Replace digest-doc and sorted-doc C programs with Lisp commands.
[bpt/emacs.git] / lisp / help-fns.el
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1;;; help-fns.el --- Complex help functions
2
a87b98ce 3;; Copyright (C) 1985, 1986, 1993, 1994, 1998, 1999, 2000, 2001, 2002,
114f9c96 4;; 2003, 2004, 2005, 2006, 2007, 2008, 2009, 2010
589a99f2 5;; Free Software Foundation, Inc.
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6
7;; Maintainer: FSF
8;; Keywords: help, internal
bd78fa1d 9;; Package: emacs
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10
11;; This file is part of GNU Emacs.
12
13;; GNU Emacs is free software: you can redistribute it and/or modify
14;; it under the terms of the GNU General Public License as published by
15;; the Free Software Foundation, either version 3 of the License, or
16;; (at your option) any later version.
17
18;; GNU Emacs is distributed in the hope that it will be useful,
19;; but WITHOUT ANY WARRANTY; without even the implied warranty of
20;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
21;; GNU General Public License for more details.
22
23;; You should have received a copy of the GNU General Public License
24;; along with GNU Emacs. If not, see <http://www.gnu.org/licenses/>.
25
26;;; Commentary:
27
28;; This file contains those help commands which are complicated, and
29;; which may not be used in every session. For example
30;; `describe-function' will probably be heavily used when doing elisp
31;; programming, but not if just editing C files. Simpler help commands
32;; are in help.el
33
34;;; Code:
35
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36;; Functions
37
38;;;###autoload
39(defun describe-function (function)
40 "Display the full documentation of FUNCTION (a symbol)."
41 (interactive
42 (let ((fn (function-called-at-point))
43 (enable-recursive-minibuffers t)
44 val)
45 (setq val (completing-read (if fn
46 (format "Describe function (default %s): " fn)
47 "Describe function: ")
48 obarray 'fboundp t nil nil
49 (and fn (symbol-name fn))))
50 (list (if (equal val "")
51 fn (intern val)))))
52 (if (null function)
53 (message "You didn't specify a function")
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54 (help-setup-xref (list #'describe-function function)
55 (called-interactively-p 'interactive))
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56 (save-excursion
57 (with-help-window (help-buffer)
58 (prin1 function)
59 ;; Use " is " instead of a colon so that
60 ;; it is easier to get out the function name using forward-sexp.
61 (princ " is ")
62 (describe-function-1 function)
63 (with-current-buffer standard-output
64 ;; Return the text we displayed.
65 (buffer-string))))))
66
67(defun help-split-fundoc (docstring def)
68 "Split a function DOCSTRING into the actual doc and the usage info.
69Return (USAGE . DOC) or nil if there's no usage info.
70DEF is the function whose usage we're looking for in DOCSTRING."
71 ;; Functions can get the calling sequence at the end of the doc string.
72 ;; In cases where `function' has been fset to a subr we can't search for
73 ;; function's name in the doc string so we use `fn' as the anonymous
74 ;; function name instead.
75 (when (and docstring (string-match "\n\n(fn\\(\\( .*\\)?)\\)\\'" docstring))
76 (cons (format "(%s%s"
77 ;; Replace `fn' with the actual function name.
78 (if (consp def) "anonymous" def)
79 (match-string 1 docstring))
80 (substring docstring 0 (match-beginning 0)))))
81
82(defun help-add-fundoc-usage (docstring arglist)
83 "Add the usage info to DOCSTRING.
84If DOCSTRING already has a usage info, then just return it unchanged.
85The usage info is built from ARGLIST. DOCSTRING can be nil.
86ARGLIST can also be t or a string of the form \"(FUN ARG1 ARG2 ...)\"."
87 (unless (stringp docstring) (setq docstring "Not documented"))
88 (if (or (string-match "\n\n(fn\\(\\( .*\\)?)\\)\\'" docstring) (eq arglist t))
89 docstring
90 (concat docstring
91 (if (string-match "\n?\n\\'" docstring)
92 (if (< (- (match-end 0) (match-beginning 0)) 2) "\n" "")
93 "\n\n")
94 (if (and (stringp arglist)
95 (string-match "\\`([^ ]+\\(.*\\))\\'" arglist))
96 (concat "(fn" (match-string 1 arglist) ")")
97 (format "%S" (help-make-usage 'fn arglist))))))
98
99(defun help-function-arglist (def)
100 ;; Handle symbols aliased to other symbols.
101 (if (and (symbolp def) (fboundp def)) (setq def (indirect-function def)))
102 ;; If definition is a macro, find the function inside it.
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103 (if (eq (car-safe def) 'macro) (setq def (cdr def)))
104 (cond
105 ((byte-code-function-p def) (aref def 0))
106 ((eq (car-safe def) 'lambda) (nth 1 def))
107 ((and (eq (car-safe def) 'autoload) (not (eq (nth 4 def) 'keymap)))
108 "[Arg list not available until function definition is loaded.]")
109 (t t)))
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110
111(defun help-make-usage (function arglist)
112 (cons (if (symbolp function) function 'anonymous)
113 (mapcar (lambda (arg)
114 (if (not (symbolp arg))
115 (if (and (consp arg) (symbolp (car arg)))
116 ;; CL style default values for optional args.
117 (cons (intern (upcase (symbol-name (car arg))))
118 (cdr arg))
119 arg)
120 (let ((name (symbol-name arg)))
121 (if (string-match "\\`&" name) arg
122 (intern (upcase name))))))
123 arglist)))
124
125;; Could be this, if we make symbol-file do the work below.
126;; (defun help-C-file-name (subr-or-var kind)
127;; "Return the name of the C file where SUBR-OR-VAR is defined.
128;; KIND should be `var' for a variable or `subr' for a subroutine."
129;; (symbol-file (if (symbolp subr-or-var) subr-or-var
130;; (subr-name subr-or-var))
131;; (if (eq kind 'var) 'defvar 'defun)))
132;;;###autoload
133(defun help-C-file-name (subr-or-var kind)
134 "Return the name of the C file where SUBR-OR-VAR is defined.
135KIND should be `var' for a variable or `subr' for a subroutine."
136 (let ((docbuf (get-buffer-create " *DOC*"))
137 (name (if (eq 'var kind)
138 (concat "V" (symbol-name subr-or-var))
139 (concat "F" (subr-name subr-or-var)))))
140 (with-current-buffer docbuf
141 (goto-char (point-min))
142 (if (eobp)
143 (insert-file-contents-literally
144 (expand-file-name internal-doc-file-name doc-directory)))
145 (let ((file (catch 'loop
146 (while t
147 (let ((pnt (search-forward (concat "\1f" name "\n"))))
148 (re-search-backward "\1fS\\(.*\\)")
149 (let ((file (match-string 1)))
150 (if (member file build-files)
151 (throw 'loop file)
152 (goto-char pnt))))))))
153 (if (string-match "^ns.*\\(\\.o\\|obj\\)\\'" file)
154 (setq file (replace-match ".m" t t file 1))
155 (if (string-match "\\.\\(o\\|obj\\)\\'" file)
156 (setq file (replace-match ".c" t t file))))
157 (if (string-match "\\.\\(c\\|m\\)\\'" file)
158 (concat "src/" file)
159 file)))))
160
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161(defcustom help-downcase-arguments nil
162 "If non-nil, argument names in *Help* buffers are downcased."
163 :type 'boolean
164 :group 'help
165 :version "23.2")
166
167(defun help-highlight-arg (arg)
168 "Highlight ARG as an argument name for a *Help* buffer.
169Return ARG in face `help-argument-name'; ARG is also downcased
170if the variable `help-downcase-arguments' is non-nil."
171 (propertize (if help-downcase-arguments (downcase arg) arg)
172 'face 'help-argument-name))
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173
174(defun help-do-arg-highlight (doc args)
175 (with-syntax-table (make-syntax-table emacs-lisp-mode-syntax-table)
176 (modify-syntax-entry ?\- "w")
177 (dolist (arg args doc)
178 (setq doc (replace-regexp-in-string
179 ;; This is heuristic, but covers all common cases
180 ;; except ARG1-ARG2
181 (concat "\\<" ; beginning of word
182 "\\(?:[a-z-]*-\\)?" ; for xxx-ARG
183 "\\("
184 (regexp-quote arg)
185 "\\)"
186 "\\(?:es\\|s\\|th\\)?" ; for ARGth, ARGs
187 "\\(?:-[a-z0-9-]+\\)?" ; for ARG-xxx, ARG-n
188 "\\(?:-[{([<`\"].*?\\)?"; for ARG-{x}, (x), <x>, [x], `x'
189 "\\>") ; end of word
1659ada0 190 (help-highlight-arg arg)
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191 doc t t 1)))))
192
193(defun help-highlight-arguments (usage doc &rest args)
194 (when usage
195 (with-temp-buffer
196 (insert usage)
197 (goto-char (point-min))
198 (let ((case-fold-search nil)
199 (next (not (or args (looking-at "\\["))))
200 (opt nil))
201 ;; Make a list of all arguments
202 (skip-chars-forward "^ ")
203 (while next
204 (or opt (not (looking-at " &")) (setq opt t))
205 (if (not (re-search-forward " \\([\\[(]*\\)\\([^] &)\.]+\\)" nil t))
206 (setq next nil)
207 (setq args (cons (match-string 2) args))
208 (when (and opt (string= (match-string 1) "("))
209 ;; A pesky CL-style optional argument with default value,
210 ;; so let's skip over it
211 (search-backward "(")
212 (goto-char (scan-sexps (point) 1)))))
213 ;; Highlight aguments in the USAGE string
214 (setq usage (help-do-arg-highlight (buffer-string) args))
215 ;; Highlight arguments in the DOC string
216 (setq doc (and doc (help-do-arg-highlight doc args))))))
217 ;; Return value is like the one from help-split-fundoc, but highlighted
218 (cons usage doc))
219
220;; The following function was compiled from the former functions
221;; `describe-simplify-lib-file-name' and `find-source-lisp-file' with
222;; some excerpts from `describe-function-1' and `describe-variable'.
223;; The only additional twists provided are (1) locate the defining file
224;; for autoloaded functions, and (2) give preference to files in the
225;; "install directory" (directories found via `load-path') rather than
226;; to files in the "compile directory" (directories found by searching
227;; the loaddefs.el file). We autoload it because it's also used by
228;; `describe-face' (instead of `describe-simplify-lib-file-name').
229
230;;;###autoload
231(defun find-lisp-object-file-name (object type)
232 "Guess the file that defined the Lisp object OBJECT, of type TYPE.
233OBJECT should be a symbol associated with a function, variable, or face;
234 alternatively, it can be a function definition.
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235If TYPE is `defvar', search for a variable definition.
236If TYPE is `defface', search for a face definition.
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237If TYPE is the value returned by `symbol-function' for a function symbol,
238 search for a function definition.
239
240The return value is the absolute name of a readable file where OBJECT is
241defined. If several such files exist, preference is given to a file
242found via `load-path'. The return value can also be `C-source', which
243means that OBJECT is a function or variable defined in C. If no
244suitable file is found, return nil."
245 (let* ((autoloaded (eq (car-safe type) 'autoload))
246 (file-name (or (and autoloaded (nth 1 type))
247 (symbol-file
248 object (if (memq type (list 'defvar 'defface))
249 type
250 'defun)))))
251 (cond
252 (autoloaded
253 ;; An autoloaded function: Locate the file since `symbol-function'
254 ;; has only returned a bare string here.
255 (setq file-name
256 (locate-file file-name load-path '(".el" ".elc") 'readable)))
257 ((and (stringp file-name)
258 (string-match "[.]*loaddefs.el\\'" file-name))
259 ;; An autoloaded variable or face. Visit loaddefs.el in a buffer
260 ;; and try to extract the defining file. The following form is
261 ;; from `describe-function-1' and `describe-variable'.
262 (let ((location
263 (condition-case nil
264 (find-function-search-for-symbol object nil file-name)
265 (error nil))))
6565b5ab 266 (when (cdr location)
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267 (with-current-buffer (car location)
268 (goto-char (cdr location))
269 (when (re-search-backward
270 "^;;; Generated autoloads from \\(.*\\)" nil t)
271 (setq file-name
272 (locate-file
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273 (file-name-sans-extension
274 (match-string-no-properties 1))
275 load-path '(".el" ".elc") 'readable))))))))
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276
277 (cond
278 ((and (not file-name) (subrp type))
279 ;; A built-in function. The form is from `describe-function-1'.
280 (if (get-buffer " *DOC*")
281 (help-C-file-name type 'subr)
282 'C-source))
283 ((and (not file-name) (symbolp object)
284 (integerp (get object 'variable-documentation)))
285 ;; A variable defined in C. The form is from `describe-variable'.
286 (if (get-buffer " *DOC*")
287 (help-C-file-name object 'var)
288 'C-source))
289 ((not (stringp file-name))
290 ;; If we don't have a file-name string by now, we lost.
291 nil)
292 ((let ((lib-name
293 (if (string-match "[.]elc\\'" file-name)
294 (substring-no-properties file-name 0 -1)
295 file-name)))
296 ;; When the Elisp source file can be found in the install
297 ;; directory return the name of that file - `file-name' should
298 ;; have become an absolute file name ny now.
299 (or (and (file-readable-p lib-name) lib-name)
300 ;; The library might be compressed.
301 (and (file-readable-p (concat lib-name ".gz")) lib-name))))
302 ((let* ((lib-name (file-name-nondirectory file-name))
303 ;; The next form is from `describe-simplify-lib-file-name'.
304 (file-name
305 ;; Try converting the absolute file name to a library
306 ;; name, convert that back to a file name and see if we
307 ;; get the original one. If so, they are equivalent.
308 (if (equal file-name (locate-file lib-name load-path '("")))
309 (if (string-match "[.]elc\\'" lib-name)
310 (substring-no-properties lib-name 0 -1)
311 lib-name)
312 file-name))
313 ;; The next three forms are from `find-source-lisp-file'.
314 (elc-file (locate-file
315 (concat file-name
316 (if (string-match "\\.el\\'" file-name)
317 "c"
318 ".elc"))
319 load-path nil 'readable))
320 (str (when elc-file
321 (with-temp-buffer
322 (insert-file-contents-literally elc-file nil 0 256)
323 (buffer-string))))
324 (src-file (and str
325 (string-match ";;; from file \\(.*\\.el\\)" str)
326 (match-string 1 str))))
327 (and src-file (file-readable-p src-file) src-file))))))
328
329(declare-function ad-get-advice-info "advice" (function))
330
331;;;###autoload
332(defun describe-function-1 (function)
333 (let* ((advised (and (symbolp function) (featurep 'advice)
334 (ad-get-advice-info function)))
335 ;; If the function is advised, use the symbol that has the
336 ;; real definition, if that symbol is already set up.
337 (real-function
338 (or (and advised
339 (let ((origname (cdr (assq 'origname advised))))
340 (and (fboundp origname) origname)))
341 function))
342 ;; Get the real definition.
343 (def (if (symbolp real-function)
344 (symbol-function real-function)
345 function))
346 file-name string
347 (beg (if (commandp def) "an interactive " "a "))
348 (pt1 (with-current-buffer (help-buffer) (point)))
349 errtype)
350 (setq string
351 (cond ((or (stringp def)
352 (vectorp def))
353 "a keyboard macro")
354 ((subrp def)
355 (if (eq 'unevalled (cdr (subr-arity def)))
356 (concat beg "special form")
357 (concat beg "built-in function")))
358 ((byte-code-function-p def)
359 (concat beg "compiled Lisp function"))
360 ((symbolp def)
361 (while (and (fboundp def)
362 (symbolp (symbol-function def)))
363 (setq def (symbol-function def)))
364 ;; Handle (defalias 'foo 'bar), where bar is undefined.
365 (or (fboundp def) (setq errtype 'alias))
366 (format "an alias for `%s'" def))
367 ((eq (car-safe def) 'lambda)
368 (concat beg "Lisp function"))
369 ((eq (car-safe def) 'macro)
370 "a Lisp macro")
371 ((eq (car-safe def) 'autoload)
372 (format "%s autoloaded %s"
373 (if (commandp def) "an interactive" "an")
374 (if (eq (nth 4 def) 'keymap) "keymap"
375 (if (nth 4 def) "Lisp macro" "Lisp function"))))
376 ((keymapp def)
377 (let ((is-full nil)
378 (elts (cdr-safe def)))
379 (while elts
380 (if (char-table-p (car-safe elts))
381 (setq is-full t
382 elts nil))
383 (setq elts (cdr-safe elts)))
384 (if is-full
385 "a full keymap"
386 "a sparse keymap")))
387 (t "")))
388 (princ string)
389 (if (eq errtype 'alias)
390 (princ ",\nwhich is not defined. Please make a bug report.")
391 (with-current-buffer standard-output
392 (save-excursion
393 (save-match-data
394 (when (re-search-backward "alias for `\\([^`']+\\)'" nil t)
395 (help-xref-button 1 'help-function def)))))
396
397 (setq file-name (find-lisp-object-file-name function def))
398 (when file-name
399 (princ " in `")
400 ;; We used to add .el to the file name,
401 ;; but that's completely wrong when the user used load-file.
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402 (princ (if (eq file-name 'C-source)
403 "C source code"
404 (file-name-nondirectory file-name)))
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405 (princ "'")
406 ;; Make a hyperlink to the library.
407 (with-current-buffer standard-output
408 (save-excursion
409 (re-search-backward "`\\([^`']+\\)'" nil t)
cebabb67 410 (help-xref-button 1 'help-function-def function file-name))))
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411 (princ ".")
412 (with-current-buffer (help-buffer)
413 (fill-region-as-paragraph (save-excursion (goto-char pt1) (forward-line 0) (point))
414 (point)))
415 (terpri)(terpri)
416 (when (commandp function)
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417 (let ((pt2 (with-current-buffer (help-buffer) (point)))
418 (remapped (command-remapping function)))
419 (unless (memq remapped '(ignore undefined))
420 (let ((keys (where-is-internal
421 (or remapped function) overriding-local-map nil nil))
422 non-modified-keys)
423 (if (and (eq function 'self-insert-command)
424 (vectorp (car-safe keys))
425 (consp (aref (car keys) 0)))
426 (princ "It is bound to many ordinary text characters.\n")
427 ;; Which non-control non-meta keys run this command?
428 (dolist (key keys)
429 (if (member (event-modifiers (aref key 0)) '(nil (shift)))
430 (push key non-modified-keys)))
431 (when remapped
432 (princ "It is remapped to `")
433 (princ (symbol-name remapped))
434 (princ "'"))
435
436 (when keys
437 (princ (if remapped ", which is bound to " "It is bound to "))
438 ;; If lots of ordinary text characters run this command,
439 ;; don't mention them one by one.
440 (if (< (length non-modified-keys) 10)
441 (princ (mapconcat 'key-description keys ", "))
442 (dolist (key non-modified-keys)
443 (setq keys (delq key keys)))
444 (if keys
445 (progn
446 (princ (mapconcat 'key-description keys ", "))
447 (princ ", and many ordinary text characters"))
448 (princ "many ordinary text characters"))))
449 (when (or remapped keys non-modified-keys)
450 (princ ".")
451 (terpri)))))
1113ff44 452
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453 (with-current-buffer (help-buffer)
454 (fill-region-as-paragraph pt2 (point))
455 (unless (looking-back "\n\n")
456 (terpri)))))
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457 ;; Note that list* etc do not get this property until
458 ;; cl-hack-byte-compiler runs, after bytecomp is loaded.
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459 (when (and (symbolp function)
460 (eq (get function 'byte-compile)
461 'cl-byte-compile-compiler-macro))
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462 (princ "This function has a compiler macro")
463 (let ((lib (get function 'compiler-macro-file)))
464 (when (stringp lib)
465 (princ (format " in `%s'" lib))
466 (with-current-buffer standard-output
467 (save-excursion
468 (re-search-backward "`\\([^`']+\\)'" nil t)
469 (help-xref-button 1 'help-function-cmacro function lib)))))
470 (princ ".\n\n"))
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471 (let* ((advertised (gethash def advertised-signature-table t))
472 (arglist (if (listp advertised)
473 advertised (help-function-arglist def)))
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474 (doc (documentation function))
475 (usage (help-split-fundoc doc function)))
476 (with-current-buffer standard-output
477 ;; If definition is a keymap, skip arglist note.
478 (unless (keymapp function)
8d6c1239 479 (if usage (setq doc (cdr usage)))
1113ff44 480 (let* ((use (cond
8d6c1239 481 ((and usage (not (listp advertised))) (car usage))
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482 ((listp arglist)
483 (format "%S" (help-make-usage function arglist)))
484 ((stringp arglist) arglist)
485 ;; Maybe the arglist is in the docstring of a symbol
486 ;; this one is aliased to.
487 ((let ((fun real-function))
488 (while (and (symbolp fun)
489 (setq fun (symbol-function fun))
490 (not (setq usage (help-split-fundoc
491 (documentation fun)
492 function)))))
493 usage)
494 (car usage))
495 ((or (stringp def)
496 (vectorp def))
497 (format "\nMacro: %s" (format-kbd-macro def)))
498 (t "[Missing arglist. Please make a bug report.]")))
499 (high (help-highlight-arguments use doc)))
500 (let ((fill-begin (point)))
501 (insert (car high) "\n")
502 (fill-region fill-begin (point)))
503 (setq doc (cdr high))))
504 (let* ((obsolete (and
505 ;; function might be a lambda construct.
506 (symbolp function)
507 (get function 'byte-obsolete-info)))
508 (use (car obsolete)))
509 (when obsolete
510 (princ "\nThis function is obsolete")
511 (when (nth 2 obsolete)
512 (insert (format " since %s" (nth 2 obsolete))))
513 (insert (cond ((stringp use) (concat ";\n" use))
514 (use (format ";\nuse `%s' instead." use))
515 (t "."))
516 "\n"))
517 (insert "\n"
518 (or doc "Not documented."))))))))
519
520\f
521;; Variables
522
523;;;###autoload
524(defun variable-at-point (&optional any-symbol)
525 "Return the bound variable symbol found at or before point.
526Return 0 if there is no such symbol.
527If ANY-SYMBOL is non-nil, don't insist the symbol be bound."
528 (with-syntax-table emacs-lisp-mode-syntax-table
529 (or (condition-case ()
530 (save-excursion
531 (or (not (zerop (skip-syntax-backward "_w")))
532 (eq (char-syntax (following-char)) ?w)
533 (eq (char-syntax (following-char)) ?_)
534 (forward-sexp -1))
535 (skip-chars-forward "'")
536 (let ((obj (read (current-buffer))))
537 (and (symbolp obj) (boundp obj) obj)))
538 (error nil))
539 (let* ((str (find-tag-default))
540 (sym (if str (intern-soft str))))
541 (if (and sym (or any-symbol (boundp sym)))
542 sym
543 (save-match-data
544 (when (and str (string-match "\\`\\W*\\(.*?\\)\\W*\\'" str))
545 (setq sym (intern-soft (match-string 1 str)))
546 (and (or any-symbol (boundp sym)) sym)))))
547 0)))
548
549(defun describe-variable-custom-version-info (variable)
550 (let ((custom-version (get variable 'custom-version))
551 (cpv (get variable 'custom-package-version))
552 (output nil))
553 (if custom-version
554 (setq output
555 (format "This variable was introduced, or its default value was changed, in\nversion %s of Emacs.\n"
556 custom-version))
557 (when cpv
558 (let* ((package (car-safe cpv))
559 (version (if (listp (cdr-safe cpv))
560 (car (cdr-safe cpv))
561 (cdr-safe cpv)))
562 (pkg-versions (assq package customize-package-emacs-version-alist))
563 (emacsv (cdr (assoc version pkg-versions))))
564 (if (and package version)
565 (setq output
566 (format (concat "This variable was introduced, or its default value was changed, in\nversion %s of the %s package"
567 (if emacsv
568 (format " that is part of Emacs %s" emacsv))
569 ".\n")
570 version package))))))
571 output))
572
573;;;###autoload
574(defun describe-variable (variable &optional buffer frame)
575 "Display the full documentation of VARIABLE (a symbol).
576Returns the documentation as a string, also.
577If VARIABLE has a buffer-local value in BUFFER or FRAME
578\(default to the current buffer and current frame),
579it is displayed along with the global value."
580 (interactive
581 (let ((v (variable-at-point))
582 (enable-recursive-minibuffers t)
583 val)
584 (setq val (completing-read (if (symbolp v)
585 (format
586 "Describe variable (default %s): " v)
587 "Describe variable: ")
588 obarray
589 '(lambda (vv)
590 (or (boundp vv)
591 (get vv 'variable-documentation)))
592 t nil nil
593 (if (symbolp v) (symbol-name v))))
594 (list (if (equal val "")
595 v (intern val)))))
596 (let (file-name)
597 (unless (buffer-live-p buffer) (setq buffer (current-buffer)))
598 (unless (frame-live-p frame) (setq frame (selected-frame)))
599 (if (not (symbolp variable))
600 (message "You did not specify a variable")
601 (save-excursion
602 (let ((valvoid (not (with-current-buffer buffer (boundp variable))))
603 val val-start-pos locus)
604 ;; Extract the value before setting up the output buffer,
605 ;; in case `buffer' *is* the output buffer.
606 (unless valvoid
607 (with-selected-frame frame
608 (with-current-buffer buffer
609 (setq val (symbol-value variable)
610 locus (variable-binding-locus variable)))))
611 (help-setup-xref (list #'describe-variable variable buffer)
32226619 612 (called-interactively-p 'interactive))
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613 (with-help-window (help-buffer)
614 (with-current-buffer buffer
615 (prin1 variable)
616 (setq file-name (find-lisp-object-file-name variable 'defvar))
617
618 (if file-name
619 (progn
620 (princ " is a variable defined in `")
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621 (princ (if (eq file-name 'C-source)
622 "C source code"
623 (file-name-nondirectory file-name)))
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624 (princ "'.\n")
625 (with-current-buffer standard-output
626 (save-excursion
627 (re-search-backward "`\\([^`']+\\)'" nil t)
628 (help-xref-button 1 'help-variable-def
629 variable file-name)))
630 (if valvoid
631 (princ "It is void as a variable.")
632 (princ "Its ")))
633 (if valvoid
634 (princ " is void as a variable.")
635 (princ "'s "))))
636 (if valvoid
637 nil
638 (with-current-buffer standard-output
639 (setq val-start-pos (point))
640 (princ "value is ")
641 (terpri)
642 (let ((from (point)))
643 (pp val)
644 ;; Hyperlinks in variable's value are quite frequently
645 ;; inappropriate e.g C-h v <RET> features <RET>
646 ;; (help-xref-on-pp from (point))
647 (if (< (point) (+ from 20))
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648 (delete-region (1- from) from))
649 (let* ((sv (get variable 'standard-value))
650 (origval (and (consp sv)
651 (condition-case nil
652 (eval (car sv))
653 (error :help-eval-error)))))
654 (when (and (consp sv)
655 (not (equal origval val))
656 (not (equal origval :help-eval-error)))
657 (princ "\nOriginal value was \n")
658 (setq from (point))
659 (pp origval)
660 (if (< (point) (+ from 20))
661 (delete-region (1- from) from)))))))
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662 (terpri)
663
664 (when locus
665 (if (bufferp locus)
666 (princ (format "%socal in buffer %s; "
667 (if (get variable 'permanent-local)
668 "Permanently l" "L")
669 (buffer-name)))
670 (princ (format "It is a frame-local variable; ")))
671 (if (not (default-boundp variable))
672 (princ "globally void")
673 (let ((val (default-value variable)))
674 (with-current-buffer standard-output
675 (princ "global value is ")
676 (terpri)
677 ;; Fixme: pp can take an age if you happen to
678 ;; ask for a very large expression. We should
679 ;; probably print it raw once and check it's a
680 ;; sensible size before prettyprinting. -- fx
681 (let ((from (point)))
682 (pp val)
683 ;; See previous comment for this function.
684 ;; (help-xref-on-pp from (point))
685 (if (< (point) (+ from 20))
686 (delete-region (1- from) from))))))
687 (terpri))
688
689 ;; If the value is large, move it to the end.
690 (with-current-buffer standard-output
691 (when (> (count-lines (point-min) (point-max)) 10)
692 ;; Note that setting the syntax table like below
693 ;; makes forward-sexp move over a `'s' at the end
694 ;; of a symbol.
695 (set-syntax-table emacs-lisp-mode-syntax-table)
696 (goto-char val-start-pos)
697 ;; The line below previously read as
698 ;; (delete-region (point) (progn (end-of-line) (point)))
699 ;; which suppressed display of the buffer local value for
700 ;; large values.
701 (when (looking-at "value is") (replace-match ""))
702 (save-excursion
703 (insert "\n\nValue:")
704 (set (make-local-variable 'help-button-cache)
705 (point-marker)))
706 (insert "value is shown ")
707 (insert-button "below"
708 'action help-button-cache
709 'follow-link t
710 'help-echo "mouse-2, RET: show value")
711 (insert ".\n")))
712 (terpri)
713
714 (let* ((alias (condition-case nil
715 (indirect-variable variable)
716 (error variable)))
717 (obsolete (get variable 'byte-obsolete-variable))
718 (use (car obsolete))
719 (safe-var (get variable 'safe-local-variable))
720 (doc (or (documentation-property variable 'variable-documentation)
721 (documentation-property alias 'variable-documentation)))
722 (extra-line nil))
723 ;; Add a note for variables that have been make-var-buffer-local.
724 (when (and (local-variable-if-set-p variable)
725 (or (not (local-variable-p variable))
726 (with-temp-buffer
727 (local-variable-if-set-p variable))))
728 (setq extra-line t)
729 (princ " Automatically becomes buffer-local when set in any fashion.\n"))
730
731 ;; Mention if it's an alias
732 (unless (eq alias variable)
733 (setq extra-line t)
734 (princ (format " This variable is an alias for `%s'.\n" alias)))
735
736 (when obsolete
737 (setq extra-line t)
738 (princ " This variable is obsolete")
739 (if (cdr obsolete) (princ (format " since %s" (cdr obsolete))))
740 (princ (cond ((stringp use) (concat ";\n " use))
741 (use (format ";\n use `%s' instead." (car obsolete)))
742 (t ".")))
743 (terpri))
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744
745 (when (member (cons variable val) file-local-variables-alist)
746 (setq extra-line t)
747 (if (member (cons variable val) dir-local-variables-alist)
748 (let ((file (and (buffer-file-name)
749 (not (file-remote-p (buffer-file-name)))
750 (dir-locals-find-file (buffer-file-name)))))
751 (princ " This variable is a directory local variable")
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752 (when file
753 (princ (concat "\n from the file \""
754 (if (consp file)
755 (car file)
756 file)
757 "\"")))
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758 (princ ".\n"))
759 (princ " This variable is a file local variable.\n")))
760
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761 (when (memq variable ignored-local-variables)
762 (setq extra-line t)
763 (princ " This variable is ignored when used as a file local \
764variable.\n"))
765
766 ;; Can be both risky and safe, eg auto-fill-function.
767 (when (risky-local-variable-p variable)
768 (setq extra-line t)
769 (princ " This variable is potentially risky when used as a \
770file local variable.\n")
771 (when (assq variable safe-local-variable-values)
772 (princ " However, you have added it to \
773`safe-local-variable-values'.\n")))
774
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775 (when safe-var
776 (setq extra-line t)
777 (princ " This variable is safe as a file local variable ")
778 (princ "if its value\n satisfies the predicate ")
779 (princ (if (byte-code-function-p safe-var)
780 "which is byte-compiled expression.\n"
781 (format "`%s'.\n" safe-var))))
782
783 (if extra-line (terpri))
784 (princ "Documentation:\n")
785 (with-current-buffer standard-output
786 (insert (or doc "Not documented as a variable."))))
787
788 ;; Make a link to customize if this variable can be customized.
789 (when (custom-variable-p variable)
790 (let ((customize-label "customize"))
791 (terpri)
792 (terpri)
793 (princ (concat "You can " customize-label " this variable."))
794 (with-current-buffer standard-output
795 (save-excursion
796 (re-search-backward
797 (concat "\\(" customize-label "\\)") nil t)
798 (help-xref-button 1 'help-customize-variable variable))))
799 ;; Note variable's version or package version
800 (let ((output (describe-variable-custom-version-info variable)))
801 (when output
802 (terpri)
803 (terpri)
804 (princ output))))
805
7fdbcd83 806 (with-current-buffer standard-output
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807 ;; Return the text we displayed.
808 (buffer-string))))))))
809
810
811;;;###autoload
812(defun describe-syntax (&optional buffer)
813 "Describe the syntax specifications in the syntax table of BUFFER.
814The descriptions are inserted in a help buffer, which is then displayed.
815BUFFER defaults to the current buffer."
816 (interactive)
817 (setq buffer (or buffer (current-buffer)))
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818 (help-setup-xref (list #'describe-syntax buffer)
819 (called-interactively-p 'interactive))
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820 (with-help-window (help-buffer)
821 (let ((table (with-current-buffer buffer (syntax-table))))
822 (with-current-buffer standard-output
823 (describe-vector table 'internal-describe-syntax-value)
824 (while (setq table (char-table-parent table))
825 (insert "\nThe parent syntax table is:")
826 (describe-vector table 'internal-describe-syntax-value))))))
827
828(defun help-describe-category-set (value)
829 (insert (cond
830 ((null value) "default")
831 ((char-table-p value) "deeper char-table ...")
832 (t (condition-case err
833 (category-set-mnemonics value)
834 (error "invalid"))))))
835
836;;;###autoload
837(defun describe-categories (&optional buffer)
838 "Describe the category specifications in the current category table.
839The descriptions are inserted in a buffer, which is then displayed.
840If BUFFER is non-nil, then describe BUFFER's category table instead.
841BUFFER should be a buffer or a buffer name."
842 (interactive)
843 (setq buffer (or buffer (current-buffer)))
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844 (help-setup-xref (list #'describe-categories buffer)
845 (called-interactively-p 'interactive))
1113ff44 846 (with-help-window (help-buffer)
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847 (let* ((table (with-current-buffer buffer (category-table)))
848 (docs (char-table-extra-slot table 0)))
849 (if (or (not (vectorp docs)) (/= (length docs) 95))
850 (error "Invalid first extra slot in this category table\n"))
1113ff44 851 (with-current-buffer standard-output
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852 (insert "Legend of category mnemonics (see the tail for the longer description)\n")
853 (let ((pos (point)) (items 0) lines n)
854 (dotimes (i 95)
855 (if (aref docs i) (setq items (1+ items))))
856 (setq lines (1+ (/ (1- items) 4)))
857 (setq n 0)
858 (dotimes (i 95)
859 (let ((elt (aref docs i)))
860 (when elt
861 (string-match ".*" elt)
862 (setq elt (match-string 0 elt))
863 (if (>= (length elt) 17)
864 (setq elt (concat (substring elt 0 14) "...")))
865 (if (< (point) (point-max))
866 (move-to-column (* 20 (/ n lines)) t))
867 (insert (+ i ?\s) ?: elt)
868 (if (< (point) (point-max))
869 (forward-line 1)
870 (insert "\n"))
871 (setq n (1+ n))
872 (if (= (% n lines) 0)
873 (goto-char pos))))))
874 (goto-char (point-max))
875 (insert "\n"
876 "character(s)\tcategory mnemonics\n"
877 "------------\t------------------")
1113ff44 878 (describe-vector table 'help-describe-category-set)
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879 (insert "Legend of category mnemonics:\n")
880 (dotimes (i 95)
881 (let ((elt (aref docs i)))
882 (when elt
883 (if (string-match "\n" elt)
884 (setq elt (substring elt (match-end 0))))
885 (insert (+ i ?\s) ": " elt "\n"))))
886 (while (setq table (char-table-parent table))
887 (insert "\nThe parent category table is:")
888 (describe-vector table 'help-describe-category-set))))))
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890\f
891;;; Replacements for old lib-src/ programs. Don't seem especially useful.
892
893;; Replaces lib-src/digest-doc.c.
894;;;###autoload
895(defun doc-file-to-man (file)
896 "Produce an nroff buffer containing the doc-strings from the DOC file."
897 (interactive (list (read-file-name "Name of DOC file: " doc-directory
898 internal-doc-file-name t)))
899 (or (file-readable-p file)
900 (error "Cannot read file `%s'" file))
901 (pop-to-buffer (generate-new-buffer "*man-doc*"))
902 (setq buffer-undo-list t)
903 (insert ".TH \"Command Summary for GNU Emacs\"\n"
904 ".AU Richard M. Stallman\n")
905 (insert-file-contents file)
906 (let (notfirst)
907 (while (search-forward "\1f" nil 'move)
908 (if (looking-at "S")
909 (delete-region (1- (point)) (line-end-position))
910 (delete-char -1)
911 (if notfirst
912 (insert "\n.DE\n")
913 (setq notfirst t))
914 (insert "\n.SH ")
915 (insert (if (looking-at "F") "Function " "Variable "))
916 (delete-char 1)
917 (forward-line 1)
918 (insert ".DS L\n"))))
919 (insert "\n.DE\n")
920 (setq buffer-undo-list nil)
921 (nroff-mode))
922
923;; Replaces lib-src/sorted-doc.c.
924;;;###autoload
925(defun doc-file-to-info (file)
926 "Produce a texinfo buffer with sorted doc-strings from the DOC file."
927 (interactive (list (read-file-name "Name of DOC file: " doc-directory
928 internal-doc-file-name t)))
929 (or (file-readable-p file)
930 (error "Cannot read file `%s'" file))
931 (let ((i 0) type name doc alist)
932 (with-temp-buffer
933 (insert-file-contents file)
934 ;; The characters "@{}" need special treatment.
935 (while (re-search-forward "[@{}]" nil t)
936 (backward-char)
937 (insert "@")
938 (forward-char 1))
939 (goto-char (point-min))
940 (while (search-forward "\1f" nil t)
941 (unless (looking-at "S")
942 (setq type (char-after)
943 name (buffer-substring (1+ (point)) (line-end-position))
944 doc (buffer-substring (line-beginning-position 2)
945 (if (search-forward "\1f" nil 'move)
946 (1- (point))
947 (point)))
948 alist (cons (list name type doc) alist))
949 (backward-char 1))))
950 (pop-to-buffer (generate-new-buffer "*info-doc*"))
951 (setq buffer-undo-list t)
952 ;; Write the output header.
953 (insert "\\input texinfo @c -*-texinfo-*-\n"
954 "@setfilename emacsdoc.info\n"
955 "@settitle Command Summary for GNU Emacs\n"
956 "@finalout\n"
957 "\n@node Top\n"
958 "@unnumbered Command Summary for GNU Emacs\n\n"
959 "@table @asis\n\n"
960 "@iftex\n"
961 "@global@let@ITEM@item\n"
962 "@def@item{@filbreak@vskip5pt@ITEM}\n"
963 "@font@tensy cmsy10 scaled @magstephalf\n"
964 "@font@teni cmmi10 scaled @magstephalf\n"
965 "@def\\{{@tensy@char110}}\n" ; this backslash goes with cmr10
966 "@def|{{@tensy@char106}}\n"
967 "@def@{{{@tensy@char102}}\n"
968 "@def@}{{@tensy@char103}}\n"
969 "@def<{{@teni@char62}}\n"
970 "@def>{{@teni@char60}}\n"
971 "@chardef@@64\n"
972 "@catcode43=12\n"
973 "@tableindent-0.2in\n"
974 "@end iftex\n")
975 ;; Sort the array by name; within each name, by type (functions first).
976 (setq alist (sort alist (lambda (e1 e2)
977 (if (string-equal (car e1) (car e2))
978 (<= (cadr e1) (cadr e2))
979 (string-lessp (car e1) (car e2))))))
980 ;; Print each function.
981 (dolist (e alist)
982 (insert "\n@item "
983 (if (char-equal (cadr e) ?\F) "Function" "Variable")
984 " @code{" (car e) "}\n@display\n"
985 (nth 2 e)
986 "\n@end display\n")
987 ;; Try to avoid a save size overflow in the TeX output routine.
988 (if (zerop (setq i (% (1+ i) 100)))
989 (insert "\n@end table\n@table @asis\n")))
990 (insert "@end table\n"
991 "@bye\n")
992 (setq buffer-undo-list nil)
993 (texinfo-mode)))
994
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995(provide 'help-fns)
996
1113ff44 997;;; help-fns.el ends here