax in addition to the
4660 normal syntactic symbols (@code{statement-block-intro} and
4661 @code{statement}, respectively). Normally @code{cpp-macro} is
4662 configured to cancel out the normal syntactic context to make all
4663 preprocessor directives stick to the first column, but that's easily
4664 changed if you want preprocessor directives to be indented like the rest
4665 of the code. Like @code{comment-intro}, a syntactic element with
4666 @code{cpp-macro} doesn't contain an anchor position.
4667
4668 @item
4669 @ssindex stream-op
4670 Line 17 is assigned @code{stream-op} syntax.
4671 @end itemize
4672
4673 @comment !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
4674 @node Multiline Macro Symbols, Objective-C Method Symbols, Literal Symbols, Syntactic Symbols
4675 @comment node-name, next, previous, up
4676 @subsection Multiline Macro Symbols
4677 @comment !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
4678
4679 @cindex multiline macros
4680 @cindex syntactic whitespace
4681 @ssindex cpp-define-intro
4682 @ssindex cpp-macro-cont
4683 Multiline preprocessor macro definitions are normally handled just like
4684 other code, i.e. the lines inside them are indented according to the
4685 syntactic analysis of the preceding lines inside the macro. The first
4686 line inside a macro definition (i.e. the line after the starting line of
4687 the cpp directive itself) gets @code{cpp-define-intro}. In this example:
4688
4689 @example
4690 1: #define LIST_LOOP(cons, listp) \
4691 2: for (cons = listp; !NILP (cons); cons = XCDR (cons)) \
4692 3: if (!CONSP (cons)) \
4693 4: signal_error ("Invalid list format", listp); \
4694 5: else
4695 @end example
4696
4697 @noindent
4698 line 1 is given the syntactic symbol @code{cpp-macro}. The first line
4699 of a cpp directive is always given that symbol. Line 2 is given
4700 @code{cpp-define-intro}, so that you can give the macro body as a whole
4701 some extra indentation. Lines 3 through 5 are then analyzed as normal
4702 code, i.e. @code{substatement} on lines 3 and 4, and @code{else-clause}
4703 on line 5.
4704
4705 The syntactic analysis inside macros can be turned off with
4706 @code{c-syntactic-indentation-in-macros} (@pxref{Custom Macros}). In
4707 that case, lines 2 through 5 would all be given @code{cpp-macro-cont}
4708 with an anchor position pointing to the @code{#} which starts the cpp
4709 directive@footnote{This is how @ccmode{} 5.28 and earlier analyzed
4710 macros.}.
4711
4712 @xref{Custom Macros}, for more info about the treatment of macros.
4713
4714 @comment !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
4715 @node Objective-C Method Symbols, Anonymous Class Symbol, Multiline Macro Symbols, Syntactic Symbols
4716 @comment node-name, next, previous, up
4717 @subsection Objective-C Method Symbols
4718 @comment !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
4719
4720 In Objective-C buffers, there are three additional syntactic symbols
4721 assigned to various message calling constructs. Here's an example
4722 illustrating these:
4723
4724 @example
4725 1: - (void)setDelegate:anObject
4726 2: withStuff:stuff
4727 3: @{
4728 4: [delegate masterWillRebind:self
4729 5: toDelegate:anObject
4730 6: withExtraStuff:stuff];
4731 7: @}
4732 @end example
4733
4734 @ssindex objc-method-intro
4735 @ssindex objc-method-args-cont
4736 @ssindex objc-method-call-cont
4737 Here, line 1 is assigned @code{objc-method-intro} syntax, and line 2 is
4738 assigned @code{objc-method-args-cont} syntax. Lines 5 and 6 are both
4739 assigned @code{objc-method-call-cont} syntax.
4740
4741 @comment !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
4742 @node Anonymous Class Symbol, Statement Block Symbols, Objective-C Method Symbols, Syntactic Symbols
4743 @comment node-name, next, previous, up
4744 @subsection Anonymous Class Symbol (Java)
4745 @comment !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
4746
4747 Java has a concept of anonymous classes which can look something like
4748 this:
4749
4750 @example
4751 1: public void watch(Observable o) @{
4752 2: o.addObserver(new Observer() @{
4753 3: public void update(Observable o, Object arg) @{
4754 4: history.addElement(arg);
4755 5: @}
4756 6: @});
4757 7: @}
4758 @end example
4759
4760 @ssindex inexpr-class
4761 The brace following the @code{new} operator opens the anonymous class.
4762 Lines 3 and 6 are assigned the @code{inexpr-class} syntax, besides the
4763 @code{inclass} symbol used in normal classes. Thus, the class will be
4764 indented just like a normal class, with the added indentation given to
4765 @code{inexpr-class}. An @code{inexpr-class} syntactic element doesn't
4766 have an anchor position.
4767
4768 @comment !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
4769 @node Statement Block Symbols, K&R Symbols, Anonymous Class Symbol, Syntactic Symbols
4770 @comment node-name, next, previous, up
4771 @subsection Statement Block Symbols
4772 @comment !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
4773
4774 There are a few occasions where a statement block might be used inside
4775 an expression. One is in C or C++ code using the gcc extension for
4776 this, e.g:
4777
4778 @example
4779 1: int res = (@{
4780 2: int y = foo (); int z;
4781 3: if (y > 0) z = y; else z = - y;
4782 4: z;
4783 5: @});
4784 @end example
4785
4786 @ssindex inexpr-statement
4787 Lines 2 and 5 get the @code{inexpr-statement} syntax, besides the
4788 symbols they'd get in a normal block. Therefore, the indentation put on
4789 @code{inexpr-statement} is added to the normal statement block
4790 indentation. An @code{inexpr-statement} syntactic element doesn't
4791 contain an anchor position.
4792
4793 In Pike code, there are a few other situations where blocks occur inside
4794 statements, as illustrated here:
4795
4796 @example
4797 1: array itgob()
4798 2: @{
4799 3: string s = map (backtrace()[-2][3..],
4800 4: lambda
4801 5: (mixed arg)
4802 6: @{
4803 7: return sprintf ("%t", arg);
4804 8: @}) * ", " + "\n";
4805 9: return catch @{
4806 10: write (s + "\n");
4807 11: @};
4808 12: @}
4809 @end example
4810
4811 @ssindex inlambda
4812 @ssindex lambda-intro-cont
4813 Lines 4 through 8 contain a lambda function, which @ccmode{} recognizes
4814 by the @code{lambda} keyword. If the function argument list is put
4815 on a line of its own, as in line 5, it gets the @code{lambda-intro-cont}
4816 syntax. The function body is handled as an inline method body, with the
4817 addition of the @code{inlambda} syntactic symbol. This means that line
4818 6 gets @code{inlambda} and @code{inline-open}, and line 8 gets
4819 @code{inline-close}@footnote{You might wonder why it doesn't get
4820 @code{inlambda} too. It's because the closing brace is relative to the
4821 opening brace, which stands on its own line in this example. If the
4822 opening brace was hanging on the previous line, then the closing brace
4823 would get the @code{inlambda} syntax too to be indented correctly.}.
4824
4825 @ssindex inexpr-statement
4826 On line 9, @code{catch} is a special function taking a statement block
4827 as its argument. The block is handled as an in-expression statement
4828 with the @code{inexpr-statement} syntax, just like the gcc extended C
4829 example above. The other similar special function, @code{gauge}, is
4830 handled like this too.
4831
4832 @comment !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
4833 @node K&R Symbols, , Statement Block Symbols, Syntactic Symbols
4834 @comment node-name, next, previous, up
4835 @subsection K&R Symbols
4836 @comment !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
4837
4838 @ssindex knr-argdecl-intro
4839 @ssindex knr-argdecl
4840 Two other syntactic symbols can appear in old style, non-prototyped C
4841 code @footnote{a.k.a. K&R C, or Kernighan & Ritchie C}:
4842
4843 @example
4844 1: int add_three_integers(a, b, c)
4845 2: int a;
4846 3: int b;
4847 4: int c;
4848 5: @{
4849 6: return a + b + c;
4850 7: @}
4851 @end example
4852
4853 Here, line 2 is the first line in an argument declaration list and so is
4854 given the @code{knr-argdecl-intro} syntactic symbol. Subsequent lines
4855 (i.e. lines 3 and 4 in this example), are given @code{knr-argdecl}
4856 syntax.
4857
4858
4859 @comment !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
4860 @node Indentation Calculation, , Syntactic Symbols, Indentation Engine Basics
4861 @comment node-name, next, previous, up
4862 @section Indentation Calculation
4863 @cindex indentation
4864 @comment !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
4865
4866 Indentation for a line is calculated from the syntactic context
4867 (@pxref{Syntactic Analysis}).
4868
4869 First, a buffer position is found whose column will be the base for the
4870 indentation calculation. It's the anchor position in the first
4871 syntactic element that provides one that is used. If no syntactic
4872 element has an anchor position then column zero is used.
4873
4874 Second, the syntactic symbols in each syntactic element are looked up
4875 in the @code{c-offsets-alist} style variable
4876 (@pxref{c-offsets-alist}), which is an association list of syntactic
4877 symbols and the offsets to apply for those symbols. These offsets are
4878 added together with the base column to produce the new indentation
4879 column.
4880
4881 Let's use our two code examples above to see how this works. Here is
4882 our first example again:
4883
4884 @example
4885 1: void swap( int& a, int& b )
4886 2: @{
4887 3: int tmp = a;
4888 4: a = b;
4889 5: b = tmp;
4890 6: @}
4891 @end example
4892
4893 Let's say point is on line 3 and we hit the @key{TAB} key to reindent
4894 the line. The syntactic context for that line is:
4895
4896 @example
4897 ((defun-block-intro 29))
4898 @end example
4899
4900 @noindent
4901 Since buffer position 29 is the first and only anchor position in the
4902 list, @ccmode{} goes there and asks for the current column. This brace
4903 is in column zero, so @ccmode{} uses @samp{0} as the base column.
4904
4905 Next, @ccmode{} looks up @code{defun-block-intro} in the
4906 @code{c-offsets-alist} style variable. Let's say it finds the value
4907 @samp{4}; it adds this to the base column @samp{0}, yielding a running
4908 total indentation of 4 spaces.
4909
4910 Since there is only one syntactic element on the list for this line,
4911 indentation calculation is complete, and the total indentation for the
4912 line is 4 spaces.
4913
4914 Here's another example:
4915
4916 @example
4917 1: int add( int val, int incr, int doit )
4918 2: @{
4919 3: if( doit )
4920 4: @{
4921 5: return( val + incr );
4922 6: @}
4923 7: return( val );
4924 8: @}
4925 @end example
4926
4927 If we were to hit @kbd{TAB} on line 4 in the above example, the same
4928 basic process is performed, despite the differences in the syntactic
4929 context. The context for this line is:
4930
4931 @example
4932 ((substatement-open 46))
4933 @end example
4934
4935 Here, @ccmode{} goes to buffer position 46, which is the @samp{i} in
4936 @code{if} on line 3. This character is in the fourth column on that
4937 line so the base column is @samp{4}. Then @ccmode{} looks up the
4938 @code{substatement-open} symbol in @code{c-offsets-alist}. Let's say it
4939 finds the value @samp{4}. It's added with the base column and yields an
4940 indentation for the line of 8 spaces.
4941
4942 Simple, huh?
4943
4944 Actually, it's a bit more complicated than that since the entries on
4945 @code{c-offsets-alist} can be much more than plain offsets.
4946 @xref{c-offsets-alist}, for the full story.
4947
4948 Anyway, the mode usually just does The Right Thing without you having to
4949 think about it in this much detail. But when customizing indentation,
4950 it's helpful to understand the general indentation model being used.
4951
4952 As you configure @ccmode{}, you might want to set the variable
4953 @code{c-echo-syntactic-information-p} to non-@code{nil} so that the
4954 syntactic context and calculated offset always is echoed in the
4955 minibuffer when you hit @kbd{TAB}.
4956
4957
4958 @comment !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
4959 @node Customizing Indentation, Custom Macros, Indentation Engine Basics, Top
4960 @comment node-name, next, previous, up
4961 @chapter Customizing Indentation
4962 @cindex customization, indentation
4963 @cindex indentation
4964 @comment !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
4965
4966 The principal variable for customizing indentation is the style
4967 variable @code{c-offsets-alist}, which gives an @dfn{offset} (an
4968 indentation rule) for each syntactic symbol. Its structure and
4969 semantics are completely described in @ref{c-offsets-alist}. The
4970 various ways you can set the variable, including the use of the
4971 @ccmode{} style system, are described in @ref{Config Basics} and its
4972 sections, in particular @ref{Style Variables}.
4973
4974 The simplest and most used kind of ``offset'' setting in
4975 @code{c-offsets-alist} is in terms of multiples of
4976 @code{c-basic-offset}:
4977
4978 @defopt c-basic-offset
4979 @vindex basic-offset (c-)
4980 This style variable holds the basic offset between indentation levels.
4981 It's factory default is 4, but all the built-in styles set it
4982 themselves, to some value between 2 (for @code{gnu} style) and 8 (for
4983 @code{bsd}, @code{linux}, and @code{python} styles).
4984 @end defopt
4985
4986 The most flexible ``offset'' setting you can make in
4987 @code{c-offsets-alist} is a line-up function (or even a list of them),
4988 either one supplied by @ccmode{} (@pxref{Line-Up Functions}) or one
4989 you write yourself (@pxref{Custom Line-Up}).
4990
4991 Finally, in @ref{Other Indentation} you'll find the tool of last
4992 resort: a hook which is called after a line has been indented. You
4993 can install functions here to make ad-hoc adjustments to any line's
4994 indentation.
4995
4996 @menu
4997 * c-offsets-alist::
4998 * Interactive Customization::
4999 * Line-Up Functions::
5000 * Custom Line-Up::
5001 * Other Indentation::
5002 @end menu
5003
5004
5005 @comment !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
5006 @node c-offsets-alist, Interactive Customization, Customizing Indentation, Customizing Indentation
5007 @comment node-name, next, previous, up
5008 @section c-offsets-alist
5009 @comment !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
5010
5011 This section explains the structure and semantics of the style
5012 variable @code{c-offset-alist}, the principal variable for configuring
5013 indentation. Details of how to set it up, and its relationship to
5014 @ccmode{}'s style system are given in @ref{Style Variables}.
5015
5016 @defopt c-offsets-alist
5017 @vindex offsets-alist (c-)
5018 This is an alist which associates an offset with each syntactic
5019 symbol. This @dfn{offset} is a rule specifying how to indent a line
5020 whose syntactic context matches the symbol. @xref{Syntactic
5021 Analysis}.
5022
5023 Note that the buffer-local binding of this alist in a @ccmode{} buffer
5024 contains an entry for @emph{every} syntactic symbol. Its global
5025 binding and its settings within style specifications usually contain
5026 only a few entries. @xref{Style Variables}.
5027
5028 The offset specification associated with any particular syntactic
5029 symbol can be an integer, a variable name, a vector, a function or
5030 lambda expression, a list, or one of the following special symbols:
5031 @code{+}, @code{-}, @code{++}, @code{--}, @code{*}, or @code{/}. The
5032 meanings of these values are described in detail below.
5033
5034 Here is an example fragment of a @code{c-offsets-alist}, showing some
5035 of these kinds of offsets:
5036
5037 @example
5038 ((statement . 0)
5039 (substatement . +)
5040 (cpp-macro . [0])
5041 (topmost-intro-cont . c-lineup-topmost-intro-cont)
5042 (statement-block-intro . (add c-lineup-whitesmith-in-block
5043 c-indent-multi-line-block))
5044 @dots{}
5045 @*)
5046 @end example
5047 @end defopt
5048
5049 @deffn Command c-set-offset (@kbd{C-c C-o})
5050 @findex set-offset (c-)
5051 @kindex C-c C-o
5052 This command changes the entry for a syntactic symbol in the current
5053 binding of @code{c-offsets-alist}, or it inserts a new entry if there
5054 isn't already one for that syntactic symbol.
5055
5056 You can use @code{c-set-offsets} interactively within a @ccmode{}
5057 buffer to make experimental changes to your indentation settings.
5058 @kbd{C-c C-o} prompts you for the syntactic symbol to change
5059 (defaulting to that of the current line) and the new offset
5060 (defaulting to the current offset).
5061
5062 @code{c-set-offsets} takes two arguments when used programmatically:
5063 @var{symbol}, the syntactic element symbol to change and @var{offset},
5064 the new offset for that syntactic element. You can call the command
5065 in your @file{.emacs} to change the global binding of
5066 @code{c-offsets-alist} (@pxref{Style Variables}); you can use it in a
5067 hook function to make changes from the current style. @ccmode{}
5068 itself uses this function when initializing styles.
5069 @end deffn
5070
5071 @cindex offset specification
5072 The ``offset specifications'' in @code{c-offsets-alist} can be any of
5073 the following:
5074
5075 @table @asis
5076 @item An integer
5077 The integer specifies a relative offset. All relative
5078 offsets@footnote{The syntactic context @code{@w{((defun-block-intro
5079 2724) (comment-intro))}} would likely have two relative offsets.} will
5080 be added together and used to calculate the indentation relative to an
5081 anchor position earlier in the buffer. @xref{Indentation
5082 Calculation}, for details. Most of the time, it's probably better to
5083 use one of the special symbols like @code{+} than an integer (apart
5084 from zero).
5085
5086 @item One of the symbols @code{+}, @code{-}, @code{++}, @code{--}, @code{*}, or @code{/}
5087 These special symbols describe a relative offset in multiples of
5088 @code{c-basic-offset}:
5089
5090 By defining a style's indentation in terms of @code{c-basic-offset},
5091 you can change the amount of whitespace given to an indentation level
5092 while maintaining the same basic shape of your code. Here are the
5093 values that the special symbols correspond to:
5094
5095 @table @code
5096 @item +
5097 @code{c-basic-offset} times 1
5098 @item -
5099 @code{c-basic-offset} times -1
5100 @item ++
5101 @code{c-basic-offset} times 2
5102 @item --
5103 @code{c-basic-offset} times -2
5104 @item *
5105 @code{c-basic-offset} times 0.5
5106 @item /
5107 @code{c-basic-offset} times -0.5
5108 @end table
5109
5110 @item A vector
5111 The first element of the vector, an integer, sets the absolute
5112 indentation column. This will override any previously calculated
5113 indentation, but won't override relative indentation calculated from
5114 syntactic elements later on in the syntactic context of the line being
5115 indented. @xref{Indentation Calculation}. Any elements in the vector
5116 beyond the first will be ignored.
5117
5118 @item A function or lambda expression
5119 The function will be called and its return value will in turn be
5120 evaluated as an offset specification. Functions are useful when more
5121 context than just the syntactic symbol is needed to get the desired
5122 indentation. @xref{Line-Up Functions}, and @ref{Custom Line-Up}, for
5123 details about them.
5124
5125 @item A symbol with a variable binding
5126 If the symbol also has a function binding, the function takes
5127 precedence over the variable. Otherwise the value of the variable is
5128 used. It must be an integer (which is used as relative offset) or a
5129 vector (an absolute offset).
5130
5131 @item A list
5132 The offset can also be a list containing several offset
5133 specifications; these are evaluated recursively and combined. A list
5134 is typically only useful when some of the offsets are line-up
5135 functions. A common strategy is calling a sequence of functions in
5136 turn until one of them recognizes that it is appropriate for the
5137 source line and returns a non-@code{nil} value.
5138
5139 @code{nil} values are always ignored when the offsets are combined.
5140 The first element of the list specifies the method of combining the
5141 non-@code{nil} offsets from the remaining elements:
5142
5143 @table @code
5144 @item first
5145 Use the first offset that doesn't evaluate to @code{nil}. Subsequent
5146 elements of the list don't get evaluated.
5147 @item min
5148 Use the minimum of all the offsets. All must be either relative or
5149 absolute - they can't be mixed.
5150 @item max
5151 Use the maximum of all the offsets. All must be either relative or
5152 absolute - they can't be mixed.
5153 @item add
5154 Add all the evaluated offsets together. Exactly one of them may be
5155 absolute, in which case the result is absolute. Any relative offsets
5156 that preceded the absolute one in the list will be ignored in that case.
5157 @end table
5158
5159 As a compatibility measure, if the first element is none of the above
5160 then it too will be taken as an offset specification and the whole list
5161 will be combined according to the method @code{first}.
5162 @end table
5163
5164 @vindex c-strict-syntax-p
5165 @vindex strict-syntax-p (c-)
5166 If an offset specification evaluates to @code{nil}, then a relative
5167 offset of 0 (zero) is used@footnote{There is however a variable
5168 @code{c-strict-syntax-p} that when set to non-@code{nil} will cause an
5169 error to be signaled in that case. It's now considered obsolete since
5170 it doesn't work well with some of the alignment functions that returns
5171 @code{nil} instead of zero. You should therefore leave
5172 @code{c-strict-syntax-p} set to @code{nil}.}.
5173
5174 @comment !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
5175 @node Interactive Customization, Line-Up Functions, c-offsets-alist, Customizing Indentation
5176 @comment node-name, next, previous, up
5177 @section Interactive Customization
5178 @cindex customization, interactive
5179 @cindex interactive customization
5180 @comment !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
5181
5182 As an example of how to customize indentation, let's change the
5183 style of this example@footnote{In this and subsequent examples, the
5184 original code is formatted using the @samp{gnu} style unless otherwise
5185 indicated. @xref{Styles}.}:
5186
5187 @example
5188 @group
5189 1: int add( int val, int incr, int doit )
5190 2: @{
5191 3: if( doit )
5192 4: @{
5193 5: return( val + incr );
5194 6: @}
5195 7: return( val );
5196 8: @}
5197 @end group
5198 @end example
5199
5200 @noindent
5201 to:
5202
5203 @example
5204 @group
5205 1: int add( int val, int incr, int doit )
5206 2: @{
5207 3: if( doit )
5208 4: @{
5209 5: return( val + incr );
5210 6: @}
5211 7: return( val );
5212 8: @}
5213 @end group
5214 @end example
5215
5216 In other words, we want to change the indentation of braces that open a
5217 block following a condition so that the braces line up under the
5218 conditional, instead of being indented. Notice that the construct we
5219 want to change starts on line 4. To change the indentation of a line,
5220 we need to see which syntactic symbols affect the offset calculations
5221 for that line. Hitting @kbd{C-c C-s} on line 4 yields:
5222
5223 @example
5224 ((substatement-open 44))
5225 @end example
5226
5227 @noindent
5228 so we know that to change the offset of the open brace, we need to
5229 change the indentation for the @code{substatement-open} syntactic
5230 symbol.
5231
5232 To do this interactively, just hit @kbd{C-c C-o}. This prompts
5233 you for the syntactic symbol to change, providing a reasonable default.
5234 In this case, the default is @code{substatement-open}, which is just the
5235 syntactic symbol we want to change!
5236
5237 After you hit return, @ccmode{} will then prompt you for the new
5238 offset value, with the old value as the default. The default in this
5239 case is @samp{+}, but we want no extra indentation so enter
5240 @samp{0} and @kbd{RET}. This will associate the offset 0 with the
5241 syntactic symbol @code{substatement-open}.
5242
5243 To check your changes quickly, just hit @kbd{C-c C-q}
5244 (@code{c-indent-defun}) to reindent the entire function. The example
5245 should now look like:
5246
5247 @example
5248 @group
5249 1: int add( int val, int incr, int doit )
5250 2: @{
5251 3: if( doit )
5252 4: @{
5253 5: return( val + incr );
5254 6: @}
5255 7: return( val );
5256 8: @}
5257 @end group
5258 @end example
5259
5260 Notice how just changing the open brace offset on line 4 is all we
5261 needed to do. Since the other affected lines are indented relative to
5262 line 4, they are automatically indented the way you'd expect. For more
5263 complicated examples, this might not always work. The general approach
5264 to take is to always start adjusting offsets for lines higher up in the
5265 file, then reindent and see if any following lines need further
5266 adjustments.
5267
5268 @c Move this bit to "Styles" (2005/10/7)
5269 @deffn Command c-set-offset symbol offset
5270 @findex set-offset (c-)
5271 @kindex C-c C-o
5272 This is the command bound to @kbd{C-c C-o}. It provides a convenient
5273 way to set offsets on @code{c-offsets-alist} both interactively (see
5274 the example above) and from your mode hook.
5275
5276 It takes two arguments when used programmatically: @var{symbol} is the
5277 syntactic element symbol to change and @var{offset} is the new offset
5278 for that syntactic element.
5279 @end deffn
5280 @c End of MOVE THIS BIT.
5281
5282 @comment !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
5283 @node Line-Up Functions, Custom Line-Up, Interactive Customization, Customizing Indentation
5284 @comment node-name, next, previous, up
5285 @section Line-Up Functions
5286 @comment !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
5287
5288 @cindex line-up function
5289 @cindex indentation function
5290 Often there are cases when a simple offset setting on a syntactic
5291 symbol isn't enough to get the desired indentation---for example, you
5292 might want to line up a closing parenthesis with the matching opening
5293 one rather than indenting relative to its ``anchor point''. @ccmode{}
5294 provides this flexibility with @dfn{line-up functions}.
5295
5296 The way you associate a line-up function with a syntactic symbol is
5297 described in @ref{c-offsets-alist}. @ccmode{} comes with many
5298 predefined line-up functions for common situations. If none of these
5299 does what you want, you can write your own. @xref{Custom Line-Up}.
5300 Sometimes, it is easier to tweak the standard indentation by adding a
5301 function to @code{c-special-indent-hook} (@pxref{Other Indentation}).
5302
5303 The line-up functions haven't been adapted for AWK buffers or tested
5304 with them. Some of them might work serendipitously. There shouldn't be
5305 any problems writing custom line-up functions for AWK mode.
5306
5307 The calling convention for line-up functions is described fully in
5308 @ref{Custom Line-Up}. Roughly speaking, the return value is either an
5309 offset itself (such as @code{+} or @code{[0]}) or it's @code{nil},
5310 meaning ``this function is inappropriate in this case - try a
5311 different one''. @xref{c-offsets-alist}.
5312
5313 The subsections below describe all the standard line-up functions,
5314 categorized by the sort of token the lining-up centres around. For
5315 each of these functions there is a ``works with'' list that indicates
5316 which syntactic symbols the function is intended to be used with.
5317
5318 @macro workswith
5319 @emph{Works with:@ }
5320 @end macro
5321 @ifinfo
5322 @unmacro workswith
5323 @macro workswith
5324 Works with:
5325 @end macro
5326 @end ifinfo
5327
5328 @macro sssTBasicOffset
5329 <--> @i{c-basic-offset}@c
5330 @end macro
5331
5332 @macro sssTsssTBasicOffset
5333 <--><--> @i{c-basic-offset}@c
5334 @end macro
5335
5336 @macro hereFn{func}
5337 <- @i{\func\}@c
5338 @end macro
5339
5340 @c The TeX backend seems to insert extra spaces around the argument. :P
5341 @iftex
5342 @unmacro hereFn
5343 @macro hereFn{func}
5344 <-@i{\func\}@c
5345 @end macro
5346 @end iftex
5347
5348 @menu
5349 * Brace/Paren Line-Up::
5350 * List Line-Up::
5351 * Operator Line-Up::
5352 * Comment Line-Up::
5353 * Misc Line-Up::
5354 @end menu
5355
5356 @comment !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
5357 @node Brace/Paren Line-Up, List Line-Up, Line-Up Functions, Line-Up Functions
5358 @comment node-name, next, previous, up
5359 @subsection Brace and Parenthesis Line-Up Functions
5360 @comment !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
5361
5362 The line-up functions here calculate the indentation for braces,
5363 parentheses and statements within brace blocks.
5364
5365 @defun c-lineup-close-paren
5366 @findex lineup-close-paren (c-)
5367 Line up the closing paren under its corresponding open paren if the
5368 open paren is followed by code. If the open paren ends its line, no
5369 indentation is added. E.g:
5370
5371 @example
5372 @group
5373 main (int,
5374 char **
5375 ) @hereFn{c-lineup-close-paren}
5376 @end group
5377 @end example
5378
5379 @noindent
5380 and
5381
5382 @example
5383 @group
5384 main (
5385 int, char **
5386 ) @hereFn{c-lineup-close-paren}
5387 @end group
5388 @end example
5389
5390 As a special case, if a brace block is opened at the same line as the
5391 open parenthesis of the argument list, the indentation is
5392 @code{c-basic-offset} instead of the open paren column. See
5393 @code{c-lineup-arglist} for further discussion of this ``DWIM'' measure.
5394
5395 @workswith All @code{*-close} symbols.
5396 @end defun
5397
5398 @comment ------------------------------------------------------------
5399
5400 @anchor{c-lineup-arglist-close-under-paren}
5401 @defun c-lineup-arglist-close-under-paren
5402 @findex lineup-arglist-close-under-paren (c-)
5403 Set your @code{arglist-close} syntactic symbol to this line-up function
5404 so that parentheses that close argument lists will line up under the
5405 parenthesis that opened the argument list. It can also be used with
5406 @code{arglist-cont} and @code{arglist-cont-nonempty} to line up all
5407 lines inside a parenthesis under the open paren.
5408
5409 As a special case, if a brace block is opened at the same line as the
5410 open parenthesis of the argument list, the indentation is
5411 @code{c-basic-offset} only. See @code{c-lineup-arglist} for further
5412 discussion of this ``DWIM'' measure.
5413
5414 @workswith Almost all symbols, but are typically most useful on
5415 @code{arglist-close}, @code{brace-list-close}, @code{arglist-cont} and
5416 @code{arglist-cont-nonempty}.
5417 @end defun
5418
5419 @comment ------------------------------------------------------------
5420
5421 @defun c-indent-one-line-block
5422 @findex indent-one-line-block (c-)
5423 Indent a one line block @code{c-basic-offset} extra. E.g:
5424
5425 @example
5426 @group
5427 if (n > 0)
5428 @{m+=n; n=0;@} @hereFn{c-indent-one-line-block}
5429 @sssTBasicOffset{}
5430 @end group
5431 @end example
5432
5433 @noindent
5434 and
5435
5436 @example
5437 @group
5438 if (n > 0)
5439 @{ @hereFn{c-indent-one-line-block}
5440 m+=n; n=0;
5441 @}
5442 @end group
5443 @end example
5444
5445 The block may be surrounded by any kind of parenthesis characters.
5446 @code{nil} is returned if the line doesn't start with a one line block,
5447 which makes the function usable in list expressions.
5448
5449 @workswith Almost all syntactic symbols, but most useful on the
5450 @code{-open} symbols.
5451 @end defun
5452
5453 @comment ------------------------------------------------------------
5454
5455 @defun c-indent-multi-line-block
5456 @findex indent-multi-line-block (c-)
5457 Indent a multiline block @code{c-basic-offset} extra. E.g:
5458
5459 @example
5460 @group
5461 int *foo[] = @{
5462 NULL,
5463 @{17@}, @hereFn{c-indent-multi-line-block}
5464 @end group
5465 @end example
5466
5467 @noindent
5468 and
5469
5470 @example
5471 @group
5472 int *foo[] = @{
5473 NULL,
5474 @{ @hereFn{c-indent-multi-line-block}
5475 17
5476 @},
5477 @sssTBasicOffset{}
5478 @end group
5479 @end example
5480
5481 The block may be surrounded by any kind of parenthesis characters.
5482 @code{nil} is returned if the line doesn't start with a multiline
5483 block, which makes the function usable in list expressions.
5484
5485 @workswith Almost all syntactic symbols, but most useful on the
5486 @code{-open} symbols.
5487 @end defun
5488
5489 @comment ------------------------------------------------------------
5490
5491 @defun c-lineup-runin-statements
5492 @findex lineup-runin-statements (c-)
5493 Line up statements for coding standards which place the first statement
5494 in a block on the same line as the block opening brace@footnote{Run-in
5495 style doesn't really work too well. You might need to write your own
5496 custom line-up functions to better support this style.}. E.g:
5497
5498 @example
5499 @group
5500 int main()
5501 @{ puts ("Hello!");
5502 return 0; @hereFn{c-lineup-runin-statements}
5503 @}
5504 @end group
5505 @end example
5506
5507 If there is no statement after the opening brace to align with,
5508 @code{nil} is returned. This makes the function usable in list
5509 expressions.
5510
5511 @workswith The @code{statement} syntactic symbol.
5512 @end defun
5513
5514 @comment ------------------------------------------------------------
5515
5516 @defun c-lineup-inexpr-block
5517 @findex lineup-inexpr-block (c-)
5518 This can be used with the in-expression block symbols to indent the
5519 whole block to the column where the construct is started. E.g. for Java
5520 anonymous classes, this lines up the class under the @samp{new} keyword,
5521 and in Pike it lines up the lambda function body under the @samp{lambda}
5522 keyword. Returns @code{nil} if the block isn't part of such a
5523 construct.
5524
5525 @workswith @code{inlambda}, @code{inexpr-statement},
5526 @code{inexpr-class}.
5527 @end defun
5528
5529 @comment ------------------------------------------------------------
5530
5531 @defun c-lineup-after-whitesmith-blocks
5532 @findex lineup-after-whitesmith-blocks (c-)
5533 Compensate for Whitesmith style indentation of blocks. Due to the way
5534 @ccmode{} calculates anchor positions for normal lines inside blocks,
5535 this function is necessary for those lines to get correct Whitesmith
5536 style indentation. Consider the following examples:
5537
5538 @example
5539 @group
5540 int foo()
5541 @{
5542 a;
5543 x; @hereFn{c-lineup-after-whitesmith-blocks}
5544 @end group
5545 @end example
5546
5547 @example
5548 @group
5549 int foo()
5550 @{
5551 @{
5552 a;
5553 @}
5554 x; @hereFn{c-lineup-after-whitesmith-blocks}
5555 @end group
5556 @end example
5557
5558 The fact that the line with @code{x} is preceded by a Whitesmith style
5559 indented block in the latter case and not the first should not affect
5560 its indentation. But since CC Mode in cases like this uses the
5561 indentation of the preceding statement as anchor position, the @code{x}
5562 would in the second case be indented too much if the offset for
5563 @code{statement} was set simply to zero.
5564
5565 This lineup function corrects for this situation by detecting if the
5566 anchor position is at an open paren character. In that case, it instead
5567 indents relative to the surrounding block just like
5568 @code{c-lineup-whitesmith-in-block}.
5569
5570 @workswith @code{brace-list-entry}, @code{brace-entry-open},
5571 @code{statement}, @code{arglist-cont}.
5572 @end defun
5573
5574 @comment ------------------------------------------------------------
5575
5576 @defun c-lineup-whitesmith-in-block
5577 @findex lineup-whitesmith-in-block (c-)
5578 Line up lines inside a block in Whitesmith style. It's done in a way
5579 that works both when the opening brace hangs and when it doesn't. E.g:
5580
5581 @example
5582 @group
5583 something
5584 @{
5585 foo; @hereFn{c-lineup-whitesmith-in-block}
5586 @}
5587 @end group
5588 @end example
5589
5590 @noindent
5591 and
5592
5593 @example
5594 @group
5595 something @{
5596 foo; @hereFn{c-lineup-whitesmith-in-block}
5597 @}
5598 @sssTBasicOffset{}
5599 @end group
5600 @end example
5601
5602 In the first case the indentation is kept unchanged, in the second
5603 @code{c-basic-offset} is added.
5604
5605 @workswith @code{defun-close}, @code{defun-block-intro},
5606 @code{inline-close}, @code{block-close}, @code{brace-list-close},
5607 @code{brace-list-intro}, @code{statement-block-intro},
5608 @code{arglist-intro}, @code{arglist-cont-nonempty},
5609 @code{arglist-close}, and all @code{in*} symbols, e.g. @code{inclass}
5610 and @code{inextern-lang}.
5611 @end defun
5612
5613 @comment !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
5614 @node List Line-Up, Operator Line-Up, Brace/Paren Line-Up, Line-Up Functions
5615 @comment node-name, next, previous, up
5616 @subsection List Line-Up Functions
5617 @comment !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
5618
5619 The line-up functions here calculate the indentation for lines which
5620 form lists of items, usually separated by commas.
5621
5622 The function @ref{c-lineup-arglist-close-under-paren}, which is mainly
5623 for indenting a close parenthesis, is also useful for the lines
5624 contained within parentheses.
5625
5626 @defun c-lineup-arglist
5627 @findex lineup-arglist (c-)
5628 Line up the current argument line under the first argument.
5629
5630 As a special case, if an argument on the same line as the open
5631 parenthesis starts with a brace block opener, the indentation is
5632 @code{c-basic-offset} only. This is intended as a ``DWIM'' measure in
5633 cases like macros that contain statement blocks, e.g:
5634
5635 @example
5636 @group
5637 A_VERY_LONG_MACRO_NAME (@{
5638 some (code, with + long, lines * in[it]);
5639 @});
5640 @sssTBasicOffset{}
5641 @end group
5642 @end example
5643
5644 This is motivated partly because it's more in line with how code
5645 blocks are handled, and partly since it approximates the behavior of
5646 earlier CC Mode versions, which due to inaccurate analysis tended to
5647 indent such cases this way.
5648
5649 @workswith @code{arglist-cont-nonempty}, @code{arglist-close}.
5650 @end defun
5651
5652 @comment ------------------------------------------------------------
5653
5654 @defun c-lineup-arglist-intro-after-paren
5655 @findex lineup-arglist-intro-after-paren (c-)
5656 Line up a line to just after the open paren of the surrounding paren or
5657 brace block.
5658
5659 @workswith @code{defun-block-intro}, @code{brace-list-intro},
5660 @code{statement-block-intro}, @code{statement-case-intro},
5661 @code{arglist-intro}.
5662 @end defun
5663
5664 @comment ------------------------------------------------------------
5665
5666 @defun c-lineup-multi-inher
5667 @findex lineup-multi-inher (c-)
5668 Line up the classes in C++ multiple inheritance clauses and member
5669 initializers under each other. E.g:
5670
5671 @example
5672 @group
5673 Foo::Foo (int a, int b):
5674 Cyphr (a),
5675 Bar (b) @hereFn{c-lineup-multi-inher}
5676 @end group
5677 @end example
5678
5679 @noindent
5680 and
5681
5682 @example
5683 @group
5684 class Foo
5685 : public Cyphr,
5686 public Bar @hereFn{c-lineup-multi-inher}
5687 @end group
5688 @end example
5689
5690 @noindent
5691 and
5692
5693 @example
5694 @group
5695 Foo::Foo (int a, int b)
5696 : Cyphr (a)
5697 , Bar (b) @hereFn{c-lineup-multi-inher}
5698 @end group
5699 @end example
5700
5701 @workswith @code{inher-cont}, @code{member-init-cont}.
5702 @end defun
5703
5704 @comment ------------------------------------------------------------
5705
5706 @defun c-lineup-java-inher
5707 @findex lineup-java-inher (c-)
5708 Line up Java implements and extends declarations. If class names
5709 follow on the same line as the @samp{implements}/@samp{extends}
5710 keyword, they are lined up under each other. Otherwise, they are
5711 indented by adding @code{c-basic-offset} to the column of the keyword.
5712 E.g:
5713
5714 @example
5715 @group
5716 class Foo
5717 extends
5718 Bar @hereFn{c-lineup-java-inher}
5719 @sssTBasicOffset{}
5720 @end group
5721 @end example
5722
5723 @noindent
5724 and
5725
5726 @example
5727 @group
5728 class Foo
5729 extends Cyphr,
5730 Bar @hereFn{c-lineup-java-inher}
5731 @end group
5732 @end example
5733
5734 @workswith @code{inher-cont}.
5735 @end defun
5736
5737 @comment ------------------------------------------------------------
5738
5739 @defun c-lineup-java-throws
5740 @findex lineup-java-throws (c-)
5741 Line up Java throws declarations. If exception names follow on the
5742 same line as the throws keyword, they are lined up under each other.
5743 Otherwise, they are indented by adding @code{c-basic-offset} to the
5744 column of the @samp{throws} keyword. The @samp{throws} keyword itself
5745 is also indented by @code{c-basic-offset} from the function declaration
5746 start if it doesn't hang. E.g:
5747
5748 @example
5749 @group
5750 int foo()
5751 throws @hereFn{c-lineup-java-throws}
5752 Bar @hereFn{c-lineup-java-throws}
5753 @sssTsssTBasicOffset{}
5754 @end group
5755 @end example
5756
5757 @noindent
5758 and
5759
5760 @example
5761 @group
5762 int foo() throws Cyphr,
5763 Bar, @hereFn{c-lineup-java-throws}
5764 Vlod @hereFn{c-lineup-java-throws}
5765 @end group
5766 @end example
5767
5768 @workswith @code{func-decl-cont}.
5769 @end defun
5770
5771 @comment ------------------------------------------------------------
5772
5773 @defun c-lineup-template-args
5774 @findex lineup-template-args (c-)
5775 Line up the arguments of a template argument list under each other, but
5776 only in the case where the first argument is on the same line as the
5777 opening @samp{<}.
5778
5779 To allow this function to be used in a list expression, @code{nil} is
5780 returned if there's no template argument on the first line.
5781
5782 @workswith @code{template-args-cont}.
5783 @end defun
5784
5785 @comment ------------------------------------------------------------
5786
5787 @defun c-lineup-ObjC-method-call
5788 @findex lineup-ObjC-method-call (c-)
5789 For Objective-C code, line up selector args as Emacs Lisp mode does
5790 with function args: go to the position right after the message receiver,
5791 and if you are at the end of the line, indent the current line
5792 c-basic-offset columns from the opening bracket; otherwise you are
5793 looking at the first character of the first method call argument, so
5794 lineup the current line with it.
5795
5796 @workswith @code{objc-method-call-cont}.
5797 @end defun
5798
5799 @comment ------------------------------------------------------------
5800
5801 @defun c-lineup-ObjC-method-args
5802 @findex lineup-ObjC-method-args (c-)
5803 For Objective-C code, line up the colons that separate args. The colon
5804 on the current line is aligned with the one on the first line.
5805
5806 @workswith @code{objc-method-args-cont}.
5807 @end defun
5808
5809 @comment ------------------------------------------------------------
5810
5811 @defun c-lineup-ObjC-method-args-2
5812 @findex lineup-ObjC-method-args-2 (c-)
5813 Similar to @code{c-lineup-ObjC-method-args} but lines up the colon on
5814 the current line with the colon on the previous line.
5815
5816 @workswith @code{objc-method-args-cont}.
5817 @end defun
5818
5819 @comment !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
5820 @node Operator Line-Up, Comment Line-Up, List Line-Up, Line-Up Functions
5821 @comment node-name, next, previous, up
5822 @subsection Operator Line-Up Functions
5823 @comment !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
5824
5825 The line-up functions here calculate the indentation for lines which
5826 start with an operator, by lining it up with something on the previous
5827 line.
5828
5829 @defun c-lineup-argcont
5830 @findex lineup-argcont (c-)
5831 Line up a continued argument. E.g:
5832
5833 @example
5834 @group
5835 foo (xyz, aaa + bbb + ccc
5836 + ddd + eee + fff); @hereFn{c-lineup-argcont}
5837 @end group
5838 @end example
5839
5840 Only continuation lines like this are touched, @code{nil} is returned on
5841 lines which are the start of an argument.
5842
5843 Within a gcc @code{asm} block, @code{:} is recognised as an argument
5844 separator, but of course only between operand specifications, not in the
5845 expressions for the operands.
5846
5847 @workswith @code{arglist-cont}, @code{arglist-cont-nonempty}.
5848 @end defun
5849
5850 @comment ------------------------------------------------------------
5851
5852 @defun c-lineup-arglist-operators
5853 @findex lineup-arglist-operators (c-)
5854 Line up lines starting with an infix operator under the open paren.
5855 Return @code{nil} on lines that don't start with an operator, to leave
5856 those cases to other line-up functions. Example:
5857
5858 @example
5859 @group
5860 if ( x < 10
5861 || at_limit (x, @hereFn{c-lineup-arglist-operators}
5862 list) @hereFn{c-lineup-arglist-operators@r{ returns nil}}
5863 )
5864 @end group
5865 @end example
5866
5867 Since this function doesn't do anything for lines without an infix
5868 operator you typically want to use it together with some other lineup
5869 settings, e.g. as follows (the @code{arglist-close} setting is just a
5870 suggestion to get a consistent style):
5871
5872 @example
5873 (c-set-offset 'arglist-cont
5874 '(c-lineup-arglist-operators 0))
5875 (c-set-offset 'arglist-cont-nonempty
5876 '(c-lineup-arglist-operators c-lineup-arglist))
5877 (c-set-offset 'arglist-close
5878 '(c-lineup-arglist-close-under-paren))
5879 @end example
5880
5881 @workswith @code{arglist-cont}, @code{arglist-cont-nonempty}.
5882 @end defun
5883
5884 @comment ------------------------------------------------------------
5885
5886 @defun c-lineup-assignments
5887 @findex lineup-assignments (c-)
5888 Line up the current line after the assignment operator on the first line
5889 in the statement. If there isn't any, return nil to allow stacking with
5890 other line-up functions. If the current line contains an assignment
5891 operator too, try to align it with the first one.
5892
5893 @workswith @code{topmost-intro-cont}, @code{statement-cont},
5894 @code{arglist-cont}, @code{arglist-cont-nonempty}.
5895
5896 @end defun
5897
5898 @comment ------------------------------------------------------------
5899
5900 @defun c-lineup-math
5901 @findex lineup-math (c-)
5902 Like @code{c-lineup-assignments} but indent with @code{c-basic-offset}
5903 if no assignment operator was found on the first line. I.e. this
5904 function is the same as specifying a list @code{(c-lineup-assignments
5905 +)}. It's provided for compatibility with old configurations.
5906
5907 @workswith @code{topmost-intro-cont}, @code{statement-cont},
5908 @code{arglist-cont}, @code{arglist-cont-nonempty}.
5909 @end defun
5910
5911 @comment ------------------------------------------------------------
5912
5913 @defun c-lineup-cascaded-calls
5914 @findex lineup-cascaded-calls (c-)
5915 Line up ``cascaded calls'' under each other. If the line begins with
5916 @code{->} or @code{.} and the preceding line ends with one or more
5917 function calls preceded by the same token, then the arrow is lined up
5918 with the first of those tokens. E.g:
5919
5920 @example
5921 @group
5922 r = proc->add(17)->add(18)
5923 ->add(19) + @hereFn{c-lineup-cascaded-calls}
5924 offset; @hereFn{c-lineup-cascaded-calls@r{ (inactive)}}
5925 @end group
5926 @end example
5927
5928 In any other situation @code{nil} is returned to allow use in list
5929 expressions.
5930
5931 @workswith @code{topmost-intro-cont}, @code{statement-cont},
5932 @code{arglist-cont}, @code{arglist-cont-nonempty}.
5933 @end defun
5934
5935 @comment ------------------------------------------------------------
5936
5937 @defun c-lineup-streamop
5938 @findex lineup-streamop (c-)
5939 Line up C++ stream operators (i.e. @samp{<<} and @samp{>>}).
5940
5941 @workswith @code{stream-op}.
5942 @end defun
5943
5944 @comment ------------------------------------------------------------
5945
5946 @defun c-lineup-string-cont
5947 @findex lineup-string-cont (c-)
5948 Line up a continued string under the one it continues. A continued
5949 string in this sense is where a string literal follows directly after
5950 another one. E.g:
5951
5952 @example
5953 @group
5954 result = prefix + "A message "
5955 "string."; @hereFn{c-lineup-string-cont}
5956 @end group
5957 @end example
5958
5959 @code{nil} is returned in other situations, to allow stacking with other
5960 lineup functions.
5961
5962 @workswith @code{topmost-intro-cont}, @code{statement-cont},
5963 @code{arglist-cont}, @code{arglist-cont-nonempty}.
5964 @end defun
5965
5966
5967 @comment !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
5968 @node Comment Line-Up, Misc Line-Up, Operator Line-Up, Line-Up Functions
5969 @comment node-name, next, previous, up
5970 @subsection Comment Line-Up Functions
5971 @comment !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
5972
5973 The lineup functions here calculate the indentation for several types
5974 of comment structure.
5975
5976 @defun c-lineup-C-comments
5977 @findex lineup-C-comments (c-)
5978 Line up C block comment continuation lines. Various heuristics are used
5979 to handle most of the common comment styles. Some examples:
5980
5981 @example
5982 @group
5983 /* /** /*
5984 * text * text text
5985 */ */ */
5986 @end group
5987 @end example
5988
5989 @example
5990 @group
5991 /* text /* /**
5992 text ** text ** text
5993 */ */ */
5994 @end group
5995 @end example
5996
5997 @example
5998 @group
5999 /**************************************************
6000 * text
6001 *************************************************/
6002 @end group
6003 @end example
6004
6005 @vindex comment-start-skip
6006 @example
6007 @group
6008 /**************************************************
6009 Free form text comments:
6010 In comments with a long delimiter line at the
6011 start, the indentation is kept unchanged for lines
6012 that start with an empty comment line prefix. The
6013 delimiter line is whatever matches the
6014 @code{comment-start-skip} regexp.
6015 **************************************************/
6016 @end group
6017 @end example
6018
6019 The style variable @code{c-comment-prefix-regexp} is used to recognize
6020 the comment line prefix, e.g. the @samp{*} that usually starts every
6021 line inside a comment.
6022
6023 @workswith The @code{c} syntactic symbol.
6024 @end defun
6025
6026 @comment ------------------------------------------------------------
6027
6028 @defun c-lineup-comment
6029 @findex lineup-comment (c-)
6030 Line up a comment-only line according to the style variable
6031 @code{c-comment-only-line-offset}. If the comment is lined up with a
6032 comment starter on the previous line, that alignment is preserved.
6033
6034 @defopt c-comment-only-line-offset
6035 @vindex comment-only-line-offset (c-)
6036 This style variable specifies the extra offset for the line. It can
6037 contain an integer or a cons cell of the form
6038
6039 @example
6040 (@r{@var{non-anchored-offset}} . @r{@var{anchored-offset}})
6041 @end example
6042
6043 @noindent
6044 where @var{non-anchored-offset} is the amount of offset given to
6045 non-column-zero anchored lines, and @var{anchored-offset} is the amount
6046 of offset to give column-zero anchored lines. Just an integer as value
6047 is equivalent to @code{(@r{@var{value}} . -1000)}.
6048 @end defopt
6049
6050 @workswith @code{comment-intro}.
6051 @end defun
6052
6053 @comment ------------------------------------------------------------
6054
6055 @defun c-lineup-knr-region-comment
6056 @findex lineup-knr-region-comment (c-)
6057 Line up a comment in the ``K&R region'' with the declaration. That is
6058 the region between the function or class header and the beginning of the
6059 block. E.g:
6060
6061 @example
6062 @group
6063 int main()
6064 /* Called at startup. */ @hereFn{c-lineup-knr-region-comment}
6065 @{
6066 return 0;
6067 @}
6068 @end group
6069 @end example
6070
6071 Return @code{nil} if called in any other situation, to be useful in list
6072 expressions.
6073
6074 @workswith @code{comment-intro}.
6075 @end defun
6076
6077 @comment !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
6078 @node Misc Line-Up, , Comment Line-Up, Line-Up Functions
6079 @comment node-name, next, previous, up
6080 @subsection Miscellaneous Line-Up Functions
6081 @comment !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
6082
6083 The line-up functions here are the odds and ends which didn't fit into
6084 any earlier category.
6085
6086 @defun c-lineup-dont-change
6087 @findex lineup-dont-change (c-)
6088 This lineup function makes the line stay at whatever indentation it
6089 already has; think of it as an identity function for lineups.
6090
6091 @workswith Any syntactic symbol.
6092 @end defun
6093
6094 @comment ------------------------------------------------------------
6095
6096 @defun c-lineup-cpp-define
6097 @findex lineup-cpp-define (c-)
6098 Line up macro continuation lines according to the indentation of the
6099 construct preceding the macro. E.g:
6100
6101 @example
6102 @group
6103 const char msg[] = @hereFn{@r{The beginning of the preceding construct.}}
6104 \"Some text.\";
6105
6106 #define X(A, B) \
6107 do @{ \ @hereFn{c-lineup-cpp-define}
6108 printf (A, B); \
6109 @} while (0)
6110 @end group
6111 @end example
6112
6113 @noindent
6114 and:
6115
6116 @example
6117 @group
6118 int dribble() @{
6119 if (!running) @hereFn{@r{The beginning of the preceding construct.}}
6120 error(\"Not running!\");
6121
6122 #define X(A, B) \
6123 do @{ \ @hereFn{c-lineup-cpp-define}
6124 printf (A, B); \
6125 @} while (0)
6126 @end group
6127 @end example
6128
6129 If @code{c-syntactic-indentation-in-macros} is non-@code{nil}, the
6130 function returns the relative indentation to the macro start line to
6131 allow accumulation with other offsets. E.g. in the following cases,
6132 @code{cpp-define-intro} is combined with the
6133 @code{statement-block-intro} that comes from the @samp{do @{} that hangs
6134 on the @samp{#define} line:
6135
6136 @example
6137 @group
6138 const char msg[] =
6139 \"Some text.\";
6140
6141 #define X(A, B) do @{ \
6142 printf (A, B); \ @hereFn{c-lineup-cpp-define}
6143 this->refs++; \
6144 @} while (0) @hereFn{c-lineup-cpp-define}
6145 @end group
6146 @end example
6147
6148 @noindent
6149 and:
6150
6151 @example
6152 @group
6153 int dribble() @{
6154 if (!running)
6155 error(\"Not running!\");
6156
6157 #define X(A, B) do @{ \
6158 printf (A, B); \ @hereFn{c-lineup-cpp-define}
6159 this->refs++; \
6160 @} while (0) @hereFn{c-lineup-cpp-define}
6161 @end group
6162 @end example
6163
6164 The relative indentation returned by @code{c-lineup-cpp-define} is zero
6165 and two, respectively, on the two lines in each of these examples. They
6166 are then added to the two column indentation that
6167 @code{statement-block-intro} gives in both cases here.
6168
6169 If the relative indentation is zero, then @code{nil} is returned
6170 instead. That is useful in a list expression to specify the default
6171 indentation on the top level.
6172
6173 If @code{c-syntactic-indentation-in-macros} is @code{nil} then this
6174 function keeps the current indentation, except for empty lines (ignoring
6175 the ending backslash) where it takes the indentation from the closest
6176 preceding nonempty line in the macro. If there's no such line in the
6177 macro then the indentation is taken from the construct preceding it, as
6178 described above.
6179
6180 @workswith @code{cpp-define-intro}.
6181 @end defun
6182
6183 @comment ------------------------------------------------------------
6184
6185 @defun c-lineup-gcc-asm-reg
6186 @findex lineup-gcc-asm-reg (c-)
6187 Line up a gcc asm register under one on a previous line.
6188
6189 @example
6190 @group
6191 asm ("foo %1, %0\n"
6192 "bar %0, %1"
6193 : "=r" (w),
6194 "=r" (x)
6195 : "0" (y),
6196 "1" (z));
6197 @end group
6198 @end example
6199
6200 The @samp{x} line is aligned to the text after the @samp{:} on the
6201 @samp{w} line, and similarly @samp{z} under @samp{y}.
6202
6203 This is done only in an @samp{asm} or @samp{__asm__} block, and only to
6204 those lines mentioned. Anywhere else @code{nil} is returned. The usual
6205 arrangement is to have this routine as an extra feature at the start of
6206 arglist lineups, e.g.
6207
6208 @example
6209 (c-lineup-gcc-asm-reg c-lineup-arglist)
6210 @end example
6211
6212 @workswith @code{arglist-cont}, @code{arglist-cont-nonempty}.
6213 @end defun
6214
6215 @comment ------------------------------------------------------------
6216
6217 @defun c-lineup-topmost-intro-cont
6218 @findex lineup-topmost-intro-cont (c-)
6219 Line up declaration continuation lines zero or one indentation
6220 step@footnote{This function is mainly provided to mimic the behavior of
6221 CC Mode 5.28 and earlier where this case wasn't handled consistently so
6222 that those lines could be analyzed as either topmost-intro-cont or
6223 statement-cont. It's used for @code{topmost-intro-cont} by default, but
6224 you might consider using @code{+} instead.}. For lines preceding a
6225 definition, zero is used. For other lines, @code{c-basic-offset} is
6226 added to the indentation. E.g:
6227
6228 @example
6229 @group
6230 int
6231 neg (int i) @hereFn{c-lineup-topmost-intro-cont}
6232 @{
6233 return -i;
6234 @}
6235 @end group
6236 @end example
6237
6238 @noindent
6239 and
6240
6241 @example
6242 @group
6243 struct
6244 larch @hereFn{c-lineup-topmost-intro-cont}
6245 @{
6246 double height;
6247 @}
6248 the_larch, @hereFn{c-lineup-topmost-intro-cont}
6249 another_larch; @hereFn{c-lineup-topmost-intro-cont}
6250 @sssTBasicOffset{}
6251 @end group
6252 @end example
6253
6254 @noindent
6255 and
6256
6257 @example
6258 @group
6259 struct larch
6260 the_larch, @hereFn{c-lineup-topmost-intro-cont}
6261 another_larch; @hereFn{c-lineup-topmost-intro-cont}
6262 @end group
6263 @end example
6264
6265 @workswith @code{topmost-intro-cont}.
6266 @end defun
6267
6268 @comment !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
6269 @node Custom Line-Up, Other Indentation, Line-Up Functions, Customizing Indentation
6270 @comment node-name, next, previous, up
6271 @section Custom Line-Up Functions
6272 @cindex customization, indentation functions
6273 @comment !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
6274
6275 The most flexible way to customize indentation is by writing custom
6276 line-up functions, and associating them with specific syntactic
6277 symbols (@pxref{c-offsets-alist}). Depending on the effect you want,
6278 it might be better to write a @code{c-special-indent-hook} function
6279 rather than a line-up function (@pxref{Other Indentation}).
6280
6281 @ccmode{} comes with an extensive set of predefined line-up functions,
6282 not all of which are used by the default styles. So there's a good
6283 chance the function you want already exists. @xref{Line-Up
6284 Functions}, for a list of them. If you write your own line-up
6285 function, it's probably a good idea to start working from one of these
6286 predefined functions, which can be found in the file
6287 @file{cc-align.el}. If you have written a line-up function that you
6288 think is generally useful, you're very welcome to contribute it;
6289 please contact @email{bug-cc-mode@@gnu.org}.
6290
6291 Line-up functions are passed a single argument, the syntactic
6292 element (see below). The return value is a @code{c-offsets-alist}
6293 offset specification: for example, an integer, a symbol such as
6294 @code{+}, a vector, @code{nil}@footnote{Returning @code{nil} is useful
6295 when the offset specification for a syntactic element is a list
6296 containing the line-up function (@pxref{c-offsets-alist}).}, or even
6297 another line-up function. Full details of these are in
6298 @ref{c-offsets-alist}.
6299
6300 Line-up functions must not move point or change the content of the
6301 buffer (except temporarily). They are however allowed to do
6302 @dfn{hidden buffer changes}, i.e. setting text properties for caching
6303 purposes etc. Buffer undo recording is disabled while they run.
6304
6305 The syntactic element passed as the parameter to a line-up function is
6306 a cons cell of the form
6307
6308 @example
6309 (@r{@var{syntactic-symbol}} . @r{@var{anchor-position}})
6310 @end example
6311
6312 @noindent
6313 @c FIXME!!! The following sentence might be better omitted, since the
6314 @c information is in the cross reference "Syntactic Analysis". 2005/10/2.
6315 where @var{syntactic-symbol} is the symbol that the function was
6316 called for, and @var{anchor-position} is the anchor position (if any)
6317 for the construct that triggered the syntactic symbol
6318 (@pxref{Syntactic Analysis}). This cons cell is how the syntactic
6319 element of a line used to be represented in @ccmode{} 5.28 and
6320 earlier. Line-up functions are still passed this cons cell, so as to
6321 preserve compatibility with older configurations. In the future, we
6322 may decide to convert to using the full list format---you can prepare
6323 your setup for this by using the access functions
6324 (@code{c-langelem-sym}, etc.) described below.
6325
6326 @vindex c-syntactic-element
6327 @vindex syntactic-element (c-)
6328 @vindex c-syntactic-context
6329 @vindex syntactic-context (c-)
6330 Some syntactic symbols, e.g. @code{arglist-cont-nonempty}, have more
6331 info in the syntactic element - typically other positions that can be
6332 interesting besides the anchor position. That info can't be accessed
6333 through the passed argument, which is a cons cell. Instead, you can
6334 get this information from the variable @code{c-syntactic-element},
6335 which is dynamically bound to the complete syntactic element. The
6336 variable @code{c-syntactic-context} might also be useful - it gets
6337 dynamically bound to the complete syntactic context. @xref{Custom
6338 Braces}.
6339
6340 @ccmode{} provides a few functions to access parts of syntactic
6341 elements in a more abstract way. Besides making the code easier to
6342 read, they also hide the difference between the old cons cell form
6343 used in the line-up function argument and the new list form used in
6344 @code{c-syntactic-element} and everywhere else. The functions are:
6345
6346 @defun c-langelem-sym langelem
6347 @findex langelem-sym (c-)
6348 Return the syntactic symbol in @var{langelem}.
6349 @end defun
6350
6351 @defun c-langelem-pos langelem
6352 @findex langelem-pos (c-)
6353 Return the anchor position in @var{langelem}, or nil if there is none.
6354 @end defun
6355
6356 @defun c-langelem-col langelem &optional preserve-point
6357 @findex langelem-col (c-)
6358 Return the column of the anchor position in @var{langelem}. Also move
6359 the point to that position unless @var{preserve-point} is
6360 non-@code{nil}.
6361 @end defun
6362
6363 @defun c-langelem-2nd-pos langelem
6364 @findex langelem-2nd-pos (c-)
6365 Return the secondary position in @var{langelem}, or @code{nil} if there
6366 is none.
6367
6368 Note that the return value of this function is always @code{nil} if
6369 @var{langelem} is in the old cons cell form. Thus this function is
6370 only meaningful when used on syntactic elements taken from
6371 @code{c-syntactic-element} or @code{c-syntactic-context}.
6372 @end defun
6373
6374 Custom line-up functions can be as simple or as complex as you like, and
6375 any syntactic symbol that appears in @code{c-offsets-alist} can have a
6376 custom line-up function associated with it.
6377
6378 @comment !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
6379 @node Other Indentation, , Custom Line-Up, Customizing Indentation
6380 @comment node-name, next, previous, up
6381 @section Other Special Indentations
6382 @comment !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
6383
6384 Here are the remaining odds and ends regarding indentation:
6385
6386 @defopt c-label-minimum-indentation
6387 @vindex label-minimum-indentation (c-)
6388 In @samp{gnu} style (@pxref{Built-in Styles}), a minimum indentation is
6389 imposed on lines inside code blocks. This minimum indentation is
6390 controlled by this style variable. The default value is 1.
6391
6392 @findex c-gnu-impose-minimum
6393 @findex gnu-impose-minimum (c-)
6394 It's the function @code{c-gnu-impose-minimum} that enforces this minimum
6395 indentation. It must be present on @code{c-special-indent-hook} to
6396 work.
6397 @end defopt
6398
6399 @defopt c-special-indent-hook
6400 @vindex special-indent-hook (c-)
6401 This style variable is a standard hook variable that is called after
6402 every line is indented by @ccmode{}. It is called only if
6403 @code{c-syntactic-indentation} is non-@code{nil} (which it is by
6404 default (@pxref{Indentation Engine Basics})). You can put a function
6405 on this hook to do any special indentation or ad hoc line adjustments
6406 your style dictates, such as adding extra indentation to constructors
6407 or destructor declarations in a class definition, etc. Sometimes it
6408 is better to write a custom Line-up Function instead (@pxref{Custom
6409 Line-Up}).
6410
6411 When the indentation engine calls this hook, the variable
6412 @code{c-syntactic-context} is bound to the current syntactic context
6413 (i.e. what you would get by typing @kbd{C-c C-s} on the source line.
6414 @xref{Custom Braces}.). Note that you should not change point or mark
6415 inside a @code{c-special-indent-hook} function, i.e. you'll probably
6416 want to wrap your function in a @code{save-excursion}@footnote{The
6417 numerical value returned by @code{point} will change if you change the
6418 indentation of the line within a @code{save-excursion} form, but point
6419 itself will still be over the same piece of text.}.
6420
6421 Setting @code{c-special-indent-hook} in style definitions is handled
6422 slightly differently from other variables---A style can only add
6423 functions to this hook, not remove them. @xref{Style Variables}.
6424 @end defopt
6425
6426
6427 @comment !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
6428 @node Custom Macros, Odds and Ends, Customizing Indentation, Top
6429 @comment node-name, next, previous, up
6430 @chapter Customizing Macros
6431 @cindex macros
6432 @cindex preprocessor directives
6433 @comment !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
6434
6435 Normally, the lines in a multi-line macro are indented relative to
6436 eachother as though they were code. You can suppress this behaviour
6437 by setting the following user option:
6438
6439 @defopt c-syntactic-indentation-in-macros
6440 @vindex syntactic-indentation-in-macros (c-)
6441 Enable syntactic analysis inside macros, which is the default. If this
6442 is @code{nil}, all lines inside macro definitions are analyzed as
6443 @code{cpp-macro-cont}.
6444 @end defopt
6445
6446 @ccmode{} provides some tools to help keep the line continuation
6447 backslashes in macros neat and tidy. Their precise action is
6448 customized with these variables:
6449
6450 @defopt c-backslash-column
6451 @vindex backslash-column (c-)
6452 @defoptx c-backslash-max-column
6453 @vindex backslash-max-column (c-)
6454 These variables control the alignment columns for line continuation
6455 backslashes in multiline macros. They are used by the functions that
6456 automatically insert or align such backslashes,
6457 e.g. @code{c-backslash-region} and @code{c-context-line-break}.
6458
6459 @code{c-backslash-column} specifies the minimum column for the
6460 backslashes. If any line in the macro goes past this column, then the
6461 next tab stop (i.e. next multiple of @code{tab-width}) in that line is
6462 used as the alignment column for all the backslashes, so that they
6463 remain in a single column. However, if any lines go past
6464 @code{c-backslash-max-column} then the backslashes in the rest of the
6465 macro will be kept at that column, so that the lines which are too
6466 long ``stick out'' instead.
6467
6468 Don't ever set these variables to @code{nil}. If you want to disable
6469 the automatic alignment of backslashes, use
6470 @code{c-auto-align-backslashes}.
6471 @end defopt
6472
6473 @defopt c-auto-align-backslashes
6474 @vindex auto-align-backslashes (c-)
6475 Align automatically inserted line continuation backslashes if
6476 non-@code{nil}. When line continuation backslashes are inserted
6477 automatically for line breaks in multiline macros, e.g. by
6478 @code{c-context-line-break}, they are aligned with the other
6479 backslashes in the same macro if this flag is set.
6480
6481 If @code{c-auto-align-backslashes} is @code{nil}, automatically
6482 inserted backslashes are preceded by a single space, and backslashes
6483 get aligned only when you explicitly invoke the command
6484 @code{c-backslash-region} (@kbd{C-c C-\}).
6485 @end defopt
6486
6487 @comment !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
6488 @node Odds and Ends, Sample .emacs File, Custom Macros, Top
6489 @comment node-name, next, previous, up
6490 @chapter Odds and Ends
6491 @comment !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
6492
6493 The stuff that didn't fit in anywhere else is documented here.
6494
6495 @defopt c-require-final-newline
6496 @vindex require-final-newline (c-)
6497 Controls whether a final newline is enforced when the file is saved.
6498 The value is an association list that for each language mode specifies
6499 the value to give to @code{require-final-newline} (@pxref{Saving
6500 Buffers,,, @lispref{}, @lispreftitle{}}) at mode initialization. If a
6501 language isn't present on the association list, CC Mode won't touch
6502 @code{require-final-newline} in buffers for that language.
6503
6504 The default is to set @code{require-final-newline} to @code{t} in the
6505 languages that mandate that source files should end with newlines.
6506 These are C, C++ and Objective-C.
6507 @end defopt
6508
6509 @defopt c-echo-syntactic-information-p
6510 @vindex echo-syntactic-information-p (c-)
6511 If non-@code{nil}, the syntactic analysis for the current line is shown
6512 in the echo area when it's indented (unless
6513 @code{c-syntactic-indentation} is @code{nil}). That's useful when
6514 finding out which syntactic symbols to modify to get the indentation you
6515 want.
6516 @end defopt
6517
6518 @defopt c-report-syntactic-errors
6519 @vindex report-syntactic-errors (c-)
6520 If non-@code{nil}, certain syntactic errors are reported with a ding and
6521 a message, for example when an @code{else} is indented for which there
6522 is no corresponding @code{if}.
6523
6524 Note however that @ccmode{} doesn't make any special effort to check for
6525 syntactic errors; that's the job of the compiler. The reason it can
6526 report cases like the one above is that it can't find the correct
6527 anchoring position to indent the line in that case.
6528 @end defopt
6529
6530
6531 @comment !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
6532 @node Sample .emacs File, Performance Issues, Odds and Ends, Top
6533 @comment node-name, next, previous, up
6534 @appendix Sample .emacs File
6535 @comment !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
6536
6537 @verbatim
6538 ;; Here's a sample .emacs file fragment that might help you along the
6539 ;; way. Just copy this region and paste it into your .emacs file.
6540 ;; You might want to change some of the actual values.
6541
6542 ;; Make some non-standard key bindings. We can put these in
6543 ;; c-mode-base-map because c-mode-map, c++-mode-map, and so on,
6544 ;; inherit from it.
6545 (defun my-c-initialization-hook ()
6546 (define-key c-mode-base-map "\C-m" 'c-context-line-break)
6547 (define-key c-mode-base-map [?\C-\M-a] 'c-beginning-of-defun)
6548 (define-key c-mode-base-map [?\C-\M-e] 'c-end-of-defun)
6549 (add-hook 'c-initialization-hook 'my-c-initialization-hook)
6550
6551 ;; offset customizations not in my-c-style
6552 ;; This will take precedence over any setting of the syntactic symbol
6553 ;; made by a style.
6554 (setq c-offsets-alist '((member-init-intro . ++)))
6555
6556 ;; Create my personal style.
6557 (defconst my-c-style
6558 '((c-tab-always-indent . t)
6559 (c-comment-only-line-offset . 4)
6560 (c-hanging-braces-alist . ((substatement-open after)
6561 (brace-list-open)))
6562 (c-hanging-colons-alist . ((member-init-intro before)
6563 (inher-intro)
6564 (case-label after)
6565 (label after)
6566 (access-label after)))
6567 (c-cleanup-list . (scope-operator
6568 empty-defun-braces
6569 defun-close-semi))
6570 (c-offsets-alist . ((arglist-close . c-lineup-arglist)
6571 (substatement-open . 0)
6572 (case-label . 4)
6573 (block-open . 0)
6574 (knr-argdecl-intro . -)))
6575 (c-echo-syntactic-information-p . t))
6576 "My C Programming Style")
6577 (c-add-style "PERSONAL" my-c-style)
6578
6579 ;; Customizations for all modes in CC Mode.
6580 (defun my-c-mode-common-hook ()
6581 ;; set my personal style for the current buffer
6582 (c-set-style "PERSONAL")
6583 ;; other customizations
6584 (setq tab-width 8
6585 ;; this will make sure spaces are used instead of tabs
6586 indent-tabs-mode nil)
6587 ;; we like auto-newline, but not hungry-delete
6588 (c-toggle-auto-newline 1))
6589 (add-hook 'c-mode-common-hook 'my-c-mode-common-hook)
6590 @end verbatim
6591
6592 @comment !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
6593 @node Performance Issues, Limitations and Known Bugs, Sample .emacs File, Top
6594 @comment node-name, next, previous, up
6595 @chapter Performance Issues
6596 @cindex performance
6597 @comment !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
6598
6599 @comment FIXME: (ACM, 2003/5/24). Check whether AWK needs mentioning here.
6600
6601 C and its derivative languages are highly complex creatures. Often,
6602 ambiguous code situations arise that require @ccmode{} to scan large
6603 portions of the buffer to determine syntactic context. Such
6604 pathological code can cause @ccmode{} to perform fairly badly. This
6605 section gives some insight in how @ccmode{} operates, how that interacts
6606 with some coding styles, and what you can use to improve performance.
6607
6608 The overall goal is that @ccmode{} shouldn't be overly slow (i.e. take
6609 more than a fraction of a second) in any interactive operation.
6610 I.e. it's tuned to limit the maximum response time in single operations,
6611 which is sometimes at the expense of batch-like operations like
6612 reindenting whole blocks. If you find that @ccmode{} gradually gets
6613 slower and slower in certain situations, perhaps as the file grows in
6614 size or as the macro or comment you're editing gets bigger, then chances
6615 are that something isn't working right. You should consider reporting
6616 it, unless it's something that's mentioned in this section.
6617
6618 Because @ccmode{} has to scan the buffer backwards from the current
6619 insertion point, and because C's syntax is fairly difficult to parse in
6620 the backwards direction, @ccmode{} often tries to find the nearest
6621 position higher up in the buffer from which to begin a forward scan
6622 (it's typically an opening or closing parenthesis of some kind). The
6623 farther this position is from the current insertion point, the slower it
6624 gets.
6625
6626 @findex beginning-of-defun
6627 In earlier versions of @ccmode{}, we used to recommend putting the
6628 opening brace of a top-level construct@footnote{E.g. a function in C,
6629 or outermost class definition in C++ or Java.} into the leftmost
6630 column. Earlier still, this used to be a rigid Emacs constraint, as
6631 embodied in the @code{beginning-of-defun} function. @ccmode now
6632 caches syntactic information much better, so that the delay caused by
6633 searching for such a brace when it's not in column 0 is minimal,
6634 except perhaps when you've just moved a long way inside the file.
6635 Don't forget to rebind @kbd{C-M-a} and @kbd{C-M-e} to the @ccmode{}
6636 functions @code{beginning-of-defun} and @code{end-of-defun} if you're
6637 going to be hanging your braces! @xref{Sample .emacs File}.
6638
6639 @findex defun-prompt-regexp
6640 @vindex c-Java-defun-prompt-regexp
6641 @vindex Java-defun-prompt-regexp (c-)
6642 A special note about @code{defun-prompt-regexp} in Java mode: The common
6643 style is to hang the opening braces of functions and classes on the
6644 right side of the line, and that doesn't work well with the Emacs
6645 approach. @ccmode{} comes with a constant
6646 @code{c-Java-defun-prompt-regexp} which tries to define a regular
6647 expression usable for this style, but there are problems with it. In
6648 some cases it can cause @code{beginning-of-defun} to hang@footnote{This
6649 has been observed in Emacs 19.34 and XEmacs 19.15.}. For this reason,
6650 it is not used by default, but if you feel adventurous, you can set
6651 @code{defun-prompt-regexp} to it in your mode hook. In any event,
6652 setting and relying on @code{defun-prompt-regexp} will definitely slow
6653 things down because (X)Emacs will be doing regular expression searches a
6654 lot, so you'll probably be taking a hit either way!
6655
6656 @ccmode{} maintains a cache of the opening parentheses of the blocks
6657 surrounding the point, and it adapts that cache as the point is moved
6658 around. That means that in bad cases it can take noticeable time to
6659 indent a line in a new surrounding, but after that it gets fast as long
6660 as the point isn't moved far off. The farther the point is moved, the
6661 less useful is the cache. Since editing typically is done in ``chunks''
6662 rather than on single lines far apart from each other, the cache
6663 typically gives good performance even when the code doesn't fit the
6664 Emacs approach to finding the defun starts.
6665
6666 @vindex c-enable-xemacs-performance-kludge-p
6667 @vindex enable-xemacs-performance-kludge-p (c-)
6668 XEmacs users can set the variable
6669 @code{c-enable-xemacs-performance-kludge-p} to non-@code{nil}. This
6670 tells @ccmode{} to use XEmacs-specific built-in functions which, in some
6671 circumstances, can locate the top-most opening brace much more quickly than
6672 @code{beginning-of-defun}. Preliminary testing has shown that for
6673 styles where these braces are hung (e.g. most JDK-derived Java styles),
6674 this hack can improve performance of the core syntax parsing routines
6675 from 3 to 60 times. However, for styles which @emph{do} conform to
6676 Emacs' recommended style of putting top-level braces in column zero,
6677 this hack can degrade performance by about as much. Thus this variable
6678 is set to @code{nil} by default, since the Emacs-friendly styles should
6679 be more common (and encouraged!). Note that this variable has no effect
6680 in Emacs since the necessary built-in functions don't exist (in Emacs
6681 21.3 as of this writing in May 2003).
6682
6683 Text properties are used to speed up skipping over syntactic whitespace,
6684 i.e. comments and preprocessor directives. Indenting a line after a
6685 huge macro definition can be slow the first time, but after that the
6686 text properties are in place and it should be fast (even after you've
6687 edited other parts of the file and then moved back).
6688
6689 Font locking can be a CPU hog, especially the font locking done on
6690 decoration level 3 which tries to be very accurate. Note that that
6691 level is designed to be used with a font lock support mode that only
6692 fontifies the text that's actually shown, i.e. Lazy Lock or Just-in-time
6693 Lock mode, so make sure you use one of them. Fontification of a whole
6694 buffer with some thousand lines can often take over a minute. That is
6695 a known weakness; the idea is that it never should happen.
6696
6697 The most effective way to speed up font locking is to reduce the
6698 decoration level to 2 by setting @code{font-lock-maximum-decoration}
6699 appropriately. That level is designed to be as pretty as possible
6700 without sacrificing performance. @xref{Font Locking Preliminaries}, for
6701 more info.
6702
6703
6704 @comment !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
6705 @node Limitations and Known Bugs, FAQ, Performance Issues, Top
6706 @comment node-name, next, previous, up
6707 @chapter Limitations and Known Bugs
6708 @cindex limitations
6709 @cindex bugs
6710 @comment !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
6711
6712 @itemize @bullet
6713 @item
6714 There is no way to apply auto newline settings (@pxref{Auto-newlines})
6715 on already typed lines. That's only a feature to ease interactive
6716 editing.
6717
6718 To generalize this issue a bit: @ccmode{} is not intended to be used as
6719 a reformatter for old code in some more or less batch-like way. With
6720 the exception of some functions like @code{c-indent-region}, it's only
6721 geared to be used interactively to edit new code. There's currently no
6722 intention to change this goal.
6723
6724 If you want to reformat old code, you're probably better off using some
6725 other tool instead, e.g. @ref{Top, , GNU indent, indent, The `indent'
6726 Manual}, which has more powerful reformatting capabilities than
6727 @ccmode{}.
6728
6729 @item
6730 The support for C++ templates (in angle brackets) is not yet complete.
6731 When a non-nested template is used in a declaration, @ccmode{} indents
6732 it and font-locks it OK. Templates used in expressions, and nested
6733 templates do not fare so well. Sometimes a workaround is to refontify
6734 the expression after typing the closing @samp{>}.
6735 @end itemize
6736
6737 @comment !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
6738 @node FAQ, Updating CC Mode, Limitations and Known Bugs, Top
6739 @comment node-name, next, previous, up
6740 @appendix Frequently Asked Questions
6741 @comment !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
6742
6743 @itemize @bullet
6744 @item
6745 @emph{How can I change the indent level from 4 spaces to 2 spaces?}
6746
6747 Set the variable @code{c-basic-offset}. @xref{Getting Started}.
6748
6749 @item
6750 @kindex RET
6751 @kindex C-j
6752 @emph{Why doesn't the @kbd{RET} key indent the new line?}
6753
6754 Emacs' convention is that @kbd{RET} just adds a newline, and that
6755 @kbd{C-j} adds a newline and indents it. You can make @kbd{RET} do this
6756 too by adding this to your @code{c-initialization-hook}:
6757
6758 @example
6759 (define-key c-mode-base-map "\C-m" 'c-context-line-break)
6760 @end example
6761
6762 @xref{Getting Started}. This is a very common question. If you want
6763 this to be the default behavior, don't lobby us, lobby RMS! @t{:-)}
6764
6765 @item
6766 @emph{How do I stop my code jumping all over the place when I type?}
6767
6768 Deactivate ``electric minor mode'' with @kbd{C-c C-l}. @xref{Getting
6769 Started}.
6770
6771 @item
6772 @kindex C-x h
6773 @kindex C-M-\
6774 @emph{How do I reindent the whole file?}
6775
6776 Visit the file and hit @kbd{C-x h} to mark the whole buffer. Then hit
6777 @kbd{C-M-\}. @xref{Indentation Commands}.
6778
6779 @item
6780 @kindex C-M-q
6781 @kindex C-M-u
6782 @emph{How do I reindent the current block?}
6783
6784 First move to the brace which opens the block with @kbd{C-M-u}, then
6785 reindent that expression with @kbd{C-M-q}. @xref{Indentation
6786 Commands}.
6787
6788 @item
6789 @emph{I put @code{(c-set-offset 'substatement-open 0)} in my
6790 @file{.emacs} file but I get an error saying that @code{c-set-offset}'s
6791 function definition is void. What's wrong?}
6792
6793 This means that @ccmode{} hasn't yet been loaded into your Emacs
6794 session by the time the @code{c-set-offset} call is reached, most
6795 likely because @ccmode{} is being autoloaded. Instead of putting the
6796 @code{c-set-offset} line in your top-level @file{.emacs} file, put it
6797 in your @code{c-initialization-hook} (@pxref{CC Hooks}), or simply
6798 modify @code{c-offsets-alist} directly:
6799
6800 @example
6801 (setq c-offsets-alist '((substatement-open . 0)))
6802 @end example
6803
6804 @item
6805 @cindex open paren in column zero
6806 @emph{I have an open paren character at column zero inside a comment or
6807 multiline string literal, and it causes the fontification and/or
6808 indentation to go haywire. What gives?}
6809
6810 It's due to the ad-hoc rule in (X)Emacs that such open parens always
6811 start defuns (which translates to functions, classes, namespaces or any
6812 other top-level block constructs in the @ccmode{} languages).
6813 @ifset XEMACS
6814 @xref{Defuns,,, xemacs, XEmacs User's Manual}, for details.
6815 @end ifset
6816 @ifclear XEMACS
6817 @xref{Left Margin Paren,,, emacs, GNU Emacs Manual}, for details
6818 (@xref{Defuns,,, emacs, GNU Emacs Manual}, in the Emacs 20 manual).
6819 @end ifclear
6820
6821 This heuristic is built into the core syntax analysis routines in
6822 (X)Emacs, so it's not really a @ccmode{} issue. However, in Emacs
6823 21.1 it became possible to turn it off@footnote{Using the variable
6824 @code{open-paren-in-column-0-is-defun-start}.} and @ccmode{} does so
6825 there since it's got its own system to keep track of blocks.
6826
6827 @end itemize
6828
6829
6830 @comment !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
6831 @node Updating CC Mode, Mailing Lists and Bug Reports, FAQ, Top
6832 @comment node-name, next, previous, up
6833 @appendix Getting the Latest CC Mode Release
6834 @comment !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
6835
6836 @ccmode{} has been standard with all versions of Emacs since 19.34 and
6837 of XEmacs since 19.16.
6838
6839 @cindex web site
6840 Due to release schedule skew, it is likely that all of these Emacsen
6841 have old versions of @ccmode{} and so should be upgraded. Access to the
6842 @ccmode{} source code, as well as more detailed information on Emacsen
6843 compatibility, etc. are all available on the web site:
6844
6845 @quotation
6846 @uref{http://cc-mode.sourceforge.net/}
6847 @end quotation
6848
6849
6850 @comment !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
6851 @node Mailing Lists and Bug Reports, Command and Function Index, Updating CC Mode, Top
6852 @comment node-name, next, previous, up
6853 @appendix Mailing Lists and Submitting Bug Reports
6854 @comment !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
6855
6856 @kindex C-c C-b
6857 @findex c-submit-bug-report
6858 @findex submit-bug-report (c-)
6859 To report bugs, use the @kbd{C-c C-b} (bound to
6860 @code{c-submit-bug-report}) command. This provides vital information
6861 we need to reproduce your problem. Make sure you include a concise,
6862 but complete code example. Please try to boil your example down to
6863 just the essential code needed to reproduce the problem, and include
6864 an exact recipe of steps needed to expose the bug. Be especially sure
6865 to include any code that appears @emph{before} your bug example, if
6866 you think it might affect our ability to reproduce it.
6867
6868 Please try to produce the problem in an Emacs instance without any
6869 customizations loaded (i.e. start it with the @samp{-q -no-site-file}
6870 arguments). If it works correctly there, the problem might be caused
6871 by faulty customizations in either your own or your site
6872 configuration. In that case, we'd appreciate if you isolate the Emacs
6873 Lisp code that triggers the bug and include it in your report.
6874
6875 @cindex bug report mailing list
6876 Bug reports should be sent to @email{bug-cc-mode@@gnu.org}. You can
6877 also send other questions and suggestions (kudos? @t{;-)} to that
6878 address. It's a mailing list which you can join or browse an archive
6879 of; see the web site at @uref{http://cc-mode.sourceforge.net/} for
6880 further details.
6881
6882 @cindex announcement mailing list
6883 If you want to get announcements of new @ccmode{} releases, send the
6884 word @emph{subscribe} in the body of a message to
6885 @email{cc-mode-announce-request@@lists.sourceforge.net}. It's possible
6886 to subscribe from the web site too. Announcements will also be posted
6887 to the Usenet newsgroups @code{gnu.emacs.sources}, @code{comp.emacs},
6888 @code{comp.emacs.xemacs}, @code{comp.lang.c}, @code{comp.lang.c++},
6889 @code{comp.lang.objective-c}, @code{comp.lang.java.softwaretools},
6890 @code{comp.lang.idl}, and @code{comp.lang.awk}.
6891 @c There is no newsgroup for Pike. :-(
6892
6893 @c Removed the tentative node "Mode Initialization" from here, 2005/8/27.
6894 @comment !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
6895 @node Command and Function Index, Variable Index, Mailing Lists and Bug Reports, Top
6896 @comment node-name, next, previous, up
6897 @unnumbered Command and Function Index
6898 @comment !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
6899
6900 Since most @ccmode{} commands are prepended with the string
6901 @samp{c-}, each appears under its @code{c-@var{thing}} name and its
6902 @code{@var{thing} (c-)} name.
6903 @iftex
6904 @sp 2
6905 @end iftex
6906 @printindex fn
6907
6908
6909 @comment !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
6910 @node Variable Index, Concept and Key Index, Command and Function Index, Top
6911 @comment node-name, next, previous, up
6912 @unnumbered Variable Index
6913 @comment !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
6914
6915 Since most @ccmode{} variables are prepended with the string
6916 @samp{c-}, each appears under its @code{c-@var{thing}} name and its
6917 @code{@var{thing} (c-)} name.
6918 @iftex
6919 @sp 2
6920 @end iftex
6921 @printindex vr
6922
6923
6924 @comment !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
6925 @node Concept and Key Index, , Variable Index, Top
6926 @comment node-name, next, previous, up
6927 @unnumbered Concept and Key Index
6928 @comment !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
6929
6930 @printindex cp
6931
6932
6933 @comment !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
6934 @comment Epilogue.
6935 @comment !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
6936
6937 @iftex
6938 @page
6939 @summarycontents
6940 @contents
6941 @end iftex
6942
6943 @bye
6944
6945 @ignore
6946 arch-tag: c4cab162-5e57-4366-bdce-4a9db2fc97f0
6947 @end ignore