1 This is ../info/xemacs.info, produced by makeinfo version 4.0 from
4 INFO-DIR-SECTION XEmacs Editor
6 * XEmacs: (xemacs). XEmacs Editor.
9 This file documents the XEmacs editor.
11 Copyright (C) 1985, 1986, 1988 Richard M. Stallman. Copyright (C)
12 1991, 1992, 1993, 1994 Lucid, Inc. Copyright (C) 1993, 1994 Sun
13 Microsystems, Inc. Copyright (C) 1995 Amdahl Corporation.
15 Permission is granted to make and distribute verbatim copies of this
16 manual provided the copyright notice and this permission notice are
17 preserved on all copies.
19 Permission is granted to copy and distribute modified versions of
20 this manual under the conditions for verbatim copying, provided also
21 that the sections entitled "The GNU Manifesto", "Distribution" and "GNU
22 General Public License" are included exactly as in the original, and
23 provided that the entire resulting derived work is distributed under the
24 terms of a permission notice identical to this one.
26 Permission is granted to copy and distribute translations of this
27 manual into another language, under the above conditions for modified
28 versions, except that the sections entitled "The GNU Manifesto",
29 "Distribution" and "GNU General Public License" may be included in a
30 translation approved by the author instead of in the original English.
33 File: xemacs.info, Node: Matching, Next: Comments, Prev: Grinding, Up: Programs
35 Automatic Display of Matching Parentheses
36 =========================================
38 The Emacs parenthesis-matching feature shows you automatically how
39 parentheses match in the text. Whenever a self-inserting character that
40 is a closing delimiter is typed, the cursor moves momentarily to the
41 location of the matching opening delimiter, provided that is visible on
42 the screen. If it is not on the screen, some text starting with that
43 opening delimiter is displayed in the echo area. Either way, you see
44 the grouping you are closing off.
46 In Lisp, automatic matching applies only to parentheses. In C, it
47 also applies to braces and brackets. Emacs knows which characters to
48 regard as matching delimiters based on the syntax table set by the major
51 If the opening delimiter and closing delimiter are mismatched--as in
52 `[x)'--the echo area displays a warning message. The correct matches
53 are specified in the syntax table.
55 Two variables control parenthesis matching displays.
56 `blink-matching-paren' turns the feature on or off. The default is `t'
57 (match display is on); `nil' turns it off.
58 `blink-matching-paren-distance' specifies how many characters back
59 Emacs searches to find a matching opening delimiter. If the match is
60 not found in the specified region, scanning stops, and nothing is
61 displayed. This prevents wasting lots of time scanning when there is no
62 match. The default is 4000.
65 File: xemacs.info, Node: Comments, Next: Balanced Editing, Prev: Matching, Up: Programs
70 The comment commands insert, kill and align comments.
73 Insert or align comment (`indent-for-comment').
76 Set comment column (`set-comment-column').
79 Kill comment on current line (`kill-comment').
82 Like <RET> followed by inserting and aligning a comment
83 (`indent-new-comment-line').
85 The command that creates a comment is `Meta-;'
86 (`indent-for-comment'). If there is no comment already on the line, a
87 new comment is created and aligned at a specific column called the
88 "comment column". Emacs creates the comment by inserting the string at
89 the value of `comment-start'; see below. Point is left after that
90 string. If the text of the line extends past the comment column,
91 indentation is done to a suitable boundary (usually, at least one space
92 is inserted). If the major mode has specified a string to terminate
93 comments, that string is inserted after point, to keep the syntax valid.
95 You can also use `Meta-;' to align an existing comment. If a line
96 already contains the string that starts comments, `M-;' just moves
97 point after it and re-indents it to the conventional place. Exception:
98 comments starting in column 0 are not moved.
100 Some major modes have special rules for indenting certain kinds of
101 comments in certain contexts. For example, in Lisp code, comments which
102 start with two semicolons are indented as if they were lines of code,
103 instead of at the comment column. Comments which start with three
104 semicolons are supposed to start at the left margin. Emacs understands
105 these conventions by indenting a double-semicolon comment using <TAB>
106 and by not changing the indentation of a triple-semicolon comment at
109 ;; This function is just an example.
110 ;;; Here either two or three semicolons are appropriate.
112 ;;; And now, the first part of the function:
113 ;; The following line adds one.
114 (1+ x)) ; This line adds one.
116 In C code, a comment preceded on its line by nothing but whitespace
117 is indented like a line of code.
119 Even when an existing comment is properly aligned, `M-;' is still
120 useful for moving directly to the start of the comment.
122 `C-u - C-x ;' (`kill-comment') kills the comment on the current
123 line, if there is one. The indentation before the start of the comment
124 is killed as well. If there does not appear to be a comment in the
125 line, nothing happens. To reinsert the comment on another line, move
126 to the end of that line, type first `C-y', and then `M-;' to realign
127 the comment. Note that `C-u - C-x ;' is not a distinct key; it is `C-x
128 ;' (`set-comment-column') with a negative argument. That command is
129 programmed to call `kill-comment' when called with a negative argument.
130 However, `kill-comment' is a valid command which you could bind
131 directly to a key if you wanted to.
133 Multiple Lines of Comments
134 --------------------------
136 If you are typing a comment and want to continue it on another line,
137 use the command `Meta-<LFD>' (`indent-new-comment-line'), which
138 terminates the comment you are typing, creates a new blank line
139 afterward, and begins a new comment indented under the old one. If
140 Auto Fill mode is on and you go past the fill column while typing, the
141 comment is continued in just this fashion. If point is not at the end
142 of the line when you type `M-<LFD>', the text on the rest of the line
143 becomes part of the new comment line.
145 Options Controlling Comments
146 ----------------------------
148 The comment column is stored in the variable `comment-column'. You
149 can explicitly set it to a number. Alternatively, the command `C-x ;'
150 (`set-comment-column') sets the comment column to the column point is
151 at. `C-u C-x ;' sets the comment column to match the last comment
152 before point in the buffer, and then calls `Meta-;' to align the
153 current line's comment under the previous one. Note that `C-u - C-x ;'
154 runs the function `kill-comment' as described above.
156 `comment-column' is a per-buffer variable; altering the variable
157 affects only the current buffer. You can also change the default value.
158 *Note Locals::. Many major modes initialize this variable for the
161 The comment commands recognize comments based on the regular
162 expression that is the value of the variable `comment-start-skip'.
163 This regexp should not match the null string. It may match more than
164 the comment starting delimiter in the strictest sense of the word; for
165 example, in C mode the value of the variable is `"/\\*+ *"', which
166 matches extra stars and spaces after the `/*' itself. (Note that `\\'
167 is needed in Lisp syntax to include a `\' in the string, which is needed
168 to deny the first star its special meaning in regexp syntax. *Note
171 When a comment command makes a new comment, it inserts the value of
172 `comment-start' to begin it. The value of `comment-end' is inserted
173 after point and will follow the text you will insert into the comment.
174 In C mode, `comment-start' has the value `"/* "' and `comment-end' has
177 `comment-multi-line' controls how `M-<LFD>'
178 (`indent-new-comment-line') behaves when used inside a comment. If
179 `comment-multi-line' is `nil', as it normally is, then `M-<LFD>'
180 terminates the comment on the starting line and starts a new comment on
181 the new following line. If `comment-multi-line' is not `nil', then
182 `M-<LFD>' sets up the new following line as part of the same comment
183 that was found on the starting line. This is done by not inserting a
184 terminator on the old line and not inserting a starter on the new line.
185 In languages where multi-line comments are legal, the value you choose
186 for this variable is a matter of taste.
188 The variable `comment-indent-hook' should contain a function that is
189 called to compute the indentation for a newly inserted comment or for
190 aligning an existing comment. Major modes set this variable
191 differently. The function is called with no arguments, but with point
192 at the beginning of the comment, or at the end of a line if a new
193 comment is to be inserted. The function should return the column in
194 which the comment ought to start. For example, in Lisp mode, the
195 indent hook function bases its decision on the number of semicolons
196 that begin an existing comment and on the code in the preceding lines.
199 File: xemacs.info, Node: Balanced Editing, Next: Lisp Completion, Prev: Comments, Up: Programs
201 Editing Without Unbalanced Parentheses
202 ======================================
205 Put parentheses around next sexp(s) (`insert-parentheses').
208 Move past next close parenthesis and re-indent
209 (`move-over-close-and-reindent').
211 The commands `M-(' (`insert-parentheses') and `M-)'
212 (`move-over-close-and-reindent') are designed to facilitate a style of
213 editing which keeps parentheses balanced at all times. `M-(' inserts a
214 pair of parentheses, either together as in `()', or, if given an
215 argument, around the next several sexps, and leaves point after the open
216 parenthesis. Instead of typing `( F O O )', you can type `M-( F O O',
217 which has the same effect except for leaving the cursor before the
218 close parenthesis. You can then type `M-)', which moves past the close
219 parenthesis, deletes any indentation preceding it (in this example
220 there is none), and indents with <LFD> after it.
223 File: xemacs.info, Node: Lisp Completion, Next: Documentation, Prev: Balanced Editing, Up: Programs
225 Completion for Lisp Symbols
226 ===========================
228 Completion usually happens in the minibuffer. An exception is
229 completion for Lisp symbol names, which is available in all buffers.
231 The command `M-<TAB>' (`lisp-complete-symbol') takes the partial
232 Lisp symbol before point to be an abbreviation, and compares it against
233 all non-trivial Lisp symbols currently known to Emacs. Any additional
234 characters that they all have in common are inserted at point.
235 Non-trivial symbols are those that have function definitions, values, or
238 If there is an open-parenthesis immediately before the beginning of
239 the partial symbol, only symbols with function definitions are
240 considered as completions.
242 If the partial name in the buffer has more than one possible
243 completion and they have no additional characters in common, a list of
244 all possible completions is displayed in another window.
247 File: xemacs.info, Node: Documentation, Next: Change Log, Prev: Lisp Completion, Up: Programs
249 Documentation Commands
250 ======================
252 As you edit Lisp code to be run in Emacs, you can use the commands
253 `C-h f' (`describe-function') and `C-h v' (`describe-variable') to
254 print documentation of functions and variables you want to call. These
255 commands use the minibuffer to read the name of a function or variable
256 to document, and display the documentation in a window.
258 For extra convenience, these commands provide default arguments
259 based on the code in the neighborhood of point. `C-h f' sets the
260 default to the function called in the innermost list containing point.
261 `C-h v' uses the symbol name around or adjacent to point as its default.
263 The `M-x manual-entry' command gives you access to documentation on
264 Unix commands, system calls, and libraries. The command reads a topic
265 as an argument, and displays the Unix manual page for that topic.
266 `manual-entry' always searches all 8 sections of the manual and
267 concatenates all the entries it finds. For example, the topic
268 `termcap' finds the description of the termcap library from section 3,
269 followed by the description of the termcap data base from section 5.
272 File: xemacs.info, Node: Change Log, Next: Tags, Prev: Documentation, Up: Programs
277 The Emacs command `M-x add-change-log-entry' helps you keep a record
278 of when and why you have changed a program. It assumes that you have a
279 file in which you write a chronological sequence of entries describing
280 individual changes. The default is to store the change entries in a
281 file called `ChangeLog' in the same directory as the file you are
282 editing. The same `ChangeLog' file therefore records changes for all
283 the files in a directory.
285 A change log entry starts with a header line that contains your name
286 and the current date. Except for these header lines, every line in the
287 change log starts with a tab. One entry can describe several changes;
288 each change starts with a line starting with a tab and a star. `M-x
289 add-change-log-entry' visits the change log file and creates a new entry
290 unless the most recent entry is for today's date and your name. In
291 either case, it adds a new line to start the description of another
292 change just after the header line of the entry. When `M-x
293 add-change-log-entry' is finished, all is prepared for you to edit in
294 the description of what you changed and how. You must then save the
295 change log file yourself.
297 The change log file is always visited in Indented Text mode, which
298 means that <LFD> and auto-filling indent each new line like the previous
299 line. This is convenient for entering the contents of an entry, which
300 must be indented. *Note Text Mode::.
302 Here is an example of the formatting conventions used in the change
305 Wed Jun 26 19:29:32 1985 Richard M. Stallman (rms at mit-prep)
307 * xdisp.c (try_window_id):
308 If C-k is done at end of next-to-last line,
309 this fn updates window_end_vpos and cannot leave
310 window_end_pos nonnegative (it is zero, in fact).
311 If display is preempted before lines are output,
312 this is inconsistent. Fix by setting
313 blank_end_of_window to nonzero.
315 Tue Jun 25 05:25:33 1985 Richard M. Stallman (rms at mit-prep)
318 Call the auto fill hook if appropriate.
320 * xdisp.c (try_window_id):
321 If point is found by compute_motion after xp, record that
322 permanently. If display_text_line sets point position wrong
323 (case where line is killed, point is at eob and that line is
324 not displayed), set it again in final compute_motion.
327 File: xemacs.info, Node: Tags, Next: Fortran, Prev: Change Log, Up: Programs
332 A "tags table" is a description of how a multi-file program is
333 broken up into files. It lists the names of the component files and the
334 names and positions of the functions (or other named subunits) in each
335 file. Grouping the related files makes it possible to search or replace
336 through all the files with one command. Recording the function names
337 and positions makes possible the `M-.' command which finds the
338 definition of a function by looking up which of the files it is in.
340 Tags tables are stored in files called "tags table files". The
341 conventional name for a tags table file is `TAGS'.
343 Each entry in the tags table records the name of one tag, the name
344 of the file that the tag is defined in (implicitly), and the position
345 in that file of the tag's definition.
347 Just what names from the described files are recorded in the tags
348 table depends on the programming language of the described file. They
349 normally include all functions and subroutines, and may also include
350 global variables, data types, and anything else convenient. Each name
351 recorded is called a "tag".
355 * Tag Syntax:: Tag syntax for various types of code and text files.
356 * Create Tags Table:: Creating a tags table with `etags'.
357 * Etags Regexps:: Create arbitrary tags using regular expressions.
358 * Select Tags Table:: How to visit a tags table.
359 * Find Tag:: Commands to find the definition of a specific tag.
360 * Tags Search:: Using a tags table for searching and replacing.
361 * List Tags:: Listing and finding tags defined in a file.
364 File: xemacs.info, Node: Tag Syntax, Next: Create Tags Table, Prev: Tags, Up: Tags
366 Source File Tag Syntax
367 ----------------------
369 Here is how tag syntax is defined for the most popular languages:
371 * In C code, any C function or typedef is a tag, and so are
372 definitions of `struct', `union' and `enum'. You can tag function
373 declarations and external variables in addition to function
374 definitions by giving the `--declarations' option to `etags'.
375 `#define' macro definitions and `enum' constants are also tags,
376 unless you specify `--no-defines' when making the tags table.
377 Similarly, global variables are tags, unless you specify
378 `--no-globals'. Use of `--no-globals' and `--no-defines' can make
379 the tags table file much smaller.
381 * In C++ code, in addition to all the tag constructs of C code,
382 member functions are also recognized, and optionally member
383 variables if you use the `--members' option. Tags for variables
384 and functions in classes are named `CLASS::VARIABLE' and
385 `CLASS::FUNCTION'. `operator' functions tags are named, for
388 * In Java code, tags include all the constructs recognized in C++,
389 plus the `interface', `extends' and `implements' constructs. Tags
390 for variables and functions in classes are named `CLASS.VARIABLE'
391 and `CLASS.FUNCTION'.
393 * In LaTeX text, the argument of any of the commands `\chapter',
394 `\section', `\subsection', `\subsubsection', `\eqno', `\label',
395 `\ref', `\cite', `\bibitem', `\part', `\appendix', `\entry', or
398 Other commands can make tags as well, if you specify them in the
399 environment variable `TEXTAGS' before invoking `etags'. The value
400 of this environment variable should be a colon-separated list of
401 command names. For example,
403 TEXTAGS="def:newcommand:newenvironment"
406 specifies (using Bourne shell syntax) that the commands `\def',
407 `\newcommand' and `\newenvironment' also define tags.
409 * In Lisp code, any function defined with `defun', any variable
410 defined with `defvar' or `defconst', and in general the first
411 argument of any expression that starts with `(def' in column zero,
414 * In Scheme code, tags include anything defined with `def' or with a
415 construct whose name starts with `def'. They also include
416 variables set with `set!' at top level in the file.
418 Several other languages are also supported:
420 * In Ada code, functions, procedures, packages, tasks, and types are
421 tags. Use the `--packages-only' option to create tags for packages
424 * In assembler code, labels appearing at the beginning of a line,
425 followed by a colon, are tags.
427 * In Bison or Yacc input files, each rule defines as a tag the
428 nonterminal it constructs. The portions of the file that contain
429 C code are parsed as C code.
431 * In Cobol code, tags are paragraph names; that is, any word
432 starting in column 8 and followed by a period.
434 * In Erlang code, the tags are the functions, records, and macros
437 * In Fortran code, functions, subroutines and blockdata are tags.
439 * In Objective C code, tags include Objective C definitions for
440 classes, class categories, methods, and protocols.
442 * In Pascal code, the tags are the functions and procedures defined
445 * In Perl code, the tags are the procedures defined by the `sub',
446 `my' and `local' keywords. Use `--globals' if you want to tag
449 * In Postscript code, the tags are the functions.
451 * In Prolog code, a tag name appears at the left margin.
453 * In Python code, `def' or `class' at the beginning of a line
456 You can also generate tags based on regexp matching (*note Etags
457 Regexps::) to handle other formats and languages.
460 File: xemacs.info, Node: Create Tags Table, Next: Etags Regexps, Prev: Tag Syntax, Up: Tags
465 The `etags' program is used to create a tags table file. It knows
466 the syntax of several languages, as described in *Note Tag Syntax::.
467 Here is how to run `etags':
471 The `etags' program reads the specified files, and writes a tags table
472 named `TAGS' in the current working directory. You can intermix
473 compressed and plain text source file names. `etags' knows about the
474 most common compression formats, and does the right thing. So you can
475 compress all your source files and have `etags' look for compressed
476 versions of its file name arguments, if it does not find uncompressed
477 versions. Under MS-DOS, `etags' also looks for file names like
478 `mycode.cgz' if it is given `mycode.c' on the command line and
479 `mycode.c' does not exist.
481 `etags' recognizes the language used in an input file based on its
482 file name and contents. You can specify the language with the
483 `--language=NAME' option, described below.
485 If the tags table data become outdated due to changes in the files
486 described in the table, the way to update the tags table is the same
487 way it was made in the first place. It is not necessary to do this
490 If the tags table fails to record a tag, or records it for the wrong
491 file, then Emacs cannot possibly find its definition. However, if the
492 position recorded in the tags table becomes a little bit wrong (due to
493 some editing in the file that the tag definition is in), the only
494 consequence is a slight delay in finding the tag. Even if the stored
495 position is very wrong, Emacs will still find the tag, but it must
496 search the entire file for it.
498 So you should update a tags table when you define new tags that you
499 want to have listed, or when you move tag definitions from one file to
500 another, or when changes become substantial. Normally there is no need
501 to update the tags table after each edit, or even every day.
503 One tags table can effectively include another. Specify the included
504 tags file name with the `--include=FILE' option when creating the file
505 that is to include it. The latter file then acts as if it contained
506 all the files specified in the included file, as well as the files it
509 If you specify the source files with relative file names when you run
510 `etags', the tags file will contain file names relative to the
511 directory where the tags file was initially written. This way, you can
512 move an entire directory tree containing both the tags file and the
513 source files, and the tags file will still refer correctly to the source
516 If you specify absolute file names as arguments to `etags', then the
517 tags file will contain absolute file names. This way, the tags file
518 will still refer to the same files even if you move it, as long as the
519 source files remain in the same place. Absolute file names start with
520 `/', or with `DEVICE:/' on MS-DOS and MS-Windows.
522 When you want to make a tags table from a great number of files, you
523 may have problems listing them on the command line, because some systems
524 have a limit on its length. The simplest way to circumvent this limit
525 is to tell `etags' to read the file names from its standard input, by
526 typing a dash in place of the file names, like this:
528 find . -name "*.[chCH]" -print | etags -
530 Use the option `--language=NAME' to specify the language explicitly.
531 You can intermix these options with file names; each one applies to
532 the file names that follow it. Specify `--language=auto' to tell
533 `etags' to resume guessing the language from the file names and file
534 contents. Specify `--language=none' to turn off language-specific
535 processing entirely; then `etags' recognizes tags by regexp matching
536 alone (*note Etags Regexps::).
538 `etags --help' prints the list of the languages `etags' knows, and
539 the file name rules for guessing the language. It also prints a list of
540 all the available `etags' options, together with a short explanation.
543 File: xemacs.info, Node: Etags Regexps, Next: Select Tags Table, Prev: Create Tags Table, Up: Tags
548 The `--regex' option provides a general way of recognizing tags
549 based on regexp matching. You can freely intermix it with file names.
550 Each `--regex' option adds to the preceding ones, and applies only to
551 the following files. The syntax is:
553 --regex=/TAGREGEXP[/NAMEREGEXP]/
555 where TAGREGEXP is used to match the lines to tag. It is always
556 anchored, that is, it behaves as if preceded by `^'. If you want to
557 account for indentation, just match any initial number of blanks by
558 beginning your regular expression with `[ \t]*'. In the regular
559 expressions, `\' quotes the next character, and `\t' stands for the tab
560 character. Note that `etags' does not handle the other C escape
561 sequences for special characters.
563 The syntax of regular expressions in `etags' is the same as in
564 Emacs, augmented with the "interval operator", which works as in `grep'
565 and `ed'. The syntax of an interval operator is `\{M,N\}', and its
566 meaning is to match the preceding expression at least M times and up to
569 You should not match more characters with TAGREGEXP than that needed
570 to recognize what you want to tag. If the match is such that more
571 characters than needed are unavoidably matched by TAGREGEXP (as will
572 usually be the case), you should add a NAMEREGEXP, to pick out just the
573 tag. This will enable Emacs to find tags more accurately and to do
574 completion on tag names more reliably. You can find some examples
577 The option `--ignore-case-regex' (or `-c') is like `--regex', except
578 that the regular expression provided will be matched without regard to
579 case, which is appropriate for various programming languages.
581 The `-R' option deletes all the regexps defined with `--regex'
582 options. It applies to the file names following it, as you can see
583 from the following example:
585 etags --regex=/REG1/ voo.doo --regex=/REG2/ \
586 bar.ber -R --lang=lisp los.er
588 Here `etags' chooses the parsing language for `voo.doo' and `bar.ber'
589 according to their contents. `etags' also uses REG1 to recognize
590 additional tags in `voo.doo', and both REG1 and REG2 to recognize
591 additional tags in `bar.ber'. `etags' uses the Lisp tags rules, and no
592 regexp matching, to recognize tags in `los.er'.
594 A regular expression can be bound to a given language, by prepending
595 it with `{lang}'. When you do this, `etags' will use the regular
596 expression only for files of that language. `etags --help' prints the
597 list of languages recognised by `etags'. The following example tags
598 the `DEFVAR' macros in the Emacs source files. `etags' applies this
599 regular expression to C files only:
601 --regex='{c}/[ \t]*DEFVAR_[A-Z_ \t(]+"\([^"]+\)"/'
603 This feature is particularly useful when storing a list of regular
604 expressions in a file. The following option syntax instructs `etags'
605 to read two files of regular expressions. The regular expressions
606 contained in the second file are matched without regard to case.
608 --regex=@first-file --ignore-case-regex=@second-file
610 A regex file contains one regular expressions per line. Empty lines,
611 and lines beginning with space or tab are ignored. When the first
612 character in a line is `@', `etags' assumes that the rest of the line
613 is the name of a file of regular expressions. This means that such
614 files can be nested. All the other lines are taken to be regular
615 expressions. For example, one can create a file called `emacs.tags'
616 with the following contents (the first line in the file is a comment):
618 -- This is for GNU Emacs source files
619 {c}/[ \t]*DEFVAR_[A-Z_ \t(]+"\([^"]+\)"/\1/
621 and then use it like this:
623 etags --regex=@emacs.tags *.[ch] */*.[ch]
625 Here are some more examples. The regexps are quoted to protect them
626 from shell interpretation.
630 etags --language=none \
631 --regex='/[ \t]*function.*=[ \t]*\([^ \t]*\)[ \t]*(/\1/' \
632 --regex='/###key \(.*\)/\1/' \
633 --regex='/[ \t]*global[ \t].*/' \
636 Note that tags are not generated for scripts so that you have to
637 add a line by yourself of the form `###key <script-name>' if you
642 etags --language=none --regex='/proc[ \t]+\([^ \t]+\)/\1/' *.tcl
647 --regex='/[ \t]*\(ARCHITECTURE\|CONFIGURATION\) +[^ ]* +OF/' \
648 --regex='/[ \t]*\(ATTRIBUTE\|ENTITY\|FUNCTION\|PACKAGE\
649 \( BODY\)?\|PROCEDURE\|PROCESS\|TYPE\)[ \t]+\([^ \t(]+\)/\3/'
652 File: xemacs.info, Node: Select Tags Table, Next: Find Tag, Prev: Etags Regexps, Up: Tags
654 Selecting a Tags Table
655 ----------------------
657 At any time Emacs has one "selected" tags table, and all the commands
658 for working with tags tables use the selected one. To select a tags
659 table, use the variable `tag-table-alist'.
661 The value of `tag-table-alist' is a list that determines which
662 `TAGS' files should be active for a given buffer. This is not really
663 an association list, in that all elements are checked. The car of each
664 element of this list is a pattern against which the buffers file name
665 is compared; if it matches, then the cdr of the list should be the name
666 of the tags table to use. If more than one element of this list
667 matches the buffers file name, all of the associated tags tables are
668 used. Earlier ones are searched first.
670 If the car of elements of this list are strings, they are treated as
671 regular-expressions against which the file is compared (like the
672 `auto-mode-alist'). If they are not strings, they are evaluated. If
673 they evaluate to non-`nil', the current buffer is considered to match.
675 If the cdr of the elements of this list are strings, they are
676 assumed to name a tags file. If they name a directory, the string
677 `tags' is appended to them to get the file name. If they are not
678 strings, they are evaluated and must return an appropriate string.
682 (setq tag-table-alist
683 '(("/usr/src/public/perl/" . "/usr/src/public/perl/perl-3.0/")
684 ("\\.el$" . "/usr/local/emacs/src/")
685 ("/jbw/gnu/" . "/usr15/degree/stud/jbw/gnu/")
686 ("" . "/usr/local/emacs/src/")
689 The example defines the tags table alist in the following way:
691 * Anything in the directory `/usr/src/public/perl/' should use the
692 `TAGS' file `/usr/src/public/perl/perl-3.0/TAGS'.
694 * Files ending in `.el' should use the `TAGS' file
695 `/usr/local/emacs/src/TAGS'.
697 * Anything in or below the directory `/jbw/gnu/' should use the
698 `TAGS' file `/usr15/degree/stud/jbw/gnu/TAGS'.
700 If you had a file called `/usr/jbw/foo.el', it would use both `TAGS'
702 `/usr/local/emacs/src/TAGS' and `/usr15/degree/stud/jbw/gnu/TAGS' (in
703 that order), because it matches both patterns.
705 If the buffer-local variable `buffer-tag-table' is set, it names a
706 tags table that is searched before all others when `find-tag' is
707 executed from this buffer.
709 If there is a file called `TAGS' in the same directory as the file
710 in question, then that tags file will always be used as well (after the
711 `buffer-tag-table' but before the tables specified by this list).
713 If the variable `tags-file-name' is set, the `TAGS' file it names
714 will apply to all buffers (for backwards compatibility.) It is searched
717 If the value of the variable `tags-always-build-completion-table' is
718 `t', the tags file will always be added to the completion table without
719 asking first, regardless of the size of the tags file.
721 The function `M-x visit-tags-table', is largely made obsolete by the
722 variable `tag-table-alist', tells tags commands to use the tags table
723 file FILE first. The FILE should be the name of a file created with
724 the `etags' program. A directory name is also acceptable; it means the
725 file `TAGS' in that directory. The function only stores the file name
726 you provide in the variable `tags-file-name'. Emacs does not actually
727 read in the tags table contents until you try to use them. You can set
728 the variable explicitly instead of using `visit-tags-table'. The value
729 of the variable `tags-file-name' is the name of the tags table used by
730 all buffers. This is for backward compatibility, and is largely
731 supplanted by the variable `tag-table-alist'.
734 File: xemacs.info, Node: Find Tag, Next: Tags Search, Prev: Select Tags Table, Up: Tags
739 The most important thing that a tags table enables you to do is to
740 find the definition of a specific tag.
742 `M-. TAG &OPTIONAL OTHER-WINDOW'
743 Find first definition of TAG (`find-tag').
746 Find next alternate definition of last tag specified.
749 Find first definition of TAG, but display it in another window
750 (`find-tag-other-window').
752 `M-.' (`find-tag') is the command to find the definition of a
753 specified tag. It searches through the tags table for that tag, as a
754 string, then uses the tags table information to determine the file in
755 which the definition is used and the approximate character position of
756 the definition in the file. Then `find-tag' visits the file, moves
757 point to the approximate character position, and starts searching
758 ever-increasing distances away for the text that should appear at the
759 beginning of the definition.
761 If an empty argument is given (by typing <RET>), the sexp in the
762 buffer before or around point is used as the name of the tag to find.
763 *Note Lists::, for information on sexps.
765 The argument to `find-tag' need not be the whole tag name; it can be
766 a substring of a tag name. However, there can be many tag names
767 containing the substring you specify. Since `find-tag' works by
768 searching the text of the tags table, it finds the first tag in the
769 table that the specified substring appears in. To find other tags that
770 match the substring, give `find-tag' a numeric argument, as in `C-u
771 M-.'. This does not read a tag name, but continues searching the tag
772 table's text for another tag containing the same substring last used.
773 If your keyboard has a real <META> key, `M-0 M-.' is an easier
774 alternative to `C-u M-.'.
776 If the optional second argument OTHER-WINDOW is non-`nil', it uses
777 another window to display the tag. Multiple active tags tables and
778 completion are supported.
780 Variables of note include the following:
783 Controls which tables apply to which buffers.
786 Stores a default tags table.
788 `tags-build-completion-table'
789 Controls completion behavior.
792 Specifies a buffer-local table.
794 `make-tags-files-invisible'
795 Sets whether tags tables should be very hidden.
798 Specifies how many tags-based hops to remember.
800 Like most commands that can switch buffers, `find-tag' has another
801 similar command that displays the new buffer in another window. `C-x 4
802 .' invokes the function `find-tag-other-window'. (This key sequence
805 Emacs comes with a tags table file `TAGS' (in the directory
806 containing Lisp libraries) that includes all the Lisp libraries and all
807 the C sources of Emacs. By specifying this file with `visit-tags-table'
808 and then using `M-.' you can quickly look at the source of any Emacs
812 File: xemacs.info, Node: Tags Search, Next: List Tags, Prev: Find Tag, Up: Tags
814 Searching and Replacing with Tags Tables
815 ----------------------------------------
817 The commands in this section visit and search all the files listed
818 in the selected tags table, one by one. For these commands, the tags
819 table serves only to specify a sequence of files to search. A related
820 command is `M-x grep' (*note Compilation::).
822 `M-x tags-search <RET> REGEXP <RET>'
823 Search for REGEXP through the files in the selected tags table.
825 `M-x tags-query-replace <RET> REGEXP <RET> REPLACEMENT <RET>'
826 Perform a `query-replace-regexp' on each file in the selected tags
830 Restart one of the commands above, from the current location of
831 point (`tags-loop-continue').
833 `M-x tags-search' reads a regexp using the minibuffer, then searches
834 for matches in all the files in the selected tags table, one file at a
835 time. It displays the name of the file being searched so you can
836 follow its progress. As soon as it finds an occurrence, `tags-search'
839 Having found one match, you probably want to find all the rest. To
840 find one more match, type `M-,' (`tags-loop-continue') to resume the
841 `tags-search'. This searches the rest of the current buffer, followed
842 by the remaining files of the tags table.
844 `M-x tags-query-replace' performs a single `query-replace-regexp'
845 through all the files in the tags table. It reads a regexp to search
846 for and a string to replace with, just like ordinary `M-x
847 query-replace-regexp'. It searches much like `M-x tags-search', but
848 repeatedly, processing matches according to your input. *Note
849 Replace::, for more information on query replace.
851 It is possible to get through all the files in the tags table with a
852 single invocation of `M-x tags-query-replace'. But often it is useful
853 to exit temporarily, which you can do with any input event that has no
854 special query replace meaning. You can resume the query replace
855 subsequently by typing `M-,'; this command resumes the last tags search
856 or replace command that you did.
858 The commands in this section carry out much broader searches than the
859 `find-tag' family. The `find-tag' commands search only for definitions
860 of tags that match your substring or regexp. The commands
861 `tags-search' and `tags-query-replace' find every occurrence of the
862 regexp, as ordinary search commands and replace commands do in the
865 These commands create buffers only temporarily for the files that
866 they have to search (those which are not already visited in Emacs
867 buffers). Buffers in which no match is found are quickly killed; the
868 others continue to exist.
870 It may have struck you that `tags-search' is a lot like `grep'. You
871 can also run `grep' itself as an inferior of Emacs and have Emacs show
872 you the matching lines one by one. This works much like running a
873 compilation; finding the source locations of the `grep' matches works
874 like finding the compilation errors. *Note Compilation::.
876 If you wish to process all the files in a selected tags table, but
877 `M-x tags-search' and `M-x tags-query-replace' are not giving you the
878 desired result, you can use `M-x next-file'.
881 With a numeric argument, regardless of its value, visit the first
882 file in the tags table and prepare to advance sequentially by
886 Visit the next file in the selected tags table.
889 File: xemacs.info, Node: List Tags, Prev: Tags Search, Up: Tags
895 Display a list of the tags defined in a specific program file.
898 Display a list of all tags matching a specified regexp.
900 `M-x list-tags' reads the name of one of the files described by the
901 selected tags table, and displays a list of all the tags defined in that
902 file. The "file name" argument is really just a string to compare
903 against the names recorded in the tags table; it is read as a string
904 rather than a file name. Therefore, completion and defaulting are not
905 available, and you must enter the string the same way it appears in the
906 tag table. Do not include a directory as part of the file name unless
907 the file name recorded in the tags table contains that directory.
909 `M-x tags-apropos' is like `apropos' for tags. It reads a regexp,
910 then finds all the tags in the selected tags table whose entries match
911 that regexp, and displays the tag names found.
914 File: xemacs.info, Node: Fortran, Next: Asm Mode, Prev: Tags, Up: Programs
919 Fortran mode provides special motion commands for Fortran statements
920 and subprograms, and indentation commands that understand Fortran
921 conventions of nesting, line numbers, and continuation statements.
923 Special commands for comments are provided because Fortran comments
924 are unlike those of other languages.
926 Built-in abbrevs optionally save typing when you insert Fortran
929 Use `M-x fortran-mode' to switch to this major mode. Doing so calls
930 the value of `fortran-mode-hook' as a function of no arguments if that
931 variable has a non-`nil' value.
935 * Motion: Fortran Motion. Moving point by statements or subprograms.
936 * Indent: Fortran Indent. Indentation commands for Fortran.
937 * Comments: Fortran Comments. Inserting and aligning comments.
938 * Columns: Fortran Columns. Measuring columns for valid Fortran.
939 * Abbrev: Fortran Abbrev. Built-in abbrevs for Fortran keywords.
941 Fortran mode was contributed by Michael Prange.
944 File: xemacs.info, Node: Fortran Motion, Next: Fortran Indent, Prev: Fortran, Up: Fortran
949 Fortran mode provides special commands to move by subprograms
950 (functions and subroutines) and by statements. There is also a command
951 to put the region around one subprogram, which is convenient for
952 killing it or moving it.
955 Move to beginning of subprogram
956 (`beginning-of-fortran-subprogram').
959 Move to end of subprogram (`end-of-fortran-subprogram').
962 Put point at beginning of subprogram and mark at end
963 (`mark-fortran-subprogram').
966 Move to beginning of current or next statement (`fortran-next-
970 Move to beginning of current or previous statement (`fortran-
971 previous-statement').
974 File: xemacs.info, Node: Fortran Indent, Next: Fortran Comments, Prev: Fortran Motion, Up: Fortran
979 Special commands and features are available for indenting Fortran
980 code. They make sure various syntactic entities (line numbers, comment
981 line indicators, and continuation line flags) appear in the columns
982 that are required for standard Fortran.
986 * Commands: ForIndent Commands. Commands for indenting Fortran.
987 * Numbers: ForIndent Num. How line numbers auto-indent.
988 * Conv: ForIndent Conv. Conventions you must obey to avoid trouble.
989 * Vars: ForIndent Vars. Variables controlling Fortran indent style.
992 File: xemacs.info, Node: ForIndent Commands, Next: ForIndent Num, Prev: Fortran Indent, Up: Fortran Indent
994 Fortran Indentation Commands
995 ............................
998 Indent the current line (`fortran-indent-line').
1001 Break the current line and set up a continuation line.
1004 Indent all the lines of the subprogram point is in
1005 (`fortran-indent-subprogram').
1007 <TAB> is redefined by Fortran mode to reindent the current line for
1008 Fortran (`fortran-indent-line'). Line numbers and continuation markers
1009 are indented to their required columns, and the body of the statement
1010 is independently indented, based on its nesting in the program.
1012 The key `C-M-q' is redefined as `fortran-indent-subprogram', a
1013 command that reindents all the lines of the Fortran subprogram
1014 (function or subroutine) containing point.
1016 The key `M-<LFD>' is redefined as `fortran-split-line', a command to
1017 split a line in the appropriate fashion for Fortran. In a non-comment
1018 line, the second half becomes a continuation line and is indented
1019 accordingly. In a comment line, both halves become separate comment
1023 File: xemacs.info, Node: ForIndent Num, Next: ForIndent Conv, Prev: ForIndent Commands, Up: Fortran Indent
1025 Line Numbers and Continuation
1026 .............................
1028 If a number is the first non-whitespace in the line, it is assumed
1029 to be a line number and is moved to columns 0 through 4. (Columns are
1030 always counted from 0 in XEmacs.) If the text on the line starts with
1031 the conventional Fortran continuation marker `$', it is moved to column
1032 5. If the text begins with any non whitespace character in column 5,
1033 it is assumed to be an unconventional continuation marker and remains
1036 Line numbers of four digits or less are normally indented one space.
1037 This amount is controlled by the variable `fortran-line-number-indent',
1038 which is the maximum indentation a line number can have. Line numbers
1039 are indented to right-justify them to end in column 4 unless that would
1040 require more than the maximum indentation. The default value of the
1043 Simply inserting a line number is enough to indent it according to
1044 these rules. As each digit is inserted, the indentation is recomputed.
1045 To turn off this feature, set the variable
1046 `fortran-electric-line-number' to `nil'. Then inserting line numbers
1047 is like inserting anything else.
1050 File: xemacs.info, Node: ForIndent Conv, Next: ForIndent Vars, Prev: ForIndent Num, Up: Fortran Indent
1052 Syntactic Conventions
1053 .....................
1055 Fortran mode assumes that you follow certain conventions that
1056 simplify the task of understanding a Fortran program well enough to
1059 * Two nested `do' loops never share a `continue' statement.
1061 * The same character appears in column 5 of all continuation lines.
1062 It is the value of the variable `fortran-continuation-char'. By
1063 default, this character is `$'.
1065 If you fail to follow these conventions, the indentation commands may
1066 indent some lines unaesthetically. However, a correct Fortran program
1067 will retain its meaning when reindented even if the conventions are not
1071 File: xemacs.info, Node: ForIndent Vars, Prev: ForIndent Conv, Up: Fortran Indent
1073 Variables for Fortran Indentation
1074 .................................
1076 Several additional variables control how Fortran indentation works.
1079 Extra indentation within each level of `do' statement (the default
1083 Extra indentation within each level of `if' statement (the default
1086 `fortran-continuation-indent'
1087 Extra indentation for bodies of continuation lines (the default is
1090 `fortran-check-all-num-for-matching-do'
1091 If this is `nil', indentation assumes that each `do' statement
1092 ends on a `continue' statement. Therefore, when computing
1093 indentation for a statement other than `continue', it can save
1094 time by not checking for a `do' statement ending there. If this
1095 is non-`nil', indenting any numbered statement must check for a
1096 `do' that ends there. The default is `nil'.
1098 `fortran-minimum-statement-indent'
1099 Minimum indentation for Fortran statements. For standard Fortran,
1100 this is 6. Statement bodies are always indented at least this
1104 File: xemacs.info, Node: Fortran Comments, Next: Fortran Columns, Prev: Fortran Indent, Up: Fortran
1109 The usual Emacs comment commands assume that a comment can follow a
1110 line of code. In Fortran, the standard comment syntax requires an
1111 entire line to be just a comment. Therefore, Fortran mode replaces the
1112 standard Emacs comment commands and defines some new variables.
1114 Fortran mode can also handle a non-standard comment syntax where
1115 comments start with `!' and can follow other text. Because only some
1116 Fortran compilers accept this syntax, Fortran mode will not insert such
1117 comments unless you have specified to do so in advance by setting the
1118 variable `comment-start' to `"!"' (*note Variables::).
1121 Align comment or insert new comment (`fortran-comment-indent').
1124 Applies to nonstandard `!' comments only.
1127 Turn all lines of the region into comments, or (with arg) turn
1128 them back into real code (`fortran-comment-region').
1130 `M-;' in Fortran mode is redefined as the command
1131 `fortran-comment-indent'. Like the usual `M-;' command, it recognizes
1132 an existing comment and aligns its text appropriately. If there is no
1133 existing comment, a comment is inserted and aligned.
1135 Inserting and aligning comments is not the same in Fortran mode as in
1136 other modes. When a new comment must be inserted, a full-line comment
1137 is inserted if the current line is blank. On a non-blank line, a
1138 non-standard `!' comment is inserted if you previously specified you
1139 wanted to use them. Otherwise a full-line comment is inserted on a new
1140 line before the current line.
1142 Non-standard `!' comments are aligned like comments in other
1143 languages, but full-line comments are aligned differently. In a
1144 standard full-line comment, the comment delimiter itself must always
1145 appear in column zero. What can be aligned is the text within the
1146 comment. You can choose from three styles of alignment by setting the
1147 variable `fortran-comment-indent-style' to one of these values:
1150 The text is aligned at a fixed column, which is the value of
1151 `fortran-comment-line-column'. This is the default.
1154 The text is aligned as if it were a line of code, but with an
1155 additional `fortran-comment-line-column' columns of indentation.
1158 Text in full-line columns is not moved automatically.
1160 You can also specify the character to be used to indent within
1161 full-line comments by setting the variable `fortran-comment-indent-char'
1162 to the character you want to use.
1164 Fortran mode introduces two variables `comment-line-start' and
1165 `comment-line-start-skip', which do for full-line comments what
1166 `comment-start' and `comment-start-skip' do for ordinary text-following
1167 comments. Normally these are set properly by Fortran mode, so you do
1168 not need to change them.
1170 The normal Emacs comment command `C-x ;' has not been redefined. It
1171 can therefore be used if you use `!' comments, but is useless in
1172 Fortran mode otherwise.
1174 The command `C-c ;' (`fortran-comment-region') turns all the lines
1175 of the region into comments by inserting the string `C$$$' at the front
1176 of each one. With a numeric arg, the region is turned back into live
1177 code by deleting `C$$$' from the front of each line. You can control
1178 the string used for the comments by setting the variable
1179 `fortran-comment-region'. Note that here we have an example of a
1180 command and a variable with the same name; the two uses of the name
1181 never conflict because in Lisp and in Emacs it is always clear from the
1182 context which one is referred to.