Fix bug #17588 with mouse highlight when an X frame is redisplayed frequently.
[emacs.git] / lisp / help-fns.el
blob5b0739ed9aeb80766fd7f0cbe2627f6be883286d
1 ;;; help-fns.el --- Complex help functions -*- lexical-binding: t -*-
3 ;; Copyright (C) 1985-1986, 1993-1994, 1998-2014 Free Software Foundation, Inc.
5 ;; Maintainer: emacs-devel@gnu.org
6 ;; Keywords: help, internal
7 ;; Package: emacs
9 ;; This file is part of GNU Emacs.
11 ;; GNU Emacs is free software: you can redistribute it and/or modify
12 ;; it under the terms of the GNU General Public License as published by
13 ;; the Free Software Foundation, either version 3 of the License, or
14 ;; (at your option) any later version.
16 ;; GNU Emacs is distributed in the hope that it will be useful,
17 ;; but WITHOUT ANY WARRANTY; without even the implied warranty of
18 ;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
19 ;; GNU General Public License for more details.
21 ;; You should have received a copy of the GNU General Public License
22 ;; along with GNU Emacs. If not, see <http://www.gnu.org/licenses/>.
24 ;;; Commentary:
26 ;; This file contains those help commands which are complicated, and
27 ;; which may not be used in every session. For example
28 ;; `describe-function' will probably be heavily used when doing elisp
29 ;; programming, but not if just editing C files. Simpler help commands
30 ;; are in help.el
32 ;;; Code:
34 (defvar help-fns-describe-function-functions nil
35 "List of functions to run in help buffer in `describe-function'.
36 Those functions will be run after the header line and argument
37 list was inserted, and before the documentation will be inserted.
38 The functions will receive the function name as argument.")
40 ;; Functions
42 ;;;###autoload
43 (defun describe-function (function)
44 "Display the full documentation of FUNCTION (a symbol)."
45 (interactive
46 (let ((fn (function-called-at-point))
47 (enable-recursive-minibuffers t)
48 val)
49 (setq val (completing-read (if fn
50 (format "Describe function (default %s): " fn)
51 "Describe function: ")
52 obarray 'fboundp t nil nil
53 (and fn (symbol-name fn))))
54 (list (if (equal val "")
55 fn (intern val)))))
56 (if (null function)
57 (message "You didn't specify a function")
58 (help-setup-xref (list #'describe-function function)
59 (called-interactively-p 'interactive))
60 (save-excursion
61 (with-help-window (help-buffer)
62 (prin1 function)
63 ;; Use " is " instead of a colon so that
64 ;; it is easier to get out the function name using forward-sexp.
65 (princ " is ")
66 (describe-function-1 function)
67 (with-current-buffer standard-output
68 ;; Return the text we displayed.
69 (buffer-string))))))
72 ;; Could be this, if we make symbol-file do the work below.
73 ;; (defun help-C-file-name (subr-or-var kind)
74 ;; "Return the name of the C file where SUBR-OR-VAR is defined.
75 ;; KIND should be `var' for a variable or `subr' for a subroutine."
76 ;; (symbol-file (if (symbolp subr-or-var) subr-or-var
77 ;; (subr-name subr-or-var))
78 ;; (if (eq kind 'var) 'defvar 'defun)))
79 ;;;###autoload
80 (defun help-C-file-name (subr-or-var kind)
81 "Return the name of the C file where SUBR-OR-VAR is defined.
82 KIND should be `var' for a variable or `subr' for a subroutine."
83 (let ((docbuf (get-buffer-create " *DOC*"))
84 (name (if (eq 'var kind)
85 (concat "V" (symbol-name subr-or-var))
86 (concat "F" (subr-name (advice--cd*r subr-or-var))))))
87 (with-current-buffer docbuf
88 (goto-char (point-min))
89 (if (eobp)
90 (insert-file-contents-literally
91 (expand-file-name internal-doc-file-name doc-directory)))
92 (let ((file (catch 'loop
93 (while t
94 (let ((pnt (search-forward (concat "\x1f" name "\n"))))
95 (re-search-backward "\x1fS\\(.*\\)")
96 (let ((file (match-string 1)))
97 (if (member file build-files)
98 (throw 'loop file)
99 (goto-char pnt))))))))
100 (if (string-match "^ns.*\\(\\.o\\|obj\\)\\'" file)
101 (setq file (replace-match ".m" t t file 1))
102 (if (string-match "\\.\\(o\\|obj\\)\\'" file)
103 (setq file (replace-match ".c" t t file))))
104 (if (string-match "\\.\\(c\\|m\\)\\'" file)
105 (concat "src/" file)
106 file)))))
108 (defcustom help-downcase-arguments nil
109 "If non-nil, argument names in *Help* buffers are downcased."
110 :type 'boolean
111 :group 'help
112 :version "23.2")
114 (defun help-highlight-arg (arg)
115 "Highlight ARG as an argument name for a *Help* buffer.
116 Return ARG in face `help-argument-name'; ARG is also downcased
117 if the variable `help-downcase-arguments' is non-nil."
118 (propertize (if help-downcase-arguments (downcase arg) arg)
119 'face 'help-argument-name))
121 (defun help-do-arg-highlight (doc args)
122 (with-syntax-table (make-syntax-table emacs-lisp-mode-syntax-table)
123 (modify-syntax-entry ?\- "w")
124 (dolist (arg args)
125 (setq doc (replace-regexp-in-string
126 ;; This is heuristic, but covers all common cases
127 ;; except ARG1-ARG2
128 (concat "\\<" ; beginning of word
129 "\\(?:[a-z-]*-\\)?" ; for xxx-ARG
130 "\\("
131 (regexp-quote arg)
132 "\\)"
133 "\\(?:es\\|s\\|th\\)?" ; for ARGth, ARGs
134 "\\(?:-[a-z0-9-]+\\)?" ; for ARG-xxx, ARG-n
135 "\\(?:-[{([<`\"].*?\\)?"; for ARG-{x}, (x), <x>, [x], `x'
136 "\\>") ; end of word
137 (help-highlight-arg arg)
138 doc t t 1)))
139 doc))
141 (defun help-highlight-arguments (usage doc &rest args)
142 (when (and usage (string-match "^(" usage))
143 (with-temp-buffer
144 (insert usage)
145 (goto-char (point-min))
146 (let ((case-fold-search nil)
147 (next (not (or args (looking-at "\\["))))
148 (opt nil))
149 ;; Make a list of all arguments
150 (skip-chars-forward "^ ")
151 (while next
152 (or opt (not (looking-at " &")) (setq opt t))
153 (if (not (re-search-forward " \\([\\[(]*\\)\\([^] &)\.]+\\)" nil t))
154 (setq next nil)
155 (setq args (cons (match-string 2) args))
156 (when (and opt (string= (match-string 1) "("))
157 ;; A pesky CL-style optional argument with default value,
158 ;; so let's skip over it
159 (search-backward "(")
160 (goto-char (scan-sexps (point) 1)))))
161 ;; Highlight arguments in the USAGE string
162 (setq usage (help-do-arg-highlight (buffer-string) args))
163 ;; Highlight arguments in the DOC string
164 (setq doc (and doc (help-do-arg-highlight doc args))))))
165 ;; Return value is like the one from help-split-fundoc, but highlighted
166 (cons usage doc))
168 ;; The following function was compiled from the former functions
169 ;; `describe-simplify-lib-file-name' and `find-source-lisp-file' with
170 ;; some excerpts from `describe-function-1' and `describe-variable'.
171 ;; The only additional twists provided are (1) locate the defining file
172 ;; for autoloaded functions, and (2) give preference to files in the
173 ;; "install directory" (directories found via `load-path') rather than
174 ;; to files in the "compile directory" (directories found by searching
175 ;; the loaddefs.el file). We autoload it because it's also used by
176 ;; `describe-face' (instead of `describe-simplify-lib-file-name').
178 ;;;###autoload
179 (defun find-lisp-object-file-name (object type)
180 "Guess the file that defined the Lisp object OBJECT, of type TYPE.
181 OBJECT should be a symbol associated with a function, variable, or face;
182 alternatively, it can be a function definition.
183 If TYPE is `defvar', search for a variable definition.
184 If TYPE is `defface', search for a face definition.
185 If TYPE is the value returned by `symbol-function' for a function symbol,
186 search for a function definition.
188 The return value is the absolute name of a readable file where OBJECT is
189 defined. If several such files exist, preference is given to a file
190 found via `load-path'. The return value can also be `C-source', which
191 means that OBJECT is a function or variable defined in C. If no
192 suitable file is found, return nil."
193 (let* ((autoloaded (autoloadp type))
194 (file-name (or (and autoloaded (nth 1 type))
195 (symbol-file
196 object (if (memq type (list 'defvar 'defface))
197 type
198 'defun)))))
199 (cond
200 (autoloaded
201 ;; An autoloaded function: Locate the file since `symbol-function'
202 ;; has only returned a bare string here.
203 (setq file-name
204 (locate-file file-name load-path '(".el" ".elc") 'readable)))
205 ((and (stringp file-name)
206 (string-match "[.]*loaddefs.el\\'" file-name))
207 ;; An autoloaded variable or face. Visit loaddefs.el in a buffer
208 ;; and try to extract the defining file. The following form is
209 ;; from `describe-function-1' and `describe-variable'.
210 (let ((location
211 (condition-case nil
212 (find-function-search-for-symbol object nil file-name)
213 (error nil))))
214 (when (cdr location)
215 (with-current-buffer (car location)
216 (goto-char (cdr location))
217 (when (re-search-backward
218 "^;;; Generated autoloads from \\(.*\\)" nil t)
219 (setq file-name
220 (locate-file
221 (file-name-sans-extension
222 (match-string-no-properties 1))
223 load-path '(".el" ".elc") 'readable))))))))
225 (cond
226 ((and (not file-name) (subrp type))
227 ;; A built-in function. The form is from `describe-function-1'.
228 (if (get-buffer " *DOC*")
229 (help-C-file-name type 'subr)
230 'C-source))
231 ((and (not file-name) (symbolp object)
232 (integerp (get object 'variable-documentation)))
233 ;; A variable defined in C. The form is from `describe-variable'.
234 (if (get-buffer " *DOC*")
235 (help-C-file-name object 'var)
236 'C-source))
237 ((not (stringp file-name))
238 ;; If we don't have a file-name string by now, we lost.
239 nil)
240 ;; Now, `file-name' should have become an absolute file name.
241 ;; For files loaded from ~/.foo.elc, try ~/.foo.
242 ;; This applies to config files like ~/.emacs,
243 ;; which people sometimes compile.
244 ((let (fn)
245 (and (string-match "\\`\\..*\\.elc\\'"
246 (file-name-nondirectory file-name))
247 (string-equal (file-name-directory file-name)
248 (file-name-as-directory (expand-file-name "~")))
249 (file-readable-p (setq fn (file-name-sans-extension file-name)))
250 fn)))
251 ;; When the Elisp source file can be found in the install
252 ;; directory, return the name of that file.
253 ((let ((lib-name
254 (if (string-match "[.]elc\\'" file-name)
255 (substring-no-properties file-name 0 -1)
256 file-name)))
257 (or (and (file-readable-p lib-name) lib-name)
258 ;; The library might be compressed.
259 (and (file-readable-p (concat lib-name ".gz")) lib-name))))
260 ((let* ((lib-name (file-name-nondirectory file-name))
261 ;; The next form is from `describe-simplify-lib-file-name'.
262 (file-name
263 ;; Try converting the absolute file name to a library
264 ;; name, convert that back to a file name and see if we
265 ;; get the original one. If so, they are equivalent.
266 (if (equal file-name (locate-file lib-name load-path '("")))
267 (if (string-match "[.]elc\\'" lib-name)
268 (substring-no-properties lib-name 0 -1)
269 lib-name)
270 file-name))
271 ;; The next three forms are from `find-source-lisp-file'.
272 (elc-file (locate-file
273 (concat file-name
274 (if (string-match "\\.el\\'" file-name)
276 ".elc"))
277 load-path nil 'readable))
278 (str (when elc-file
279 (with-temp-buffer
280 (insert-file-contents-literally elc-file nil 0 256)
281 (buffer-string))))
282 (src-file (and str
283 (string-match ";;; from file \\(.*\\.el\\)" str)
284 (match-string 1 str))))
285 (and src-file (file-readable-p src-file) src-file))))))
287 (defun help-fns--key-bindings (function)
288 (when (commandp function)
289 (let ((pt2 (with-current-buffer standard-output (point)))
290 (remapped (command-remapping function)))
291 (unless (memq remapped '(ignore undefined))
292 (let ((keys (where-is-internal
293 (or remapped function) overriding-local-map nil nil))
294 non-modified-keys)
295 (if (and (eq function 'self-insert-command)
296 (vectorp (car-safe keys))
297 (consp (aref (car keys) 0)))
298 (princ "It is bound to many ordinary text characters.\n")
299 ;; Which non-control non-meta keys run this command?
300 (dolist (key keys)
301 (if (member (event-modifiers (aref key 0)) '(nil (shift)))
302 (push key non-modified-keys)))
303 (when remapped
304 (princ "Its keys are remapped to ")
305 (princ (if (symbolp remapped)
306 (concat "`" (symbol-name remapped) "'")
307 "an anonymous command"))
308 (princ ".\n"))
310 (when keys
311 (princ (if remapped
312 "Without this remapping, it would be bound to "
313 "It is bound to "))
314 ;; If lots of ordinary text characters run this command,
315 ;; don't mention them one by one.
316 (if (< (length non-modified-keys) 10)
317 (princ (mapconcat 'key-description keys ", "))
318 (dolist (key non-modified-keys)
319 (setq keys (delq key keys)))
320 (if keys
321 (progn
322 (princ (mapconcat 'key-description keys ", "))
323 (princ ", and many ordinary text characters"))
324 (princ "many ordinary text characters"))))
325 (when (or remapped keys non-modified-keys)
326 (princ ".")
327 (terpri)))))
329 (with-current-buffer standard-output
330 (fill-region-as-paragraph pt2 (point))
331 (unless (looking-back "\n\n")
332 (terpri))))))
334 (defun help-fns--compiler-macro (function)
335 (let ((handler (function-get function 'compiler-macro)))
336 (when handler
337 (insert "\nThis function has a compiler macro")
338 (if (symbolp handler)
339 (progn
340 (insert (format " `%s'" handler))
341 (save-excursion
342 (re-search-backward "`\\([^`']+\\)'" nil t)
343 (help-xref-button 1 'help-function handler)))
344 ;; FIXME: Obsolete since 24.4.
345 (let ((lib (get function 'compiler-macro-file)))
346 (when (stringp lib)
347 (insert (format " in `%s'" lib))
348 (save-excursion
349 (re-search-backward "`\\([^`']+\\)'" nil t)
350 (help-xref-button 1 'help-function-cmacro function lib)))))
351 (insert ".\n"))))
353 (defun help-fns--signature (function doc real-def real-function)
354 (unless (keymapp function) ; If definition is a keymap, skip arglist note.
355 (let* ((advertised (gethash real-def advertised-signature-table t))
356 (arglist (if (listp advertised)
357 advertised (help-function-arglist real-def)))
358 (usage (help-split-fundoc doc function)))
359 (if usage (setq doc (cdr usage)))
360 (let* ((use (cond
361 ((and usage (not (listp advertised))) (car usage))
362 ((listp arglist)
363 (format "%S" (help-make-usage function arglist)))
364 ((stringp arglist) arglist)
365 ;; Maybe the arglist is in the docstring of a symbol
366 ;; this one is aliased to.
367 ((let ((fun real-function))
368 (while (and (symbolp fun)
369 (setq fun (symbol-function fun))
370 (not (setq usage (help-split-fundoc
371 (documentation fun)
372 function)))))
373 usage)
374 (car usage))
375 ((or (stringp real-def)
376 (vectorp real-def))
377 (format "\nMacro: %s" (format-kbd-macro real-def)))
378 (t "[Missing arglist. Please make a bug report.]")))
379 (high (help-highlight-arguments use doc)))
380 (let ((fill-begin (point)))
381 (insert (car high) "\n")
382 (fill-region fill-begin (point)))
383 (cdr high)))))
385 (defun help-fns--parent-mode (function)
386 ;; If this is a derived mode, link to the parent.
387 (let ((parent-mode (and (symbolp function)
388 (get function
389 'derived-mode-parent))))
390 (when parent-mode
391 (insert "\nParent mode: `")
392 (let ((beg (point)))
393 (insert (format "%s" parent-mode))
394 (make-text-button beg (point)
395 'type 'help-function
396 'help-args (list parent-mode)))
397 (insert "'.\n"))))
399 (defun help-fns--obsolete (function)
400 ;; Ignore lambda constructs, keyboard macros, etc.
401 (let* ((obsolete (and (symbolp function)
402 (get function 'byte-obsolete-info)))
403 (use (car obsolete)))
404 (when obsolete
405 (insert "\nThis "
406 (if (eq (car-safe (symbol-function function)) 'macro)
407 "macro"
408 "function")
409 " is obsolete")
410 (when (nth 2 obsolete)
411 (insert (format " since %s" (nth 2 obsolete))))
412 (insert (cond ((stringp use) (concat ";\n" use))
413 (use (format ";\nuse `%s' instead." use))
414 (t "."))
415 "\n"))))
417 ;; We could use `symbol-file' but this is a wee bit more efficient.
418 (defun help-fns--autoloaded-p (function file)
419 "Return non-nil if FUNCTION has previously been autoloaded.
420 FILE is the file where FUNCTION was probably defined."
421 (let* ((file (file-name-sans-extension (file-truename file)))
422 (load-hist load-history)
423 (target (cons t function))
424 found)
425 (while (and load-hist (not found))
426 (and (caar load-hist)
427 (equal (file-name-sans-extension (caar load-hist)) file)
428 (setq found (member target (cdar load-hist))))
429 (setq load-hist (cdr load-hist)))
430 found))
432 ;;;###autoload
433 (defun describe-function-1 (function)
434 (let* ((advised (and (symbolp function)
435 (featurep 'nadvice)
436 (advice--p (advice--symbol-function function))))
437 ;; If the function is advised, use the symbol that has the
438 ;; real definition, if that symbol is already set up.
439 (real-function
440 (or (and advised
441 (advice--cd*r (advice--symbol-function function)))
442 function))
443 ;; Get the real definition.
444 (def (if (symbolp real-function)
445 (symbol-function real-function)
446 real-function))
447 (aliased (or (symbolp def)
448 ;; Advised & aliased function.
449 (and advised (symbolp real-function))))
450 (real-def (cond
451 (aliased (let ((f real-function))
452 (while (and (fboundp f)
453 (symbolp (symbol-function f)))
454 (setq f (symbol-function f)))
456 ((subrp def) (intern (subr-name def)))
457 (t def)))
458 (file-name (find-lisp-object-file-name function def))
459 (pt1 (with-current-buffer (help-buffer) (point)))
460 (beg (if (and (or (byte-code-function-p def)
461 (keymapp def)
462 (memq (car-safe def) '(macro lambda closure)))
463 file-name
464 (help-fns--autoloaded-p function file-name))
465 (if (commandp def)
466 "an interactive autoloaded "
467 "an autoloaded ")
468 (if (commandp def) "an interactive " "a "))))
470 ;; Print what kind of function-like object FUNCTION is.
471 (princ (cond ((or (stringp def) (vectorp def))
472 "a keyboard macro")
473 ((subrp def)
474 (if (eq 'unevalled (cdr (subr-arity def)))
475 (concat beg "special form")
476 (concat beg "built-in function")))
477 ;; Aliases are Lisp functions, so we need to check
478 ;; aliases before functions.
479 (aliased
480 (format "an alias for `%s'" real-def))
481 ((autoloadp def)
482 (format "%s autoloaded %s"
483 (if (commandp def) "an interactive" "an")
484 (if (eq (nth 4 def) 'keymap) "keymap"
485 (if (nth 4 def) "Lisp macro" "Lisp function"))))
486 ((or (eq (car-safe def) 'macro)
487 ;; For advised macros, def is a lambda
488 ;; expression or a byte-code-function-p, so we
489 ;; need to check macros before functions.
490 (macrop function))
491 (concat beg "Lisp macro"))
492 ((byte-code-function-p def)
493 (concat beg "compiled Lisp function"))
494 ((eq (car-safe def) 'lambda)
495 (concat beg "Lisp function"))
496 ((eq (car-safe def) 'closure)
497 (concat beg "Lisp closure"))
498 ((keymapp def)
499 (let ((is-full nil)
500 (elts (cdr-safe def)))
501 (while elts
502 (if (char-table-p (car-safe elts))
503 (setq is-full t
504 elts nil))
505 (setq elts (cdr-safe elts)))
506 (concat beg (if is-full "keymap" "sparse keymap"))))
507 (t "")))
509 (if (and aliased (not (fboundp real-def)))
510 (princ ",\nwhich is not defined. Please make a bug report.")
511 (with-current-buffer standard-output
512 (save-excursion
513 (save-match-data
514 (when (re-search-backward "alias for `\\([^`']+\\)'" nil t)
515 (help-xref-button 1 'help-function real-def)))))
517 (when file-name
518 (princ " in `")
519 ;; We used to add .el to the file name,
520 ;; but that's completely wrong when the user used load-file.
521 (princ (if (eq file-name 'C-source)
522 "C source code"
523 (file-name-nondirectory file-name)))
524 (princ "'")
525 ;; Make a hyperlink to the library.
526 (with-current-buffer standard-output
527 (save-excursion
528 (re-search-backward "`\\([^`']+\\)'" nil t)
529 (help-xref-button 1 'help-function-def function file-name))))
530 (princ ".")
531 (with-current-buffer (help-buffer)
532 (fill-region-as-paragraph (save-excursion (goto-char pt1) (forward-line 0) (point))
533 (point)))
534 (terpri)(terpri)
536 (let* ((doc-raw (documentation function t))
537 ;; If the function is autoloaded, and its docstring has
538 ;; key substitution constructs, load the library.
539 (doc (progn
540 (and (autoloadp real-def) doc-raw
541 help-enable-auto-load
542 (string-match "\\([^\\]=\\|[^=]\\|\\`\\)\\\\[[{<]"
543 doc-raw)
544 (load (cadr real-def) t))
545 (substitute-command-keys doc-raw))))
547 (help-fns--key-bindings function)
548 (with-current-buffer standard-output
549 (setq doc (help-fns--signature function doc real-def real-function))
550 (run-hook-with-args 'help-fns-describe-function-functions function)
551 (insert "\n"
552 (or doc "Not documented.")))))))
554 ;; Add defaults to `help-fns-describe-function-functions'.
555 (add-hook 'help-fns-describe-function-functions #'help-fns--obsolete)
556 (add-hook 'help-fns-describe-function-functions #'help-fns--parent-mode)
557 (add-hook 'help-fns-describe-function-functions #'help-fns--compiler-macro)
560 ;; Variables
562 ;;;###autoload
563 (defun variable-at-point (&optional any-symbol)
564 "Return the bound variable symbol found at or before point.
565 Return 0 if there is no such symbol.
566 If ANY-SYMBOL is non-nil, don't insist the symbol be bound."
567 (with-syntax-table emacs-lisp-mode-syntax-table
568 (or (condition-case ()
569 (save-excursion
570 (skip-chars-forward "'")
571 (or (not (zerop (skip-syntax-backward "_w")))
572 (eq (char-syntax (following-char)) ?w)
573 (eq (char-syntax (following-char)) ?_)
574 (forward-sexp -1))
575 (skip-chars-forward "'")
576 (let ((obj (read (current-buffer))))
577 (and (symbolp obj) (boundp obj) obj)))
578 (error nil))
579 (let* ((str (find-tag-default))
580 (sym (if str (intern-soft str))))
581 (if (and sym (or any-symbol (boundp sym)))
583 (save-match-data
584 (when (and str (string-match "\\`\\W*\\(.*?\\)\\W*\\'" str))
585 (setq sym (intern-soft (match-string 1 str)))
586 (and (or any-symbol (boundp sym)) sym)))))
587 0)))
589 (defun describe-variable-custom-version-info (variable)
590 (let ((custom-version (get variable 'custom-version))
591 (cpv (get variable 'custom-package-version))
592 (output nil))
593 (if custom-version
594 (setq output
595 (format "This variable was introduced, or its default value was changed, in\nversion %s of Emacs.\n"
596 custom-version))
597 (when cpv
598 (let* ((package (car-safe cpv))
599 (version (if (listp (cdr-safe cpv))
600 (car (cdr-safe cpv))
601 (cdr-safe cpv)))
602 (pkg-versions (assq package customize-package-emacs-version-alist))
603 (emacsv (cdr (assoc version pkg-versions))))
604 (if (and package version)
605 (setq output
606 (format (concat "This variable was introduced, or its default value was changed, in\nversion %s of the %s package"
607 (if emacsv
608 (format " that is part of Emacs %s" emacsv))
609 ".\n")
610 version package))))))
611 output))
613 ;;;###autoload
614 (defun describe-variable (variable &optional buffer frame)
615 "Display the full documentation of VARIABLE (a symbol).
616 Returns the documentation as a string, also.
617 If VARIABLE has a buffer-local value in BUFFER or FRAME
618 \(default to the current buffer and current frame),
619 it is displayed along with the global value."
620 (interactive
621 (let ((v (variable-at-point))
622 (enable-recursive-minibuffers t)
623 val)
624 (setq val (completing-read (if (symbolp v)
625 (format
626 "Describe variable (default %s): " v)
627 "Describe variable: ")
628 obarray
629 (lambda (vv)
630 (or (get vv 'variable-documentation)
631 (and (boundp vv) (not (keywordp vv)))))
632 t nil nil
633 (if (symbolp v) (symbol-name v))))
634 (list (if (equal val "")
635 v (intern val)))))
636 (let (file-name)
637 (unless (buffer-live-p buffer) (setq buffer (current-buffer)))
638 (unless (frame-live-p frame) (setq frame (selected-frame)))
639 (if (not (symbolp variable))
640 (message "You did not specify a variable")
641 (save-excursion
642 (let ((valvoid (not (with-current-buffer buffer (boundp variable))))
643 (permanent-local (get variable 'permanent-local))
644 val val-start-pos locus)
645 ;; Extract the value before setting up the output buffer,
646 ;; in case `buffer' *is* the output buffer.
647 (unless valvoid
648 (with-selected-frame frame
649 (with-current-buffer buffer
650 (setq val (symbol-value variable)
651 locus (variable-binding-locus variable)))))
652 (help-setup-xref (list #'describe-variable variable buffer)
653 (called-interactively-p 'interactive))
654 (with-help-window (help-buffer)
655 (with-current-buffer buffer
656 (prin1 variable)
657 (setq file-name (find-lisp-object-file-name variable 'defvar))
659 (if file-name
660 (progn
661 (princ " is a variable defined in `")
662 (princ (if (eq file-name 'C-source)
663 "C source code"
664 (file-name-nondirectory file-name)))
665 (princ "'.\n")
666 (with-current-buffer standard-output
667 (save-excursion
668 (re-search-backward "`\\([^`']+\\)'" nil t)
669 (help-xref-button 1 'help-variable-def
670 variable file-name)))
671 (if valvoid
672 (princ "It is void as a variable.")
673 (princ "Its ")))
674 (if valvoid
675 (princ " is void as a variable.")
676 (princ "'s "))))
677 (unless valvoid
678 (with-current-buffer standard-output
679 (setq val-start-pos (point))
680 (princ "value is ")
681 (let ((from (point))
682 (line-beg (line-beginning-position))
683 (print-rep
684 (let ((print-quoted t))
685 (prin1-to-string val))))
686 (if (< (+ (length print-rep) (point) (- line-beg)) 68)
687 (insert print-rep)
688 (terpri)
689 (pp val)
690 (if (< (point) (+ 68 (line-beginning-position 0)))
691 (delete-region from (1+ from))
692 (delete-region (1- from) from)))
693 (let* ((sv (get variable 'standard-value))
694 (origval (and (consp sv)
695 (condition-case nil
696 (eval (car sv))
697 (error :help-eval-error)))))
698 (when (and (consp sv)
699 (not (equal origval val))
700 (not (equal origval :help-eval-error)))
701 (princ "\nOriginal value was \n")
702 (setq from (point))
703 (pp origval)
704 (if (< (point) (+ from 20))
705 (delete-region (1- from) from)))))))
706 (terpri)
707 (when locus
708 (cond
709 ((bufferp locus)
710 (princ (format "Local in buffer %s; "
711 (buffer-name buffer))))
712 ((framep locus)
713 (princ (format "It is a frame-local variable; ")))
714 ((terminal-live-p locus)
715 (princ (format "It is a terminal-local variable; ")))
717 (princ (format "It is local to %S" locus))))
718 (if (not (default-boundp variable))
719 (princ "globally void")
720 (let ((global-val (default-value variable)))
721 (with-current-buffer standard-output
722 (princ "global value is ")
723 (if (eq val global-val)
724 (princ "the same.")
725 (terpri)
726 ;; Fixme: pp can take an age if you happen to
727 ;; ask for a very large expression. We should
728 ;; probably print it raw once and check it's a
729 ;; sensible size before prettyprinting. -- fx
730 (let ((from (point)))
731 (pp global-val)
732 ;; See previous comment for this function.
733 ;; (help-xref-on-pp from (point))
734 (if (< (point) (+ from 20))
735 (delete-region (1- from) from)))))))
736 (terpri))
738 ;; If the value is large, move it to the end.
739 (with-current-buffer standard-output
740 (when (> (count-lines (point-min) (point-max)) 10)
741 ;; Note that setting the syntax table like below
742 ;; makes forward-sexp move over a `'s' at the end
743 ;; of a symbol.
744 (set-syntax-table emacs-lisp-mode-syntax-table)
745 (goto-char val-start-pos)
746 ;; The line below previously read as
747 ;; (delete-region (point) (progn (end-of-line) (point)))
748 ;; which suppressed display of the buffer local value for
749 ;; large values.
750 (when (looking-at "value is") (replace-match ""))
751 (save-excursion
752 (insert "\n\nValue:")
753 (set (make-local-variable 'help-button-cache)
754 (point-marker)))
755 (insert "value is shown ")
756 (insert-button "below"
757 'action help-button-cache
758 'follow-link t
759 'help-echo "mouse-2, RET: show value")
760 (insert ".\n")))
761 (terpri)
763 (let* ((alias (condition-case nil
764 (indirect-variable variable)
765 (error variable)))
766 (obsolete (get variable 'byte-obsolete-variable))
767 (use (car obsolete))
768 (safe-var (get variable 'safe-local-variable))
769 (doc (or (documentation-property
770 variable 'variable-documentation)
771 (documentation-property
772 alias 'variable-documentation)))
773 (extra-line nil))
775 ;; Mention if it's a local variable.
776 (cond
777 ((and (local-variable-if-set-p variable)
778 (or (not (local-variable-p variable))
779 (with-temp-buffer
780 (local-variable-if-set-p variable))))
781 (setq extra-line t)
782 (princ " Automatically becomes ")
783 (if permanent-local
784 (princ "permanently "))
785 (princ "buffer-local when set.\n"))
786 ((not permanent-local))
787 ((bufferp locus)
788 (setq extra-line t)
789 (princ " This variable's buffer-local value is permanent.\n"))
791 (setq extra-line t)
792 (princ " This variable's value is permanent \
793 if it is given a local binding.\n")))
795 ;; Mention if it's an alias.
796 (unless (eq alias variable)
797 (setq extra-line t)
798 (princ (format " This variable is an alias for `%s'.\n" alias)))
800 (when obsolete
801 (setq extra-line t)
802 (princ " This variable is obsolete")
803 (if (nth 2 obsolete)
804 (princ (format " since %s" (nth 2 obsolete))))
805 (princ (cond ((stringp use) (concat ";\n " use))
806 (use (format ";\n use `%s' instead." (car obsolete)))
807 (t ".")))
808 (terpri))
810 (when (member (cons variable val)
811 (with-current-buffer buffer
812 file-local-variables-alist))
813 (setq extra-line t)
814 (if (member (cons variable val)
815 (with-current-buffer buffer
816 dir-local-variables-alist))
817 (let ((file (and (buffer-file-name buffer)
818 (not (file-remote-p
819 (buffer-file-name buffer)))
820 (dir-locals-find-file
821 (buffer-file-name buffer))))
822 (dir-file t))
823 (princ " This variable's value is directory-local")
824 (if (null file)
825 (princ ".\n")
826 (princ ", set ")
827 (if (consp file) ; result from cache
828 ;; If the cache element has an mtime, we
829 ;; assume it came from a file.
830 (if (nth 2 file)
831 (setq file (expand-file-name
832 dir-locals-file (car file)))
833 ;; Otherwise, assume it was set directly.
834 (setq file (car file)
835 dir-file nil)))
836 (princ (if dir-file
837 "by the file\n `"
838 "for the directory\n `"))
839 (with-current-buffer standard-output
840 (insert-text-button
841 file 'type 'help-dir-local-var-def
842 'help-args (list variable file)))
843 (princ "'.\n")))
844 (princ " This variable's value is file-local.\n")))
846 (when (memq variable ignored-local-variables)
847 (setq extra-line t)
848 (princ " This variable is ignored as a file-local \
849 variable.\n"))
851 ;; Can be both risky and safe, eg auto-fill-function.
852 (when (risky-local-variable-p variable)
853 (setq extra-line t)
854 (princ " This variable may be risky if used as a \
855 file-local variable.\n")
856 (when (assq variable safe-local-variable-values)
857 (princ " However, you have added it to \
858 `safe-local-variable-values'.\n")))
860 (when safe-var
861 (setq extra-line t)
862 (princ " This variable is safe as a file local variable ")
863 (princ "if its value\n satisfies the predicate ")
864 (princ (if (byte-code-function-p safe-var)
865 "which is a byte-compiled expression.\n"
866 (format "`%s'.\n" safe-var))))
868 (if extra-line (terpri))
869 (princ "Documentation:\n")
870 (with-current-buffer standard-output
871 (insert (or doc "Not documented as a variable."))))
873 ;; Make a link to customize if this variable can be customized.
874 (when (custom-variable-p variable)
875 (let ((customize-label "customize"))
876 (terpri)
877 (terpri)
878 (princ (concat "You can " customize-label " this variable."))
879 (with-current-buffer standard-output
880 (save-excursion
881 (re-search-backward
882 (concat "\\(" customize-label "\\)") nil t)
883 (help-xref-button 1 'help-customize-variable variable))))
884 ;; Note variable's version or package version
885 (let ((output (describe-variable-custom-version-info variable)))
886 (when output
887 (terpri)
888 (terpri)
889 (princ output))))
891 (with-current-buffer standard-output
892 ;; Return the text we displayed.
893 (buffer-string))))))))
896 ;;;###autoload
897 (defun describe-syntax (&optional buffer)
898 "Describe the syntax specifications in the syntax table of BUFFER.
899 The descriptions are inserted in a help buffer, which is then displayed.
900 BUFFER defaults to the current buffer."
901 (interactive)
902 (setq buffer (or buffer (current-buffer)))
903 (help-setup-xref (list #'describe-syntax buffer)
904 (called-interactively-p 'interactive))
905 (with-help-window (help-buffer)
906 (let ((table (with-current-buffer buffer (syntax-table))))
907 (with-current-buffer standard-output
908 (describe-vector table 'internal-describe-syntax-value)
909 (while (setq table (char-table-parent table))
910 (insert "\nThe parent syntax table is:")
911 (describe-vector table 'internal-describe-syntax-value))))))
913 (defun help-describe-category-set (value)
914 (insert (cond
915 ((null value) "default")
916 ((char-table-p value) "deeper char-table ...")
917 (t (condition-case nil
918 (category-set-mnemonics value)
919 (error "invalid"))))))
921 ;;;###autoload
922 (defun describe-categories (&optional buffer)
923 "Describe the category specifications in the current category table.
924 The descriptions are inserted in a buffer, which is then displayed.
925 If BUFFER is non-nil, then describe BUFFER's category table instead.
926 BUFFER should be a buffer or a buffer name."
927 (interactive)
928 (setq buffer (or buffer (current-buffer)))
929 (help-setup-xref (list #'describe-categories buffer)
930 (called-interactively-p 'interactive))
931 (with-help-window (help-buffer)
932 (let* ((table (with-current-buffer buffer (category-table)))
933 (docs (char-table-extra-slot table 0)))
934 (if (or (not (vectorp docs)) (/= (length docs) 95))
935 (error "Invalid first extra slot in this category table\n"))
936 (with-current-buffer standard-output
937 (insert "Legend of category mnemonics (see the tail for the longer description)\n")
938 (let ((pos (point)) (items 0) lines n)
939 (dotimes (i 95)
940 (if (aref docs i) (setq items (1+ items))))
941 (setq lines (1+ (/ (1- items) 4)))
942 (setq n 0)
943 (dotimes (i 95)
944 (let ((elt (aref docs i)))
945 (when elt
946 (string-match ".*" elt)
947 (setq elt (match-string 0 elt))
948 (if (>= (length elt) 17)
949 (setq elt (concat (substring elt 0 14) "...")))
950 (if (< (point) (point-max))
951 (move-to-column (* 20 (/ n lines)) t))
952 (insert (+ i ?\s) ?: elt)
953 (if (< (point) (point-max))
954 (forward-line 1)
955 (insert "\n"))
956 (setq n (1+ n))
957 (if (= (% n lines) 0)
958 (goto-char pos))))))
959 (goto-char (point-max))
960 (insert "\n"
961 "character(s)\tcategory mnemonics\n"
962 "------------\t------------------")
963 (describe-vector table 'help-describe-category-set)
964 (insert "Legend of category mnemonics:\n")
965 (dotimes (i 95)
966 (let ((elt (aref docs i)))
967 (when elt
968 (if (string-match "\n" elt)
969 (setq elt (substring elt (match-end 0))))
970 (insert (+ i ?\s) ": " elt "\n"))))
971 (while (setq table (char-table-parent table))
972 (insert "\nThe parent category table is:")
973 (describe-vector table 'help-describe-category-set))))))
976 ;;; Replacements for old lib-src/ programs. Don't seem especially useful.
978 ;; Replaces lib-src/digest-doc.c.
979 ;;;###autoload
980 (defun doc-file-to-man (file)
981 "Produce an nroff buffer containing the doc-strings from the DOC file."
982 (interactive (list (read-file-name "Name of DOC file: " doc-directory
983 internal-doc-file-name t)))
984 (or (file-readable-p file)
985 (error "Cannot read file `%s'" file))
986 (pop-to-buffer (generate-new-buffer "*man-doc*"))
987 (setq buffer-undo-list t)
988 (insert ".TH \"Command Summary for GNU Emacs\"\n"
989 ".AU Richard M. Stallman\n")
990 (insert-file-contents file)
991 (let (notfirst)
992 (while (search-forward "\x1f" nil 'move)
993 (if (looking-at "S")
994 (delete-region (1- (point)) (line-end-position))
995 (delete-char -1)
996 (if notfirst
997 (insert "\n.DE\n")
998 (setq notfirst t))
999 (insert "\n.SH ")
1000 (insert (if (looking-at "F") "Function " "Variable "))
1001 (delete-char 1)
1002 (forward-line 1)
1003 (insert ".DS L\n"))))
1004 (insert "\n.DE\n")
1005 (setq buffer-undo-list nil)
1006 (nroff-mode))
1008 ;; Replaces lib-src/sorted-doc.c.
1009 ;;;###autoload
1010 (defun doc-file-to-info (file)
1011 "Produce a texinfo buffer with sorted doc-strings from the DOC file."
1012 (interactive (list (read-file-name "Name of DOC file: " doc-directory
1013 internal-doc-file-name t)))
1014 (or (file-readable-p file)
1015 (error "Cannot read file `%s'" file))
1016 (let ((i 0) type name doc alist)
1017 (with-temp-buffer
1018 (insert-file-contents file)
1019 ;; The characters "@{}" need special treatment.
1020 (while (re-search-forward "[@{}]" nil t)
1021 (backward-char)
1022 (insert "@")
1023 (forward-char 1))
1024 (goto-char (point-min))
1025 (while (search-forward "\x1f" nil t)
1026 (unless (looking-at "S")
1027 (setq type (char-after)
1028 name (buffer-substring (1+ (point)) (line-end-position))
1029 doc (buffer-substring (line-beginning-position 2)
1030 (if (search-forward "\x1f" nil 'move)
1031 (1- (point))
1032 (point)))
1033 alist (cons (list name type doc) alist))
1034 (backward-char 1))))
1035 (pop-to-buffer (generate-new-buffer "*info-doc*"))
1036 (setq buffer-undo-list t)
1037 ;; Write the output header.
1038 (insert "\\input texinfo @c -*-texinfo-*-\n"
1039 "@setfilename emacsdoc.info\n"
1040 "@settitle Command Summary for GNU Emacs\n"
1041 "@finalout\n"
1042 "\n@node Top\n"
1043 "@unnumbered Command Summary for GNU Emacs\n\n"
1044 "@table @asis\n\n"
1045 "@iftex\n"
1046 "@global@let@ITEM@item\n"
1047 "@def@item{@filbreak@vskip5pt@ITEM}\n"
1048 "@font@tensy cmsy10 scaled @magstephalf\n"
1049 "@font@teni cmmi10 scaled @magstephalf\n"
1050 "@def\\{{@tensy@char110}}\n" ; this backslash goes with cmr10
1051 "@def|{{@tensy@char106}}\n"
1052 "@def@{{{@tensy@char102}}\n"
1053 "@def@}{{@tensy@char103}}\n"
1054 "@def<{{@teni@char62}}\n"
1055 "@def>{{@teni@char60}}\n"
1056 "@chardef@@64\n"
1057 "@catcode43=12\n"
1058 "@tableindent-0.2in\n"
1059 "@end iftex\n")
1060 ;; Sort the array by name; within each name, by type (functions first).
1061 (setq alist (sort alist (lambda (e1 e2)
1062 (if (string-equal (car e1) (car e2))
1063 (<= (cadr e1) (cadr e2))
1064 (string-lessp (car e1) (car e2))))))
1065 ;; Print each function.
1066 (dolist (e alist)
1067 (insert "\n@item "
1068 (if (char-equal (cadr e) ?\F) "Function" "Variable")
1069 " @code{" (car e) "}\n@display\n"
1070 (nth 2 e)
1071 "\n@end display\n")
1072 ;; Try to avoid a save size overflow in the TeX output routine.
1073 (if (zerop (setq i (% (1+ i) 100)))
1074 (insert "\n@end table\n@table @asis\n")))
1075 (insert "@end table\n"
1076 "@bye\n")
1077 (setq buffer-undo-list nil)
1078 (texinfo-mode)))
1080 (provide 'help-fns)
1082 ;;; help-fns.el ends here