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1 ;;; help-fns.el --- Complex help functions -*- lexical-binding: t -*-
3 ;; Copyright (C) 1985-1986, 1993-1994, 1998-2014
4 ;; Free Software 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 (if (null function)
58 (message "You didn't specify a function")
59 (help-setup-xref (list #'describe-function function)
60 (called-interactively-p 'interactive))
61 (save-excursion
62 (with-help-window (help-buffer)
63 (prin1 function)
64 ;; Use " is " instead of a colon so that
65 ;; it is easier to get out the function name using forward-sexp.
66 (princ " is ")
67 (describe-function-1 function)
68 (with-current-buffer standard-output
69 ;; Return the text we displayed.
70 (buffer-string))))))
73 ;; Could be this, if we make symbol-file do the work below.
74 ;; (defun help-C-file-name (subr-or-var kind)
75 ;; "Return the name of the C file where SUBR-OR-VAR is defined.
76 ;; KIND should be `var' for a variable or `subr' for a subroutine."
77 ;; (symbol-file (if (symbolp subr-or-var) subr-or-var
78 ;; (subr-name subr-or-var))
79 ;; (if (eq kind 'var) 'defvar 'defun)))
80 ;;;###autoload
81 (defun help-C-file-name (subr-or-var kind)
82 "Return the name of the C file where SUBR-OR-VAR is defined.
83 KIND should be `var' for a variable or `subr' for a subroutine."
84 (let ((docbuf (get-buffer-create " *DOC*"))
85 (name (if (eq 'var kind)
86 (concat "V" (symbol-name subr-or-var))
87 (concat "F" (subr-name (advice--cd*r subr-or-var))))))
88 (with-current-buffer docbuf
89 (goto-char (point-min))
90 (if (eobp)
91 (insert-file-contents-literally
92 (expand-file-name internal-doc-file-name doc-directory)))
93 (let ((file (catch 'loop
94 (while t
95 (let ((pnt (search-forward (concat "\x1f" name "\n"))))
96 (re-search-backward "\x1fS\\(.*\\)")
97 (let ((file (match-string 1)))
98 (if (member file build-files)
99 (throw 'loop file)
100 (goto-char pnt))))))))
101 (if (string-match "^ns.*\\(\\.o\\|obj\\)\\'" file)
102 (setq file (replace-match ".m" t t file 1))
103 (if (string-match "\\.\\(o\\|obj\\)\\'" file)
104 (setq file (replace-match ".c" t t file))))
105 (if (string-match "\\.\\(c\\|m\\)\\'" file)
106 (concat "src/" file)
107 file)))))
109 (defcustom help-downcase-arguments nil
110 "If non-nil, argument names in *Help* buffers are downcased."
111 :type 'boolean
112 :group 'help
113 :version "23.2")
115 (defun help-highlight-arg (arg)
116 "Highlight ARG as an argument name for a *Help* buffer.
117 Return ARG in face `help-argument-name'; ARG is also downcased
118 if the variable `help-downcase-arguments' is non-nil."
119 (propertize (if help-downcase-arguments (downcase arg) arg)
120 'face 'help-argument-name))
122 (defun help-do-arg-highlight (doc args)
123 (with-syntax-table (make-syntax-table emacs-lisp-mode-syntax-table)
124 (modify-syntax-entry ?\- "w")
125 (dolist (arg args)
126 (setq doc (replace-regexp-in-string
127 ;; This is heuristic, but covers all common cases
128 ;; except ARG1-ARG2
129 (concat "\\<" ; beginning of word
130 "\\(?:[a-z-]*-\\)?" ; for xxx-ARG
131 "\\("
132 (regexp-quote arg)
133 "\\)"
134 "\\(?:es\\|s\\|th\\)?" ; for ARGth, ARGs
135 "\\(?:-[a-z0-9-]+\\)?" ; for ARG-xxx, ARG-n
136 "\\(?:-[{([<`\"].*?\\)?"; for ARG-{x}, (x), <x>, [x], `x'
137 "\\>") ; end of word
138 (help-highlight-arg arg)
139 doc t t 1)))
140 doc))
142 (defun help-highlight-arguments (usage doc &rest args)
143 (when (and usage (string-match "^(" usage))
144 (with-temp-buffer
145 (insert usage)
146 (goto-char (point-min))
147 (let ((case-fold-search nil)
148 (next (not (or args (looking-at "\\["))))
149 (opt nil))
150 ;; Make a list of all arguments
151 (skip-chars-forward "^ ")
152 (while next
153 (or opt (not (looking-at " &")) (setq opt t))
154 (if (not (re-search-forward " \\([\\[(]*\\)\\([^] &)\.]+\\)" nil t))
155 (setq next nil)
156 (setq args (cons (match-string 2) args))
157 (when (and opt (string= (match-string 1) "("))
158 ;; A pesky CL-style optional argument with default value,
159 ;; so let's skip over it
160 (search-backward "(")
161 (goto-char (scan-sexps (point) 1)))))
162 ;; Highlight arguments in the USAGE string
163 (setq usage (help-do-arg-highlight (buffer-string) args))
164 ;; Highlight arguments in the DOC string
165 (setq doc (and doc (help-do-arg-highlight doc args))))))
166 ;; Return value is like the one from help-split-fundoc, but highlighted
167 (cons usage doc))
169 ;; The following function was compiled from the former functions
170 ;; `describe-simplify-lib-file-name' and `find-source-lisp-file' with
171 ;; some excerpts from `describe-function-1' and `describe-variable'.
172 ;; The only additional twists provided are (1) locate the defining file
173 ;; for autoloaded functions, and (2) give preference to files in the
174 ;; "install directory" (directories found via `load-path') rather than
175 ;; to files in the "compile directory" (directories found by searching
176 ;; the loaddefs.el file). We autoload it because it's also used by
177 ;; `describe-face' (instead of `describe-simplify-lib-file-name').
179 ;;;###autoload
180 (defun find-lisp-object-file-name (object type)
181 "Guess the file that defined the Lisp object OBJECT, of type TYPE.
182 OBJECT should be a symbol associated with a function, variable, or face;
183 alternatively, it can be a function definition.
184 If TYPE is `defvar', search for a variable definition.
185 If TYPE is `defface', search for a face definition.
186 If TYPE is the value returned by `symbol-function' for a function symbol,
187 search for a function definition.
189 The return value is the absolute name of a readable file where OBJECT is
190 defined. If several such files exist, preference is given to a file
191 found via `load-path'. The return value can also be `C-source', which
192 means that OBJECT is a function or variable defined in C. If no
193 suitable file is found, return nil."
194 (let* ((autoloaded (autoloadp type))
195 (file-name (or (and autoloaded (nth 1 type))
196 (symbol-file
197 object (if (memq type (list 'defvar 'defface))
198 type
199 'defun)))))
200 (cond
201 (autoloaded
202 ;; An autoloaded function: Locate the file since `symbol-function'
203 ;; has only returned a bare string here.
204 (setq file-name
205 (locate-file file-name load-path '(".el" ".elc") 'readable)))
206 ((and (stringp file-name)
207 (string-match "[.]*loaddefs.el\\'" file-name))
208 ;; An autoloaded variable or face. Visit loaddefs.el in a buffer
209 ;; and try to extract the defining file. The following form is
210 ;; from `describe-function-1' and `describe-variable'.
211 (let ((location
212 (condition-case nil
213 (find-function-search-for-symbol object nil file-name)
214 (error nil))))
215 (when (cdr location)
216 (with-current-buffer (car location)
217 (goto-char (cdr location))
218 (when (re-search-backward
219 "^;;; Generated autoloads from \\(.*\\)" nil t)
220 (setq file-name
221 (locate-file
222 (file-name-sans-extension
223 (match-string-no-properties 1))
224 load-path '(".el" ".elc") 'readable))))))))
226 (cond
227 ((and (not file-name) (subrp type))
228 ;; A built-in function. The form is from `describe-function-1'.
229 (if (get-buffer " *DOC*")
230 (help-C-file-name type 'subr)
231 'C-source))
232 ((and (not file-name) (symbolp object)
233 (integerp (get object 'variable-documentation)))
234 ;; A variable defined in C. The form is from `describe-variable'.
235 (if (get-buffer " *DOC*")
236 (help-C-file-name object 'var)
237 'C-source))
238 ((not (stringp file-name))
239 ;; If we don't have a file-name string by now, we lost.
240 nil)
241 ;; Now, `file-name' should have become an absolute file name.
242 ;; For files loaded from ~/.foo.elc, try ~/.foo.
243 ;; This applies to config files like ~/.emacs,
244 ;; which people sometimes compile.
245 ((let (fn)
246 (and (string-match "\\`\\..*\\.elc\\'"
247 (file-name-nondirectory file-name))
248 (string-equal (file-name-directory file-name)
249 (file-name-as-directory (expand-file-name "~")))
250 (file-readable-p (setq fn (file-name-sans-extension file-name)))
251 fn)))
252 ;; When the Elisp source file can be found in the install
253 ;; directory, return the name of that file.
254 ((let ((lib-name
255 (if (string-match "[.]elc\\'" file-name)
256 (substring-no-properties file-name 0 -1)
257 file-name)))
258 (or (and (file-readable-p lib-name) lib-name)
259 ;; The library might be compressed.
260 (and (file-readable-p (concat lib-name ".gz")) lib-name))))
261 ((let* ((lib-name (file-name-nondirectory file-name))
262 ;; The next form is from `describe-simplify-lib-file-name'.
263 (file-name
264 ;; Try converting the absolute file name to a library
265 ;; name, convert that back to a file name and see if we
266 ;; get the original one. If so, they are equivalent.
267 (if (equal file-name (locate-file lib-name load-path '("")))
268 (if (string-match "[.]elc\\'" lib-name)
269 (substring-no-properties lib-name 0 -1)
270 lib-name)
271 file-name))
272 ;; The next three forms are from `find-source-lisp-file'.
273 (elc-file (locate-file
274 (concat file-name
275 (if (string-match "\\.el\\'" file-name)
277 ".elc"))
278 load-path nil 'readable))
279 (str (when elc-file
280 (with-temp-buffer
281 (insert-file-contents-literally elc-file nil 0 256)
282 (buffer-string))))
283 (src-file (and str
284 (string-match ";;; from file \\(.*\\.el\\)" str)
285 (match-string 1 str))))
286 (and src-file (file-readable-p src-file) src-file))))))
288 (defun help-fns--key-bindings (function)
289 (when (commandp function)
290 (let ((pt2 (with-current-buffer standard-output (point)))
291 (remapped (command-remapping function)))
292 (unless (memq remapped '(ignore undefined))
293 (let ((keys (where-is-internal
294 (or remapped function) overriding-local-map nil nil))
295 non-modified-keys)
296 (if (and (eq function 'self-insert-command)
297 (vectorp (car-safe keys))
298 (consp (aref (car keys) 0)))
299 (princ "It is bound to many ordinary text characters.\n")
300 ;; Which non-control non-meta keys run this command?
301 (dolist (key keys)
302 (if (member (event-modifiers (aref key 0)) '(nil (shift)))
303 (push key non-modified-keys)))
304 (when remapped
305 (princ "Its keys are remapped to ")
306 (princ (if (symbolp remapped)
307 (concat "`" (symbol-name remapped) "'")
308 "an anonymous command"))
309 (princ ".\n"))
311 (when keys
312 (princ (if remapped
313 "Without this remapping, it would be bound to "
314 "It is bound to "))
315 ;; If lots of ordinary text characters run this command,
316 ;; don't mention them one by one.
317 (if (< (length non-modified-keys) 10)
318 (princ (mapconcat 'key-description keys ", "))
319 (dolist (key non-modified-keys)
320 (setq keys (delq key keys)))
321 (if keys
322 (progn
323 (princ (mapconcat 'key-description keys ", "))
324 (princ ", and many ordinary text characters"))
325 (princ "many ordinary text characters"))))
326 (when (or remapped keys non-modified-keys)
327 (princ ".")
328 (terpri)))))
330 (with-current-buffer standard-output
331 (fill-region-as-paragraph pt2 (point))
332 (unless (looking-back "\n\n")
333 (terpri))))))
335 (defun help-fns--compiler-macro (function)
336 (let ((handler (function-get function 'compiler-macro)))
337 (when handler
338 (insert "\nThis function has a compiler macro")
339 (if (symbolp handler)
340 (progn
341 (insert (format " `%s'" handler))
342 (save-excursion
343 (re-search-backward "`\\([^`']+\\)'" nil t)
344 (help-xref-button 1 'help-function handler)))
345 ;; FIXME: Obsolete since 24.4.
346 (let ((lib (get function 'compiler-macro-file)))
347 (when (stringp lib)
348 (insert (format " in `%s'" lib))
349 (save-excursion
350 (re-search-backward "`\\([^`']+\\)'" nil t)
351 (help-xref-button 1 'help-function-cmacro function lib)))))
352 (insert ".\n"))))
354 (defun help-fns--signature (function doc real-def real-function)
355 (unless (keymapp function) ; If definition is a keymap, skip arglist note.
356 (let* ((advertised (gethash real-def advertised-signature-table t))
357 (arglist (if (listp advertised)
358 advertised (help-function-arglist real-def)))
359 (usage (help-split-fundoc doc function)))
360 (if usage (setq doc (cdr usage)))
361 (let* ((use (cond
362 ((and usage (not (listp advertised))) (car usage))
363 ((listp arglist)
364 (format "%S" (help-make-usage function arglist)))
365 ((stringp arglist) arglist)
366 ;; Maybe the arglist is in the docstring of a symbol
367 ;; this one is aliased to.
368 ((let ((fun real-function))
369 (while (and (symbolp fun)
370 (setq fun (symbol-function fun))
371 (not (setq usage (help-split-fundoc
372 (documentation fun)
373 function)))))
374 usage)
375 (car usage))
376 ((or (stringp real-def)
377 (vectorp real-def))
378 (format "\nMacro: %s" (format-kbd-macro real-def)))
379 (t "[Missing arglist. Please make a bug report.]")))
380 (high (help-highlight-arguments use doc)))
381 (let ((fill-begin (point)))
382 (insert (car high) "\n")
383 (fill-region fill-begin (point)))
384 (cdr high)))))
386 (defun help-fns--parent-mode (function)
387 ;; If this is a derived mode, link to the parent.
388 (let ((parent-mode (and (symbolp function)
389 (get function
390 'derived-mode-parent))))
391 (when parent-mode
392 (insert "\nParent mode: `")
393 (let ((beg (point)))
394 (insert (format "%s" parent-mode))
395 (make-text-button beg (point)
396 'type 'help-function
397 'help-args (list parent-mode)))
398 (insert "'.\n"))))
400 (defun help-fns--obsolete (function)
401 ;; Ignore lambda constructs, keyboard macros, etc.
402 (let* ((obsolete (and (symbolp function)
403 (get function 'byte-obsolete-info)))
404 (use (car obsolete)))
405 (when obsolete
406 (insert "\nThis "
407 (if (eq (car-safe (symbol-function function)) 'macro)
408 "macro"
409 "function")
410 " is obsolete")
411 (when (nth 2 obsolete)
412 (insert (format " since %s" (nth 2 obsolete))))
413 (insert (cond ((stringp use) (concat ";\n" use))
414 (use (format ";\nuse `%s' instead." use))
415 (t "."))
416 "\n"))))
418 ;; We could use `symbol-file' but this is a wee bit more efficient.
419 (defun help-fns--autoloaded-p (function file)
420 "Return non-nil if FUNCTION has previously been autoloaded.
421 FILE is the file where FUNCTION was probably defined."
422 (let* ((file (file-name-sans-extension (file-truename file)))
423 (load-hist load-history)
424 (target (cons t function))
425 found)
426 (while (and load-hist (not found))
427 (and (caar load-hist)
428 (equal (file-name-sans-extension (caar load-hist)) file)
429 (setq found (member target (cdar load-hist))))
430 (setq load-hist (cdr load-hist)))
431 found))
433 (defun help-fns--interactive-only (function)
434 "Insert some help blurb if FUNCTION should only be used interactively."
435 ;; Ignore lambda constructs, keyboard macros, etc.
436 (and (symbolp function)
437 (not (eq (car-safe (symbol-function function)) 'macro))
438 (let* ((interactive-only
439 (or (get function 'interactive-only)
440 (if (boundp 'byte-compile-interactive-only-functions)
441 (memq function
442 byte-compile-interactive-only-functions)))))
443 (when interactive-only
444 (insert "\nThis function is for interactive use only"
445 ;; Cf byte-compile-form.
446 (cond ((stringp interactive-only)
447 (format ";\nin Lisp code %s" interactive-only))
448 ((and (symbolp 'interactive-only)
449 (not (eq interactive-only t)))
450 (format ";\nin Lisp code use `%s' instead."
451 interactive-only))
452 (t "."))
453 "\n")))))
455 ;;;###autoload
456 (defun describe-function-1 (function)
457 (let* ((advised (and (symbolp function)
458 (featurep 'nadvice)
459 (advice--p (advice--symbol-function function))))
460 ;; If the function is advised, use the symbol that has the
461 ;; real definition, if that symbol is already set up.
462 (real-function
463 (or (and advised
464 (advice--cd*r (advice--symbol-function function)))
465 function))
466 ;; Get the real definition.
467 (def (if (symbolp real-function)
468 (symbol-function real-function)
469 real-function))
470 (aliased (or (symbolp def)
471 ;; Advised & aliased function.
472 (and advised (symbolp real-function))))
473 (real-def (cond
474 (aliased (let ((f real-function))
475 (while (and (fboundp f)
476 (symbolp (symbol-function f)))
477 (setq f (symbol-function f)))
479 ((subrp def) (intern (subr-name def)))
480 (t def)))
481 (file-name (find-lisp-object-file-name function def))
482 (pt1 (with-current-buffer (help-buffer) (point)))
483 (beg (if (and (or (byte-code-function-p def)
484 (keymapp def)
485 (memq (car-safe def) '(macro lambda closure)))
486 file-name
487 (help-fns--autoloaded-p function file-name))
488 (if (commandp def)
489 "an interactive autoloaded "
490 "an autoloaded ")
491 (if (commandp def) "an interactive " "a "))))
493 ;; Print what kind of function-like object FUNCTION is.
494 (princ (cond ((or (stringp def) (vectorp def))
495 "a keyboard macro")
496 ((subrp def)
497 (if (eq 'unevalled (cdr (subr-arity def)))
498 (concat beg "special form")
499 (concat beg "built-in function")))
500 ;; Aliases are Lisp functions, so we need to check
501 ;; aliases before functions.
502 (aliased
503 (format "an alias for `%s'" real-def))
504 ((or (eq (car-safe def) 'macro)
505 ;; For advised macros, def is a lambda
506 ;; expression or a byte-code-function-p, so we
507 ;; need to check macros before functions.
508 (macrop function))
509 (concat beg "Lisp macro"))
510 ((byte-code-function-p def)
511 (concat beg "compiled Lisp function"))
512 ((eq (car-safe def) 'lambda)
513 (concat beg "Lisp function"))
514 ((eq (car-safe def) 'closure)
515 (concat beg "Lisp closure"))
516 ((autoloadp def)
517 (format "%s autoloaded %s"
518 (if (commandp def) "an interactive" "an")
519 (if (eq (nth 4 def) 'keymap) "keymap"
520 (if (nth 4 def) "Lisp macro" "Lisp function"))))
521 ((keymapp def)
522 (let ((is-full nil)
523 (elts (cdr-safe def)))
524 (while elts
525 (if (char-table-p (car-safe elts))
526 (setq is-full t
527 elts nil))
528 (setq elts (cdr-safe elts)))
529 (concat beg (if is-full "keymap" "sparse keymap"))))
530 (t "")))
532 (if (and aliased (not (fboundp real-def)))
533 (princ ",\nwhich is not defined. Please make a bug report.")
534 (with-current-buffer standard-output
535 (save-excursion
536 (save-match-data
537 (when (re-search-backward "alias for `\\([^`']+\\)'" nil t)
538 (help-xref-button 1 'help-function real-def)))))
540 (when file-name
541 (princ " in `")
542 ;; We used to add .el to the file name,
543 ;; but that's completely wrong when the user used load-file.
544 (princ (if (eq file-name 'C-source)
545 "C source code"
546 (file-name-nondirectory file-name)))
547 (princ "'")
548 ;; Make a hyperlink to the library.
549 (with-current-buffer standard-output
550 (save-excursion
551 (re-search-backward "`\\([^`']+\\)'" nil t)
552 (help-xref-button 1 'help-function-def function file-name))))
553 (princ ".")
554 (with-current-buffer (help-buffer)
555 (fill-region-as-paragraph (save-excursion (goto-char pt1) (forward-line 0) (point))
556 (point)))
557 (terpri)(terpri)
559 (let* ((doc-raw (documentation function t))
560 ;; If the function is autoloaded, and its docstring has
561 ;; key substitution constructs, load the library.
562 (doc (progn
563 (and (autoloadp real-def) doc-raw
564 help-enable-auto-load
565 (string-match "\\([^\\]=\\|[^=]\\|\\`\\)\\\\[[{<]"
566 doc-raw)
567 (load (cadr real-def) t))
568 (substitute-command-keys doc-raw))))
570 (help-fns--key-bindings function)
571 (with-current-buffer standard-output
572 (setq doc (help-fns--signature function doc real-def real-function))
573 (run-hook-with-args 'help-fns-describe-function-functions function)
574 (insert "\n"
575 (or doc "Not documented.")))))))
577 ;; Add defaults to `help-fns-describe-function-functions'.
578 (add-hook 'help-fns-describe-function-functions #'help-fns--obsolete)
579 (add-hook 'help-fns-describe-function-functions #'help-fns--interactive-only)
580 (add-hook 'help-fns-describe-function-functions #'help-fns--parent-mode)
581 (add-hook 'help-fns-describe-function-functions #'help-fns--compiler-macro)
584 ;; Variables
586 ;;;###autoload
587 (defun variable-at-point (&optional any-symbol)
588 "Return the bound variable symbol found at or before point.
589 Return 0 if there is no such symbol.
590 If ANY-SYMBOL is non-nil, don't insist the symbol be bound."
591 (with-syntax-table emacs-lisp-mode-syntax-table
592 (or (condition-case ()
593 (save-excursion
594 (skip-chars-forward "'")
595 (or (not (zerop (skip-syntax-backward "_w")))
596 (eq (char-syntax (following-char)) ?w)
597 (eq (char-syntax (following-char)) ?_)
598 (forward-sexp -1))
599 (skip-chars-forward "'")
600 (let ((obj (read (current-buffer))))
601 (and (symbolp obj) (boundp obj) obj)))
602 (error nil))
603 (let* ((str (find-tag-default))
604 (sym (if str (intern-soft str))))
605 (if (and sym (or any-symbol (boundp sym)))
607 (save-match-data
608 (when (and str (string-match "\\`\\W*\\(.*?\\)\\W*\\'" str))
609 (setq sym (intern-soft (match-string 1 str)))
610 (and (or any-symbol (boundp sym)) sym)))))
611 0)))
613 (defun describe-variable-custom-version-info (variable)
614 (let ((custom-version (get variable 'custom-version))
615 (cpv (get variable 'custom-package-version))
616 (output nil))
617 (if custom-version
618 (setq output
619 (format "This variable was introduced, or its default value was changed, in\nversion %s of Emacs.\n"
620 custom-version))
621 (when cpv
622 (let* ((package (car-safe cpv))
623 (version (if (listp (cdr-safe cpv))
624 (car (cdr-safe cpv))
625 (cdr-safe cpv)))
626 (pkg-versions (assq package customize-package-emacs-version-alist))
627 (emacsv (cdr (assoc version pkg-versions))))
628 (if (and package version)
629 (setq output
630 (format (concat "This variable was introduced, or its default value was changed, in\nversion %s of the %s package"
631 (if emacsv
632 (format " that is part of Emacs %s" emacsv))
633 ".\n")
634 version package))))))
635 output))
637 ;;;###autoload
638 (defun describe-variable (variable &optional buffer frame)
639 "Display the full documentation of VARIABLE (a symbol).
640 Returns the documentation as a string, also.
641 If VARIABLE has a buffer-local value in BUFFER or FRAME
642 \(default to the current buffer and current frame),
643 it is displayed along with the global value."
644 (interactive
645 (let ((v (variable-at-point))
646 (enable-recursive-minibuffers t)
647 val)
648 (setq val (completing-read (if (symbolp v)
649 (format
650 "Describe variable (default %s): " v)
651 "Describe variable: ")
652 obarray
653 (lambda (vv)
654 (or (get vv 'variable-documentation)
655 (and (boundp vv) (not (keywordp vv)))))
656 t nil nil
657 (if (symbolp v) (symbol-name v))))
658 (list (if (equal val "")
659 v (intern val)))))
660 (let (file-name)
661 (unless (buffer-live-p buffer) (setq buffer (current-buffer)))
662 (unless (frame-live-p frame) (setq frame (selected-frame)))
663 (if (not (symbolp variable))
664 (message "You did not specify a variable")
665 (save-excursion
666 (let ((valvoid (not (with-current-buffer buffer (boundp variable))))
667 (permanent-local (get variable 'permanent-local))
668 val val-start-pos locus)
669 ;; Extract the value before setting up the output buffer,
670 ;; in case `buffer' *is* the output buffer.
671 (unless valvoid
672 (with-selected-frame frame
673 (with-current-buffer buffer
674 (setq val (symbol-value variable)
675 locus (variable-binding-locus variable)))))
676 (help-setup-xref (list #'describe-variable variable buffer)
677 (called-interactively-p 'interactive))
678 (with-help-window (help-buffer)
679 (with-current-buffer buffer
680 (prin1 variable)
681 (setq file-name (find-lisp-object-file-name variable 'defvar))
683 (if file-name
684 (progn
685 (princ " is a variable defined in `")
686 (princ (if (eq file-name 'C-source)
687 "C source code"
688 (file-name-nondirectory file-name)))
689 (princ "'.\n")
690 (with-current-buffer standard-output
691 (save-excursion
692 (re-search-backward "`\\([^`']+\\)'" nil t)
693 (help-xref-button 1 'help-variable-def
694 variable file-name)))
695 (if valvoid
696 (princ "It is void as a variable.")
697 (princ "Its ")))
698 (if valvoid
699 (princ " is void as a variable.")
700 (princ "'s "))))
701 (unless valvoid
702 (with-current-buffer standard-output
703 (setq val-start-pos (point))
704 (princ "value is ")
705 (let ((from (point))
706 (line-beg (line-beginning-position))
707 (print-rep
708 (let ((print-quoted t))
709 (prin1-to-string val))))
710 (if (< (+ (length print-rep) (point) (- line-beg)) 68)
711 (insert print-rep)
712 (terpri)
713 (pp val)
714 (if (< (point) (+ 68 (line-beginning-position 0)))
715 (delete-region from (1+ from))
716 (delete-region (1- from) from)))
717 (let* ((sv (get variable 'standard-value))
718 (origval (and (consp sv)
719 (condition-case nil
720 (eval (car sv))
721 (error :help-eval-error)))))
722 (when (and (consp sv)
723 (not (equal origval val))
724 (not (equal origval :help-eval-error)))
725 (princ "\nOriginal value was \n")
726 (setq from (point))
727 (pp origval)
728 (if (< (point) (+ from 20))
729 (delete-region (1- from) from)))))))
730 (terpri)
731 (when locus
732 (cond
733 ((bufferp locus)
734 (princ (format "Local in buffer %s; "
735 (buffer-name buffer))))
736 ((framep locus)
737 (princ (format "It is a frame-local variable; ")))
738 ((terminal-live-p locus)
739 (princ (format "It is a terminal-local variable; ")))
741 (princ (format "It is local to %S" locus))))
742 (if (not (default-boundp variable))
743 (princ "globally void")
744 (let ((global-val (default-value variable)))
745 (with-current-buffer standard-output
746 (princ "global value is ")
747 (if (eq val global-val)
748 (princ "the same.")
749 (terpri)
750 ;; Fixme: pp can take an age if you happen to
751 ;; ask for a very large expression. We should
752 ;; probably print it raw once and check it's a
753 ;; sensible size before prettyprinting. -- fx
754 (let ((from (point)))
755 (pp global-val)
756 ;; See previous comment for this function.
757 ;; (help-xref-on-pp from (point))
758 (if (< (point) (+ from 20))
759 (delete-region (1- from) from)))))))
760 (terpri))
762 ;; If the value is large, move it to the end.
763 (with-current-buffer standard-output
764 (when (> (count-lines (point-min) (point-max)) 10)
765 ;; Note that setting the syntax table like below
766 ;; makes forward-sexp move over a `'s' at the end
767 ;; of a symbol.
768 (set-syntax-table emacs-lisp-mode-syntax-table)
769 (goto-char val-start-pos)
770 ;; The line below previously read as
771 ;; (delete-region (point) (progn (end-of-line) (point)))
772 ;; which suppressed display of the buffer local value for
773 ;; large values.
774 (when (looking-at "value is") (replace-match ""))
775 (save-excursion
776 (insert "\n\nValue:")
777 (set (make-local-variable 'help-button-cache)
778 (point-marker)))
779 (insert "value is shown ")
780 (insert-button "below"
781 'action help-button-cache
782 'follow-link t
783 'help-echo "mouse-2, RET: show value")
784 (insert ".\n")))
785 (terpri)
787 (let* ((alias (condition-case nil
788 (indirect-variable variable)
789 (error variable)))
790 (obsolete (get variable 'byte-obsolete-variable))
791 (use (car obsolete))
792 (safe-var (get variable 'safe-local-variable))
793 (doc (or (documentation-property
794 variable 'variable-documentation)
795 (documentation-property
796 alias 'variable-documentation)))
797 (extra-line nil))
799 ;; Mention if it's a local variable.
800 (cond
801 ((and (local-variable-if-set-p variable)
802 (or (not (local-variable-p variable))
803 (with-temp-buffer
804 (local-variable-if-set-p variable))))
805 (setq extra-line t)
806 (princ " Automatically becomes ")
807 (if permanent-local
808 (princ "permanently "))
809 (princ "buffer-local when set.\n"))
810 ((not permanent-local))
811 ((bufferp locus)
812 (setq extra-line t)
813 (princ " This variable's buffer-local value is permanent.\n"))
815 (setq extra-line t)
816 (princ " This variable's value is permanent \
817 if it is given a local binding.\n")))
819 ;; Mention if it's an alias.
820 (unless (eq alias variable)
821 (setq extra-line t)
822 (princ (format " This variable is an alias for `%s'.\n" alias)))
824 (when obsolete
825 (setq extra-line t)
826 (princ " This variable is obsolete")
827 (if (nth 2 obsolete)
828 (princ (format " since %s" (nth 2 obsolete))))
829 (princ (cond ((stringp use) (concat ";\n " use))
830 (use (format ";\n use `%s' instead." (car obsolete)))
831 (t ".")))
832 (terpri))
834 (when (member (cons variable val)
835 (with-current-buffer buffer
836 file-local-variables-alist))
837 (setq extra-line t)
838 (if (member (cons variable val)
839 (with-current-buffer buffer
840 dir-local-variables-alist))
841 (let ((file (and (buffer-file-name buffer)
842 (not (file-remote-p
843 (buffer-file-name buffer)))
844 (dir-locals-find-file
845 (buffer-file-name buffer))))
846 (dir-file t))
847 (princ " This variable's value is directory-local")
848 (if (null file)
849 (princ ".\n")
850 (princ ", set ")
851 (if (consp file) ; result from cache
852 ;; If the cache element has an mtime, we
853 ;; assume it came from a file.
854 (if (nth 2 file)
855 (setq file (expand-file-name
856 dir-locals-file (car file)))
857 ;; Otherwise, assume it was set directly.
858 (setq file (car file)
859 dir-file nil)))
860 (princ (if dir-file
861 "by the file\n `"
862 "for the directory\n `"))
863 (with-current-buffer standard-output
864 (insert-text-button
865 file 'type 'help-dir-local-var-def
866 'help-args (list variable file)))
867 (princ "'.\n")))
868 (princ " This variable's value is file-local.\n")))
870 (when (memq variable ignored-local-variables)
871 (setq extra-line t)
872 (princ " This variable is ignored as a file-local \
873 variable.\n"))
875 ;; Can be both risky and safe, eg auto-fill-function.
876 (when (risky-local-variable-p variable)
877 (setq extra-line t)
878 (princ " This variable may be risky if used as a \
879 file-local variable.\n")
880 (when (assq variable safe-local-variable-values)
881 (princ " However, you have added it to \
882 `safe-local-variable-values'.\n")))
884 (when safe-var
885 (setq extra-line t)
886 (princ " This variable is safe as a file local variable ")
887 (princ "if its value\n satisfies the predicate ")
888 (princ (if (byte-code-function-p safe-var)
889 "which is a byte-compiled expression.\n"
890 (format "`%s'.\n" safe-var))))
892 (if extra-line (terpri))
893 (princ "Documentation:\n")
894 (with-current-buffer standard-output
895 (insert (or doc "Not documented as a variable."))))
897 ;; Make a link to customize if this variable can be customized.
898 (when (custom-variable-p variable)
899 (let ((customize-label "customize"))
900 (terpri)
901 (terpri)
902 (princ (concat "You can " customize-label " this variable."))
903 (with-current-buffer standard-output
904 (save-excursion
905 (re-search-backward
906 (concat "\\(" customize-label "\\)") nil t)
907 (help-xref-button 1 'help-customize-variable variable))))
908 ;; Note variable's version or package version
909 (let ((output (describe-variable-custom-version-info variable)))
910 (when output
911 (terpri)
912 (terpri)
913 (princ output))))
915 (with-current-buffer standard-output
916 ;; Return the text we displayed.
917 (buffer-string))))))))
920 ;;;###autoload
921 (defun describe-syntax (&optional buffer)
922 "Describe the syntax specifications in the syntax table of BUFFER.
923 The descriptions are inserted in a help buffer, which is then displayed.
924 BUFFER defaults to the current buffer."
925 (interactive)
926 (setq buffer (or buffer (current-buffer)))
927 (help-setup-xref (list #'describe-syntax buffer)
928 (called-interactively-p 'interactive))
929 (with-help-window (help-buffer)
930 (let ((table (with-current-buffer buffer (syntax-table))))
931 (with-current-buffer standard-output
932 (describe-vector table 'internal-describe-syntax-value)
933 (while (setq table (char-table-parent table))
934 (insert "\nThe parent syntax table is:")
935 (describe-vector table 'internal-describe-syntax-value))))))
937 (defun help-describe-category-set (value)
938 (insert (cond
939 ((null value) "default")
940 ((char-table-p value) "deeper char-table ...")
941 (t (condition-case nil
942 (category-set-mnemonics value)
943 (error "invalid"))))))
945 ;;;###autoload
946 (defun describe-categories (&optional buffer)
947 "Describe the category specifications in the current category table.
948 The descriptions are inserted in a buffer, which is then displayed.
949 If BUFFER is non-nil, then describe BUFFER's category table instead.
950 BUFFER should be a buffer or a buffer name."
951 (interactive)
952 (setq buffer (or buffer (current-buffer)))
953 (help-setup-xref (list #'describe-categories buffer)
954 (called-interactively-p 'interactive))
955 (with-help-window (help-buffer)
956 (let* ((table (with-current-buffer buffer (category-table)))
957 (docs (char-table-extra-slot table 0)))
958 (if (or (not (vectorp docs)) (/= (length docs) 95))
959 (error "Invalid first extra slot in this category table\n"))
960 (with-current-buffer standard-output
961 (insert "Legend of category mnemonics (see the tail for the longer description)\n")
962 (let ((pos (point)) (items 0) lines n)
963 (dotimes (i 95)
964 (if (aref docs i) (setq items (1+ items))))
965 (setq lines (1+ (/ (1- items) 4)))
966 (setq n 0)
967 (dotimes (i 95)
968 (let ((elt (aref docs i)))
969 (when elt
970 (string-match ".*" elt)
971 (setq elt (match-string 0 elt))
972 (if (>= (length elt) 17)
973 (setq elt (concat (substring elt 0 14) "...")))
974 (if (< (point) (point-max))
975 (move-to-column (* 20 (/ n lines)) t))
976 (insert (+ i ?\s) ?: elt)
977 (if (< (point) (point-max))
978 (forward-line 1)
979 (insert "\n"))
980 (setq n (1+ n))
981 (if (= (% n lines) 0)
982 (goto-char pos))))))
983 (goto-char (point-max))
984 (insert "\n"
985 "character(s)\tcategory mnemonics\n"
986 "------------\t------------------")
987 (describe-vector table 'help-describe-category-set)
988 (insert "Legend of category mnemonics:\n")
989 (dotimes (i 95)
990 (let ((elt (aref docs i)))
991 (when elt
992 (if (string-match "\n" elt)
993 (setq elt (substring elt (match-end 0))))
994 (insert (+ i ?\s) ": " elt "\n"))))
995 (while (setq table (char-table-parent table))
996 (insert "\nThe parent category table is:")
997 (describe-vector table 'help-describe-category-set))))))
1000 ;;; Replacements for old lib-src/ programs. Don't seem especially useful.
1002 ;; Replaces lib-src/digest-doc.c.
1003 ;;;###autoload
1004 (defun doc-file-to-man (file)
1005 "Produce an nroff buffer containing the doc-strings from the DOC file."
1006 (interactive (list (read-file-name "Name of DOC file: " doc-directory
1007 internal-doc-file-name t)))
1008 (or (file-readable-p file)
1009 (error "Cannot read file `%s'" file))
1010 (pop-to-buffer (generate-new-buffer "*man-doc*"))
1011 (setq buffer-undo-list t)
1012 (insert ".TH \"Command Summary for GNU Emacs\"\n"
1013 ".AU Richard M. Stallman\n")
1014 (insert-file-contents file)
1015 (let (notfirst)
1016 (while (search-forward "\x1f" nil 'move)
1017 (if (looking-at "S")
1018 (delete-region (1- (point)) (line-end-position))
1019 (delete-char -1)
1020 (if notfirst
1021 (insert "\n.DE\n")
1022 (setq notfirst t))
1023 (insert "\n.SH ")
1024 (insert (if (looking-at "F") "Function " "Variable "))
1025 (delete-char 1)
1026 (forward-line 1)
1027 (insert ".DS L\n"))))
1028 (insert "\n.DE\n")
1029 (setq buffer-undo-list nil)
1030 (nroff-mode))
1032 ;; Replaces lib-src/sorted-doc.c.
1033 ;;;###autoload
1034 (defun doc-file-to-info (file)
1035 "Produce a texinfo buffer with sorted doc-strings from the DOC file."
1036 (interactive (list (read-file-name "Name of DOC file: " doc-directory
1037 internal-doc-file-name t)))
1038 (or (file-readable-p file)
1039 (error "Cannot read file `%s'" file))
1040 (let ((i 0) type name doc alist)
1041 (with-temp-buffer
1042 (insert-file-contents file)
1043 ;; The characters "@{}" need special treatment.
1044 (while (re-search-forward "[@{}]" nil t)
1045 (backward-char)
1046 (insert "@")
1047 (forward-char 1))
1048 (goto-char (point-min))
1049 (while (search-forward "\x1f" nil t)
1050 (unless (looking-at "S")
1051 (setq type (char-after)
1052 name (buffer-substring (1+ (point)) (line-end-position))
1053 doc (buffer-substring (line-beginning-position 2)
1054 (if (search-forward "\x1f" nil 'move)
1055 (1- (point))
1056 (point)))
1057 alist (cons (list name type doc) alist))
1058 (backward-char 1))))
1059 (pop-to-buffer (generate-new-buffer "*info-doc*"))
1060 (setq buffer-undo-list t)
1061 ;; Write the output header.
1062 (insert "\\input texinfo @c -*-texinfo-*-\n"
1063 "@setfilename emacsdoc.info\n"
1064 "@settitle Command Summary for GNU Emacs\n"
1065 "@finalout\n"
1066 "\n@node Top\n"
1067 "@unnumbered Command Summary for GNU Emacs\n\n"
1068 "@table @asis\n\n"
1069 "@iftex\n"
1070 "@global@let@ITEM@item\n"
1071 "@def@item{@filbreak@vskip5pt@ITEM}\n"
1072 "@font@tensy cmsy10 scaled @magstephalf\n"
1073 "@font@teni cmmi10 scaled @magstephalf\n"
1074 "@def\\{{@tensy@char110}}\n" ; this backslash goes with cmr10
1075 "@def|{{@tensy@char106}}\n"
1076 "@def@{{{@tensy@char102}}\n"
1077 "@def@}{{@tensy@char103}}\n"
1078 "@def<{{@teni@char62}}\n"
1079 "@def>{{@teni@char60}}\n"
1080 "@chardef@@64\n"
1081 "@catcode43=12\n"
1082 "@tableindent-0.2in\n"
1083 "@end iftex\n")
1084 ;; Sort the array by name; within each name, by type (functions first).
1085 (setq alist (sort alist (lambda (e1 e2)
1086 (if (string-equal (car e1) (car e2))
1087 (<= (cadr e1) (cadr e2))
1088 (string-lessp (car e1) (car e2))))))
1089 ;; Print each function.
1090 (dolist (e alist)
1091 (insert "\n@item "
1092 (if (char-equal (cadr e) ?\F) "Function" "Variable")
1093 " @code{" (car e) "}\n@display\n"
1094 (nth 2 e)
1095 "\n@end display\n")
1096 ;; Try to avoid a save size overflow in the TeX output routine.
1097 (if (zerop (setq i (% (1+ i) 100)))
1098 (insert "\n@end table\n@table @asis\n")))
1099 (insert "@end table\n"
1100 "@bye\n")
1101 (setq buffer-undo-list nil)
1102 (texinfo-mode)))
1104 (provide 'help-fns)
1106 ;;; help-fns.el ends here