1 ;;; help-fns.el --- Complex help functions
3 ;; Copyright (C) 1985, 1986, 1993, 1994, 1998, 1999, 2000, 2001,
4 ;; 2002, 2003, 2004, 2005, 2006, 2007, 2008 Free Software Foundation, Inc.
7 ;; Keywords: help, internal
9 ;; This file is part of GNU Emacs.
11 ;; GNU Emacs is free software: you can redistribute it and/or modify
12 ;; it under the terms of the GNU General Public License as published by
13 ;; the Free Software Foundation, either version 3 of the License, or
14 ;; (at your option) any later version.
16 ;; GNU Emacs is distributed in the hope that it will be useful,
17 ;; but WITHOUT ANY WARRANTY; without even the implied warranty of
18 ;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
19 ;; GNU General Public License for more details.
21 ;; You should have received a copy of the GNU General Public License
22 ;; along with GNU Emacs. If not, see <http://www.gnu.org/licenses/>.
26 ;; This file contains those help commands which are complicated, and
27 ;; which may not be used in every session. For example
28 ;; `describe-function' will probably be heavily used when doing elisp
29 ;; programming, but not if just editing C files. Simpler help commands
39 (defun describe-function (function)
40 "Display the full documentation of FUNCTION (a symbol)."
42 (let ((fn (function-called-at-point))
43 (enable-recursive-minibuffers t
)
45 (setq val
(completing-read (if fn
46 (format "Describe function (default %s): " fn
)
47 "Describe function: ")
48 obarray
'fboundp t nil nil
49 (and fn
(symbol-name fn
))))
50 (list (if (equal val
"")
53 (message "You didn't specify a function")
54 (help-setup-xref (list #'describe-function function
) (interactive-p))
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
)))
104 ((byte-code-function-p def
) (aref def
0))
105 ((eq (car-safe def
) 'lambda
) (nth 1 def
))
106 ((and (eq (car-safe def
) 'autoload
) (not (eq (nth 4 def
) 'keymap
)))
107 "[Arg list not available until function definition is loaded.]")
110 (defun help-make-usage (function arglist
)
111 (cons (if (symbolp function
) function
'anonymous
)
112 (mapcar (lambda (arg)
113 (if (not (symbolp arg
))
114 (if (and (consp arg
) (symbolp (car arg
)))
115 ;; CL style default values for optional args.
116 (cons (intern (upcase (symbol-name (car arg
))))
119 (let ((name (symbol-name arg
)))
120 (if (string-match "\\`&" name
) arg
121 (intern (upcase name
))))))
124 ;; Could be this, if we make symbol-file do the work below.
125 ;; (defun help-C-file-name (subr-or-var kind)
126 ;; "Return the name of the C file where SUBR-OR-VAR is defined.
127 ;; KIND should be `var' for a variable or `subr' for a subroutine."
128 ;; (symbol-file (if (symbolp subr-or-var) subr-or-var
129 ;; (subr-name subr-or-var))
130 ;; (if (eq kind 'var) 'defvar 'defun)))
132 (defun help-C-file-name (subr-or-var kind
)
133 "Return the name of the C file where SUBR-OR-VAR is defined.
134 KIND should be `var' for a variable or `subr' for a subroutine."
135 (let ((docbuf (get-buffer-create " *DOC*"))
136 (name (if (eq 'var kind
)
137 (concat "V" (symbol-name subr-or-var
))
138 (concat "F" (subr-name subr-or-var
)))))
139 (with-current-buffer docbuf
140 (goto-char (point-min))
142 (insert-file-contents-literally
143 (expand-file-name internal-doc-file-name doc-directory
)))
144 (let ((file (catch 'loop
146 (let ((pnt (search-forward (concat "\x1f" name
"\n"))))
147 (re-search-backward "\x1fS\\(.*\\)")
148 (let ((file (match-string 1)))
149 (if (member file build-files
)
151 (goto-char pnt
))))))))
152 (if (string-match "^ns.*\\(\\.o\\|obj\\)\\'" file
)
153 (setq file
(replace-match ".m" t t file
1))
154 (if (string-match "\\.\\(o\\|obj\\)\\'" file
)
155 (setq file
(replace-match ".c" t t file
))))
156 (if (string-match "\\.\\(c\\|m\\)\\'" file
)
160 (defface help-argument-name
'((((supports :slant italic
)) :inherit italic
))
161 "Face to highlight argument names in *Help* buffers."
164 (defun help-default-arg-highlight (arg)
165 "Default function to highlight arguments in *Help* buffers.
166 It returns ARG in face `help-argument-name'; ARG is also
167 downcased if it displays differently than the default
168 face (according to `face-differs-from-default-p')."
169 (propertize (if (face-differs-from-default-p 'help-argument-name
)
172 'face
'help-argument-name
))
174 (defun help-do-arg-highlight (doc args
)
175 (with-syntax-table (make-syntax-table emacs-lisp-mode-syntax-table
)
176 (modify-syntax-entry ?\-
"w")
177 (dolist (arg args doc
)
178 (setq doc
(replace-regexp-in-string
179 ;; This is heuristic, but covers all common cases
181 (concat "\\<" ; beginning of word
182 "\\(?:[a-z-]*-\\)?" ; for xxx-ARG
186 "\\(?:es\\|s\\|th\\)?" ; for ARGth, ARGs
187 "\\(?:-[a-z0-9-]+\\)?" ; for ARG-xxx, ARG-n
188 "\\(?:-[{([<`\"].*?\\)?"; for ARG-{x}, (x), <x>, [x], `x'
190 (help-default-arg-highlight arg
)
193 (defun help-highlight-arguments (usage doc
&rest args
)
197 (goto-char (point-min))
198 (let ((case-fold-search nil
)
199 (next (not (or args
(looking-at "\\["))))
201 ;; Make a list of all arguments
202 (skip-chars-forward "^ ")
204 (or opt
(not (looking-at " &")) (setq opt t
))
205 (if (not (re-search-forward " \\([\\[(]*\\)\\([^] &)\.]+\\)" nil t
))
207 (setq args
(cons (match-string 2) args
))
208 (when (and opt
(string= (match-string 1) "("))
209 ;; A pesky CL-style optional argument with default value,
210 ;; so let's skip over it
211 (search-backward "(")
212 (goto-char (scan-sexps (point) 1)))))
213 ;; Highlight aguments in the USAGE string
214 (setq usage
(help-do-arg-highlight (buffer-string) args
))
215 ;; Highlight arguments in the DOC string
216 (setq doc
(and doc
(help-do-arg-highlight doc args
))))))
217 ;; Return value is like the one from help-split-fundoc, but highlighted
220 ;; The following function was compiled from the former functions
221 ;; `describe-simplify-lib-file-name' and `find-source-lisp-file' with
222 ;; some excerpts from `describe-function-1' and `describe-variable'.
223 ;; The only additional twists provided are (1) locate the defining file
224 ;; for autoloaded functions, and (2) give preference to files in the
225 ;; "install directory" (directories found via `load-path') rather than
226 ;; to files in the "compile directory" (directories found by searching
227 ;; the loaddefs.el file). We autoload it because it's also used by
228 ;; `describe-face' (instead of `describe-simplify-lib-file-name').
231 (defun find-lisp-object-file-name (object type
)
232 "Guess the file that defined the Lisp object OBJECT, of type TYPE.
233 OBJECT should be a symbol associated with a function, variable, or face;
234 alternatively, it can be a function definition.
235 If TYPE is `variable', search for a variable definition.
236 If TYPE is `face', search for a face definition.
237 If TYPE is the value returned by `symbol-function' for a function symbol,
238 search for a function definition.
240 The return value is the absolute name of a readable file where OBJECT is
241 defined. If several such files exist, preference is given to a file
242 found via `load-path'. The return value can also be `C-source', which
243 means that OBJECT is a function or variable defined in C. If no
244 suitable file is found, return nil."
245 (let* ((autoloaded (eq (car-safe type
) 'autoload
))
246 (file-name (or (and autoloaded
(nth 1 type
))
248 object
(if (memq type
(list 'defvar
'defface
))
253 ;; An autoloaded function: Locate the file since `symbol-function'
254 ;; has only returned a bare string here.
256 (locate-file file-name load-path
'(".el" ".elc") 'readable
)))
257 ((and (stringp file-name
)
258 (string-match "[.]*loaddefs.el\\'" file-name
))
259 ;; An autoloaded variable or face. Visit loaddefs.el in a buffer
260 ;; and try to extract the defining file. The following form is
261 ;; from `describe-function-1' and `describe-variable'.
264 (find-function-search-for-symbol object nil file-name
)
267 (with-current-buffer (car location
)
268 (goto-char (cdr location
))
269 (when (re-search-backward
270 "^;;; Generated autoloads from \\(.*\\)" nil t
)
273 (match-string-no-properties 1)
274 load-path nil
'readable
))))))))
277 ((and (not file-name
) (subrp type
))
278 ;; A built-in function. The form is from `describe-function-1'.
279 (if (get-buffer " *DOC*")
280 (help-C-file-name type
'subr
)
282 ((and (not file-name
) (symbolp object
)
283 (integerp (get object
'variable-documentation
)))
284 ;; A variable defined in C. The form is from `describe-variable'.
285 (if (get-buffer " *DOC*")
286 (help-C-file-name object
'var
)
288 ((not (stringp file-name
))
289 ;; If we don't have a file-name string by now, we lost.
292 (if (string-match "[.]elc\\'" file-name
)
293 (substring-no-properties file-name
0 -
1)
295 ;; When the Elisp source file can be found in the install
296 ;; directory return the name of that file - `file-name' should
297 ;; have become an absolute file name ny now.
298 (or (and (file-readable-p lib-name
) lib-name
)
299 ;; The library might be compressed.
300 (and (file-readable-p (concat lib-name
".gz")) lib-name
))))
301 ((let* ((lib-name (file-name-nondirectory file-name
))
302 ;; The next form is from `describe-simplify-lib-file-name'.
304 ;; Try converting the absolute file name to a library
305 ;; name, convert that back to a file name and see if we
306 ;; get the original one. If so, they are equivalent.
307 (if (equal file-name
(locate-file lib-name load-path
'("")))
308 (if (string-match "[.]elc\\'" lib-name
)
309 (substring-no-properties lib-name
0 -
1)
312 ;; The next three forms are from `find-source-lisp-file'.
313 (elc-file (locate-file
315 (if (string-match "\\.el\\'" file-name
)
318 load-path nil
'readable
))
321 (insert-file-contents-literally elc-file nil
0 256)
324 (string-match ";;; from file \\(.*\\.el\\)" str
)
325 (match-string 1 str
))))
326 (and src-file
(file-readable-p src-file
) src-file
))))))
328 (declare-function ad-get-advice-info
"advice" (function))
331 (defun describe-function-1 (function)
332 (let* ((advised (and (symbolp function
) (featurep 'advice
)
333 (ad-get-advice-info function
)))
334 ;; If the function is advised, use the symbol that has the
335 ;; real definition, if that symbol is already set up.
338 (let ((origname (cdr (assq 'origname advised
))))
339 (and (fboundp origname
) origname
)))
341 ;; Get the real definition.
342 (def (if (symbolp real-function
)
343 (symbol-function real-function
)
346 (beg (if (commandp def
) "an interactive " "a "))
347 (pt1 (with-current-buffer (help-buffer) (point)))
350 (cond ((or (stringp def
)
354 (if (eq 'unevalled
(cdr (subr-arity def
)))
355 (concat beg
"special form")
356 (concat beg
"built-in function")))
357 ((byte-code-function-p def
)
358 (concat beg
"compiled Lisp function"))
360 (while (and (fboundp def
)
361 (symbolp (symbol-function def
)))
362 (setq def
(symbol-function def
)))
363 ;; Handle (defalias 'foo 'bar), where bar is undefined.
364 (or (fboundp def
) (setq errtype
'alias
))
365 (format "an alias for `%s'" def
))
366 ((eq (car-safe def
) 'lambda
)
367 (concat beg
"Lisp function"))
368 ((eq (car-safe def
) 'macro
)
370 ((eq (car-safe def
) 'autoload
)
371 (format "%s autoloaded %s"
372 (if (commandp def
) "an interactive" "an")
373 (if (eq (nth 4 def
) 'keymap
) "keymap"
374 (if (nth 4 def
) "Lisp macro" "Lisp function"))))
377 (elts (cdr-safe def
)))
379 (if (char-table-p (car-safe elts
))
382 (setq elts
(cdr-safe elts
)))
388 (if (eq errtype
'alias
)
389 (princ ",\nwhich is not defined. Please make a bug report.")
390 (with-current-buffer standard-output
393 (when (re-search-backward "alias for `\\([^`']+\\)'" nil t
)
394 (help-xref-button 1 'help-function def
)))))
396 (setq file-name
(find-lisp-object-file-name function def
))
399 ;; We used to add .el to the file name,
400 ;; but that's completely wrong when the user used load-file.
401 (princ (if (eq file-name
'C-source
) "C source code" file-name
))
403 ;; Make a hyperlink to the library.
404 (with-current-buffer standard-output
406 (re-search-backward "`\\([^`']+\\)'" nil t
)
407 (help-xref-button 1 'help-function-def real-function file-name
))))
409 (with-current-buffer (help-buffer)
410 (fill-region-as-paragraph (save-excursion (goto-char pt1
) (forward-line 0) (point))
413 (when (commandp function
)
414 (let ((pt2 (with-current-buffer (help-buffer) (point))))
415 (if (and (eq function
'self-insert-command
)
416 (eq (key-binding "a") 'self-insert-command
)
417 (eq (key-binding "b") 'self-insert-command
)
418 (eq (key-binding "c") 'self-insert-command
))
419 (princ "It is bound to many ordinary text characters.\n")
420 (let* ((remapped (command-remapping function
))
421 (keys (where-is-internal
422 (or remapped function
) overriding-local-map nil nil
))
424 ;; Which non-control non-meta keys run this command?
426 (if (member (event-modifiers (aref key
0)) '(nil (shift)))
427 (push key non-modified-keys
)))
429 (princ "It is remapped to `")
430 (princ (symbol-name remapped
))
434 (princ (if remapped
", which is bound to " "It is bound to "))
435 ;; If lots of ordinary text characters run this command,
436 ;; don't mention them one by one.
437 (if (< (length non-modified-keys
) 10)
438 (princ (mapconcat 'key-description keys
", "))
439 (dolist (key non-modified-keys
)
440 (setq keys
(delq key keys
)))
443 (princ (mapconcat 'key-description keys
", "))
444 (princ ", and many ordinary text characters"))
445 (princ "many ordinary text characters"))))
446 (when (or remapped keys non-modified-keys
)
449 (with-current-buffer (help-buffer)
450 (fill-region-as-paragraph pt2
(point))
451 (unless (looking-back "\n\n")
453 (let* ((arglist (help-function-arglist def
))
454 (doc (documentation function
))
455 (usage (help-split-fundoc doc function
)))
456 (with-current-buffer standard-output
457 ;; If definition is a keymap, skip arglist note.
458 (unless (keymapp function
)
460 (usage (setq doc
(cdr usage
)) (car usage
))
462 (format "%S" (help-make-usage function arglist
)))
463 ((stringp arglist
) arglist
)
464 ;; Maybe the arglist is in the docstring of a symbol
465 ;; this one is aliased to.
466 ((let ((fun real-function
))
467 (while (and (symbolp fun
)
468 (setq fun
(symbol-function fun
))
469 (not (setq usage
(help-split-fundoc
476 (format "\nMacro: %s" (format-kbd-macro def
)))
477 (t "[Missing arglist. Please make a bug report.]")))
478 (high (help-highlight-arguments use doc
)))
479 (let ((fill-begin (point)))
480 (insert (car high
) "\n")
481 (fill-region fill-begin
(point)))
482 (setq doc
(cdr high
))))
483 (let* ((obsolete (and
484 ;; function might be a lambda construct.
486 (get function
'byte-obsolete-info
)))
487 (use (car obsolete
)))
489 (princ "\nThis function is obsolete")
490 (when (nth 2 obsolete
)
491 (insert (format " since %s" (nth 2 obsolete
))))
492 (insert (cond ((stringp use
) (concat ";\n" use
))
493 (use (format ";\nuse `%s' instead." use
))
497 (or doc
"Not documented."))))))))
503 (defun variable-at-point (&optional any-symbol
)
504 "Return the bound variable symbol found at or before point.
505 Return 0 if there is no such symbol.
506 If ANY-SYMBOL is non-nil, don't insist the symbol be bound."
507 (with-syntax-table emacs-lisp-mode-syntax-table
508 (or (condition-case ()
510 (or (not (zerop (skip-syntax-backward "_w")))
511 (eq (char-syntax (following-char)) ?w
)
512 (eq (char-syntax (following-char)) ?_
)
514 (skip-chars-forward "'")
515 (let ((obj (read (current-buffer))))
516 (and (symbolp obj
) (boundp obj
) obj
)))
518 (let* ((str (find-tag-default))
519 (sym (if str
(intern-soft str
))))
520 (if (and sym
(or any-symbol
(boundp sym
)))
523 (when (and str
(string-match "\\`\\W*\\(.*?\\)\\W*\\'" str
))
524 (setq sym
(intern-soft (match-string 1 str
)))
525 (and (or any-symbol
(boundp sym
)) sym
)))))
528 (defun describe-variable-custom-version-info (variable)
529 (let ((custom-version (get variable
'custom-version
))
530 (cpv (get variable
'custom-package-version
))
534 (format "This variable was introduced, or its default value was changed, in\nversion %s of Emacs.\n"
537 (let* ((package (car-safe cpv
))
538 (version (if (listp (cdr-safe cpv
))
541 (pkg-versions (assq package customize-package-emacs-version-alist
))
542 (emacsv (cdr (assoc version pkg-versions
))))
543 (if (and package version
)
545 (format (concat "This variable was introduced, or its default value was changed, in\nversion %s of the %s package"
547 (format " that is part of Emacs %s" emacsv
))
549 version package
))))))
553 (defun describe-variable (variable &optional buffer frame
)
554 "Display the full documentation of VARIABLE (a symbol).
555 Returns the documentation as a string, also.
556 If VARIABLE has a buffer-local value in BUFFER or FRAME
557 \(default to the current buffer and current frame),
558 it is displayed along with the global value."
560 (let ((v (variable-at-point))
561 (enable-recursive-minibuffers t
)
563 (setq val
(completing-read (if (symbolp v
)
565 "Describe variable (default %s): " v
)
566 "Describe variable: ")
570 (get vv
'variable-documentation
)))
572 (if (symbolp v
) (symbol-name v
))))
573 (list (if (equal val
"")
576 (unless (buffer-live-p buffer
) (setq buffer
(current-buffer)))
577 (unless (frame-live-p frame
) (setq frame
(selected-frame)))
578 (if (not (symbolp variable
))
579 (message "You did not specify a variable")
581 (let ((valvoid (not (with-current-buffer buffer
(boundp variable
))))
582 val val-start-pos locus
)
583 ;; Extract the value before setting up the output buffer,
584 ;; in case `buffer' *is* the output buffer.
586 (with-selected-frame frame
587 (with-current-buffer buffer
588 (setq val
(symbol-value variable
)
589 locus
(variable-binding-locus variable
)))))
590 (help-setup-xref (list #'describe-variable variable buffer
)
592 (with-help-window (help-buffer)
593 (with-current-buffer buffer
595 (setq file-name
(find-lisp-object-file-name variable
'defvar
))
599 (princ " is a variable defined in `")
600 (princ (if (eq file-name
'C-source
) "C source code" file-name
))
602 (with-current-buffer standard-output
604 (re-search-backward "`\\([^`']+\\)'" nil t
)
605 (help-xref-button 1 'help-variable-def
606 variable file-name
)))
608 (princ "It is void as a variable.")
611 (princ " is void as a variable.")
615 (with-current-buffer standard-output
616 (setq val-start-pos
(point))
619 (let ((from (point)))
621 ;; Hyperlinks in variable's value are quite frequently
622 ;; inappropriate e.g C-h v <RET> features <RET>
623 ;; (help-xref-on-pp from (point))
624 (if (< (point) (+ from
20))
625 (delete-region (1- from
) from
)))))
630 (princ (format "%socal in buffer %s; "
631 (if (get variable
'permanent-local
)
634 (princ (format "It is a frame-local variable; ")))
635 (if (not (default-boundp variable
))
636 (princ "globally void")
637 (let ((val (default-value variable
)))
638 (with-current-buffer standard-output
639 (princ "global value is ")
641 ;; Fixme: pp can take an age if you happen to
642 ;; ask for a very large expression. We should
643 ;; probably print it raw once and check it's a
644 ;; sensible size before prettyprinting. -- fx
645 (let ((from (point)))
647 ;; See previous comment for this function.
648 ;; (help-xref-on-pp from (point))
649 (if (< (point) (+ from
20))
650 (delete-region (1- from
) from
))))))
653 ;; If the value is large, move it to the end.
654 (with-current-buffer standard-output
655 (when (> (count-lines (point-min) (point-max)) 10)
656 ;; Note that setting the syntax table like below
657 ;; makes forward-sexp move over a `'s' at the end
659 (set-syntax-table emacs-lisp-mode-syntax-table
)
660 (goto-char val-start-pos
)
661 ;; The line below previously read as
662 ;; (delete-region (point) (progn (end-of-line) (point)))
663 ;; which suppressed display of the buffer local value for
665 (when (looking-at "value is") (replace-match ""))
667 (insert "\n\nValue:")
668 (set (make-local-variable 'help-button-cache
)
670 (insert "value is shown ")
671 (insert-button "below"
672 'action help-button-cache
674 'help-echo
"mouse-2, RET: show value")
678 (let* ((alias (condition-case nil
679 (indirect-variable variable
)
681 (obsolete (get variable
'byte-obsolete-variable
))
683 (safe-var (get variable
'safe-local-variable
))
684 (doc (or (documentation-property variable
'variable-documentation
)
685 (documentation-property alias
'variable-documentation
)))
687 ;; Add a note for variables that have been make-var-buffer-local.
688 (when (and (local-variable-if-set-p variable
)
689 (or (not (local-variable-p variable
))
691 (local-variable-if-set-p variable
))))
693 (princ " Automatically becomes buffer-local when set in any fashion.\n"))
695 ;; Mention if it's an alias
696 (unless (eq alias variable
)
698 (princ (format " This variable is an alias for `%s'.\n" alias
)))
702 (princ " This variable is obsolete")
703 (if (cdr obsolete
) (princ (format " since %s" (cdr obsolete
))))
704 (princ (cond ((stringp use
) (concat ";\n " use
))
705 (use (format ";\n use `%s' instead." (car obsolete
)))
710 (princ " This variable is safe as a file local variable ")
711 (princ "if its value\n satisfies the predicate ")
712 (princ (if (byte-code-function-p safe-var
)
713 "which is byte-compiled expression.\n"
714 (format "`%s'.\n" safe-var
))))
716 (if extra-line
(terpri))
717 (princ "Documentation:\n")
718 (with-current-buffer standard-output
719 (insert (or doc
"Not documented as a variable."))))
721 ;; Make a link to customize if this variable can be customized.
722 (when (custom-variable-p variable
)
723 (let ((customize-label "customize"))
726 (princ (concat "You can " customize-label
" this variable."))
727 (with-current-buffer standard-output
730 (concat "\\(" customize-label
"\\)") nil t
)
731 (help-xref-button 1 'help-customize-variable variable
))))
732 ;; Note variable's version or package version
733 (let ((output (describe-variable-custom-version-info variable
)))
740 (set-buffer standard-output
)
741 ;; Return the text we displayed.
742 (buffer-string))))))))
746 (defun describe-syntax (&optional buffer
)
747 "Describe the syntax specifications in the syntax table of BUFFER.
748 The descriptions are inserted in a help buffer, which is then displayed.
749 BUFFER defaults to the current buffer."
751 (setq buffer
(or buffer
(current-buffer)))
752 (help-setup-xref (list #'describe-syntax buffer
) (interactive-p))
753 (with-help-window (help-buffer)
754 (let ((table (with-current-buffer buffer
(syntax-table))))
755 (with-current-buffer standard-output
756 (describe-vector table
'internal-describe-syntax-value
)
757 (while (setq table
(char-table-parent table
))
758 (insert "\nThe parent syntax table is:")
759 (describe-vector table
'internal-describe-syntax-value
))))))
761 (defun help-describe-category-set (value)
763 ((null value
) "default")
764 ((char-table-p value
) "deeper char-table ...")
765 (t (condition-case err
766 (category-set-mnemonics value
)
767 (error "invalid"))))))
770 (defun describe-categories (&optional buffer
)
771 "Describe the category specifications in the current category table.
772 The descriptions are inserted in a buffer, which is then displayed.
773 If BUFFER is non-nil, then describe BUFFER's category table instead.
774 BUFFER should be a buffer or a buffer name."
776 (setq buffer
(or buffer
(current-buffer)))
777 (help-setup-xref (list #'describe-categories buffer
) (interactive-p))
778 (with-help-window (help-buffer)
779 (let ((table (with-current-buffer buffer
(category-table))))
780 (with-current-buffer standard-output
781 (describe-vector table
'help-describe-category-set
)
782 (let ((docs (char-table-extra-slot table
0)))
783 (if (or (not (vectorp docs
)) (/= (length docs
) 95))
784 (insert "Invalid first extra slot in this char table\n")
785 (insert "Meanings of mnemonic characters are:\n")
787 (let ((elt (aref docs i
)))
789 (insert (+ i ?\s
) ": " elt
"\n"))))
790 (while (setq table
(char-table-parent table
))
791 (insert "\nThe parent category table is:")
792 (describe-vector table
'help-describe-category-set
))))))))
796 ;; arch-tag: 9e10331c-ae81-4d13-965d-c4819aaab0b3
797 ;;; help-fns.el ends here