1 ;;; help-fns.el --- Complex help functions
3 ;; Copyright (C) 1985-1986, 1993-1994, 1998-2011
4 ;; Free Software Foundation, Inc.
7 ;; Keywords: help, internal
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/>.
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
38 (defun describe-function (function)
39 "Display the full documentation of FUNCTION (a symbol)."
41 (let ((fn (function-called-at-point))
42 (enable-recursive-minibuffers t)
44 (setq val (completing-read (if fn
45 (format "Describe function (default %s): " fn)
46 "Describe function: ")
47 obarray 'fboundp t nil nil
48 (and fn (symbol-name fn))))
49 (list (if (equal val "")
52 (message "You didn't specify a function")
53 (help-setup-xref (list #'describe-function function)
54 (called-interactively-p 'interactive))
56 (with-help-window (help-buffer)
58 ;; Use " is " instead of a colon so that
59 ;; it is easier to get out the function name using forward-sexp.
61 (describe-function-1 function)
62 (with-current-buffer standard-output
63 ;; Return the text we displayed.
66 (defun help-split-fundoc (docstring def)
67 "Split a function DOCSTRING into the actual doc and the usage info.
68 Return (USAGE . DOC) or nil if there's no usage info.
69 DEF is the function whose usage we're looking for in DOCSTRING."
70 ;; Functions can get the calling sequence at the end of the doc string.
71 ;; In cases where `function' has been fset to a subr we can't search for
72 ;; function's name in the doc string so we use `fn' as the anonymous
73 ;; function name instead.
74 (when (and docstring (string-match "\n\n(fn\\(\\( .*\\)?)\\)\\'" docstring))
76 ;; Replace `fn' with the actual function name.
77 (if (consp def) "anonymous" def)
78 (match-string 1 docstring))
79 (substring docstring 0 (match-beginning 0)))))
81 (defun help-add-fundoc-usage (docstring arglist)
82 "Add the usage info to DOCSTRING.
83 If DOCSTRING already has a usage info, then just return it unchanged.
84 The usage info is built from ARGLIST. DOCSTRING can be nil.
85 ARGLIST can also be t or a string of the form \"(FUN ARG1 ARG2 ...)\"."
86 (unless (stringp docstring) (setq docstring "Not documented"))
87 (if (or (string-match "\n\n(fn\\(\\( .*\\)?)\\)\\'" docstring) (eq arglist t))
90 (if (string-match "\n?\n\\'" docstring)
91 (if (< (- (match-end 0) (match-beginning 0)) 2) "\n" "")
93 (if (and (stringp arglist)
94 (string-match "\\`([^ ]+\\(.*\\))\\'" arglist))
95 (concat "(fn" (match-string 1 arglist) ")")
96 (format "%S" (help-make-usage 'fn arglist))))))
98 (defun help-function-arglist (def)
99 ;; Handle symbols aliased to other symbols.
100 (if (and (symbolp def) (fboundp def)) (setq def (indirect-function def)))
101 ;; If definition is a macro, find the function inside it.
102 (if (eq (car-safe def) 'macro) (setq def (cdr def)))
103 ;; and do the same for interpreted closures
104 (if (eq (car-safe def) 'closure) (setq def (cddr def)))
106 ((byte-code-function-p def) (aref def 0))
107 ((eq (car-safe def) 'lambda) (nth 1 def))
108 ((and (eq (car-safe def) 'autoload) (not (eq (nth 4 def) 'keymap)))
109 "[Arg list not available until function definition is loaded.]")
112 (defun help-make-usage (function arglist)
113 (cons (if (symbolp function) function 'anonymous)
114 (mapcar (lambda (arg)
115 (if (not (symbolp arg))
116 (if (and (consp arg) (symbolp (car arg)))
117 ;; CL style default values for optional args.
118 (cons (intern (upcase (symbol-name (car arg))))
121 (let ((name (symbol-name arg)))
122 (if (string-match "\\`&" name) arg
123 (intern (upcase name))))))
126 ;; Could be this, if we make symbol-file do the work below.
127 ;; (defun help-C-file-name (subr-or-var kind)
128 ;; "Return the name of the C file where SUBR-OR-VAR is defined.
129 ;; KIND should be `var' for a variable or `subr' for a subroutine."
130 ;; (symbol-file (if (symbolp subr-or-var) subr-or-var
131 ;; (subr-name subr-or-var))
132 ;; (if (eq kind 'var) 'defvar 'defun)))
134 (defun help-C-file-name (subr-or-var kind)
135 "Return the name of the C file where SUBR-OR-VAR is defined.
136 KIND should be `var' for a variable or `subr' for a subroutine."
137 (let ((docbuf (get-buffer-create " *DOC*"))
138 (name (if (eq 'var kind)
139 (concat "V" (symbol-name subr-or-var))
140 (concat "F" (subr-name subr-or-var)))))
141 (with-current-buffer docbuf
142 (goto-char (point-min))
144 (insert-file-contents-literally
145 (expand-file-name internal-doc-file-name doc-directory)))
146 (let ((file (catch 'loop
148 (let ((pnt (search-forward (concat "
\1f" name "\n"))))
149 (re-search-backward "
\1fS\\(.*\\)")
150 (let ((file (match-string 1)))
151 (if (member file build-files)
153 (goto-char pnt))))))))
154 (if (string-match "^ns.*\\(\\.o\\|obj\\)\\'" file)
155 (setq file (replace-match ".m" t t file 1))
156 (if (string-match "\\.\\(o\\|obj\\)\\'" file)
157 (setq file (replace-match ".c" t t file))))
158 (if (string-match "\\.\\(c\\|m\\)\\'" file)
162 (defcustom help-downcase-arguments nil
163 "If non-nil, argument names in *Help* buffers are downcased."
168 (defun help-highlight-arg (arg)
169 "Highlight ARG as an argument name for a *Help* buffer.
170 Return ARG in face `help-argument-name'; ARG is also downcased
171 if the variable `help-downcase-arguments' is non-nil."
172 (propertize (if help-downcase-arguments (downcase arg) arg)
173 'face 'help-argument-name))
175 (defun help-do-arg-highlight (doc args)
176 (with-syntax-table (make-syntax-table emacs-lisp-mode-syntax-table)
177 (modify-syntax-entry ?\- "w")
178 (dolist (arg args doc)
179 (setq doc (replace-regexp-in-string
180 ;; This is heuristic, but covers all common cases
182 (concat "\\<" ; beginning of word
183 "\\(?:[a-z-]*-\\)?" ; for xxx-ARG
187 "\\(?:es\\|s\\|th\\)?" ; for ARGth, ARGs
188 "\\(?:-[a-z0-9-]+\\)?" ; for ARG-xxx, ARG-n
189 "\\(?:-[{([<`\"].*?\\)?"; for ARG-{x}, (x), <x>, [x], `x'
191 (help-highlight-arg arg)
194 (defun help-highlight-arguments (usage doc &rest args)
195 (when (and usage (string-match "^(" usage))
198 (goto-char (point-min))
199 (let ((case-fold-search nil)
200 (next (not (or args (looking-at "\\["))))
202 ;; Make a list of all arguments
203 (skip-chars-forward "^ ")
205 (or opt (not (looking-at " &")) (setq opt t))
206 (if (not (re-search-forward " \\([\\[(]*\\)\\([^] &)\.]+\\)" nil t))
208 (setq args (cons (match-string 2) args))
209 (when (and opt (string= (match-string 1) "("))
210 ;; A pesky CL-style optional argument with default value,
211 ;; so let's skip over it
212 (search-backward "(")
213 (goto-char (scan-sexps (point) 1)))))
214 ;; Highlight aguments in the USAGE string
215 (setq usage (help-do-arg-highlight (buffer-string) args))
216 ;; Highlight arguments in the DOC string
217 (setq doc (and doc (help-do-arg-highlight doc args))))))
218 ;; Return value is like the one from help-split-fundoc, but highlighted
221 ;; The following function was compiled from the former functions
222 ;; `describe-simplify-lib-file-name' and `find-source-lisp-file' with
223 ;; some excerpts from `describe-function-1' and `describe-variable'.
224 ;; The only additional twists provided are (1) locate the defining file
225 ;; for autoloaded functions, and (2) give preference to files in the
226 ;; "install directory" (directories found via `load-path') rather than
227 ;; to files in the "compile directory" (directories found by searching
228 ;; the loaddefs.el file). We autoload it because it's also used by
229 ;; `describe-face' (instead of `describe-simplify-lib-file-name').
232 (defun find-lisp-object-file-name (object type)
233 "Guess the file that defined the Lisp object OBJECT, of type TYPE.
234 OBJECT should be a symbol associated with a function, variable, or face;
235 alternatively, it can be a function definition.
236 If TYPE is `defvar', search for a variable definition.
237 If TYPE is `defface', search for a face definition.
238 If TYPE is the value returned by `symbol-function' for a function symbol,
239 search for a function definition.
241 The return value is the absolute name of a readable file where OBJECT is
242 defined. If several such files exist, preference is given to a file
243 found via `load-path'. The return value can also be `C-source', which
244 means that OBJECT is a function or variable defined in C. If no
245 suitable file is found, return nil."
246 (let* ((autoloaded (eq (car-safe type) 'autoload))
247 (file-name (or (and autoloaded (nth 1 type))
249 object (if (memq type (list 'defvar 'defface))
254 ;; An autoloaded function: Locate the file since `symbol-function'
255 ;; has only returned a bare string here.
257 (locate-file file-name load-path '(".el" ".elc") 'readable)))
258 ((and (stringp file-name)
259 (string-match "[.]*loaddefs.el\\'" file-name))
260 ;; An autoloaded variable or face. Visit loaddefs.el in a buffer
261 ;; and try to extract the defining file. The following form is
262 ;; from `describe-function-1' and `describe-variable'.
265 (find-function-search-for-symbol object nil file-name)
268 (with-current-buffer (car location)
269 (goto-char (cdr location))
270 (when (re-search-backward
271 "^;;; Generated autoloads from \\(.*\\)" nil t)
274 (file-name-sans-extension
275 (match-string-no-properties 1))
276 load-path '(".el" ".elc") 'readable))))))))
279 ((and (not file-name) (subrp type))
280 ;; A built-in function. The form is from `describe-function-1'.
281 (if (get-buffer " *DOC*")
282 (help-C-file-name type 'subr)
284 ((and (not file-name) (symbolp object)
285 (integerp (get object 'variable-documentation)))
286 ;; A variable defined in C. The form is from `describe-variable'.
287 (if (get-buffer " *DOC*")
288 (help-C-file-name object 'var)
290 ((not (stringp file-name))
291 ;; If we don't have a file-name string by now, we lost.
293 ;; Now, `file-name' should have become an absolute file name.
294 ;; For files loaded from ~/.emacs.elc, try ~/.emacs.
296 (and (string-equal file-name
297 (expand-file-name ".emacs.elc" "~"))
298 (file-readable-p (setq fn (expand-file-name ".emacs" "~")))
300 ;; When the Elisp source file can be found in the install
301 ;; directory, return the name of that file.
303 (if (string-match "[.]elc\\'" file-name)
304 (substring-no-properties file-name 0 -1)
306 (or (and (file-readable-p lib-name) lib-name)
307 ;; The library might be compressed.
308 (and (file-readable-p (concat lib-name ".gz")) lib-name))))
309 ((let* ((lib-name (file-name-nondirectory file-name))
310 ;; The next form is from `describe-simplify-lib-file-name'.
312 ;; Try converting the absolute file name to a library
313 ;; name, convert that back to a file name and see if we
314 ;; get the original one. If so, they are equivalent.
315 (if (equal file-name (locate-file lib-name load-path '("")))
316 (if (string-match "[.]elc\\'" lib-name)
317 (substring-no-properties lib-name 0 -1)
320 ;; The next three forms are from `find-source-lisp-file'.
321 (elc-file (locate-file
323 (if (string-match "\\.el\\'" file-name)
326 load-path nil 'readable))
329 (insert-file-contents-literally elc-file nil 0 256)
332 (string-match ";;; from file \\(.*\\.el\\)" str)
333 (match-string 1 str))))
334 (and src-file (file-readable-p src-file) src-file))))))
336 (declare-function ad-get-advice-info "advice" (function))
339 (defun describe-function-1 (function)
340 (let* ((advised (and (symbolp function) (featurep 'advice)
341 (ad-get-advice-info function)))
342 ;; If the function is advised, use the symbol that has the
343 ;; real definition, if that symbol is already set up.
346 (let ((origname (cdr (assq 'origname advised))))
347 (and (fboundp origname) origname)))
349 ;; Get the real definition.
350 (def (if (symbolp real-function)
351 (symbol-function real-function)
354 (beg (if (commandp def) "an interactive " "a "))
355 (pt1 (with-current-buffer (help-buffer) (point)))
358 (cond ((or (stringp def) (vectorp def))
361 (if (eq 'unevalled (cdr (subr-arity def)))
362 (concat beg "special form")
363 (concat beg "built-in function")))
364 ((byte-code-function-p def)
365 (concat beg "compiled Lisp function"))
367 (while (and (fboundp def)
368 (symbolp (symbol-function def)))
369 (setq def (symbol-function def)))
370 ;; Handle (defalias 'foo 'bar), where bar is undefined.
371 (or (fboundp def) (setq errtype 'alias))
372 (format "an alias for `%s'" def))
373 ((eq (car-safe def) 'lambda)
374 (concat beg "Lisp function"))
375 ((eq (car-safe def) 'macro)
377 ((eq (car-safe def) 'closure)
378 (concat beg "Lisp closure"))
379 ((eq (car-safe def) 'autoload)
380 (format "%s autoloaded %s"
381 (if (commandp def) "an interactive" "an")
382 (if (eq (nth 4 def) 'keymap) "keymap"
383 (if (nth 4 def) "Lisp macro" "Lisp function"))))
386 (elts (cdr-safe def)))
388 (if (char-table-p (car-safe elts))
391 (setq elts (cdr-safe elts)))
397 (if (eq errtype 'alias)
398 (princ ",\nwhich is not defined. Please make a bug report.")
399 (with-current-buffer standard-output
402 (when (re-search-backward "alias for `\\([^`']+\\)'" nil t)
403 (help-xref-button 1 'help-function def)))))
405 (setq file-name (find-lisp-object-file-name function def))
408 ;; We used to add .el to the file name,
409 ;; but that's completely wrong when the user used load-file.
410 (princ (if (eq file-name 'C-source)
412 (file-name-nondirectory file-name)))
414 ;; Make a hyperlink to the library.
415 (with-current-buffer standard-output
417 (re-search-backward "`\\([^`']+\\)'" nil t)
418 (help-xref-button 1 'help-function-def function file-name))))
420 (with-current-buffer (help-buffer)
421 (fill-region-as-paragraph (save-excursion (goto-char pt1) (forward-line 0) (point))
424 (when (commandp function)
425 (let ((pt2 (with-current-buffer (help-buffer) (point)))
426 (remapped (command-remapping function)))
427 (unless (memq remapped '(ignore undefined))
428 (let ((keys (where-is-internal
429 (or remapped function) overriding-local-map nil nil))
431 (if (and (eq function 'self-insert-command)
432 (vectorp (car-safe keys))
433 (consp (aref (car keys) 0)))
434 (princ "It is bound to many ordinary text characters.\n")
435 ;; Which non-control non-meta keys run this command?
437 (if (member (event-modifiers (aref key 0)) '(nil (shift)))
438 (push key non-modified-keys)))
440 (princ "It is remapped to `")
441 (princ (symbol-name remapped))
445 (princ (if remapped ", which is bound to " "It is bound to "))
446 ;; If lots of ordinary text characters run this command,
447 ;; don't mention them one by one.
448 (if (< (length non-modified-keys) 10)
449 (princ (mapconcat 'key-description keys ", "))
450 (dolist (key non-modified-keys)
451 (setq keys (delq key keys)))
454 (princ (mapconcat 'key-description keys ", "))
455 (princ ", and many ordinary text characters"))
456 (princ "many ordinary text characters"))))
457 (when (or remapped keys non-modified-keys)
461 (with-current-buffer (help-buffer)
462 (fill-region-as-paragraph pt2 (point))
463 (unless (looking-back "\n\n")
465 ;; Note that list* etc do not get this property until
466 ;; cl-hack-byte-compiler runs, after bytecomp is loaded.
467 (when (and (symbolp function)
468 (eq (get function 'byte-compile)
469 'cl-byte-compile-compiler-macro))
470 (princ "This function has a compiler macro")
471 (let ((lib (get function 'compiler-macro-file)))
473 (princ (format " in `%s'" lib))
474 (with-current-buffer standard-output
476 (re-search-backward "`\\([^`']+\\)'" nil t)
477 (help-xref-button 1 'help-function-cmacro function lib)))))
479 (let* ((advertised (gethash def advertised-signature-table t))
480 (arglist (if (listp advertised)
481 advertised (help-function-arglist def)))
482 (doc (documentation function))
483 (usage (help-split-fundoc doc function)))
484 (with-current-buffer standard-output
485 ;; If definition is a keymap, skip arglist note.
486 (unless (keymapp function)
487 (if usage (setq doc (cdr usage)))
489 ((and usage (not (listp advertised))) (car usage))
491 (format "%S" (help-make-usage function arglist)))
492 ((stringp arglist) arglist)
493 ;; Maybe the arglist is in the docstring of a symbol
494 ;; this one is aliased to.
495 ((let ((fun real-function))
496 (while (and (symbolp fun)
497 (setq fun (symbol-function fun))
498 (not (setq usage (help-split-fundoc
505 (format "\nMacro: %s" (format-kbd-macro def)))
506 (t "[Missing arglist. Please make a bug report.]")))
507 (high (help-highlight-arguments use doc)))
508 (let ((fill-begin (point)))
509 (insert (car high) "\n")
510 (fill-region fill-begin (point)))
511 (setq doc (cdr high))))
512 (let* ((obsolete (and
513 ;; function might be a lambda construct.
515 (get function 'byte-obsolete-info)))
516 (use (car obsolete)))
518 (princ "\nThis function is obsolete")
519 (when (nth 2 obsolete)
520 (insert (format " since %s" (nth 2 obsolete))))
521 (insert (cond ((stringp use) (concat ";\n" use))
522 (use (format ";\nuse `%s' instead." use))
526 (or doc "Not documented."))))))))
532 (defun variable-at-point (&optional any-symbol)
533 "Return the bound variable symbol found at or before point.
534 Return 0 if there is no such symbol.
535 If ANY-SYMBOL is non-nil, don't insist the symbol be bound."
536 (with-syntax-table emacs-lisp-mode-syntax-table
537 (or (condition-case ()
539 (or (not (zerop (skip-syntax-backward "_w")))
540 (eq (char-syntax (following-char)) ?w)
541 (eq (char-syntax (following-char)) ?_)
543 (skip-chars-forward "'")
544 (let ((obj (read (current-buffer))))
545 (and (symbolp obj) (boundp obj) obj)))
547 (let* ((str (find-tag-default))
548 (sym (if str (intern-soft str))))
549 (if (and sym (or any-symbol (boundp sym)))
552 (when (and str (string-match "\\`\\W*\\(.*?\\)\\W*\\'" str))
553 (setq sym (intern-soft (match-string 1 str)))
554 (and (or any-symbol (boundp sym)) sym)))))
557 (defun describe-variable-custom-version-info (variable)
558 (let ((custom-version (get variable 'custom-version))
559 (cpv (get variable 'custom-package-version))
563 (format "This variable was introduced, or its default value was changed, in\nversion %s of Emacs.\n"
566 (let* ((package (car-safe cpv))
567 (version (if (listp (cdr-safe cpv))
570 (pkg-versions (assq package customize-package-emacs-version-alist))
571 (emacsv (cdr (assoc version pkg-versions))))
572 (if (and package version)
574 (format (concat "This variable was introduced, or its default value was changed, in\nversion %s of the %s package"
576 (format " that is part of Emacs %s" emacsv))
578 version package))))))
582 (defun describe-variable (variable &optional buffer frame)
583 "Display the full documentation of VARIABLE (a symbol).
584 Returns the documentation as a string, also.
585 If VARIABLE has a buffer-local value in BUFFER or FRAME
586 \(default to the current buffer and current frame),
587 it is displayed along with the global value."
589 (let ((v (variable-at-point))
590 (enable-recursive-minibuffers t)
592 (setq val (completing-read (if (symbolp v)
594 "Describe variable (default %s): " v)
595 "Describe variable: ")
599 (get vv 'variable-documentation)))
601 (if (symbolp v) (symbol-name v))))
602 (list (if (equal val "")
605 (unless (buffer-live-p buffer) (setq buffer (current-buffer)))
606 (unless (frame-live-p frame) (setq frame (selected-frame)))
607 (if (not (symbolp variable))
608 (message "You did not specify a variable")
610 (let ((valvoid (not (with-current-buffer buffer (boundp variable))))
611 val val-start-pos locus)
612 ;; Extract the value before setting up the output buffer,
613 ;; in case `buffer' *is* the output buffer.
615 (with-selected-frame frame
616 (with-current-buffer buffer
617 (setq val (symbol-value variable)
618 locus (variable-binding-locus variable)))))
619 (help-setup-xref (list #'describe-variable variable buffer)
620 (called-interactively-p 'interactive))
621 (with-help-window (help-buffer)
622 (with-current-buffer buffer
624 (setq file-name (find-lisp-object-file-name variable 'defvar))
628 (princ " is a variable defined in `")
629 (princ (if (eq file-name 'C-source)
631 (file-name-nondirectory file-name)))
633 (with-current-buffer standard-output
635 (re-search-backward "`\\([^`']+\\)'" nil t)
636 (help-xref-button 1 'help-variable-def
637 variable file-name)))
639 (princ "It is void as a variable.")
642 (princ " is void as a variable.")
645 (with-current-buffer standard-output
646 (setq val-start-pos (point))
648 (let ((from (point)))
651 (if (< (point) (+ 68 (line-beginning-position 0)))
652 (delete-region from (1+ from))
653 (delete-region (1- from) from))
654 (let* ((sv (get variable 'standard-value))
655 (origval (and (consp sv)
658 (error :help-eval-error)))))
659 (when (and (consp sv)
660 (not (equal origval val))
661 (not (equal origval :help-eval-error)))
662 (princ "\nOriginal value was \n")
665 (if (< (point) (+ from 20))
666 (delete-region (1- from) from)))))))
670 (princ (format "%socal in buffer %s; "
671 (if (get variable 'permanent-local)
674 (princ (format "It is a frame-local variable; ")))
675 (if (not (default-boundp variable))
676 (princ "globally void")
677 (let ((val (default-value variable)))
678 (with-current-buffer standard-output
679 (princ "global value is ")
681 ;; Fixme: pp can take an age if you happen to
682 ;; ask for a very large expression. We should
683 ;; probably print it raw once and check it's a
684 ;; sensible size before prettyprinting. -- fx
685 (let ((from (point)))
687 ;; See previous comment for this function.
688 ;; (help-xref-on-pp from (point))
689 (if (< (point) (+ from 20))
690 (delete-region (1- from) from))))))
693 ;; If the value is large, move it to the end.
694 (with-current-buffer standard-output
695 (when (> (count-lines (point-min) (point-max)) 10)
696 ;; Note that setting the syntax table like below
697 ;; makes forward-sexp move over a `'s' at the end
699 (set-syntax-table emacs-lisp-mode-syntax-table)
700 (goto-char val-start-pos)
701 ;; The line below previously read as
702 ;; (delete-region (point) (progn (end-of-line) (point)))
703 ;; which suppressed display of the buffer local value for
705 (when (looking-at "value is") (replace-match ""))
707 (insert "\n\nValue:")
708 (set (make-local-variable 'help-button-cache)
710 (insert "value is shown ")
711 (insert-button "below"
712 'action help-button-cache
714 'help-echo "mouse-2, RET: show value")
718 (let* ((alias (condition-case nil
719 (indirect-variable variable)
721 (obsolete (get variable 'byte-obsolete-variable))
723 (safe-var (get variable 'safe-local-variable))
724 (doc (or (documentation-property variable 'variable-documentation)
725 (documentation-property alias 'variable-documentation)))
727 ;; Add a note for variables that have been make-var-buffer-local.
728 (when (and (local-variable-if-set-p variable)
729 (or (not (local-variable-p variable))
731 (local-variable-if-set-p variable))))
733 (princ " Automatically becomes buffer-local when set in any fashion.\n"))
735 ;; Mention if it's an alias
736 (unless (eq alias variable)
738 (princ (format " This variable is an alias for `%s'.\n" alias)))
742 (princ " This variable is obsolete")
743 (if (cdr obsolete) (princ (format " since %s" (cdr obsolete))))
744 (princ (cond ((stringp use) (concat ";\n " use))
745 (use (format ";\n use `%s' instead." (car obsolete)))
749 (when (member (cons variable val) file-local-variables-alist)
751 (if (member (cons variable val) dir-local-variables-alist)
752 (let ((file (and (buffer-file-name)
753 (not (file-remote-p (buffer-file-name)))
754 (dir-locals-find-file (buffer-file-name)))))
755 (princ " This variable is a directory local variable")
757 (princ (concat "\n from the file \""
763 (princ " This variable is a file local variable.\n")))
765 (when (memq variable ignored-local-variables)
767 (princ " This variable is ignored when used as a file local \
770 ;; Can be both risky and safe, eg auto-fill-function.
771 (when (risky-local-variable-p variable)
773 (princ " This variable is potentially risky when used as a \
774 file local variable.\n")
775 (when (assq variable safe-local-variable-values)
776 (princ " However, you have added it to \
777 `safe-local-variable-values'.\n")))
781 (princ " This variable is safe as a file local variable ")
782 (princ "if its value\n satisfies the predicate ")
783 (princ (if (byte-code-function-p safe-var)
784 "which is byte-compiled expression.\n"
785 (format "`%s'.\n" safe-var))))
787 (if extra-line (terpri))
788 (princ "Documentation:\n")
789 (with-current-buffer standard-output
790 (insert (or doc "Not documented as a variable."))))
792 ;; Make a link to customize if this variable can be customized.
793 (when (custom-variable-p variable)
794 (let ((customize-label "customize"))
797 (princ (concat "You can " customize-label " this variable."))
798 (with-current-buffer standard-output
801 (concat "\\(" customize-label "\\)") nil t)
802 (help-xref-button 1 'help-customize-variable variable))))
803 ;; Note variable's version or package version
804 (let ((output (describe-variable-custom-version-info variable)))
810 (with-current-buffer standard-output
811 ;; Return the text we displayed.
812 (buffer-string))))))))
816 (defun describe-syntax (&optional buffer)
817 "Describe the syntax specifications in the syntax table of BUFFER.
818 The descriptions are inserted in a help buffer, which is then displayed.
819 BUFFER defaults to the current buffer."
821 (setq buffer (or buffer (current-buffer)))
822 (help-setup-xref (list #'describe-syntax buffer)
823 (called-interactively-p 'interactive))
824 (with-help-window (help-buffer)
825 (let ((table (with-current-buffer buffer (syntax-table))))
826 (with-current-buffer standard-output
827 (describe-vector table 'internal-describe-syntax-value)
828 (while (setq table (char-table-parent table))
829 (insert "\nThe parent syntax table is:")
830 (describe-vector table 'internal-describe-syntax-value))))))
832 (defun help-describe-category-set (value)
834 ((null value) "default")
835 ((char-table-p value) "deeper char-table ...")
836 (t (condition-case err
837 (category-set-mnemonics value)
838 (error "invalid"))))))
841 (defun describe-categories (&optional buffer)
842 "Describe the category specifications in the current category table.
843 The descriptions are inserted in a buffer, which is then displayed.
844 If BUFFER is non-nil, then describe BUFFER's category table instead.
845 BUFFER should be a buffer or a buffer name."
847 (setq buffer (or buffer (current-buffer)))
848 (help-setup-xref (list #'describe-categories buffer)
849 (called-interactively-p 'interactive))
850 (with-help-window (help-buffer)
851 (let* ((table (with-current-buffer buffer (category-table)))
852 (docs (char-table-extra-slot table 0)))
853 (if (or (not (vectorp docs)) (/= (length docs) 95))
854 (error "Invalid first extra slot in this category table\n"))
855 (with-current-buffer standard-output
856 (insert "Legend of category mnemonics (see the tail for the longer description)\n")
857 (let ((pos (point)) (items 0) lines n)
859 (if (aref docs i) (setq items (1+ items))))
860 (setq lines (1+ (/ (1- items) 4)))
863 (let ((elt (aref docs i)))
865 (string-match ".*" elt)
866 (setq elt (match-string 0 elt))
867 (if (>= (length elt) 17)
868 (setq elt (concat (substring elt 0 14) "...")))
869 (if (< (point) (point-max))
870 (move-to-column (* 20 (/ n lines)) t))
871 (insert (+ i ?\s) ?: elt)
872 (if (< (point) (point-max))
876 (if (= (% n lines) 0)
878 (goto-char (point-max))
880 "character(s)\tcategory mnemonics\n"
881 "------------\t------------------")
882 (describe-vector table 'help-describe-category-set)
883 (insert "Legend of category mnemonics:\n")
885 (let ((elt (aref docs i)))
887 (if (string-match "\n" elt)
888 (setq elt (substring elt (match-end 0))))
889 (insert (+ i ?\s) ": " elt "\n"))))
890 (while (setq table (char-table-parent table))
891 (insert "\nThe parent category table is:")
892 (describe-vector table 'help-describe-category-set))))))
895 ;;; Replacements for old lib-src/ programs. Don't seem especially useful.
897 ;; Replaces lib-src/digest-doc.c.
899 (defun doc-file-to-man (file)
900 "Produce an nroff buffer containing the doc-strings from the DOC file."
901 (interactive (list (read-file-name "Name of DOC file: " doc-directory
902 internal-doc-file-name t)))
903 (or (file-readable-p file)
904 (error "Cannot read file `%s'" file))
905 (pop-to-buffer (generate-new-buffer "*man-doc*"))
906 (setq buffer-undo-list t)
907 (insert ".TH \"Command Summary for GNU Emacs\"\n"
908 ".AU Richard M. Stallman\n")
909 (insert-file-contents file)
911 (while (search-forward "
\1f" nil 'move)
913 (delete-region (1- (point)) (line-end-position))
919 (insert (if (looking-at "F") "Function " "Variable "))
922 (insert ".DS L\n"))))
924 (setq buffer-undo-list nil)
927 ;; Replaces lib-src/sorted-doc.c.
929 (defun doc-file-to-info (file)
930 "Produce a texinfo buffer with sorted doc-strings from the DOC file."
931 (interactive (list (read-file-name "Name of DOC file: " doc-directory
932 internal-doc-file-name t)))
933 (or (file-readable-p file)
934 (error "Cannot read file `%s'" file))
935 (let ((i 0) type name doc alist)
937 (insert-file-contents file)
938 ;; The characters "@{}" need special treatment.
939 (while (re-search-forward "[@{}]" nil t)
943 (goto-char (point-min))
944 (while (search-forward "
\1f" nil t)
945 (unless (looking-at "S")
946 (setq type (char-after)
947 name (buffer-substring (1+ (point)) (line-end-position))
948 doc (buffer-substring (line-beginning-position 2)
949 (if (search-forward "
\1f" nil 'move)
952 alist (cons (list name type doc) alist))
954 (pop-to-buffer (generate-new-buffer "*info-doc*"))
955 (setq buffer-undo-list t)
956 ;; Write the output header.
957 (insert "\\input texinfo @c -*-texinfo-*-\n"
958 "@setfilename emacsdoc.info\n"
959 "@settitle Command Summary for GNU Emacs\n"
962 "@unnumbered Command Summary for GNU Emacs\n\n"
965 "@global@let@ITEM@item\n"
966 "@def@item{@filbreak@vskip5pt@ITEM}\n"
967 "@font@tensy cmsy10 scaled @magstephalf\n"
968 "@font@teni cmmi10 scaled @magstephalf\n"
969 "@def\\{{@tensy@char110}}\n" ; this backslash goes with cmr10
970 "@def|{{@tensy@char106}}\n"
971 "@def@{{{@tensy@char102}}\n"
972 "@def@}{{@tensy@char103}}\n"
973 "@def<{{@teni@char62}}\n"
974 "@def>{{@teni@char60}}\n"
977 "@tableindent-0.2in\n"
979 ;; Sort the array by name; within each name, by type (functions first).
980 (setq alist (sort alist (lambda (e1 e2)
981 (if (string-equal (car e1) (car e2))
982 (<= (cadr e1) (cadr e2))
983 (string-lessp (car e1) (car e2))))))
984 ;; Print each function.
987 (if (char-equal (cadr e) ?\F) "Function" "Variable")
988 " @code{" (car e) "}\n@display\n"
991 ;; Try to avoid a save size overflow in the TeX output routine.
992 (if (zerop (setq i (% (1+ i) 100)))
993 (insert "\n@end table\n@table @asis\n")))
994 (insert "@end table\n"
996 (setq buffer-undo-list nil)
1001 ;;; help-fns.el ends here