Fix documentation of forward-line
[emacs.git] / lisp / help-fns.el
blob4982ee54f467fa58ee4d1df7d2ecc4c57876cb7c
1 ;;; help-fns.el --- Complex help functions -*- lexical-binding: t -*-
3 ;; Copyright (C) 1985-1986, 1993-1994, 1998-2015 Free Software
4 ;; Foundation, Inc.
6 ;; Maintainer: emacs-devel@gnu.org
7 ;; Keywords: help, internal
8 ;; Package: emacs
10 ;; This file is part of GNU Emacs.
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.
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.
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/>.
25 ;;; Commentary:
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
33 ;;; Code:
35 (defvar help-fns-describe-function-functions nil
36 "List of functions to run in help buffer in `describe-function'.
37 Those functions will be run after the header line and argument
38 list was inserted, and before the documentation will be inserted.
39 The functions will receive the function name as argument.")
41 ;; Functions
43 ;;;###autoload
44 (defun describe-function (function)
45 "Display the full documentation of FUNCTION (a symbol)."
46 (interactive
47 (let ((fn (function-called-at-point))
48 (enable-recursive-minibuffers t)
49 val)
50 (setq val (completing-read (if fn
51 (format "Describe function (default %s): " fn)
52 "Describe function: ")
53 obarray 'fboundp t nil nil
54 (and fn (symbol-name fn))))
55 (list (if (equal val "")
56 fn (intern val)))))
57 (or (and function (symbolp function))
58 (user-error "You didn't specify a function symbol"))
59 (or (fboundp function)
60 (user-error "Symbol's function definition is void: %s" function))
61 (help-setup-xref (list #'describe-function function)
62 (called-interactively-p 'interactive))
63 (save-excursion
64 (with-help-window (help-buffer)
65 (prin1 function)
66 ;; Use " is " instead of a colon so that
67 ;; it is easier to get out the function name using forward-sexp.
68 (princ " is ")
69 (describe-function-1 function)
70 (with-current-buffer standard-output
71 ;; Return the text we displayed.
72 (buffer-string)))))
75 ;; Could be this, if we make symbol-file do the work below.
76 ;; (defun help-C-file-name (subr-or-var kind)
77 ;; "Return the name of the C file where SUBR-OR-VAR is defined.
78 ;; KIND should be `var' for a variable or `subr' for a subroutine."
79 ;; (symbol-file (if (symbolp subr-or-var) subr-or-var
80 ;; (subr-name subr-or-var))
81 ;; (if (eq kind 'var) 'defvar 'defun)))
82 ;;;###autoload
83 (defun help-C-file-name (subr-or-var kind)
84 "Return the name of the C file where SUBR-OR-VAR is defined.
85 KIND should be `var' for a variable or `subr' for a subroutine."
86 (let ((docbuf (get-buffer-create " *DOC*"))
87 (name (if (eq 'var kind)
88 (concat "V" (symbol-name subr-or-var))
89 (concat "F" (subr-name (advice--cd*r subr-or-var))))))
90 (with-current-buffer docbuf
91 (goto-char (point-min))
92 (if (eobp)
93 (insert-file-contents-literally
94 (expand-file-name internal-doc-file-name doc-directory)))
95 (let ((file (catch 'loop
96 (while t
97 (let ((pnt (search-forward (concat "\x1f" name "\n"))))
98 (re-search-backward "\x1fS\\(.*\\)")
99 (let ((file (match-string 1)))
100 (if (member file build-files)
101 (throw 'loop file)
102 (goto-char pnt))))))))
103 (if (string-match "^ns.*\\(\\.o\\|obj\\)\\'" file)
104 (setq file (replace-match ".m" t t file 1))
105 (if (string-match "\\.\\(o\\|obj\\)\\'" file)
106 (setq file (replace-match ".c" t t file))))
107 (if (string-match "\\.\\(c\\|m\\)\\'" file)
108 (concat "src/" file)
109 file)))))
111 (defcustom help-downcase-arguments nil
112 "If non-nil, argument names in *Help* buffers are downcased."
113 :type 'boolean
114 :group 'help
115 :version "23.2")
117 (defun help-highlight-arg (arg)
118 "Highlight ARG as an argument name for a *Help* buffer.
119 Return ARG in face `help-argument-name'; ARG is also downcased
120 if the variable `help-downcase-arguments' is non-nil."
121 (propertize (if help-downcase-arguments (downcase arg) arg)
122 'face 'help-argument-name))
124 (defun help-do-arg-highlight (doc args)
125 (with-syntax-table (make-syntax-table emacs-lisp-mode-syntax-table)
126 (modify-syntax-entry ?\- "w")
127 (dolist (arg args)
128 (setq doc (replace-regexp-in-string
129 ;; This is heuristic, but covers all common cases
130 ;; except ARG1-ARG2
131 (concat "\\<" ; beginning of word
132 "\\(?:[a-z-]*-\\)?" ; for xxx-ARG
133 "\\("
134 (regexp-quote arg)
135 "\\)"
136 "\\(?:es\\|s\\|th\\)?" ; for ARGth, ARGs
137 "\\(?:-[a-z0-9-]+\\)?" ; for ARG-xxx, ARG-n
138 "\\(?:-[{([<`\"].*?\\)?"; for ARG-{x}, (x), <x>, [x], `x'
139 "\\>") ; end of word
140 (help-highlight-arg arg)
141 doc t t 1)))
142 doc))
144 (defun help-highlight-arguments (usage doc &rest args)
145 (when (and usage (string-match "^(" usage))
146 (with-temp-buffer
147 (insert usage)
148 (goto-char (point-min))
149 (let ((case-fold-search nil)
150 (next (not (or args (looking-at "\\["))))
151 (opt nil))
152 ;; Make a list of all arguments
153 (skip-chars-forward "^ ")
154 (while next
155 (or opt (not (looking-at " &")) (setq opt t))
156 (if (not (re-search-forward " \\([\\[(]*\\)\\([^] &)\.]+\\)" nil t))
157 (setq next nil)
158 (setq args (cons (match-string 2) args))
159 (when (and opt (string= (match-string 1) "("))
160 ;; A pesky CL-style optional argument with default value,
161 ;; so let's skip over it
162 (search-backward "(")
163 (goto-char (scan-sexps (point) 1)))))
164 ;; Highlight arguments in the USAGE string
165 (setq usage (help-do-arg-highlight (buffer-string) args))
166 ;; Highlight arguments in the DOC string
167 (setq doc (and doc (help-do-arg-highlight doc args))))))
168 ;; Return value is like the one from help-split-fundoc, but highlighted
169 (cons usage doc))
171 ;; The following function was compiled from the former functions
172 ;; `describe-simplify-lib-file-name' and `find-source-lisp-file' with
173 ;; some excerpts from `describe-function-1' and `describe-variable'.
174 ;; The only additional twists provided are (1) locate the defining file
175 ;; for autoloaded functions, and (2) give preference to files in the
176 ;; "install directory" (directories found via `load-path') rather than
177 ;; to files in the "compile directory" (directories found by searching
178 ;; the loaddefs.el file). We autoload it because it's also used by
179 ;; `describe-face' (instead of `describe-simplify-lib-file-name').
181 ;;;###autoload
182 (defun find-lisp-object-file-name (object type)
183 "Guess the file that defined the Lisp object OBJECT, of type TYPE.
184 OBJECT should be a symbol associated with a function, variable, or face;
185 alternatively, it can be a function definition.
186 If TYPE is `defvar', search for a variable definition.
187 If TYPE is `defface', search for a face definition.
188 If TYPE is not a symbol, search for a function definition.
190 The return value is the absolute name of a readable file where OBJECT is
191 defined. If several such files exist, preference is given to a file
192 found via `load-path'. The return value can also be `C-source', which
193 means that OBJECT is a function or variable defined in C. If no
194 suitable file is found, return nil."
195 (let* ((autoloaded (autoloadp type))
196 (file-name (or (and autoloaded (nth 1 type))
197 (symbol-file
198 ;; FIXME: Why do we have this weird "If TYPE is the
199 ;; value returned by `symbol-function' for a function
200 ;; symbol" exception?
201 object (or (if (symbolp type) type) 'defun)))))
202 (cond
203 (autoloaded
204 ;; An autoloaded function: Locate the file since `symbol-function'
205 ;; has only returned a bare string here.
206 (setq file-name
207 (locate-file file-name load-path '(".el" ".elc") 'readable)))
208 ((and (stringp file-name)
209 (string-match "[.]*loaddefs.el\\'" file-name))
210 ;; An autoloaded variable or face. Visit loaddefs.el in a buffer
211 ;; and try to extract the defining file. The following form is
212 ;; from `describe-function-1' and `describe-variable'.
213 (let ((location
214 (condition-case nil
215 (find-function-search-for-symbol object nil file-name)
216 (error nil))))
217 (when (cdr location)
218 (with-current-buffer (car location)
219 (goto-char (cdr location))
220 (when (re-search-backward
221 "^;;; Generated autoloads from \\(.*\\)" nil t)
222 (setq file-name
223 (locate-file
224 (file-name-sans-extension
225 (match-string-no-properties 1))
226 load-path '(".el" ".elc") 'readable))))))))
228 (cond
229 ((and (not file-name) (subrp type))
230 ;; A built-in function. The form is from `describe-function-1'.
231 (if (get-buffer " *DOC*")
232 (help-C-file-name type 'subr)
233 'C-source))
234 ((and (not file-name) (symbolp object)
235 (integerp (get object 'variable-documentation)))
236 ;; A variable defined in C. The form is from `describe-variable'.
237 (if (get-buffer " *DOC*")
238 (help-C-file-name object 'var)
239 'C-source))
240 ((not (stringp file-name))
241 ;; If we don't have a file-name string by now, we lost.
242 nil)
243 ;; Now, `file-name' should have become an absolute file name.
244 ;; For files loaded from ~/.foo.elc, try ~/.foo.
245 ;; This applies to config files like ~/.emacs,
246 ;; which people sometimes compile.
247 ((let (fn)
248 (and (string-match "\\`\\..*\\.elc\\'"
249 (file-name-nondirectory file-name))
250 (string-equal (file-name-directory file-name)
251 (file-name-as-directory (expand-file-name "~")))
252 (file-readable-p (setq fn (file-name-sans-extension file-name)))
253 fn)))
254 ;; When the Elisp source file can be found in the install
255 ;; directory, return the name of that file.
256 ((let ((lib-name
257 (if (string-match "[.]elc\\'" file-name)
258 (substring-no-properties file-name 0 -1)
259 file-name)))
260 (or (and (file-readable-p lib-name) lib-name)
261 ;; The library might be compressed.
262 (and (file-readable-p (concat lib-name ".gz")) lib-name))))
263 ((let* ((lib-name (file-name-nondirectory file-name))
264 ;; The next form is from `describe-simplify-lib-file-name'.
265 (file-name
266 ;; Try converting the absolute file name to a library
267 ;; name, convert that back to a file name and see if we
268 ;; get the original one. If so, they are equivalent.
269 (if (equal file-name (locate-file lib-name load-path '("")))
270 (if (string-match "[.]elc\\'" lib-name)
271 (substring-no-properties lib-name 0 -1)
272 lib-name)
273 file-name))
274 ;; The next three forms are from `find-source-lisp-file'.
275 (elc-file (locate-file
276 (concat file-name
277 (if (string-match "\\.el\\'" file-name)
279 ".elc"))
280 load-path nil 'readable))
281 (str (when elc-file
282 (with-temp-buffer
283 (insert-file-contents-literally elc-file nil 0 256)
284 (buffer-string))))
285 (src-file (and str
286 (string-match ";;; from file \\(.*\\.el\\)" str)
287 (match-string 1 str))))
288 (and src-file (file-readable-p src-file) src-file))))))
290 (defun help-fns--key-bindings (function)
291 (when (commandp function)
292 (let ((pt2 (with-current-buffer standard-output (point)))
293 (remapped (command-remapping function)))
294 (unless (memq remapped '(ignore undefined))
295 (let ((keys (where-is-internal
296 (or remapped function) overriding-local-map nil nil))
297 non-modified-keys)
298 (if (and (eq function 'self-insert-command)
299 (vectorp (car-safe keys))
300 (consp (aref (car keys) 0)))
301 (princ "It is bound to many ordinary text characters.\n")
302 ;; Which non-control non-meta keys run this command?
303 (dolist (key keys)
304 (if (member (event-modifiers (aref key 0)) '(nil (shift)))
305 (push key non-modified-keys)))
306 (when remapped
307 (princ "Its keys are remapped to ")
308 (princ (if (symbolp remapped)
309 (concat "`" (symbol-name remapped) "'")
310 "an anonymous command"))
311 (princ ".\n"))
313 (when keys
314 (princ (if remapped
315 "Without this remapping, it would be bound to "
316 "It is bound to "))
317 ;; If lots of ordinary text characters run this command,
318 ;; don't mention them one by one.
319 (if (< (length non-modified-keys) 10)
320 (princ (mapconcat 'key-description keys ", "))
321 (dolist (key non-modified-keys)
322 (setq keys (delq key keys)))
323 (if keys
324 (progn
325 (princ (mapconcat 'key-description keys ", "))
326 (princ ", and many ordinary text characters"))
327 (princ "many ordinary text characters"))))
328 (when (or remapped keys non-modified-keys)
329 (princ ".")
330 (terpri)))))
332 (with-current-buffer standard-output
333 (fill-region-as-paragraph pt2 (point))
334 (unless (looking-back "\n\n" (- (point) 2))
335 (terpri))))))
337 (defun help-fns--compiler-macro (function)
338 (let ((handler (function-get function 'compiler-macro)))
339 (when handler
340 (insert "\nThis function has a compiler macro")
341 (if (symbolp handler)
342 (progn
343 (insert (format " `%s'" handler))
344 (save-excursion
345 (re-search-backward "`\\([^`']+\\)'" nil t)
346 (help-xref-button 1 'help-function handler)))
347 ;; FIXME: Obsolete since 24.4.
348 (let ((lib (get function 'compiler-macro-file)))
349 (when (stringp lib)
350 (insert (format " in `%s'" lib))
351 (save-excursion
352 (re-search-backward "`\\([^`']+\\)'" nil t)
353 (help-xref-button 1 'help-function-cmacro function lib)))))
354 (insert ".\n"))))
356 (defun help-fns--signature (function doc real-def real-function)
357 "Insert usage at point and return docstring. With highlighting."
358 (if (keymapp function)
359 doc ; If definition is a keymap, skip arglist note.
360 (let* ((advertised (gethash real-def advertised-signature-table t))
361 (arglist (if (listp advertised)
362 advertised (help-function-arglist real-def)))
363 (usage (help-split-fundoc doc function)))
364 (if usage (setq doc (cdr usage)))
365 (let* ((use (cond
366 ((and usage (not (listp advertised))) (car usage))
367 ((listp arglist)
368 (format "%S" (help-make-usage function arglist)))
369 ((stringp arglist) arglist)
370 ;; Maybe the arglist is in the docstring of a symbol
371 ;; this one is aliased to.
372 ((let ((fun real-function))
373 (while (and (symbolp fun)
374 (setq fun (symbol-function fun))
375 (not (setq usage (help-split-fundoc
376 (documentation fun)
377 function)))))
378 usage)
379 (car usage))
380 ((or (stringp real-def)
381 (vectorp real-def))
382 (format "\nMacro: %s" (format-kbd-macro real-def)))
383 (t "[Missing arglist. Please make a bug report.]")))
384 (high (help-highlight-arguments use doc)))
385 (let ((fill-begin (point)))
386 (insert (car high) "\n")
387 (fill-region fill-begin (point)))
388 (cdr high)))))
390 (defun help-fns--parent-mode (function)
391 ;; If this is a derived mode, link to the parent.
392 (let ((parent-mode (and (symbolp function)
393 (get function
394 'derived-mode-parent))))
395 (when parent-mode
396 (insert "\nParent mode: `")
397 (let ((beg (point)))
398 (insert (format "%s" parent-mode))
399 (make-text-button beg (point)
400 'type 'help-function
401 'help-args (list parent-mode)))
402 (insert "'.\n"))))
404 (defun help-fns--obsolete (function)
405 ;; Ignore lambda constructs, keyboard macros, etc.
406 (let* ((obsolete (and (symbolp function)
407 (get function 'byte-obsolete-info)))
408 (use (car obsolete)))
409 (when obsolete
410 (insert "\nThis "
411 (if (eq (car-safe (symbol-function function)) 'macro)
412 "macro"
413 "function")
414 " is obsolete")
415 (when (nth 2 obsolete)
416 (insert (format " since %s" (nth 2 obsolete))))
417 (insert (cond ((stringp use) (concat ";\n" use))
418 (use (format ";\nuse `%s' instead." use))
419 (t "."))
420 "\n"))))
422 ;; We could use `symbol-file' but this is a wee bit more efficient.
423 (defun help-fns--autoloaded-p (function file)
424 "Return non-nil if FUNCTION has previously been autoloaded.
425 FILE is the file where FUNCTION was probably defined."
426 (let* ((file (file-name-sans-extension (file-truename file)))
427 (load-hist load-history)
428 (target (cons t function))
429 found)
430 (while (and load-hist (not found))
431 (and (caar load-hist)
432 (equal (file-name-sans-extension (caar load-hist)) file)
433 (setq found (member target (cdar load-hist))))
434 (setq load-hist (cdr load-hist)))
435 found))
437 (defun help-fns--interactive-only (function)
438 "Insert some help blurb if FUNCTION should only be used interactively."
439 ;; Ignore lambda constructs, keyboard macros, etc.
440 (and (symbolp function)
441 (not (eq (car-safe (symbol-function function)) 'macro))
442 (let* ((interactive-only
443 (or (get function 'interactive-only)
444 (if (boundp 'byte-compile-interactive-only-functions)
445 (memq function
446 byte-compile-interactive-only-functions)))))
447 (when interactive-only
448 (insert "\nThis function is for interactive use only"
449 ;; Cf byte-compile-form.
450 (cond ((stringp interactive-only)
451 (format ";\nin Lisp code %s" interactive-only))
452 ((and (symbolp 'interactive-only)
453 (not (eq interactive-only t)))
454 (format ";\nin Lisp code use `%s' instead."
455 interactive-only))
456 (t "."))
457 "\n")))))
459 (defun help-fns-short-filename (filename)
460 (let* ((abbrev (abbreviate-file-name filename))
461 (short abbrev))
462 (dolist (dir load-path)
463 (let ((rel (file-relative-name filename dir)))
464 (if (< (length rel) (length short))
465 (setq short rel)))
466 (let ((rel (file-relative-name abbrev dir)))
467 (if (< (length rel) (length short))
468 (setq short rel))))
469 short))
471 ;;;###autoload
472 (defun describe-function-1 (function)
473 (let* ((advised (and (symbolp function)
474 (featurep 'nadvice)
475 (advice--p (advice--symbol-function function))))
476 ;; If the function is advised, use the symbol that has the
477 ;; real definition, if that symbol is already set up.
478 (real-function
479 (or (and advised
480 (advice--cd*r (advice--symbol-function function)))
481 function))
482 ;; Get the real definition.
483 (def (if (symbolp real-function)
484 (or (symbol-function real-function)
485 (signal 'void-function (list real-function)))
486 real-function))
487 (aliased (or (symbolp def)
488 ;; Advised & aliased function.
489 (and advised (symbolp real-function))))
490 (real-def (cond
491 (aliased (let ((f real-function))
492 (while (and (fboundp f)
493 (symbolp (symbol-function f)))
494 (setq f (symbol-function f)))
496 ((subrp def) (intern (subr-name def)))
497 (t def)))
498 (sig-key (if (subrp def)
499 (indirect-function real-def)
500 real-def))
501 (file-name (find-lisp-object-file-name function def))
502 (pt1 (with-current-buffer (help-buffer) (point)))
503 (beg (if (and (or (byte-code-function-p def)
504 (keymapp def)
505 (memq (car-safe def) '(macro lambda closure)))
506 (stringp file-name)
507 (help-fns--autoloaded-p function file-name))
508 (if (commandp def)
509 "an interactive autoloaded "
510 "an autoloaded ")
511 (if (commandp def) "an interactive " "a "))))
513 ;; Print what kind of function-like object FUNCTION is.
514 (princ (cond ((or (stringp def) (vectorp def))
515 "a keyboard macro")
516 ((subrp def)
517 (if (eq 'unevalled (cdr (subr-arity def)))
518 (concat beg "special form")
519 (concat beg "built-in function")))
520 ;; Aliases are Lisp functions, so we need to check
521 ;; aliases before functions.
522 (aliased
523 (format "an alias for `%s'" real-def))
524 ((autoloadp def)
525 (format "%s autoloaded %s"
526 (if (commandp def) "an interactive" "an")
527 (if (eq (nth 4 def) 'keymap) "keymap"
528 (if (nth 4 def) "Lisp macro" "Lisp function"))))
529 ((or (eq (car-safe def) 'macro)
530 ;; For advised macros, def is a lambda
531 ;; expression or a byte-code-function-p, so we
532 ;; need to check macros before functions.
533 (macrop function))
534 (concat beg "Lisp macro"))
535 ((byte-code-function-p def)
536 (concat beg "compiled Lisp function"))
537 ((eq (car-safe def) 'lambda)
538 (concat beg "Lisp function"))
539 ((eq (car-safe def) 'closure)
540 (concat beg "Lisp closure"))
541 ((keymapp def)
542 (let ((is-full nil)
543 (elts (cdr-safe def)))
544 (while elts
545 (if (char-table-p (car-safe elts))
546 (setq is-full t
547 elts nil))
548 (setq elts (cdr-safe elts)))
549 (concat beg (if is-full "keymap" "sparse keymap"))))
550 (t "")))
552 (if (and aliased (not (fboundp real-def)))
553 (princ ",\nwhich is not defined. Please make a bug report.")
554 (with-current-buffer standard-output
555 (save-excursion
556 (save-match-data
557 (when (re-search-backward "alias for `\\([^`']+\\)'" nil t)
558 (help-xref-button 1 'help-function real-def)))))
560 (when file-name
561 (princ " in `")
562 ;; We used to add .el to the file name,
563 ;; but that's completely wrong when the user used load-file.
564 (princ (if (eq file-name 'C-source)
565 "C source code"
566 (help-fns-short-filename file-name)))
567 (princ "'")
568 ;; Make a hyperlink to the library.
569 (with-current-buffer standard-output
570 (save-excursion
571 (re-search-backward "`\\([^`']+\\)'" nil t)
572 (help-xref-button 1 'help-function-def function file-name))))
573 (princ ".")
574 (with-current-buffer (help-buffer)
575 (fill-region-as-paragraph (save-excursion (goto-char pt1) (forward-line 0) (point))
576 (point)))
577 (terpri)(terpri)
579 (let* ((doc-raw (documentation function t))
580 ;; If the function is autoloaded, and its docstring has
581 ;; key substitution constructs, load the library.
582 (doc (progn
583 (and (autoloadp real-def) doc-raw
584 help-enable-auto-load
585 (string-match "\\([^\\]=\\|[^=]\\|\\`\\)\\\\[[{<]"
586 doc-raw)
587 (autoload-do-load real-def))
588 (substitute-command-keys doc-raw))))
590 (help-fns--key-bindings function)
591 (with-current-buffer standard-output
592 (setq doc (help-fns--signature function doc sig-key real-function))
593 (run-hook-with-args 'help-fns-describe-function-functions function)
594 (insert "\n"
595 (or doc "Not documented.")))))))
597 ;; Add defaults to `help-fns-describe-function-functions'.
598 (add-hook 'help-fns-describe-function-functions #'help-fns--obsolete)
599 (add-hook 'help-fns-describe-function-functions #'help-fns--interactive-only)
600 (add-hook 'help-fns-describe-function-functions #'help-fns--parent-mode)
601 (add-hook 'help-fns-describe-function-functions #'help-fns--compiler-macro)
604 ;; Variables
606 ;;;###autoload
607 (defun variable-at-point (&optional any-symbol)
608 "Return the bound variable symbol found at or before point.
609 Return 0 if there is no such symbol.
610 If ANY-SYMBOL is non-nil, don't insist the symbol be bound."
611 (with-syntax-table emacs-lisp-mode-syntax-table
612 (or (condition-case ()
613 (save-excursion
614 (skip-chars-forward "'")
615 (or (not (zerop (skip-syntax-backward "_w")))
616 (eq (char-syntax (following-char)) ?w)
617 (eq (char-syntax (following-char)) ?_)
618 (forward-sexp -1))
619 (skip-chars-forward "'")
620 (let ((obj (read (current-buffer))))
621 (and (symbolp obj) (boundp obj) obj)))
622 (error nil))
623 (let* ((str (find-tag-default))
624 (sym (if str (intern-soft str))))
625 (if (and sym (or any-symbol (boundp sym)))
627 (save-match-data
628 (when (and str (string-match "\\`\\W*\\(.*?\\)\\W*\\'" str))
629 (setq sym (intern-soft (match-string 1 str)))
630 (and (or any-symbol (boundp sym)) sym)))))
631 0)))
633 (defun describe-variable-custom-version-info (variable)
634 (let ((custom-version (get variable 'custom-version))
635 (cpv (get variable 'custom-package-version))
636 (output nil))
637 (if custom-version
638 (setq output
639 (format "This variable was introduced, or its default value was changed, in\nversion %s of Emacs.\n"
640 custom-version))
641 (when cpv
642 (let* ((package (car-safe cpv))
643 (version (if (listp (cdr-safe cpv))
644 (car (cdr-safe cpv))
645 (cdr-safe cpv)))
646 (pkg-versions (assq package customize-package-emacs-version-alist))
647 (emacsv (cdr (assoc version pkg-versions))))
648 (if (and package version)
649 (setq output
650 (format (concat "This variable was introduced, or its default value was changed, in\nversion %s of the %s package"
651 (if emacsv
652 (format " that is part of Emacs %s" emacsv))
653 ".\n")
654 version package))))))
655 output))
657 ;;;###autoload
658 (defun describe-variable (variable &optional buffer frame)
659 "Display the full documentation of VARIABLE (a symbol).
660 Returns the documentation as a string, also.
661 If VARIABLE has a buffer-local value in BUFFER or FRAME
662 \(default to the current buffer and current frame),
663 it is displayed along with the global value."
664 (interactive
665 (let ((v (variable-at-point))
666 (enable-recursive-minibuffers t)
667 val)
668 (setq val (completing-read (if (symbolp v)
669 (format
670 "Describe variable (default %s): " v)
671 "Describe variable: ")
672 obarray
673 (lambda (vv)
674 (or (get vv 'variable-documentation)
675 (and (boundp vv) (not (keywordp vv)))))
676 t nil nil
677 (if (symbolp v) (symbol-name v))))
678 (list (if (equal val "")
679 v (intern val)))))
680 (let (file-name)
681 (unless (buffer-live-p buffer) (setq buffer (current-buffer)))
682 (unless (frame-live-p frame) (setq frame (selected-frame)))
683 (if (not (symbolp variable))
684 (message "You did not specify a variable")
685 (save-excursion
686 (let ((valvoid (not (with-current-buffer buffer (boundp variable))))
687 (permanent-local (get variable 'permanent-local))
688 val val-start-pos locus)
689 ;; Extract the value before setting up the output buffer,
690 ;; in case `buffer' *is* the output buffer.
691 (unless valvoid
692 (with-selected-frame frame
693 (with-current-buffer buffer
694 (setq val (symbol-value variable)
695 locus (variable-binding-locus variable)))))
696 (help-setup-xref (list #'describe-variable variable buffer)
697 (called-interactively-p 'interactive))
698 (with-help-window (help-buffer)
699 (with-current-buffer buffer
700 (prin1 variable)
701 (setq file-name (find-lisp-object-file-name variable 'defvar))
703 (if file-name
704 (progn
705 (princ " is a variable defined in `")
706 (princ (if (eq file-name 'C-source)
707 "C source code"
708 (file-name-nondirectory file-name)))
709 (princ "'.\n")
710 (with-current-buffer standard-output
711 (save-excursion
712 (re-search-backward "`\\([^`']+\\)'" nil t)
713 (help-xref-button 1 'help-variable-def
714 variable file-name)))
715 (if valvoid
716 (princ "It is void as a variable.")
717 (princ "Its ")))
718 (if valvoid
719 (princ " is void as a variable.")
720 (princ "'s "))))
721 (unless valvoid
722 (with-current-buffer standard-output
723 (setq val-start-pos (point))
724 (princ "value is ")
725 (let ((from (point))
726 (line-beg (line-beginning-position))
727 (print-rep
728 (let ((print-quoted t))
729 (prin1-to-string val))))
730 (if (< (+ (length print-rep) (point) (- line-beg)) 68)
731 (insert print-rep)
732 (terpri)
733 (pp val)
734 (if (< (point) (+ 68 (line-beginning-position 0)))
735 (delete-region from (1+ from))
736 (delete-region (1- from) from)))
737 (let* ((sv (get variable 'standard-value))
738 (origval (and (consp sv)
739 (condition-case nil
740 (eval (car sv))
741 (error :help-eval-error)))))
742 (when (and (consp sv)
743 (not (equal origval val))
744 (not (equal origval :help-eval-error)))
745 (princ "\nOriginal value was \n")
746 (setq from (point))
747 (pp origval)
748 (if (< (point) (+ from 20))
749 (delete-region (1- from) from)))))))
750 (terpri)
751 (when locus
752 (cond
753 ((bufferp locus)
754 (princ (format "Local in buffer %s; "
755 (buffer-name buffer))))
756 ((framep locus)
757 (princ (format "It is a frame-local variable; ")))
758 ((terminal-live-p locus)
759 (princ (format "It is a terminal-local variable; ")))
761 (princ (format "It is local to %S" locus))))
762 (if (not (default-boundp variable))
763 (princ "globally void")
764 (let ((global-val (default-value variable)))
765 (with-current-buffer standard-output
766 (princ "global value is ")
767 (if (eq val global-val)
768 (princ "the same.")
769 (terpri)
770 ;; Fixme: pp can take an age if you happen to
771 ;; ask for a very large expression. We should
772 ;; probably print it raw once and check it's a
773 ;; sensible size before prettyprinting. -- fx
774 (let ((from (point)))
775 (pp global-val)
776 ;; See previous comment for this function.
777 ;; (help-xref-on-pp from (point))
778 (if (< (point) (+ from 20))
779 (delete-region (1- from) from)))))))
780 (terpri))
782 ;; If the value is large, move it to the end.
783 (with-current-buffer standard-output
784 (when (> (count-lines (point-min) (point-max)) 10)
785 ;; Note that setting the syntax table like below
786 ;; makes forward-sexp move over a `'s' at the end
787 ;; of a symbol.
788 (set-syntax-table emacs-lisp-mode-syntax-table)
789 (goto-char val-start-pos)
790 ;; The line below previously read as
791 ;; (delete-region (point) (progn (end-of-line) (point)))
792 ;; which suppressed display of the buffer local value for
793 ;; large values.
794 (when (looking-at "value is") (replace-match ""))
795 (save-excursion
796 (insert "\n\nValue:")
797 (set (make-local-variable 'help-button-cache)
798 (point-marker)))
799 (insert "value is shown ")
800 (insert-button "below"
801 'action help-button-cache
802 'follow-link t
803 'help-echo "mouse-2, RET: show value")
804 (insert ".\n")))
805 (terpri)
807 (let* ((alias (condition-case nil
808 (indirect-variable variable)
809 (error variable)))
810 (obsolete (get variable 'byte-obsolete-variable))
811 (use (car obsolete))
812 (safe-var (get variable 'safe-local-variable))
813 (doc (or (documentation-property
814 variable 'variable-documentation)
815 (documentation-property
816 alias 'variable-documentation)))
817 (extra-line nil))
819 ;; Mention if it's a local variable.
820 (cond
821 ((and (local-variable-if-set-p variable)
822 (or (not (local-variable-p variable))
823 (with-temp-buffer
824 (local-variable-if-set-p variable))))
825 (setq extra-line t)
826 (princ " Automatically becomes ")
827 (if permanent-local
828 (princ "permanently "))
829 (princ "buffer-local when set.\n"))
830 ((not permanent-local))
831 ((bufferp locus)
832 (setq extra-line t)
833 (princ " This variable's buffer-local value is permanent.\n"))
835 (setq extra-line t)
836 (princ " This variable's value is permanent \
837 if it is given a local binding.\n")))
839 ;; Mention if it's an alias.
840 (unless (eq alias variable)
841 (setq extra-line t)
842 (princ (format " This variable is an alias for `%s'.\n" alias)))
844 (when obsolete
845 (setq extra-line t)
846 (princ " This variable is obsolete")
847 (if (nth 2 obsolete)
848 (princ (format " since %s" (nth 2 obsolete))))
849 (princ (cond ((stringp use) (concat ";\n " use))
850 (use (format ";\n use `%s' instead." (car obsolete)))
851 (t ".")))
852 (terpri))
854 (when (member (cons variable val)
855 (with-current-buffer buffer
856 file-local-variables-alist))
857 (setq extra-line t)
858 (if (member (cons variable val)
859 (with-current-buffer buffer
860 dir-local-variables-alist))
861 (let ((file (and (buffer-file-name buffer)
862 (not (file-remote-p
863 (buffer-file-name buffer)))
864 (dir-locals-find-file
865 (buffer-file-name buffer))))
866 (dir-file t))
867 (princ " This variable's value is directory-local")
868 (if (null file)
869 (princ ".\n")
870 (princ ", set ")
871 (if (consp file) ; result from cache
872 ;; If the cache element has an mtime, we
873 ;; assume it came from a file.
874 (if (nth 2 file)
875 (setq file (expand-file-name
876 dir-locals-file (car file)))
877 ;; Otherwise, assume it was set directly.
878 (setq file (car file)
879 dir-file nil)))
880 (princ (if dir-file
881 "by the file\n `"
882 "for the directory\n `"))
883 (with-current-buffer standard-output
884 (insert-text-button
885 file 'type 'help-dir-local-var-def
886 'help-args (list variable file)))
887 (princ "'.\n")))
888 (princ " This variable's value is file-local.\n")))
890 (when (memq variable ignored-local-variables)
891 (setq extra-line t)
892 (princ " This variable is ignored as a file-local \
893 variable.\n"))
895 ;; Can be both risky and safe, eg auto-fill-function.
896 (when (risky-local-variable-p variable)
897 (setq extra-line t)
898 (princ " This variable may be risky if used as a \
899 file-local variable.\n")
900 (when (assq variable safe-local-variable-values)
901 (princ " However, you have added it to \
902 `safe-local-variable-values'.\n")))
904 (when safe-var
905 (setq extra-line t)
906 (princ " This variable is safe as a file local variable ")
907 (princ "if its value\n satisfies the predicate ")
908 (princ (if (byte-code-function-p safe-var)
909 "which is a byte-compiled expression.\n"
910 (format "`%s'.\n" safe-var))))
912 (if extra-line (terpri))
913 (princ "Documentation:\n")
914 (with-current-buffer standard-output
915 (insert (or doc "Not documented as a variable."))))
917 ;; Make a link to customize if this variable can be customized.
918 (when (custom-variable-p variable)
919 (let ((customize-label "customize"))
920 (terpri)
921 (terpri)
922 (princ (concat "You can " customize-label " this variable."))
923 (with-current-buffer standard-output
924 (save-excursion
925 (re-search-backward
926 (concat "\\(" customize-label "\\)") nil t)
927 (help-xref-button 1 'help-customize-variable variable))))
928 ;; Note variable's version or package version
929 (let ((output (describe-variable-custom-version-info variable)))
930 (when output
931 (terpri)
932 (terpri)
933 (princ output))))
935 (with-current-buffer standard-output
936 ;; Return the text we displayed.
937 (buffer-string))))))))
940 ;;;###autoload
941 (defun describe-function-or-variable (symbol &optional buffer frame)
942 "Display the full documentation of the function or variable SYMBOL.
943 If SYMBOL is a variable and has a buffer-local value in BUFFER or FRAME
944 \(default to the current buffer and current frame), it is displayed along
945 with the global value."
946 (interactive
947 (let* ((v-or-f (variable-at-point))
948 (found (symbolp v-or-f))
949 (v-or-f (if found v-or-f (function-called-at-point)))
950 (found (or found v-or-f))
951 (enable-recursive-minibuffers t)
952 val)
953 (setq val (completing-read (if found
954 (format
955 "Describe function or variable (default %s): " v-or-f)
956 "Describe function or variable: ")
957 obarray
958 (lambda (vv)
959 (or (fboundp vv)
960 (get vv 'variable-documentation)
961 (and (boundp vv) (not (keywordp vv)))))
962 t nil nil
963 (if found (symbol-name v-or-f))))
964 (list (if (equal val "")
965 v-or-f (intern val)))))
966 (if (not (symbolp symbol)) (message "You didn't specify a function or variable")
967 (unless (buffer-live-p buffer) (setq buffer (current-buffer)))
968 (unless (frame-live-p frame) (setq frame (selected-frame)))
969 (help-xref-interned symbol buffer frame)))
971 ;;;###autoload
972 (defun describe-syntax (&optional buffer)
973 "Describe the syntax specifications in the syntax table of BUFFER.
974 The descriptions are inserted in a help buffer, which is then displayed.
975 BUFFER defaults to the current buffer."
976 (interactive)
977 (setq buffer (or buffer (current-buffer)))
978 (help-setup-xref (list #'describe-syntax buffer)
979 (called-interactively-p 'interactive))
980 (with-help-window (help-buffer)
981 (let ((table (with-current-buffer buffer (syntax-table))))
982 (with-current-buffer standard-output
983 (describe-vector table 'internal-describe-syntax-value)
984 (while (setq table (char-table-parent table))
985 (insert "\nThe parent syntax table is:")
986 (describe-vector table 'internal-describe-syntax-value))))))
988 (defun help-describe-category-set (value)
989 (insert (cond
990 ((null value) "default")
991 ((char-table-p value) "deeper char-table ...")
992 (t (condition-case nil
993 (category-set-mnemonics value)
994 (error "invalid"))))))
996 ;;;###autoload
997 (defun describe-categories (&optional buffer)
998 "Describe the category specifications in the current category table.
999 The descriptions are inserted in a buffer, which is then displayed.
1000 If BUFFER is non-nil, then describe BUFFER's category table instead.
1001 BUFFER should be a buffer or a buffer name."
1002 (interactive)
1003 (setq buffer (or buffer (current-buffer)))
1004 (help-setup-xref (list #'describe-categories buffer)
1005 (called-interactively-p 'interactive))
1006 (with-help-window (help-buffer)
1007 (let* ((table (with-current-buffer buffer (category-table)))
1008 (docs (char-table-extra-slot table 0)))
1009 (if (or (not (vectorp docs)) (/= (length docs) 95))
1010 (error "Invalid first extra slot in this category table\n"))
1011 (with-current-buffer standard-output
1012 (insert "Legend of category mnemonics (see the tail for the longer description)\n")
1013 (let ((pos (point)) (items 0) lines n)
1014 (dotimes (i 95)
1015 (if (aref docs i) (setq items (1+ items))))
1016 (setq lines (1+ (/ (1- items) 4)))
1017 (setq n 0)
1018 (dotimes (i 95)
1019 (let ((elt (aref docs i)))
1020 (when elt
1021 (string-match ".*" elt)
1022 (setq elt (match-string 0 elt))
1023 (if (>= (length elt) 17)
1024 (setq elt (concat (substring elt 0 14) "...")))
1025 (if (< (point) (point-max))
1026 (move-to-column (* 20 (/ n lines)) t))
1027 (insert (+ i ?\s) ?: elt)
1028 (if (< (point) (point-max))
1029 (forward-line 1)
1030 (insert "\n"))
1031 (setq n (1+ n))
1032 (if (= (% n lines) 0)
1033 (goto-char pos))))))
1034 (goto-char (point-max))
1035 (insert "\n"
1036 "character(s)\tcategory mnemonics\n"
1037 "------------\t------------------")
1038 (describe-vector table 'help-describe-category-set)
1039 (insert "Legend of category mnemonics:\n")
1040 (dotimes (i 95)
1041 (let ((elt (aref docs i)))
1042 (when elt
1043 (if (string-match "\n" elt)
1044 (setq elt (substring elt (match-end 0))))
1045 (insert (+ i ?\s) ": " elt "\n"))))
1046 (while (setq table (char-table-parent table))
1047 (insert "\nThe parent category table is:")
1048 (describe-vector table 'help-describe-category-set))))))
1051 ;;; Replacements for old lib-src/ programs. Don't seem especially useful.
1053 ;; Replaces lib-src/digest-doc.c.
1054 ;;;###autoload
1055 (defun doc-file-to-man (file)
1056 "Produce an nroff buffer containing the doc-strings from the DOC file."
1057 (interactive (list (read-file-name "Name of DOC file: " doc-directory
1058 internal-doc-file-name t)))
1059 (or (file-readable-p file)
1060 (error "Cannot read file `%s'" file))
1061 (pop-to-buffer (generate-new-buffer "*man-doc*"))
1062 (setq buffer-undo-list t)
1063 (insert ".TH \"Command Summary for GNU Emacs\"\n"
1064 ".AU Richard M. Stallman\n")
1065 (insert-file-contents file)
1066 (let (notfirst)
1067 (while (search-forward "\x1f" nil 'move)
1068 (if (looking-at "S")
1069 (delete-region (1- (point)) (line-end-position))
1070 (delete-char -1)
1071 (if notfirst
1072 (insert "\n.DE\n")
1073 (setq notfirst t))
1074 (insert "\n.SH ")
1075 (insert (if (looking-at "F") "Function " "Variable "))
1076 (delete-char 1)
1077 (forward-line 1)
1078 (insert ".DS L\n"))))
1079 (insert "\n.DE\n")
1080 (setq buffer-undo-list nil)
1081 (nroff-mode))
1083 ;; Replaces lib-src/sorted-doc.c.
1084 ;;;###autoload
1085 (defun doc-file-to-info (file)
1086 "Produce a texinfo buffer with sorted doc-strings from the DOC file."
1087 (interactive (list (read-file-name "Name of DOC file: " doc-directory
1088 internal-doc-file-name t)))
1089 (or (file-readable-p file)
1090 (error "Cannot read file `%s'" file))
1091 (let ((i 0) type name doc alist)
1092 (with-temp-buffer
1093 (insert-file-contents file)
1094 ;; The characters "@{}" need special treatment.
1095 (while (re-search-forward "[@{}]" nil t)
1096 (backward-char)
1097 (insert "@")
1098 (forward-char 1))
1099 (goto-char (point-min))
1100 (while (search-forward "\x1f" nil t)
1101 (unless (looking-at "S")
1102 (setq type (char-after)
1103 name (buffer-substring (1+ (point)) (line-end-position))
1104 doc (buffer-substring (line-beginning-position 2)
1105 (if (search-forward "\x1f" nil 'move)
1106 (1- (point))
1107 (point)))
1108 alist (cons (list name type doc) alist))
1109 (backward-char 1))))
1110 (pop-to-buffer (generate-new-buffer "*info-doc*"))
1111 (setq buffer-undo-list t)
1112 ;; Write the output header.
1113 (insert "\\input texinfo @c -*-texinfo-*-\n"
1114 "@setfilename emacsdoc.info\n"
1115 "@settitle Command Summary for GNU Emacs\n"
1116 "@finalout\n"
1117 "\n@node Top\n"
1118 "@unnumbered Command Summary for GNU Emacs\n\n"
1119 "@table @asis\n\n"
1120 "@iftex\n"
1121 "@global@let@ITEM@item\n"
1122 "@def@item{@filbreak@vskip5pt@ITEM}\n"
1123 "@font@tensy cmsy10 scaled @magstephalf\n"
1124 "@font@teni cmmi10 scaled @magstephalf\n"
1125 "@def\\{{@tensy@char110}}\n" ; this backslash goes with cmr10
1126 "@def|{{@tensy@char106}}\n"
1127 "@def@{{{@tensy@char102}}\n"
1128 "@def@}{{@tensy@char103}}\n"
1129 "@def<{{@teni@char62}}\n"
1130 "@def>{{@teni@char60}}\n"
1131 "@chardef@@64\n"
1132 "@catcode43=12\n"
1133 "@tableindent-0.2in\n"
1134 "@end iftex\n")
1135 ;; Sort the array by name; within each name, by type (functions first).
1136 (setq alist (sort alist (lambda (e1 e2)
1137 (if (string-equal (car e1) (car e2))
1138 (<= (cadr e1) (cadr e2))
1139 (string-lessp (car e1) (car e2))))))
1140 ;; Print each function.
1141 (dolist (e alist)
1142 (insert "\n@item "
1143 (if (char-equal (cadr e) ?\F) "Function" "Variable")
1144 " @code{" (car e) "}\n@display\n"
1145 (nth 2 e)
1146 "\n@end display\n")
1147 ;; Try to avoid a save size overflow in the TeX output routine.
1148 (if (zerop (setq i (% (1+ i) 100)))
1149 (insert "\n@end table\n@table @asis\n")))
1150 (insert "@end table\n"
1151 "@bye\n")
1152 (setq buffer-undo-list nil)
1153 (texinfo-mode)))
1155 (provide 'help-fns)
1157 ;;; help-fns.el ends here