Get rid of funvec.
[bpt/emacs.git] / lisp / help-fns.el
CommitLineData
1113ff44
MR
1;;; help-fns.el --- Complex help functions
2
73b0cd50 3;; Copyright (C) 1985-1986, 1993-1994, 1998-2011
589a99f2 4;; Free Software Foundation, Inc.
1113ff44
MR
5
6;; Maintainer: FSF
7;; Keywords: help, internal
bd78fa1d 8;; Package: emacs
1113ff44
MR
9
10;; This file is part of GNU Emacs.
11
12;; GNU Emacs is free software: you can redistribute it and/or modify
13;; it under the terms of the GNU General Public License as published by
14;; the Free Software Foundation, either version 3 of the License, or
15;; (at your option) any later version.
16
17;; GNU Emacs is distributed in the hope that it will be useful,
18;; but WITHOUT ANY WARRANTY; without even the implied warranty of
19;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
20;; GNU General Public License for more details.
21
22;; You should have received a copy of the GNU General Public License
23;; along with GNU Emacs. If not, see <http://www.gnu.org/licenses/>.
24
25;;; Commentary:
26
27;; This file contains those help commands which are complicated, and
28;; which may not be used in every session. For example
29;; `describe-function' will probably be heavily used when doing elisp
30;; programming, but not if just editing C files. Simpler help commands
31;; are in help.el
32
33;;; Code:
34
1113ff44
MR
35;; Functions
36
37;;;###autoload
38(defun describe-function (function)
39 "Display the full documentation of FUNCTION (a symbol)."
40 (interactive
41 (let ((fn (function-called-at-point))
42 (enable-recursive-minibuffers t)
43 val)
44 (setq val (completing-read (if fn
45 (format "Describe function (default %s): " fn)
46 "Describe function: ")
47 obarray 'fboundp t nil nil
48 (and fn (symbol-name fn))))
49 (list (if (equal val "")
50 fn (intern val)))))
51 (if (null function)
52 (message "You didn't specify a function")
32226619
JB
53 (help-setup-xref (list #'describe-function function)
54 (called-interactively-p 'interactive))
1113ff44
MR
55 (save-excursion
56 (with-help-window (help-buffer)
57 (prin1 function)
58 ;; Use " is " instead of a colon so that
59 ;; it is easier to get out the function name using forward-sexp.
60 (princ " is ")
61 (describe-function-1 function)
62 (with-current-buffer standard-output
63 ;; Return the text we displayed.
64 (buffer-string))))))
65
66(defun help-split-fundoc (docstring def)
67 "Split a function DOCSTRING into the actual doc and the usage info.
68Return (USAGE . DOC) or nil if there's no usage info.
69DEF is the function whose usage we're looking for in DOCSTRING."
70 ;; Functions can get the calling sequence at the end of the doc string.
71 ;; In cases where `function' has been fset to a subr we can't search for
72 ;; function's name in the doc string so we use `fn' as the anonymous
73 ;; function name instead.
74 (when (and docstring (string-match "\n\n(fn\\(\\( .*\\)?)\\)\\'" docstring))
75 (cons (format "(%s%s"
76 ;; Replace `fn' with the actual function name.
77 (if (consp def) "anonymous" def)
78 (match-string 1 docstring))
79 (substring docstring 0 (match-beginning 0)))))
80
81(defun help-add-fundoc-usage (docstring arglist)
82 "Add the usage info to DOCSTRING.
83If DOCSTRING already has a usage info, then just return it unchanged.
84The usage info is built from ARGLIST. DOCSTRING can be nil.
85ARGLIST can also be t or a string of the form \"(FUN ARG1 ARG2 ...)\"."
86 (unless (stringp docstring) (setq docstring "Not documented"))
87 (if (or (string-match "\n\n(fn\\(\\( .*\\)?)\\)\\'" docstring) (eq arglist t))
88 docstring
89 (concat docstring
90 (if (string-match "\n?\n\\'" docstring)
91 (if (< (- (match-end 0) (match-beginning 0)) 2) "\n" "")
92 "\n\n")
93 (if (and (stringp arglist)
94 (string-match "\\`([^ ]+\\(.*\\))\\'" arglist))
95 (concat "(fn" (match-string 1 arglist) ")")
96 (format "%S" (help-make-usage 'fn arglist))))))
97
98(defun help-function-arglist (def)
99 ;; Handle symbols aliased to other symbols.
100 (if (and (symbolp def) (fboundp def)) (setq def (indirect-function def)))
101 ;; If definition is a macro, find the function inside it.
8d6c1239 102 (if (eq (car-safe def) 'macro) (setq def (cdr def)))
b9598260
SM
103 ;; and do the same for interpreted closures
104 (if (eq (car-safe def) 'closure) (setq def (cddr def)))
8d6c1239
SM
105 (cond
106 ((byte-code-function-p def) (aref def 0))
107 ((eq (car-safe def) 'lambda) (nth 1 def))
108 ((and (eq (car-safe def) 'autoload) (not (eq (nth 4 def) 'keymap)))
109 "[Arg list not available until function definition is loaded.]")
110 (t t)))
1113ff44
MR
111
112(defun help-make-usage (function arglist)
113 (cons (if (symbolp function) function 'anonymous)
114 (mapcar (lambda (arg)
115 (if (not (symbolp arg))
116 (if (and (consp arg) (symbolp (car arg)))
117 ;; CL style default values for optional args.
118 (cons (intern (upcase (symbol-name (car arg))))
119 (cdr arg))
120 arg)
121 (let ((name (symbol-name arg)))
122 (if (string-match "\\`&" name) arg
123 (intern (upcase name))))))
124 arglist)))
125
126;; Could be this, if we make symbol-file do the work below.
127;; (defun help-C-file-name (subr-or-var kind)
128;; "Return the name of the C file where SUBR-OR-VAR is defined.
129;; KIND should be `var' for a variable or `subr' for a subroutine."
130;; (symbol-file (if (symbolp subr-or-var) subr-or-var
131;; (subr-name subr-or-var))
132;; (if (eq kind 'var) 'defvar 'defun)))
133;;;###autoload
134(defun help-C-file-name (subr-or-var kind)
135 "Return the name of the C file where SUBR-OR-VAR is defined.
136KIND should be `var' for a variable or `subr' for a subroutine."
137 (let ((docbuf (get-buffer-create " *DOC*"))
138 (name (if (eq 'var kind)
139 (concat "V" (symbol-name subr-or-var))
140 (concat "F" (subr-name subr-or-var)))))
141 (with-current-buffer docbuf
142 (goto-char (point-min))
143 (if (eobp)
144 (insert-file-contents-literally
145 (expand-file-name internal-doc-file-name doc-directory)))
146 (let ((file (catch 'loop
147 (while t
148 (let ((pnt (search-forward (concat "\1f" name "\n"))))
149 (re-search-backward "\1fS\\(.*\\)")
150 (let ((file (match-string 1)))
151 (if (member file build-files)
152 (throw 'loop file)
153 (goto-char pnt))))))))
154 (if (string-match "^ns.*\\(\\.o\\|obj\\)\\'" file)
155 (setq file (replace-match ".m" t t file 1))
156 (if (string-match "\\.\\(o\\|obj\\)\\'" file)
157 (setq file (replace-match ".c" t t file))))
158 (if (string-match "\\.\\(c\\|m\\)\\'" file)
159 (concat "src/" file)
160 file)))))
161
1659ada0
JB
162(defcustom help-downcase-arguments nil
163 "If non-nil, argument names in *Help* buffers are downcased."
164 :type 'boolean
165 :group 'help
166 :version "23.2")
167
168(defun help-highlight-arg (arg)
169 "Highlight ARG as an argument name for a *Help* buffer.
170Return ARG in face `help-argument-name'; ARG is also downcased
171if the variable `help-downcase-arguments' is non-nil."
172 (propertize (if help-downcase-arguments (downcase arg) arg)
173 'face 'help-argument-name))
1113ff44
MR
174
175(defun help-do-arg-highlight (doc args)
176 (with-syntax-table (make-syntax-table emacs-lisp-mode-syntax-table)
177 (modify-syntax-entry ?\- "w")
178 (dolist (arg args doc)
179 (setq doc (replace-regexp-in-string
180 ;; This is heuristic, but covers all common cases
181 ;; except ARG1-ARG2
182 (concat "\\<" ; beginning of word
183 "\\(?:[a-z-]*-\\)?" ; for xxx-ARG
184 "\\("
185 (regexp-quote arg)
186 "\\)"
187 "\\(?:es\\|s\\|th\\)?" ; for ARGth, ARGs
188 "\\(?:-[a-z0-9-]+\\)?" ; for ARG-xxx, ARG-n
189 "\\(?:-[{([<`\"].*?\\)?"; for ARG-{x}, (x), <x>, [x], `x'
190 "\\>") ; end of word
1659ada0 191 (help-highlight-arg arg)
1113ff44
MR
192 doc t t 1)))))
193
194(defun help-highlight-arguments (usage doc &rest args)
b9598260 195 (when (and usage (string-match "^(" usage))
1113ff44
MR
196 (with-temp-buffer
197 (insert usage)
198 (goto-char (point-min))
199 (let ((case-fold-search nil)
200 (next (not (or args (looking-at "\\["))))
201 (opt nil))
202 ;; Make a list of all arguments
203 (skip-chars-forward "^ ")
204 (while next
205 (or opt (not (looking-at " &")) (setq opt t))
206 (if (not (re-search-forward " \\([\\[(]*\\)\\([^] &)\.]+\\)" nil t))
207 (setq next nil)
208 (setq args (cons (match-string 2) args))
209 (when (and opt (string= (match-string 1) "("))
210 ;; A pesky CL-style optional argument with default value,
211 ;; so let's skip over it
212 (search-backward "(")
213 (goto-char (scan-sexps (point) 1)))))
214 ;; Highlight aguments in the USAGE string
215 (setq usage (help-do-arg-highlight (buffer-string) args))
216 ;; Highlight arguments in the DOC string
217 (setq doc (and doc (help-do-arg-highlight doc args))))))
218 ;; Return value is like the one from help-split-fundoc, but highlighted
219 (cons usage doc))
220
221;; The following function was compiled from the former functions
222;; `describe-simplify-lib-file-name' and `find-source-lisp-file' with
223;; some excerpts from `describe-function-1' and `describe-variable'.
224;; The only additional twists provided are (1) locate the defining file
225;; for autoloaded functions, and (2) give preference to files in the
226;; "install directory" (directories found via `load-path') rather than
227;; to files in the "compile directory" (directories found by searching
228;; the loaddefs.el file). We autoload it because it's also used by
229;; `describe-face' (instead of `describe-simplify-lib-file-name').
230
231;;;###autoload
232(defun find-lisp-object-file-name (object type)
233 "Guess the file that defined the Lisp object OBJECT, of type TYPE.
234OBJECT should be a symbol associated with a function, variable, or face;
235 alternatively, it can be a function definition.
fe4be04c
JB
236If TYPE is `defvar', search for a variable definition.
237If TYPE is `defface', search for a face definition.
1113ff44
MR
238If TYPE is the value returned by `symbol-function' for a function symbol,
239 search for a function definition.
240
241The return value is the absolute name of a readable file where OBJECT is
242defined. If several such files exist, preference is given to a file
243found via `load-path'. The return value can also be `C-source', which
244means that OBJECT is a function or variable defined in C. If no
245suitable file is found, return nil."
246 (let* ((autoloaded (eq (car-safe type) 'autoload))
247 (file-name (or (and autoloaded (nth 1 type))
248 (symbol-file
249 object (if (memq type (list 'defvar 'defface))
250 type
251 'defun)))))
252 (cond
253 (autoloaded
254 ;; An autoloaded function: Locate the file since `symbol-function'
255 ;; has only returned a bare string here.
256 (setq file-name
257 (locate-file file-name load-path '(".el" ".elc") 'readable)))
258 ((and (stringp file-name)
259 (string-match "[.]*loaddefs.el\\'" file-name))
260 ;; An autoloaded variable or face. Visit loaddefs.el in a buffer
261 ;; and try to extract the defining file. The following form is
262 ;; from `describe-function-1' and `describe-variable'.
263 (let ((location
264 (condition-case nil
265 (find-function-search-for-symbol object nil file-name)
266 (error nil))))
6565b5ab 267 (when (cdr location)
1113ff44
MR
268 (with-current-buffer (car location)
269 (goto-char (cdr location))
270 (when (re-search-backward
271 "^;;; Generated autoloads from \\(.*\\)" nil t)
272 (setq file-name
273 (locate-file
273cefaa
GM
274 (file-name-sans-extension
275 (match-string-no-properties 1))
276 load-path '(".el" ".elc") 'readable))))))))
1113ff44
MR
277
278 (cond
279 ((and (not file-name) (subrp type))
280 ;; A built-in function. The form is from `describe-function-1'.
281 (if (get-buffer " *DOC*")
282 (help-C-file-name type 'subr)
283 'C-source))
284 ((and (not file-name) (symbolp object)
285 (integerp (get object 'variable-documentation)))
286 ;; A variable defined in C. The form is from `describe-variable'.
287 (if (get-buffer " *DOC*")
288 (help-C-file-name object 'var)
289 'C-source))
290 ((not (stringp file-name))
291 ;; If we don't have a file-name string by now, we lost.
292 nil)
d78cdcf7
CY
293 ;; Now, `file-name' should have become an absolute file name.
294 ;; For files loaded from ~/.emacs.elc, try ~/.emacs.
295 ((let (fn)
296 (and (string-equal file-name
297 (expand-file-name ".emacs.elc" "~"))
298 (file-readable-p (setq fn (expand-file-name ".emacs" "~")))
299 fn)))
300 ;; When the Elisp source file can be found in the install
301 ;; directory, return the name of that file.
1113ff44
MR
302 ((let ((lib-name
303 (if (string-match "[.]elc\\'" file-name)
304 (substring-no-properties file-name 0 -1)
305 file-name)))
1113ff44
MR
306 (or (and (file-readable-p lib-name) lib-name)
307 ;; The library might be compressed.
308 (and (file-readable-p (concat lib-name ".gz")) lib-name))))
309 ((let* ((lib-name (file-name-nondirectory file-name))
310 ;; The next form is from `describe-simplify-lib-file-name'.
311 (file-name
312 ;; Try converting the absolute file name to a library
313 ;; name, convert that back to a file name and see if we
314 ;; get the original one. If so, they are equivalent.
315 (if (equal file-name (locate-file lib-name load-path '("")))
316 (if (string-match "[.]elc\\'" lib-name)
317 (substring-no-properties lib-name 0 -1)
318 lib-name)
319 file-name))
320 ;; The next three forms are from `find-source-lisp-file'.
321 (elc-file (locate-file
322 (concat file-name
323 (if (string-match "\\.el\\'" file-name)
324 "c"
325 ".elc"))
326 load-path nil 'readable))
327 (str (when elc-file
328 (with-temp-buffer
329 (insert-file-contents-literally elc-file nil 0 256)
330 (buffer-string))))
331 (src-file (and str
332 (string-match ";;; from file \\(.*\\.el\\)" str)
333 (match-string 1 str))))
334 (and src-file (file-readable-p src-file) src-file))))))
335
336(declare-function ad-get-advice-info "advice" (function))
337
338;;;###autoload
339(defun describe-function-1 (function)
340 (let* ((advised (and (symbolp function) (featurep 'advice)
341 (ad-get-advice-info function)))
342 ;; If the function is advised, use the symbol that has the
343 ;; real definition, if that symbol is already set up.
344 (real-function
345 (or (and advised
346 (let ((origname (cdr (assq 'origname advised))))
347 (and (fboundp origname) origname)))
348 function))
349 ;; Get the real definition.
350 (def (if (symbolp real-function)
351 (symbol-function real-function)
352 function))
353 file-name string
354 (beg (if (commandp def) "an interactive " "a "))
355 (pt1 (with-current-buffer (help-buffer) (point)))
356 errtype)
357 (setq string
b9598260 358 (cond ((or (stringp def) (vectorp def))
1113ff44
MR
359 "a keyboard macro")
360 ((subrp def)
361 (if (eq 'unevalled (cdr (subr-arity def)))
362 (concat beg "special form")
363 (concat beg "built-in function")))
364 ((byte-code-function-p def)
365 (concat beg "compiled Lisp function"))
366 ((symbolp def)
367 (while (and (fboundp def)
368 (symbolp (symbol-function def)))
369 (setq def (symbol-function def)))
370 ;; Handle (defalias 'foo 'bar), where bar is undefined.
371 (or (fboundp def) (setq errtype 'alias))
372 (format "an alias for `%s'" def))
373 ((eq (car-safe def) 'lambda)
374 (concat beg "Lisp function"))
375 ((eq (car-safe def) 'macro)
376 "a Lisp macro")
b9598260
SM
377 ((eq (car-safe def) 'closure)
378 (concat beg "Lisp closure"))
1113ff44
MR
379 ((eq (car-safe def) 'autoload)
380 (format "%s autoloaded %s"
381 (if (commandp def) "an interactive" "an")
382 (if (eq (nth 4 def) 'keymap) "keymap"
383 (if (nth 4 def) "Lisp macro" "Lisp function"))))
384 ((keymapp def)
385 (let ((is-full nil)
386 (elts (cdr-safe def)))
387 (while elts
388 (if (char-table-p (car-safe elts))
389 (setq is-full t
390 elts nil))
391 (setq elts (cdr-safe elts)))
392 (if is-full
393 "a full keymap"
394 "a sparse keymap")))
395 (t "")))
396 (princ string)
397 (if (eq errtype 'alias)
398 (princ ",\nwhich is not defined. Please make a bug report.")
399 (with-current-buffer standard-output
400 (save-excursion
401 (save-match-data
402 (when (re-search-backward "alias for `\\([^`']+\\)'" nil t)
403 (help-xref-button 1 'help-function def)))))
404
405 (setq file-name (find-lisp-object-file-name function def))
406 (when file-name
407 (princ " in `")
408 ;; We used to add .el to the file name,
409 ;; but that's completely wrong when the user used load-file.
e8e8dbf9
MR
410 (princ (if (eq file-name 'C-source)
411 "C source code"
412 (file-name-nondirectory file-name)))
1113ff44
MR
413 (princ "'")
414 ;; Make a hyperlink to the library.
415 (with-current-buffer standard-output
416 (save-excursion
417 (re-search-backward "`\\([^`']+\\)'" nil t)
cebabb67 418 (help-xref-button 1 'help-function-def function file-name))))
1113ff44
MR
419 (princ ".")
420 (with-current-buffer (help-buffer)
421 (fill-region-as-paragraph (save-excursion (goto-char pt1) (forward-line 0) (point))
422 (point)))
423 (terpri)(terpri)
424 (when (commandp function)
63326785
CY
425 (let ((pt2 (with-current-buffer (help-buffer) (point)))
426 (remapped (command-remapping function)))
427 (unless (memq remapped '(ignore undefined))
428 (let ((keys (where-is-internal
429 (or remapped function) overriding-local-map nil nil))
430 non-modified-keys)
431 (if (and (eq function 'self-insert-command)
432 (vectorp (car-safe keys))
433 (consp (aref (car keys) 0)))
434 (princ "It is bound to many ordinary text characters.\n")
435 ;; Which non-control non-meta keys run this command?
436 (dolist (key keys)
437 (if (member (event-modifiers (aref key 0)) '(nil (shift)))
438 (push key non-modified-keys)))
439 (when remapped
440 (princ "It is remapped to `")
441 (princ (symbol-name remapped))
442 (princ "'"))
443
444 (when keys
445 (princ (if remapped ", which is bound to " "It is bound to "))
446 ;; If lots of ordinary text characters run this command,
447 ;; don't mention them one by one.
448 (if (< (length non-modified-keys) 10)
449 (princ (mapconcat 'key-description keys ", "))
450 (dolist (key non-modified-keys)
451 (setq keys (delq key keys)))
452 (if keys
453 (progn
454 (princ (mapconcat 'key-description keys ", "))
455 (princ ", and many ordinary text characters"))
456 (princ "many ordinary text characters"))))
457 (when (or remapped keys non-modified-keys)
458 (princ ".")
459 (terpri)))))
1113ff44 460
1113ff44
MR
461 (with-current-buffer (help-buffer)
462 (fill-region-as-paragraph pt2 (point))
463 (unless (looking-back "\n\n")
464 (terpri)))))
a87b98ce
GM
465 ;; Note that list* etc do not get this property until
466 ;; cl-hack-byte-compiler runs, after bytecomp is loaded.
82882188
SM
467 (when (and (symbolp function)
468 (eq (get function 'byte-compile)
469 'cl-byte-compile-compiler-macro))
a87b98ce
GM
470 (princ "This function has a compiler macro")
471 (let ((lib (get function 'compiler-macro-file)))
472 (when (stringp lib)
473 (princ (format " in `%s'" lib))
474 (with-current-buffer standard-output
475 (save-excursion
476 (re-search-backward "`\\([^`']+\\)'" nil t)
477 (help-xref-button 1 'help-function-cmacro function lib)))))
478 (princ ".\n\n"))
8d6c1239
SM
479 (let* ((advertised (gethash def advertised-signature-table t))
480 (arglist (if (listp advertised)
481 advertised (help-function-arglist def)))
1113ff44
MR
482 (doc (documentation function))
483 (usage (help-split-fundoc doc function)))
484 (with-current-buffer standard-output
485 ;; If definition is a keymap, skip arglist note.
486 (unless (keymapp function)
8d6c1239 487 (if usage (setq doc (cdr usage)))
1113ff44 488 (let* ((use (cond
8d6c1239 489 ((and usage (not (listp advertised))) (car usage))
1113ff44
MR
490 ((listp arglist)
491 (format "%S" (help-make-usage function arglist)))
492 ((stringp arglist) arglist)
493 ;; Maybe the arglist is in the docstring of a symbol
494 ;; this one is aliased to.
495 ((let ((fun real-function))
496 (while (and (symbolp fun)
497 (setq fun (symbol-function fun))
498 (not (setq usage (help-split-fundoc
499 (documentation fun)
500 function)))))
501 usage)
502 (car usage))
503 ((or (stringp def)
504 (vectorp def))
505 (format "\nMacro: %s" (format-kbd-macro def)))
506 (t "[Missing arglist. Please make a bug report.]")))
507 (high (help-highlight-arguments use doc)))
508 (let ((fill-begin (point)))
509 (insert (car high) "\n")
ce5b520a 510 (fill-region fill-begin (point)))
b38b1ec0 511 (setq doc (cdr high))))
ce5b520a
SM
512 (let* ((obsolete (and
513 ;; function might be a lambda construct.
514 (symbolp function)
515 (get function 'byte-obsolete-info)))
516 (use (car obsolete)))
517 (when obsolete
518 (princ "\nThis function is obsolete")
519 (when (nth 2 obsolete)
520 (insert (format " since %s" (nth 2 obsolete))))
521 (insert (cond ((stringp use) (concat ";\n" use))
522 (use (format ";\nuse `%s' instead." use))
523 (t "."))
524 "\n"))
525 (insert "\n"
526 (or doc "Not documented."))))))))
1113ff44
MR
527
528\f
529;; Variables
530
531;;;###autoload
532(defun variable-at-point (&optional any-symbol)
533 "Return the bound variable symbol found at or before point.
534Return 0 if there is no such symbol.
535If ANY-SYMBOL is non-nil, don't insist the symbol be bound."
536 (with-syntax-table emacs-lisp-mode-syntax-table
537 (or (condition-case ()
538 (save-excursion
539 (or (not (zerop (skip-syntax-backward "_w")))
540 (eq (char-syntax (following-char)) ?w)
541 (eq (char-syntax (following-char)) ?_)
542 (forward-sexp -1))
543 (skip-chars-forward "'")
544 (let ((obj (read (current-buffer))))
545 (and (symbolp obj) (boundp obj) obj)))
546 (error nil))
547 (let* ((str (find-tag-default))
548 (sym (if str (intern-soft str))))
549 (if (and sym (or any-symbol (boundp sym)))
550 sym
551 (save-match-data
552 (when (and str (string-match "\\`\\W*\\(.*?\\)\\W*\\'" str))
553 (setq sym (intern-soft (match-string 1 str)))
554 (and (or any-symbol (boundp sym)) sym)))))
555 0)))
556
557(defun describe-variable-custom-version-info (variable)
558 (let ((custom-version (get variable 'custom-version))
559 (cpv (get variable 'custom-package-version))
560 (output nil))
561 (if custom-version
562 (setq output
563 (format "This variable was introduced, or its default value was changed, in\nversion %s of Emacs.\n"
564 custom-version))
565 (when cpv
566 (let* ((package (car-safe cpv))
567 (version (if (listp (cdr-safe cpv))
568 (car (cdr-safe cpv))
569 (cdr-safe cpv)))
570 (pkg-versions (assq package customize-package-emacs-version-alist))
571 (emacsv (cdr (assoc version pkg-versions))))
572 (if (and package version)
573 (setq output
574 (format (concat "This variable was introduced, or its default value was changed, in\nversion %s of the %s package"
575 (if emacsv
576 (format " that is part of Emacs %s" emacsv))
577 ".\n")
578 version package))))))
579 output))
580
581;;;###autoload
582(defun describe-variable (variable &optional buffer frame)
583 "Display the full documentation of VARIABLE (a symbol).
584Returns the documentation as a string, also.
585If VARIABLE has a buffer-local value in BUFFER or FRAME
586\(default to the current buffer and current frame),
587it is displayed along with the global value."
588 (interactive
589 (let ((v (variable-at-point))
590 (enable-recursive-minibuffers t)
591 val)
592 (setq val (completing-read (if (symbolp v)
593 (format
594 "Describe variable (default %s): " v)
595 "Describe variable: ")
596 obarray
597 '(lambda (vv)
598 (or (boundp vv)
599 (get vv 'variable-documentation)))
600 t nil nil
601 (if (symbolp v) (symbol-name v))))
602 (list (if (equal val "")
603 v (intern val)))))
604 (let (file-name)
605 (unless (buffer-live-p buffer) (setq buffer (current-buffer)))
606 (unless (frame-live-p frame) (setq frame (selected-frame)))
607 (if (not (symbolp variable))
608 (message "You did not specify a variable")
609 (save-excursion
610 (let ((valvoid (not (with-current-buffer buffer (boundp variable))))
611 val val-start-pos locus)
612 ;; Extract the value before setting up the output buffer,
613 ;; in case `buffer' *is* the output buffer.
614 (unless valvoid
615 (with-selected-frame frame
616 (with-current-buffer buffer
617 (setq val (symbol-value variable)
618 locus (variable-binding-locus variable)))))
619 (help-setup-xref (list #'describe-variable variable buffer)
32226619 620 (called-interactively-p 'interactive))
1113ff44
MR
621 (with-help-window (help-buffer)
622 (with-current-buffer buffer
623 (prin1 variable)
624 (setq file-name (find-lisp-object-file-name variable 'defvar))
625
626 (if file-name
627 (progn
628 (princ " is a variable defined in `")
e8e8dbf9
MR
629 (princ (if (eq file-name 'C-source)
630 "C source code"
631 (file-name-nondirectory file-name)))
1113ff44
MR
632 (princ "'.\n")
633 (with-current-buffer standard-output
634 (save-excursion
635 (re-search-backward "`\\([^`']+\\)'" nil t)
636 (help-xref-button 1 'help-variable-def
637 variable file-name)))
638 (if valvoid
639 (princ "It is void as a variable.")
640 (princ "Its ")))
641 (if valvoid
642 (princ " is void as a variable.")
643 (princ "'s "))))
3c505d31 644 (unless valvoid
1113ff44
MR
645 (with-current-buffer standard-output
646 (setq val-start-pos (point))
647 (princ "value is ")
1113ff44 648 (let ((from (point)))
3c505d31 649 (terpri)
1113ff44 650 (pp val)
e1a23575 651 (if (< (point) (+ 68 (line-beginning-position 0)))
3c505d31 652 (delete-region from (1+ from))
7c420169 653 (delete-region (1- from) from))
0097720d
SM
654 (let* ((sv (get variable 'standard-value))
655 (origval (and (consp sv)
656 (condition-case nil
657 (eval (car sv))
658 (error :help-eval-error)))))
659 (when (and (consp sv)
660 (not (equal origval val))
661 (not (equal origval :help-eval-error)))
662 (princ "\nOriginal value was \n")
663 (setq from (point))
664 (pp origval)
665 (if (< (point) (+ from 20))
666 (delete-region (1- from) from)))))))
1113ff44 667 (terpri)
1113ff44
MR
668 (when locus
669 (if (bufferp locus)
670 (princ (format "%socal in buffer %s; "
671 (if (get variable 'permanent-local)
672 "Permanently l" "L")
673 (buffer-name)))
674 (princ (format "It is a frame-local variable; ")))
675 (if (not (default-boundp variable))
676 (princ "globally void")
677 (let ((val (default-value variable)))
678 (with-current-buffer standard-output
679 (princ "global value is ")
680 (terpri)
681 ;; Fixme: pp can take an age if you happen to
682 ;; ask for a very large expression. We should
683 ;; probably print it raw once and check it's a
684 ;; sensible size before prettyprinting. -- fx
685 (let ((from (point)))
686 (pp val)
687 ;; See previous comment for this function.
688 ;; (help-xref-on-pp from (point))
689 (if (< (point) (+ from 20))
690 (delete-region (1- from) from))))))
691 (terpri))
692
693 ;; If the value is large, move it to the end.
694 (with-current-buffer standard-output
695 (when (> (count-lines (point-min) (point-max)) 10)
696 ;; Note that setting the syntax table like below
697 ;; makes forward-sexp move over a `'s' at the end
698 ;; of a symbol.
699 (set-syntax-table emacs-lisp-mode-syntax-table)
700 (goto-char val-start-pos)
701 ;; The line below previously read as
702 ;; (delete-region (point) (progn (end-of-line) (point)))
703 ;; which suppressed display of the buffer local value for
704 ;; large values.
705 (when (looking-at "value is") (replace-match ""))
706 (save-excursion
707 (insert "\n\nValue:")
708 (set (make-local-variable 'help-button-cache)
709 (point-marker)))
710 (insert "value is shown ")
711 (insert-button "below"
712 'action help-button-cache
713 'follow-link t
714 'help-echo "mouse-2, RET: show value")
715 (insert ".\n")))
716 (terpri)
717
718 (let* ((alias (condition-case nil
719 (indirect-variable variable)
720 (error variable)))
721 (obsolete (get variable 'byte-obsolete-variable))
722 (use (car obsolete))
723 (safe-var (get variable 'safe-local-variable))
724 (doc (or (documentation-property variable 'variable-documentation)
725 (documentation-property alias 'variable-documentation)))
726 (extra-line nil))
727 ;; Add a note for variables that have been make-var-buffer-local.
728 (when (and (local-variable-if-set-p variable)
729 (or (not (local-variable-p variable))
730 (with-temp-buffer
731 (local-variable-if-set-p variable))))
732 (setq extra-line t)
733 (princ " Automatically becomes buffer-local when set in any fashion.\n"))
734
735 ;; Mention if it's an alias
736 (unless (eq alias variable)
737 (setq extra-line t)
738 (princ (format " This variable is an alias for `%s'.\n" alias)))
739
740 (when obsolete
741 (setq extra-line t)
742 (princ " This variable is obsolete")
743 (if (cdr obsolete) (princ (format " since %s" (cdr obsolete))))
744 (princ (cond ((stringp use) (concat ";\n " use))
745 (use (format ";\n use `%s' instead." (car obsolete)))
746 (t ".")))
747 (terpri))
2ee20f24
JL
748
749 (when (member (cons variable val) file-local-variables-alist)
750 (setq extra-line t)
751 (if (member (cons variable val) dir-local-variables-alist)
752 (let ((file (and (buffer-file-name)
753 (not (file-remote-p (buffer-file-name)))
754 (dir-locals-find-file (buffer-file-name)))))
755 (princ " This variable is a directory local variable")
b6ce92f1
CY
756 (when file
757 (princ (concat "\n from the file \""
758 (if (consp file)
759 (car file)
760 file)
761 "\"")))
2ee20f24
JL
762 (princ ".\n"))
763 (princ " This variable is a file local variable.\n")))
764
589a99f2
GM
765 (when (memq variable ignored-local-variables)
766 (setq extra-line t)
767 (princ " This variable is ignored when used as a file local \
768variable.\n"))
769
770 ;; Can be both risky and safe, eg auto-fill-function.
771 (when (risky-local-variable-p variable)
772 (setq extra-line t)
773 (princ " This variable is potentially risky when used as a \
774file local variable.\n")
775 (when (assq variable safe-local-variable-values)
776 (princ " However, you have added it to \
777`safe-local-variable-values'.\n")))
778
1113ff44
MR
779 (when safe-var
780 (setq extra-line t)
781 (princ " This variable is safe as a file local variable ")
782 (princ "if its value\n satisfies the predicate ")
783 (princ (if (byte-code-function-p safe-var)
784 "which is byte-compiled expression.\n"
785 (format "`%s'.\n" safe-var))))
786
787 (if extra-line (terpri))
788 (princ "Documentation:\n")
789 (with-current-buffer standard-output
790 (insert (or doc "Not documented as a variable."))))
791
792 ;; Make a link to customize if this variable can be customized.
793 (when (custom-variable-p variable)
794 (let ((customize-label "customize"))
795 (terpri)
796 (terpri)
797 (princ (concat "You can " customize-label " this variable."))
798 (with-current-buffer standard-output
799 (save-excursion
800 (re-search-backward
801 (concat "\\(" customize-label "\\)") nil t)
802 (help-xref-button 1 'help-customize-variable variable))))
803 ;; Note variable's version or package version
804 (let ((output (describe-variable-custom-version-info variable)))
805 (when output
806 (terpri)
807 (terpri)
808 (princ output))))
809
7fdbcd83 810 (with-current-buffer standard-output
1113ff44
MR
811 ;; Return the text we displayed.
812 (buffer-string))))))))
813
814
815;;;###autoload
816(defun describe-syntax (&optional buffer)
817 "Describe the syntax specifications in the syntax table of BUFFER.
818The descriptions are inserted in a help buffer, which is then displayed.
819BUFFER defaults to the current buffer."
820 (interactive)
821 (setq buffer (or buffer (current-buffer)))
32226619
JB
822 (help-setup-xref (list #'describe-syntax buffer)
823 (called-interactively-p 'interactive))
1113ff44
MR
824 (with-help-window (help-buffer)
825 (let ((table (with-current-buffer buffer (syntax-table))))
826 (with-current-buffer standard-output
827 (describe-vector table 'internal-describe-syntax-value)
828 (while (setq table (char-table-parent table))
829 (insert "\nThe parent syntax table is:")
830 (describe-vector table 'internal-describe-syntax-value))))))
831
832(defun help-describe-category-set (value)
833 (insert (cond
834 ((null value) "default")
835 ((char-table-p value) "deeper char-table ...")
836 (t (condition-case err
837 (category-set-mnemonics value)
838 (error "invalid"))))))
839
840;;;###autoload
841(defun describe-categories (&optional buffer)
842 "Describe the category specifications in the current category table.
843The descriptions are inserted in a buffer, which is then displayed.
844If BUFFER is non-nil, then describe BUFFER's category table instead.
845BUFFER should be a buffer or a buffer name."
846 (interactive)
847 (setq buffer (or buffer (current-buffer)))
32226619
JB
848 (help-setup-xref (list #'describe-categories buffer)
849 (called-interactively-p 'interactive))
1113ff44 850 (with-help-window (help-buffer)
c6ec96f8
KH
851 (let* ((table (with-current-buffer buffer (category-table)))
852 (docs (char-table-extra-slot table 0)))
853 (if (or (not (vectorp docs)) (/= (length docs) 95))
854 (error "Invalid first extra slot in this category table\n"))
1113ff44 855 (with-current-buffer standard-output
c6ec96f8
KH
856 (insert "Legend of category mnemonics (see the tail for the longer description)\n")
857 (let ((pos (point)) (items 0) lines n)
858 (dotimes (i 95)
859 (if (aref docs i) (setq items (1+ items))))
860 (setq lines (1+ (/ (1- items) 4)))
861 (setq n 0)
862 (dotimes (i 95)
863 (let ((elt (aref docs i)))
864 (when elt
865 (string-match ".*" elt)
866 (setq elt (match-string 0 elt))
867 (if (>= (length elt) 17)
868 (setq elt (concat (substring elt 0 14) "...")))
869 (if (< (point) (point-max))
870 (move-to-column (* 20 (/ n lines)) t))
871 (insert (+ i ?\s) ?: elt)
872 (if (< (point) (point-max))
873 (forward-line 1)
874 (insert "\n"))
875 (setq n (1+ n))
876 (if (= (% n lines) 0)
877 (goto-char pos))))))
878 (goto-char (point-max))
879 (insert "\n"
880 "character(s)\tcategory mnemonics\n"
881 "------------\t------------------")
1113ff44 882 (describe-vector table 'help-describe-category-set)
c6ec96f8
KH
883 (insert "Legend of category mnemonics:\n")
884 (dotimes (i 95)
885 (let ((elt (aref docs i)))
886 (when elt
887 (if (string-match "\n" elt)
888 (setq elt (substring elt (match-end 0))))
889 (insert (+ i ?\s) ": " elt "\n"))))
890 (while (setq table (char-table-parent table))
891 (insert "\nThe parent category table is:")
892 (describe-vector table 'help-describe-category-set))))))
1113ff44 893
17284e30
GM
894\f
895;;; Replacements for old lib-src/ programs. Don't seem especially useful.
896
897;; Replaces lib-src/digest-doc.c.
898;;;###autoload
899(defun doc-file-to-man (file)
900 "Produce an nroff buffer containing the doc-strings from the DOC file."
901 (interactive (list (read-file-name "Name of DOC file: " doc-directory
902 internal-doc-file-name t)))
903 (or (file-readable-p file)
904 (error "Cannot read file `%s'" file))
905 (pop-to-buffer (generate-new-buffer "*man-doc*"))
906 (setq buffer-undo-list t)
907 (insert ".TH \"Command Summary for GNU Emacs\"\n"
908 ".AU Richard M. Stallman\n")
909 (insert-file-contents file)
910 (let (notfirst)
911 (while (search-forward "\1f" nil 'move)
912 (if (looking-at "S")
913 (delete-region (1- (point)) (line-end-position))
914 (delete-char -1)
915 (if notfirst
916 (insert "\n.DE\n")
917 (setq notfirst t))
918 (insert "\n.SH ")
919 (insert (if (looking-at "F") "Function " "Variable "))
920 (delete-char 1)
921 (forward-line 1)
922 (insert ".DS L\n"))))
923 (insert "\n.DE\n")
924 (setq buffer-undo-list nil)
925 (nroff-mode))
926
927;; Replaces lib-src/sorted-doc.c.
928;;;###autoload
929(defun doc-file-to-info (file)
930 "Produce a texinfo buffer with sorted doc-strings from the DOC file."
931 (interactive (list (read-file-name "Name of DOC file: " doc-directory
932 internal-doc-file-name t)))
933 (or (file-readable-p file)
934 (error "Cannot read file `%s'" file))
935 (let ((i 0) type name doc alist)
936 (with-temp-buffer
937 (insert-file-contents file)
938 ;; The characters "@{}" need special treatment.
939 (while (re-search-forward "[@{}]" nil t)
940 (backward-char)
941 (insert "@")
942 (forward-char 1))
943 (goto-char (point-min))
944 (while (search-forward "\1f" nil t)
945 (unless (looking-at "S")
946 (setq type (char-after)
947 name (buffer-substring (1+ (point)) (line-end-position))
948 doc (buffer-substring (line-beginning-position 2)
949 (if (search-forward "\1f" nil 'move)
950 (1- (point))
951 (point)))
952 alist (cons (list name type doc) alist))
953 (backward-char 1))))
954 (pop-to-buffer (generate-new-buffer "*info-doc*"))
955 (setq buffer-undo-list t)
956 ;; Write the output header.
957 (insert "\\input texinfo @c -*-texinfo-*-\n"
958 "@setfilename emacsdoc.info\n"
959 "@settitle Command Summary for GNU Emacs\n"
960 "@finalout\n"
961 "\n@node Top\n"
962 "@unnumbered Command Summary for GNU Emacs\n\n"
963 "@table @asis\n\n"
964 "@iftex\n"
965 "@global@let@ITEM@item\n"
966 "@def@item{@filbreak@vskip5pt@ITEM}\n"
967 "@font@tensy cmsy10 scaled @magstephalf\n"
968 "@font@teni cmmi10 scaled @magstephalf\n"
969 "@def\\{{@tensy@char110}}\n" ; this backslash goes with cmr10
970 "@def|{{@tensy@char106}}\n"
971 "@def@{{{@tensy@char102}}\n"
972 "@def@}{{@tensy@char103}}\n"
973 "@def<{{@teni@char62}}\n"
974 "@def>{{@teni@char60}}\n"
975 "@chardef@@64\n"
976 "@catcode43=12\n"
977 "@tableindent-0.2in\n"
978 "@end iftex\n")
979 ;; Sort the array by name; within each name, by type (functions first).
980 (setq alist (sort alist (lambda (e1 e2)
981 (if (string-equal (car e1) (car e2))
982 (<= (cadr e1) (cadr e2))
983 (string-lessp (car e1) (car e2))))))
984 ;; Print each function.
985 (dolist (e alist)
986 (insert "\n@item "
987 (if (char-equal (cadr e) ?\F) "Function" "Variable")
988 " @code{" (car e) "}\n@display\n"
989 (nth 2 e)
990 "\n@end display\n")
991 ;; Try to avoid a save size overflow in the TeX output routine.
992 (if (zerop (setq i (% (1+ i) 100)))
993 (insert "\n@end table\n@table @asis\n")))
994 (insert "@end table\n"
995 "@bye\n")
996 (setq buffer-undo-list nil)
997 (texinfo-mode)))
998
1113ff44
MR
999(provide 'help-fns)
1000
1113ff44 1001;;; help-fns.el ends here