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f00366c2 | 1 | @c This is part of the Emacs manual. |
21e9e795 | 2 | @c Copyright (C) 1985, 1986, 1987, 1993, 1994, 1995, 1997, 1999, 2000, |
3f548a7c | 3 | @c 2001, 2002, 2003, 2004, 2005, 2006, 2007, 2008 Free Software Foundation, Inc. |
f00366c2 RS |
4 | @c See file emacs.texi for copying conditions. |
5 | @node Maintaining, Abbrevs, Building, Top | |
2f15c7c3 | 6 | @chapter Maintaining Large Programs |
f00366c2 | 7 | |
2f15c7c3 RS |
8 | This chapter describes Emacs features for maintaining large |
9 | programs. The version control features (@pxref{Version Control}) are | |
10 | also particularly useful for this purpose. | |
f00366c2 RS |
11 | |
12 | @menu | |
13 | * Change Log:: Maintaining a change history for your program. | |
191f7d86 | 14 | * Format of ChangeLog:: What the change log file looks like. |
f00366c2 RS |
15 | * Tags:: Go direct to any function in your program in one |
16 | command. Tags remembers which file it is in. | |
4984edc7 EZ |
17 | @ifnottex |
18 | * Emerge:: A convenient way of merging two versions of a program. | |
19 | @end ifnottex | |
f00366c2 RS |
20 | @end menu |
21 | ||
22 | @node Change Log | |
23 | @section Change Logs | |
24 | ||
191f7d86 RS |
25 | A change log file contains a chronological record of when and why you |
26 | have changed a program, consisting of a sequence of entries describing | |
27 | individual changes. Normally it is kept in a file called | |
28 | @file{ChangeLog} in the same directory as the file you are editing, or | |
29 | one of its parent directories. A single @file{ChangeLog} file can | |
30 | record changes for all the files in its directory and all its | |
31 | subdirectories. | |
32 | ||
f00366c2 RS |
33 | @cindex change log |
34 | @kindex C-x 4 a | |
35 | @findex add-change-log-entry-other-window | |
36 | The Emacs command @kbd{C-x 4 a} adds a new entry to the change log | |
37 | file for the file you are editing | |
38 | (@code{add-change-log-entry-other-window}). If that file is actually | |
39 | a backup file, it makes an entry appropriate for the file's | |
40 | parent---that is useful for making log entries for functions that | |
41 | have been deleted in the current version. | |
42 | ||
f00366c2 RS |
43 | @kbd{C-x 4 a} visits the change log file and creates a new entry |
44 | unless the most recent entry is for today's date and your name. It | |
45 | also creates a new item for the current file. For many languages, it | |
46 | can even guess the name of the function or other object that was | |
47 | changed. | |
48 | ||
49 | @vindex add-log-keep-changes-together | |
19b2c4ca | 50 | When the variable @code{add-log-keep-changes-together} is |
6742e765 RS |
51 | non-@code{nil}, @kbd{C-x 4 a} adds to any existing item for the file |
52 | rather than starting a new item. | |
f00366c2 | 53 | |
191f7d86 RS |
54 | @vindex add-log-always-start-new-record |
55 | If @code{add-log-always-start-new-record} is non-@code{nil}, | |
56 | @kbd{C-x 4 a} always makes a new entry, even if the last entry | |
57 | was made by you and on the same date. | |
58 | ||
f00366c2 RS |
59 | @vindex change-log-version-info-enabled |
60 | @vindex change-log-version-number-regexp-list | |
61 | @cindex file version in change log entries | |
62 | If the value of the variable @code{change-log-version-info-enabled} | |
63 | is non-@code{nil}, @kbd{C-x 4 a} adds the file's version number to the | |
64 | change log entry. It finds the version number by searching the first | |
65 | ten percent of the file, using regular expressions from the variable | |
66 | @code{change-log-version-number-regexp-list}. | |
67 | ||
68 | @cindex Change Log mode | |
69 | @findex change-log-mode | |
70 | The change log file is visited in Change Log mode. In this major | |
71 | mode, each bunch of grouped items counts as one paragraph, and each | |
72 | entry is considered a page. This facilitates editing the entries. | |
73 | @kbd{C-j} and auto-fill indent each new line like the previous line; | |
74 | this is convenient for entering the contents of an entry. | |
75 | ||
76 | @findex change-log-merge | |
77 | You can use the command @kbd{M-x change-log-merge} to merge other | |
78 | log files into a buffer in Change Log Mode, preserving the date | |
79 | ordering of entries. | |
80 | ||
191f7d86 RS |
81 | Version control systems are another way to keep track of changes in your |
82 | program and keep a change log. @xref{Log Buffer}. | |
f00366c2 | 83 | |
191f7d86 RS |
84 | @node Format of ChangeLog |
85 | @section Format of ChangeLog | |
86 | ||
87 | A change log entry starts with a header line that contains the current | |
88 | date, your name, and your email address (taken from the variable | |
89 | @code{add-log-mailing-address}). Aside from these header lines, every | |
90 | line in the change log starts with a space or a tab. The bulk of the | |
91 | entry consists of @dfn{items}, each of which starts with a line starting | |
92 | with whitespace and a star. Here are two entries, both dated in May | |
93 | 1993, with two items and one item respectively. | |
94 | ||
95 | @iftex | |
96 | @medbreak | |
97 | @end iftex | |
f00366c2 | 98 | @smallexample |
191f7d86 RS |
99 | 1993-05-25 Richard Stallman <rms@@gnu.org> |
100 | ||
101 | * man.el: Rename symbols `man-*' to `Man-*'. | |
102 | (manual-entry): Make prompt string clearer. | |
103 | ||
104 | * simple.el (blink-matching-paren-distance): | |
105 | Change default to 12,000. | |
106 | ||
107 | 1993-05-24 Richard Stallman <rms@@gnu.org> | |
108 | ||
109 | * vc.el (minor-mode-map-alist): Don't use it if it's void. | |
110 | (vc-cancel-version): Doc fix. | |
f00366c2 RS |
111 | @end smallexample |
112 | ||
191f7d86 RS |
113 | One entry can describe several changes; each change should have its |
114 | own item, or its own line in an item. Normally there should be a | |
115 | blank line between items. When items are related (parts of the same | |
116 | change, in different places), group them by leaving no blank line | |
117 | between them. | |
f00366c2 | 118 | |
191f7d86 RS |
119 | You should put a copyright notice and permission notice at the |
120 | end of the change log file. Here is an example: | |
121 | ||
444246ca | 122 | @smallexample |
191f7d86 RS |
123 | Copyright 1997, 1998 Free Software Foundation, Inc. |
124 | Copying and distribution of this file, with or without modification, are | |
125 | permitted provided the copyright notice and this notice are preserved. | |
444246ca | 126 | @end smallexample |
f00366c2 | 127 | |
191f7d86 RS |
128 | @noindent |
129 | Of course, you should substitute the proper years and copyright holder. | |
f00366c2 RS |
130 | |
131 | @node Tags | |
132 | @section Tags Tables | |
133 | @cindex tags table | |
134 | ||
135 | A @dfn{tags table} is a description of how a multi-file program is | |
136 | broken up into files. It lists the names of the component files and the | |
137 | names and positions of the functions (or other named subunits) in each | |
138 | file. Grouping the related files makes it possible to search or replace | |
139 | through all the files with one command. Recording the function names | |
140 | and positions makes possible the @kbd{M-.} command which finds the | |
141 | definition of a function by looking up which of the files it is in. | |
142 | ||
143 | Tags tables are stored in files called @dfn{tags table files}. The | |
144 | conventional name for a tags table file is @file{TAGS}. | |
145 | ||
146 | Each entry in the tags table records the name of one tag, the name of the | |
bf8dd4e3 FP |
147 | file that the tag is defined in (implicitly), and the position in that |
148 | file of the tag's definition. When a file parsed by @code{etags} is | |
0f5401a8 FP |
149 | generated from a different source file, like a C file generated from a |
150 | Cweb source file, the tags of the parsed file reference the source | |
151 | file. | |
f00366c2 RS |
152 | |
153 | Just what names from the described files are recorded in the tags table | |
154 | depends on the programming language of the described file. They | |
155 | normally include all file names, functions and subroutines, and may | |
156 | also include global variables, data types, and anything else | |
157 | convenient. Each name recorded is called a @dfn{tag}. | |
158 | ||
159 | @cindex C++ class browser, tags | |
160 | @cindex tags, C++ | |
161 | @cindex class browser, C++ | |
162 | @cindex Ebrowse | |
163 | See also the Ebrowse facility, which is tailored for C++. | |
164 | @xref{Top,, Ebrowse, ebrowse, Ebrowse User's Manual}. | |
165 | ||
166 | @menu | |
167 | * Tag Syntax:: Tag syntax for various types of code and text files. | |
168 | * Create Tags Table:: Creating a tags table with @code{etags}. | |
169 | * Etags Regexps:: Create arbitrary tags using regular expressions. | |
170 | * Select Tags Table:: How to visit a tags table. | |
171 | * Find Tag:: Commands to find the definition of a specific tag. | |
172 | * Tags Search:: Using a tags table for searching and replacing. | |
173 | * List Tags:: Listing and finding tags defined in a file. | |
174 | @end menu | |
175 | ||
176 | @node Tag Syntax | |
177 | @subsection Source File Tag Syntax | |
178 | ||
179 | Here is how tag syntax is defined for the most popular languages: | |
180 | ||
181 | @itemize @bullet | |
182 | @item | |
183 | In C code, any C function or typedef is a tag, and so are definitions of | |
184 | @code{struct}, @code{union} and @code{enum}. | |
5f7c79f9 | 185 | @code{#define} macro definitions, @code{#undef} and @code{enum} |
049b41a4 | 186 | constants are also |
f00366c2 RS |
187 | tags, unless you specify @samp{--no-defines} when making the tags table. |
188 | Similarly, global variables are tags, unless you specify | |
dd8ff1b7 FP |
189 | @samp{--no-globals}. Use of @samp{--no-globals} and @samp{--no-defines} |
190 | can make the tags table file much smaller. | |
f00366c2 RS |
191 | |
192 | You can tag function declarations and external variables in addition | |
193 | to function definitions by giving the @samp{--declarations} option to | |
dd8ff1b7 FP |
194 | @code{etags}. You can tag struct members with the @samp{--members} |
195 | option. | |
f00366c2 RS |
196 | |
197 | @item | |
198 | In C++ code, in addition to all the tag constructs of C code, member | |
dd8ff1b7 FP |
199 | functions are also recognized, and optionally member variables if you |
200 | use the @samp{--members} option. Tags for variables and functions in | |
201 | classes are named @samp{@var{class}::@var{variable}} and | |
f00366c2 RS |
202 | @samp{@var{class}::@var{function}}. @code{operator} definitions have |
203 | tag names like @samp{operator+}. | |
204 | ||
205 | @item | |
206 | In Java code, tags include all the constructs recognized in C++, plus | |
207 | the @code{interface}, @code{extends} and @code{implements} constructs. | |
208 | Tags for variables and functions in classes are named | |
209 | @samp{@var{class}.@var{variable}} and @samp{@var{class}.@var{function}}. | |
210 | ||
211 | @item | |
212 | In La@TeX{} text, the argument of any of the commands @code{\chapter}, | |
213 | @code{\section}, @code{\subsection}, @code{\subsubsection}, | |
e4a1e8d9 FP |
214 | @code{\eqno}, @code{\label}, @code{\ref}, @code{\cite}, |
215 | @code{\bibitem}, @code{\part}, @code{\appendix}, @code{\entry}, | |
28665d46 | 216 | @code{\index}, @code{\def}, @code{\newcommand}, @code{\renewcommand}, |
e4a1e8d9 | 217 | @code{\newenvironment} or @code{\renewenvironment} is a tag.@refill |
f00366c2 RS |
218 | |
219 | Other commands can make tags as well, if you specify them in the | |
220 | environment variable @env{TEXTAGS} before invoking @code{etags}. The | |
221 | value of this environment variable should be a colon-separated list of | |
222 | command names. For example, | |
223 | ||
224 | @example | |
e4a1e8d9 | 225 | TEXTAGS="mycommand:myothercommand" |
f00366c2 RS |
226 | export TEXTAGS |
227 | @end example | |
228 | ||
229 | @noindent | |
e4a1e8d9 FP |
230 | specifies (using Bourne shell syntax) that the commands |
231 | @samp{\mycommand} and @samp{\myothercommand} also define tags. | |
f00366c2 RS |
232 | |
233 | @item | |
234 | In Lisp code, any function defined with @code{defun}, any variable | |
235 | defined with @code{defvar} or @code{defconst}, and in general the first | |
f01f5735 | 236 | argument of any expression that starts with @samp{(def} in column zero is |
f00366c2 RS |
237 | a tag. |
238 | ||
239 | @item | |
240 | In Scheme code, tags include anything defined with @code{def} or with a | |
241 | construct whose name starts with @samp{def}. They also include variables | |
242 | set with @code{set!} at top level in the file. | |
243 | @end itemize | |
244 | ||
245 | Several other languages are also supported: | |
246 | ||
247 | @itemize @bullet | |
248 | ||
249 | @item | |
f01f5735 | 250 | In Ada code, functions, procedures, packages, tasks and types are |
f00366c2 RS |
251 | tags. Use the @samp{--packages-only} option to create tags for |
252 | packages only. | |
253 | ||
254 | In Ada, the same name can be used for different kinds of entity | |
255 | (e.g.@:, for a procedure and for a function). Also, for things like | |
256 | packages, procedures and functions, there is the spec (i.e.@: the | |
257 | interface) and the body (i.e.@: the implementation). To make it | |
258 | easier to pick the definition you want, Ada tag name have suffixes | |
259 | indicating the type of entity: | |
260 | ||
261 | @table @samp | |
262 | @item /b | |
263 | package body. | |
264 | @item /f | |
265 | function. | |
266 | @item /k | |
267 | task. | |
268 | @item /p | |
269 | procedure. | |
270 | @item /s | |
271 | package spec. | |
272 | @item /t | |
273 | type. | |
274 | @end table | |
275 | ||
276 | Thus, @kbd{M-x find-tag @key{RET} bidule/b @key{RET}} will go | |
277 | directly to the body of the package @code{bidule}, while @kbd{M-x | |
278 | find-tag @key{RET} bidule @key{RET}} will just search for any tag | |
279 | @code{bidule}. | |
280 | ||
281 | @item | |
282 | In assembler code, labels appearing at the beginning of a line, | |
283 | followed by a colon, are tags. | |
284 | ||
285 | @item | |
286 | In Bison or Yacc input files, each rule defines as a tag the nonterminal | |
287 | it constructs. The portions of the file that contain C code are parsed | |
288 | as C code. | |
289 | ||
290 | @item | |
291 | In Cobol code, tags are paragraph names; that is, any word starting in | |
292 | column 8 and followed by a period. | |
293 | ||
294 | @item | |
f01f5735 | 295 | In Erlang code, the tags are the functions, records and macros defined |
f00366c2 RS |
296 | in the file. |
297 | ||
298 | @item | |
47d7776c | 299 | In Fortran code, functions, subroutines and block data are tags. |
f00366c2 | 300 | |
2c37653c FP |
301 | @item |
302 | In HTML input files, the tags are the @code{title} and the @code{h1}, | |
303 | @code{h2}, @code{h3} headers. Also, tags are @code{name=} in anchors | |
304 | and all occurrences of @code{id=}. | |
305 | ||
dfcb9727 FP |
306 | @item |
307 | In Lua input files, all functions are tags. | |
308 | ||
f00366c2 | 309 | @item |
f175bfff FP |
310 | In makefiles, targets are tags; additionally, variables are tags |
311 | unless you specify @samp{--no-globals}. | |
f00366c2 RS |
312 | |
313 | @item | |
314 | In Objective C code, tags include Objective C definitions for classes, | |
f01f5735 | 315 | class categories, methods and protocols. Tags for variables and |
3e7eaab2 FP |
316 | functions in classes are named @samp{@var{class}::@var{variable}} and |
317 | @samp{@var{class}::@var{function}}. | |
f00366c2 RS |
318 | |
319 | @item | |
320 | In Pascal code, the tags are the functions and procedures defined in | |
321 | the file. | |
322 | ||
323 | @item | |
3e7eaab2 FP |
324 | In Perl code, the tags are the packages, subroutines and variables |
325 | defined by the @code{package}, @code{sub}, @code{my} and @code{local} | |
326 | keywords. Use @samp{--globals} if you want to tag global variables. | |
327 | Tags for subroutines are named @samp{@var{package}::@var{sub}}. The | |
328 | name for subroutines defined in the default package is | |
329 | @samp{main::@var{sub}}. | |
f00366c2 | 330 | |
e94a3679 | 331 | @item |
dd8ff1b7 FP |
332 | In PHP code, tags are functions, classes and defines. When using the |
333 | @samp{--members} option, vars are tags too. | |
e94a3679 | 334 | |
f00366c2 RS |
335 | @item |
336 | In PostScript code, the tags are the functions. | |
337 | ||
338 | @item | |
e94a3679 FP |
339 | In Prolog code, tags are predicates and rules at the beginning of |
340 | line. | |
f00366c2 RS |
341 | |
342 | @item | |
343 | In Python code, @code{def} or @code{class} at the beginning of a line | |
344 | generate a tag. | |
345 | @end itemize | |
346 | ||
347 | You can also generate tags based on regexp matching (@pxref{Etags | |
348 | Regexps}) to handle other formats and languages. | |
349 | ||
350 | @node Create Tags Table | |
351 | @subsection Creating Tags Tables | |
352 | @cindex @code{etags} program | |
353 | ||
354 | The @code{etags} program is used to create a tags table file. It knows | |
355 | the syntax of several languages, as described in | |
356 | @iftex | |
357 | the previous section. | |
358 | @end iftex | |
af566730 | 359 | @ifnottex |
f00366c2 | 360 | @ref{Tag Syntax}. |
af566730 | 361 | @end ifnottex |
f00366c2 RS |
362 | Here is how to run @code{etags}: |
363 | ||
364 | @example | |
365 | etags @var{inputfiles}@dots{} | |
366 | @end example | |
367 | ||
368 | @noindent | |
369 | The @code{etags} program reads the specified files, and writes a tags | |
370 | table named @file{TAGS} in the current working directory. | |
371 | ||
372 | If the specified files don't exist, @code{etags} looks for | |
373 | compressed versions of them and uncompresses them to read them. Under | |
374 | MS-DOS, @code{etags} also looks for file names like @file{mycode.cgz} | |
375 | if it is given @samp{mycode.c} on the command line and @file{mycode.c} | |
376 | does not exist. | |
377 | ||
378 | @code{etags} recognizes the language used in an input file based on | |
379 | its file name and contents. You can specify the language with the | |
380 | @samp{--language=@var{name}} option, described below. | |
381 | ||
382 | If the tags table data become outdated due to changes in the files | |
383 | described in the table, the way to update the tags table is the same | |
55d3737d RS |
384 | way it was made in the first place. If the tags table fails to record |
385 | a tag, or records it for the wrong file, then Emacs cannot possibly | |
386 | find its definition until you update the tags table. However, if the | |
f00366c2 | 387 | position recorded in the tags table becomes a little bit wrong (due to |
191f7d86 | 388 | other editing), the worst consequence is a slight delay in finding the |
55d3737d | 389 | tag. Even if the stored position is very far wrong, Emacs will still |
191f7d86 RS |
390 | find the tag, after searching most of the file for it. That delay is |
391 | hardly noticeable with today's computers. | |
f00366c2 | 392 | |
191f7d86 RS |
393 | Thus, there is no need to update the tags table after each edit. |
394 | You should update a tags table when you define new tags that you want | |
395 | to have listed, or when you move tag definitions from one file to | |
396 | another, or when changes become substantial. | |
f00366c2 RS |
397 | |
398 | One tags table can virtually include another. Specify the included | |
399 | tags file name with the @samp{--include=@var{file}} option when | |
400 | creating the file that is to include it. The latter file then acts as | |
401 | if it covered all the source files specified in the included file, as | |
402 | well as the files it directly contains. | |
403 | ||
404 | If you specify the source files with relative file names when you run | |
405 | @code{etags}, the tags file will contain file names relative to the | |
406 | directory where the tags file was initially written. This way, you can | |
407 | move an entire directory tree containing both the tags file and the | |
408 | source files, and the tags file will still refer correctly to the source | |
4559d619 | 409 | files. If the tags file is in @file{/dev}, however, the file names are |
1899ba36 FP |
410 | made relative to the current working directory. This is useful, for |
411 | example, when writing the tags to @file{/dev/stdout}. | |
2e28f52d JB |
412 | |
413 | When using a relative file name, it should not be a symbolic link | |
500c43ed RS |
414 | pointing to a tags file in a different directory, because this would |
415 | generally render the file names invalid. | |
f00366c2 RS |
416 | |
417 | If you specify absolute file names as arguments to @code{etags}, then | |
418 | the tags file will contain absolute file names. This way, the tags file | |
419 | will still refer to the same files even if you move it, as long as the | |
420 | source files remain in the same place. Absolute file names start with | |
421 | @samp{/}, or with @samp{@var{device}:/} on MS-DOS and MS-Windows. | |
422 | ||
423 | When you want to make a tags table from a great number of files, you | |
424 | may have problems listing them on the command line, because some systems | |
425 | have a limit on its length. The simplest way to circumvent this limit | |
426 | is to tell @code{etags} to read the file names from its standard input, | |
427 | by typing a dash in place of the file names, like this: | |
428 | ||
429 | @smallexample | |
430 | find . -name "*.[chCH]" -print | etags - | |
431 | @end smallexample | |
432 | ||
433 | Use the option @samp{--language=@var{name}} to specify the language | |
434 | explicitly. You can intermix these options with file names; each one | |
435 | applies to the file names that follow it. Specify | |
436 | @samp{--language=auto} to tell @code{etags} to resume guessing the | |
437 | language from the file names and file contents. Specify | |
438 | @samp{--language=none} to turn off language-specific processing | |
439 | entirely; then @code{etags} recognizes tags by regexp matching alone | |
440 | (@pxref{Etags Regexps}). | |
441 | ||
e4a1e8d9 FP |
442 | The option @samp{--parse-stdin=@var{file}} is mostly useful when |
443 | calling @code{etags} from programs. It can be used (only once) in | |
444 | place of a file name on the command line. @code{Etags} will read from | |
445 | standard input and mark the produced tags as belonging to the file | |
446 | @var{file}. | |
447 | ||
191f7d86 | 448 | @samp{etags --help} outputs the list of the languages @code{etags} |
f00366c2 RS |
449 | knows, and the file name rules for guessing the language. It also prints |
450 | a list of all the available @code{etags} options, together with a short | |
f01f5735 | 451 | explanation. If followed by one or more @samp{--language=@var{lang}} |
191f7d86 | 452 | options, it outputs detailed information about how tags are generated for |
177c0ea7 | 453 | @var{lang}. |
f00366c2 RS |
454 | |
455 | @node Etags Regexps | |
456 | @subsection Etags Regexps | |
457 | ||
458 | The @samp{--regex} option provides a general way of recognizing tags | |
191f7d86 RS |
459 | based on regexp matching. You can freely intermix this option with |
460 | file names, and each one applies to the source files that follow it. | |
ed1b7d5e | 461 | If you specify multiple @samp{--regex} options, all of them are used |
191f7d86 | 462 | in parallel. The syntax is: |
f00366c2 RS |
463 | |
464 | @smallexample | |
cc76b311 FP |
465 | --regex=[@var{@{language@}}]/@var{tagregexp}/[@var{nameregexp}/]@var{modifiers} |
466 | @end smallexample | |
467 | ||
ed1b7d5e RS |
468 | The essential part of the option value is @var{tagregexp}, the |
469 | regexp for matching tags. It is always used anchored, that is, it | |
470 | only matches at the beginning of a line. If you want to allow | |
471 | indented tags, use a regexp that matches initial whitespace; start it | |
472 | with @samp{[ \t]*}. | |
473 | ||
474 | In these regular expressions, @samp{\} quotes the next character, and | |
475 | all the GCC character escape sequences are supported (@samp{\a} for | |
476 | bell, @samp{\b} for back space, @samp{\d} for delete, @samp{\e} for | |
477 | escape, @samp{\f} for formfeed, @samp{\n} for newline, @samp{\r} for | |
478 | carriage return, @samp{\t} for tab, and @samp{\v} for vertical tab). | |
479 | ||
480 | Ideally, @var{tagregexp} should not match more characters than are | |
481 | needed to recognize what you want to tag. If the syntax requires you | |
482 | to write @var{tagregexp} so it matches more characters beyond the tag | |
483 | itself, you should add a @var{nameregexp}, to pick out just the tag. | |
484 | This will enable Emacs to find tags more accurately and to do | |
485 | completion on tag names more reliably. You can find some examples | |
486 | below. | |
487 | ||
488 | The @var{modifiers} are a sequence of zero or more characters that | |
489 | modify the way @code{etags} does the matching. A regexp with no | |
490 | modifiers is applied sequentially to each line of the input file, in a | |
491 | case-sensitive way. The modifiers and their meanings are: | |
cc76b311 FP |
492 | |
493 | @table @samp | |
494 | @item i | |
ed1b7d5e | 495 | Ignore case when matching this regexp. |
cc76b311 | 496 | @item m |
ed1b7d5e RS |
497 | Match this regular expression against the whole file, so that |
498 | multi-line matches are possible. | |
cc76b311 | 499 | @item s |
ed1b7d5e RS |
500 | Match this regular expression against the whole file, and allow |
501 | @samp{.} in @var{tagregexp} to match newlines. | |
cc76b311 FP |
502 | @end table |
503 | ||
ed1b7d5e | 504 | The @samp{-R} option cancels all the regexps defined by preceding |
191f7d86 RS |
505 | @samp{--regex} options. It too applies to the file names following |
506 | it. Here's an example: | |
f00366c2 RS |
507 | |
508 | @smallexample | |
648ed8f4 | 509 | etags --regex=/@var{reg1}/i voo.doo --regex=/@var{reg2}/m \ |
f00366c2 RS |
510 | bar.ber -R --lang=lisp los.er |
511 | @end smallexample | |
512 | ||
513 | @noindent | |
514 | Here @code{etags} chooses the parsing language for @file{voo.doo} and | |
515 | @file{bar.ber} according to their contents. @code{etags} also uses | |
516 | @var{reg1} to recognize additional tags in @file{voo.doo}, and both | |
517 | @var{reg1} and @var{reg2} to recognize additional tags in | |
648ed8f4 FP |
518 | @file{bar.ber}. @var{reg1} is checked against each line of |
519 | @file{voo.doo} and @file{bar.ber}, in a case-insensitive way, while | |
520 | @var{reg2} is checked against the whole @file{bar.ber} file, | |
521 | permitting multi-line matches, in a case-sensitive way. @code{etags} | |
ed1b7d5e RS |
522 | uses only the Lisp tags rules, with no user-specified regexp matching, |
523 | to recognize tags in @file{los.er}. | |
f00366c2 | 524 | |
b8fc5a9c FP |
525 | You can restrict a @samp{--regex} option to match only files of a |
526 | given language by using the optional prefix @var{@{language@}}. | |
648ed8f4 FP |
527 | (@samp{etags --help} prints the list of languages recognized by |
528 | @code{etags}.) This is particularly useful when storing many | |
529 | predefined regular expressions for @code{etags} in a file. The | |
f00366c2 RS |
530 | following example tags the @code{DEFVAR} macros in the Emacs source |
531 | files, for the C language only: | |
532 | ||
533 | @smallexample | |
534 | --regex='@{c@}/[ \t]*DEFVAR_[A-Z_ \t(]+"\([^"]+\)"/' | |
535 | @end smallexample | |
536 | ||
537 | @noindent | |
ed1b7d5e RS |
538 | When you have complex regular expressions, you can store the list of |
539 | them in a file. The following option syntax instructs @code{etags} to | |
540 | read two files of regular expressions. The regular expressions | |
541 | contained in the second file are matched without regard to case. | |
f00366c2 RS |
542 | |
543 | @smallexample | |
ed1b7d5e | 544 | --regex=@@@var{case-sensitive-file} --ignore-case-regex=@@@var{ignore-case-file} |
f00366c2 RS |
545 | @end smallexample |
546 | ||
547 | @noindent | |
ed1b7d5e RS |
548 | A regex file for @code{etags} contains one regular expression per |
549 | line. Empty lines, and lines beginning with space or tab are ignored. | |
550 | When the first character in a line is @samp{@@}, @code{etags} assumes | |
551 | that the rest of the line is the name of another file of regular | |
552 | expressions; thus, one such file can include another file. All the | |
553 | other lines are taken to be regular expressions. If the first | |
554 | non-whitespace text on the line is @samp{--}, that line is a comment. | |
555 | ||
556 | For example, we can create a file called @samp{emacs.tags} with the | |
f00366c2 RS |
557 | following contents: |
558 | ||
559 | @smallexample | |
560 | -- This is for GNU Emacs C source files | |
561 | @{c@}/[ \t]*DEFVAR_[A-Z_ \t(]+"\([^"]+\)"/\1/ | |
562 | @end smallexample | |
563 | ||
564 | @noindent | |
565 | and then use it like this: | |
566 | ||
567 | @smallexample | |
568 | etags --regex=@@emacs.tags *.[ch] */*.[ch] | |
569 | @end smallexample | |
570 | ||
571 | Here are some more examples. The regexps are quoted to protect them | |
572 | from shell interpretation. | |
573 | ||
574 | @itemize @bullet | |
575 | ||
576 | @item | |
577 | Tag Octave files: | |
578 | ||
579 | @smallexample | |
580 | etags --language=none \ | |
581 | --regex='/[ \t]*function.*=[ \t]*\([^ \t]*\)[ \t]*(/\1/' \ | |
582 | --regex='/###key \(.*\)/\1/' \ | |
583 | --regex='/[ \t]*global[ \t].*/' \ | |
584 | *.m | |
585 | @end smallexample | |
586 | ||
587 | @noindent | |
588 | Note that tags are not generated for scripts, so that you have to add | |
589 | a line by yourself of the form @samp{###key @var{scriptname}} if you | |
590 | want to jump to it. | |
591 | ||
592 | @item | |
593 | Tag Tcl files: | |
594 | ||
595 | @smallexample | |
596 | etags --language=none --regex='/proc[ \t]+\([^ \t]+\)/\1/' *.tcl | |
597 | @end smallexample | |
598 | ||
599 | @item | |
600 | Tag VHDL files: | |
601 | ||
602 | @smallexample | |
603 | etags --language=none \ | |
604 | --regex='/[ \t]*\(ARCHITECTURE\|CONFIGURATION\) +[^ ]* +OF/' \ | |
605 | --regex='/[ \t]*\(ATTRIBUTE\|ENTITY\|FUNCTION\|PACKAGE\ | |
606 | \( BODY\)?\|PROCEDURE\|PROCESS\|TYPE\)[ \t]+\([^ \t(]+\)/\3/' | |
607 | @end smallexample | |
608 | @end itemize | |
609 | ||
610 | @node Select Tags Table | |
611 | @subsection Selecting a Tags Table | |
612 | ||
613 | @vindex tags-file-name | |
614 | @findex visit-tags-table | |
191f7d86 RS |
615 | Emacs has at any time one @dfn{selected} tags table, and all the |
616 | commands for working with tags tables use the selected one. To select | |
617 | a tags table, type @kbd{M-x visit-tags-table}, which reads the tags | |
618 | table file name as an argument, with @file{TAGS} in the default | |
619 | directory as the default. | |
620 | ||
621 | Emacs does not actually read in the tags table contents until you | |
622 | try to use them; all @code{visit-tags-table} does is store the file | |
623 | name in the variable @code{tags-file-name}, and setting the variable | |
624 | yourself is just as good. The variable's initial value is @code{nil}; | |
625 | that value tells all the commands for working with tags tables that | |
626 | they must ask for a tags table file name to use. | |
f00366c2 RS |
627 | |
628 | Using @code{visit-tags-table} when a tags table is already loaded | |
629 | gives you a choice: you can add the new tags table to the current list | |
630 | of tags tables, or start a new list. The tags commands use all the tags | |
631 | tables in the current list. If you start a new list, the new tags table | |
632 | is used @emph{instead} of others. If you add the new table to the | |
191f7d86 | 633 | current list, it is used @emph{as well as} the others. |
f00366c2 RS |
634 | |
635 | @vindex tags-table-list | |
636 | You can specify a precise list of tags tables by setting the variable | |
637 | @code{tags-table-list} to a list of strings, like this: | |
638 | ||
639 | @c keep this on two lines for formatting in smallbook | |
640 | @example | |
641 | @group | |
642 | (setq tags-table-list | |
643 | '("~/emacs" "/usr/local/lib/emacs/src")) | |
644 | @end group | |
645 | @end example | |
646 | ||
647 | @noindent | |
648 | This tells the tags commands to look at the @file{TAGS} files in your | |
649 | @file{~/emacs} directory and in the @file{/usr/local/lib/emacs/src} | |
650 | directory. The order depends on which file you are in and which tags | |
651 | table mentions that file, as explained above. | |
652 | ||
653 | Do not set both @code{tags-file-name} and @code{tags-table-list}. | |
654 | ||
655 | @node Find Tag | |
656 | @subsection Finding a Tag | |
657 | ||
658 | The most important thing that a tags table enables you to do is to find | |
659 | the definition of a specific tag. | |
660 | ||
661 | @table @kbd | |
662 | @item M-.@: @var{tag} @key{RET} | |
663 | Find first definition of @var{tag} (@code{find-tag}). | |
664 | @item C-u M-. | |
665 | Find next alternate definition of last tag specified. | |
666 | @item C-u - M-. | |
667 | Go back to previous tag found. | |
668 | @item C-M-. @var{pattern} @key{RET} | |
669 | Find a tag whose name matches @var{pattern} (@code{find-tag-regexp}). | |
670 | @item C-u C-M-. | |
671 | Find the next tag whose name matches the last pattern used. | |
672 | @item C-x 4 .@: @var{tag} @key{RET} | |
673 | Find first definition of @var{tag}, but display it in another window | |
674 | (@code{find-tag-other-window}). | |
675 | @item C-x 5 .@: @var{tag} @key{RET} | |
676 | Find first definition of @var{tag}, and create a new frame to select the | |
677 | buffer (@code{find-tag-other-frame}). | |
678 | @item M-* | |
679 | Pop back to where you previously invoked @kbd{M-.} and friends. | |
680 | @end table | |
681 | ||
682 | @kindex M-. | |
683 | @findex find-tag | |
684 | @kbd{M-.}@: (@code{find-tag}) is the command to find the definition of | |
685 | a specified tag. It searches through the tags table for that tag, as a | |
686 | string, and then uses the tags table info to determine the file that the | |
687 | definition is in and the approximate character position in the file of | |
688 | the definition. Then @code{find-tag} visits that file, moves point to | |
689 | the approximate character position, and searches ever-increasing | |
690 | distances away to find the tag definition. | |
691 | ||
692 | If an empty argument is given (just type @key{RET}), the balanced | |
693 | expression in the buffer before or around point is used as the | |
694 | @var{tag} argument. @xref{Expressions}. | |
695 | ||
696 | You don't need to give @kbd{M-.} the full name of the tag; a part | |
697 | will do. This is because @kbd{M-.} finds tags in the table which | |
698 | contain @var{tag} as a substring. However, it prefers an exact match | |
699 | to a substring match. To find other tags that match the same | |
700 | substring, give @code{find-tag} a numeric argument, as in @kbd{C-u | |
701 | M-.}; this does not read a tag name, but continues searching the tags | |
702 | table's text for another tag containing the same substring last used. | |
703 | If you have a real @key{META} key, @kbd{M-0 M-.}@: is an easier | |
704 | alternative to @kbd{C-u M-.}. | |
705 | ||
706 | @kindex C-x 4 . | |
707 | @findex find-tag-other-window | |
708 | @kindex C-x 5 . | |
709 | @findex find-tag-other-frame | |
710 | Like most commands that can switch buffers, @code{find-tag} has a | |
711 | variant that displays the new buffer in another window, and one that | |
191f7d86 RS |
712 | makes a new frame for it. The former is @w{@kbd{C-x 4 .}}, which invokes |
713 | the command @code{find-tag-other-window}. The latter is @w{@kbd{C-x 5 .}}, | |
f00366c2 RS |
714 | which invokes @code{find-tag-other-frame}. |
715 | ||
716 | To move back to places you've found tags recently, use @kbd{C-u - | |
717 | M-.}; more generally, @kbd{M-.} with a negative numeric argument. This | |
191f7d86 | 718 | command can take you to another buffer. @w{@kbd{C-x 4 .}} with a negative |
f00366c2 RS |
719 | argument finds the previous tag location in another window. |
720 | ||
721 | @kindex M-* | |
722 | @findex pop-tag-mark | |
723 | @vindex find-tag-marker-ring-length | |
724 | As well as going back to places you've found tags recently, you can go | |
725 | back to places @emph{from where} you found them. Use @kbd{M-*}, which | |
726 | invokes the command @code{pop-tag-mark}, for this. Typically you would | |
727 | find and study the definition of something with @kbd{M-.} and then | |
728 | return to where you were with @kbd{M-*}. | |
729 | ||
730 | Both @kbd{C-u - M-.} and @kbd{M-*} allow you to retrace your steps to | |
731 | a depth determined by the variable @code{find-tag-marker-ring-length}. | |
732 | ||
733 | @findex find-tag-regexp | |
734 | @kindex C-M-. | |
735 | The command @kbd{C-M-.} (@code{find-tag-regexp}) visits the tags that | |
736 | match a specified regular expression. It is just like @kbd{M-.} except | |
737 | that it does regexp matching instead of substring matching. | |
738 | ||
739 | @node Tags Search | |
740 | @subsection Searching and Replacing with Tags Tables | |
741 | @cindex search and replace in multiple files | |
742 | @cindex multiple-file search and replace | |
743 | ||
191f7d86 RS |
744 | The commands in this section visit and search all the files listed |
745 | in the selected tags table, one by one. For these commands, the tags | |
746 | table serves only to specify a sequence of files to search. These | |
747 | commands scan the list of tags tables starting with the first tags | |
748 | table (if any) that describes the current file, proceed from there to | |
749 | the end of the list, and then scan from the beginning of the list | |
750 | until they have covered all the tables in the list. | |
f00366c2 RS |
751 | |
752 | @table @kbd | |
753 | @item M-x tags-search @key{RET} @var{regexp} @key{RET} | |
754 | Search for @var{regexp} through the files in the selected tags | |
755 | table. | |
756 | @item M-x tags-query-replace @key{RET} @var{regexp} @key{RET} @var{replacement} @key{RET} | |
757 | Perform a @code{query-replace-regexp} on each file in the selected tags table. | |
758 | @item M-, | |
759 | Restart one of the commands above, from the current location of point | |
760 | (@code{tags-loop-continue}). | |
761 | @end table | |
762 | ||
763 | @findex tags-search | |
764 | @kbd{M-x tags-search} reads a regexp using the minibuffer, then | |
765 | searches for matches in all the files in the selected tags table, one | |
766 | file at a time. It displays the name of the file being searched so you | |
767 | can follow its progress. As soon as it finds an occurrence, | |
768 | @code{tags-search} returns. | |
769 | ||
770 | @kindex M-, | |
771 | @findex tags-loop-continue | |
772 | Having found one match, you probably want to find all the rest. To find | |
773 | one more match, type @kbd{M-,} (@code{tags-loop-continue}) to resume the | |
774 | @code{tags-search}. This searches the rest of the current buffer, followed | |
775 | by the remaining files of the tags table.@refill | |
776 | ||
777 | @findex tags-query-replace | |
778 | @kbd{M-x tags-query-replace} performs a single | |
779 | @code{query-replace-regexp} through all the files in the tags table. It | |
780 | reads a regexp to search for and a string to replace with, just like | |
781 | ordinary @kbd{M-x query-replace-regexp}. It searches much like @kbd{M-x | |
782 | tags-search}, but repeatedly, processing matches according to your | |
783 | input. @xref{Replace}, for more information on query replace. | |
784 | ||
785 | @vindex tags-case-fold-search | |
786 | @cindex case-sensitivity and tags search | |
787 | You can control the case-sensitivity of tags search commands by | |
788 | customizing the value of the variable @code{tags-case-fold-search}. The | |
789 | default is to use the same setting as the value of | |
790 | @code{case-fold-search} (@pxref{Search Case}). | |
791 | ||
792 | It is possible to get through all the files in the tags table with a | |
793 | single invocation of @kbd{M-x tags-query-replace}. But often it is | |
794 | useful to exit temporarily, which you can do with any input event that | |
795 | has no special query replace meaning. You can resume the query replace | |
796 | subsequently by typing @kbd{M-,}; this command resumes the last tags | |
797 | search or replace command that you did. | |
798 | ||
799 | The commands in this section carry out much broader searches than the | |
800 | @code{find-tag} family. The @code{find-tag} commands search only for | |
801 | definitions of tags that match your substring or regexp. The commands | |
802 | @code{tags-search} and @code{tags-query-replace} find every occurrence | |
803 | of the regexp, as ordinary search commands and replace commands do in | |
804 | the current buffer. | |
805 | ||
806 | These commands create buffers only temporarily for the files that they | |
807 | have to search (those which are not already visited in Emacs buffers). | |
808 | Buffers in which no match is found are quickly killed; the others | |
809 | continue to exist. | |
810 | ||
811 | It may have struck you that @code{tags-search} is a lot like | |
812 | @code{grep}. You can also run @code{grep} itself as an inferior of | |
191f7d86 | 813 | Emacs and have Emacs show you the matching lines one by one. |
5d9b307f | 814 | @xref{Grep Searching}. |
f00366c2 RS |
815 | |
816 | @node List Tags | |
817 | @subsection Tags Table Inquiries | |
818 | ||
819 | @table @kbd | |
820 | @item M-x list-tags @key{RET} @var{file} @key{RET} | |
821 | Display a list of the tags defined in the program file @var{file}. | |
822 | @item M-x tags-apropos @key{RET} @var{regexp} @key{RET} | |
823 | Display a list of all tags matching @var{regexp}. | |
824 | @end table | |
825 | ||
826 | @findex list-tags | |
827 | @kbd{M-x list-tags} reads the name of one of the files described by | |
828 | the selected tags table, and displays a list of all the tags defined in | |
829 | that file. The ``file name'' argument is really just a string to | |
830 | compare against the file names recorded in the tags table; it is read as | |
831 | a string rather than as a file name. Therefore, completion and | |
832 | defaulting are not available, and you must enter the file name the same | |
833 | way it appears in the tags table. Do not include a directory as part of | |
834 | the file name unless the file name recorded in the tags table includes a | |
835 | directory. | |
836 | ||
837 | @findex tags-apropos | |
838 | @vindex tags-apropos-verbose | |
839 | @kbd{M-x tags-apropos} is like @code{apropos} for tags | |
840 | (@pxref{Apropos}). It finds all the tags in the selected tags table | |
841 | whose entries match @var{regexp}, and displays them. If the variable | |
842 | @code{tags-apropos-verbose} is non-@code{nil}, it displays the names | |
843 | of the tags files together with the tag names. | |
844 | ||
845 | @vindex tags-tag-face | |
846 | @vindex tags-apropos-additional-actions | |
191f7d86 RS |
847 | You can customize the appearance of the output by setting the |
848 | variable @code{tags-tag-face} to a face. You can display additional | |
849 | output with @kbd{M-x tags-apropos} by customizing the variable | |
f00366c2 RS |
850 | @code{tags-apropos-additional-actions}---see its documentation for |
851 | details. | |
852 | ||
853 | You can also use the collection of tag names to complete a symbol | |
854 | name in the buffer. @xref{Symbol Completion}. | |
855 | ||
4984edc7 EZ |
856 | @ifnottex |
857 | @include emerge-xtra.texi | |
858 | @end ifnottex | |
859 | ||
ab5796a9 MB |
860 | @ignore |
861 | arch-tag: b9d83dfb-82ea-4ff6-bab5-05a3617091fb | |
862 | @end ignore |