1 ;;; help-fns.el --- Complex help functions
3 ;; Copyright (C) 1985, 1986, 1993, 1994, 1998, 1999, 2000, 2001, 2002,
4 ;; 2003, 2004, 2005, 2006, 2007, 2008, 2009
5 ;; Free Software Foundation, Inc.
8 ;; 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
40 (defun describe-function (function)
41 "Display the full documentation of FUNCTION (a symbol)."
43 (let ((fn (function-called-at-point))
44 (enable-recursive-minibuffers t
)
46 (setq val
(completing-read (if fn
47 (format "Describe function (default %s): " fn
)
48 "Describe function: ")
49 obarray
'fboundp t nil nil
50 (and fn
(symbol-name fn
))))
51 (list (if (equal val
"")
54 (message "You didn't specify a function")
55 (help-setup-xref (list #'describe-function function
) (interactive-p))
57 (with-help-window (help-buffer)
59 ;; Use " is " instead of a colon so that
60 ;; it is easier to get out the function name using forward-sexp.
62 (describe-function-1 function
)
63 (with-current-buffer standard-output
64 ;; Return the text we displayed.
67 (defun help-split-fundoc (docstring def
)
68 "Split a function DOCSTRING into the actual doc and the usage info.
69 Return (USAGE . DOC) or nil if there's no usage info.
70 DEF is the function whose usage we're looking for in DOCSTRING."
71 ;; Functions can get the calling sequence at the end of the doc string.
72 ;; In cases where `function' has been fset to a subr we can't search for
73 ;; function's name in the doc string so we use `fn' as the anonymous
74 ;; function name instead.
75 (when (and docstring
(string-match "\n\n(fn\\(\\( .*\\)?)\\)\\'" docstring
))
77 ;; Replace `fn' with the actual function name.
78 (if (consp def
) "anonymous" def
)
79 (match-string 1 docstring
))
80 (substring docstring
0 (match-beginning 0)))))
82 (defun help-add-fundoc-usage (docstring arglist
)
83 "Add the usage info to DOCSTRING.
84 If DOCSTRING already has a usage info, then just return it unchanged.
85 The usage info is built from ARGLIST. DOCSTRING can be nil.
86 ARGLIST can also be t or a string of the form \"(FUN ARG1 ARG2 ...)\"."
87 (unless (stringp docstring
) (setq docstring
"Not documented"))
88 (if (or (string-match "\n\n(fn\\(\\( .*\\)?)\\)\\'" docstring
) (eq arglist t
))
91 (if (string-match "\n?\n\\'" docstring
)
92 (if (< (- (match-end 0) (match-beginning 0)) 2) "\n" "")
94 (if (and (stringp arglist
)
95 (string-match "\\`([^ ]+\\(.*\\))\\'" arglist
))
96 (concat "(fn" (match-string 1 arglist
) ")")
97 (format "%S" (help-make-usage 'fn arglist
))))))
99 (defun help-function-arglist (def)
100 ;; Handle symbols aliased to other symbols.
101 (if (and (symbolp def
) (fboundp def
)) (setq def
(indirect-function def
)))
102 ;; If definition is a macro, find the function inside it.
103 (if (eq (car-safe def
) 'macro
) (setq def
(cdr def
)))
105 ((byte-code-function-p def
) (aref def
0))
106 ((eq (car-safe def
) 'lambda
) (nth 1 def
))
107 ((and (eq (car-safe def
) 'autoload
) (not (eq (nth 4 def
) 'keymap
)))
108 "[Arg list not available until function definition is loaded.]")
111 (defun help-make-usage (function arglist
)
112 (cons (if (symbolp function
) function
'anonymous
)
113 (mapcar (lambda (arg)
114 (if (not (symbolp arg
))
115 (if (and (consp arg
) (symbolp (car arg
)))
116 ;; CL style default values for optional args.
117 (cons (intern (upcase (symbol-name (car arg
))))
120 (let ((name (symbol-name arg
)))
121 (if (string-match "\\`&" name
) arg
122 (intern (upcase name
))))))
125 ;; Could be this, if we make symbol-file do the work below.
126 ;; (defun help-C-file-name (subr-or-var kind)
127 ;; "Return the name of the C file where SUBR-OR-VAR is defined.
128 ;; KIND should be `var' for a variable or `subr' for a subroutine."
129 ;; (symbol-file (if (symbolp subr-or-var) subr-or-var
130 ;; (subr-name subr-or-var))
131 ;; (if (eq kind 'var) 'defvar 'defun)))
133 (defun help-C-file-name (subr-or-var kind
)
134 "Return the name of the C file where SUBR-OR-VAR is defined.
135 KIND should be `var' for a variable or `subr' for a subroutine."
136 (let ((docbuf (get-buffer-create " *DOC*"))
137 (name (if (eq 'var kind
)
138 (concat "V" (symbol-name subr-or-var
))
139 (concat "F" (subr-name subr-or-var
)))))
140 (with-current-buffer docbuf
141 (goto-char (point-min))
143 (insert-file-contents-literally
144 (expand-file-name internal-doc-file-name doc-directory
)))
145 (let ((file (catch 'loop
147 (let ((pnt (search-forward (concat "\x1f" name
"\n"))))
148 (re-search-backward "\x1fS\\(.*\\)")
149 (let ((file (match-string 1)))
150 (if (member file build-files
)
152 (goto-char pnt
))))))))
153 (if (string-match "^ns.*\\(\\.o\\|obj\\)\\'" file
)
154 (setq file
(replace-match ".m" t t file
1))
155 (if (string-match "\\.\\(o\\|obj\\)\\'" file
)
156 (setq file
(replace-match ".c" t t file
))))
157 (if (string-match "\\.\\(c\\|m\\)\\'" file
)
161 (defun help-default-arg-highlight (arg)
162 "Default function to highlight arguments in *Help* buffers.
163 It returns ARG in face `help-argument-name'; ARG is also
164 downcased if it displays differently than the default
165 face (according to `face-differs-from-default-p')."
166 (propertize (if (face-differs-from-default-p 'help-argument-name
)
169 'face
'help-argument-name
))
171 (defun help-do-arg-highlight (doc args
)
172 (with-syntax-table (make-syntax-table emacs-lisp-mode-syntax-table
)
173 (modify-syntax-entry ?\-
"w")
174 (dolist (arg args doc
)
175 (setq doc
(replace-regexp-in-string
176 ;; This is heuristic, but covers all common cases
178 (concat "\\<" ; beginning of word
179 "\\(?:[a-z-]*-\\)?" ; for xxx-ARG
183 "\\(?:es\\|s\\|th\\)?" ; for ARGth, ARGs
184 "\\(?:-[a-z0-9-]+\\)?" ; for ARG-xxx, ARG-n
185 "\\(?:-[{([<`\"].*?\\)?"; for ARG-{x}, (x), <x>, [x], `x'
187 (help-default-arg-highlight arg
)
190 (defun help-highlight-arguments (usage doc
&rest args
)
194 (goto-char (point-min))
195 (let ((case-fold-search nil
)
196 (next (not (or args
(looking-at "\\["))))
198 ;; Make a list of all arguments
199 (skip-chars-forward "^ ")
201 (or opt
(not (looking-at " &")) (setq opt t
))
202 (if (not (re-search-forward " \\([\\[(]*\\)\\([^] &)\.]+\\)" nil t
))
204 (setq args
(cons (match-string 2) args
))
205 (when (and opt
(string= (match-string 1) "("))
206 ;; A pesky CL-style optional argument with default value,
207 ;; so let's skip over it
208 (search-backward "(")
209 (goto-char (scan-sexps (point) 1)))))
210 ;; Highlight aguments in the USAGE string
211 (setq usage
(help-do-arg-highlight (buffer-string) args
))
212 ;; Highlight arguments in the DOC string
213 (setq doc
(and doc
(help-do-arg-highlight doc args
))))))
214 ;; Return value is like the one from help-split-fundoc, but highlighted
217 ;; The following function was compiled from the former functions
218 ;; `describe-simplify-lib-file-name' and `find-source-lisp-file' with
219 ;; some excerpts from `describe-function-1' and `describe-variable'.
220 ;; The only additional twists provided are (1) locate the defining file
221 ;; for autoloaded functions, and (2) give preference to files in the
222 ;; "install directory" (directories found via `load-path') rather than
223 ;; to files in the "compile directory" (directories found by searching
224 ;; the loaddefs.el file). We autoload it because it's also used by
225 ;; `describe-face' (instead of `describe-simplify-lib-file-name').
228 (defun find-lisp-object-file-name (object type
)
229 "Guess the file that defined the Lisp object OBJECT, of type TYPE.
230 OBJECT should be a symbol associated with a function, variable, or face;
231 alternatively, it can be a function definition.
232 If TYPE is `variable', search for a variable definition.
233 If TYPE is `face', search for a face definition.
234 If TYPE is the value returned by `symbol-function' for a function symbol,
235 search for a function definition.
237 The return value is the absolute name of a readable file where OBJECT is
238 defined. If several such files exist, preference is given to a file
239 found via `load-path'. The return value can also be `C-source', which
240 means that OBJECT is a function or variable defined in C. If no
241 suitable file is found, return nil."
242 (let* ((autoloaded (eq (car-safe type
) 'autoload
))
243 (file-name (or (and autoloaded
(nth 1 type
))
245 object
(if (memq type
(list 'defvar
'defface
))
250 ;; An autoloaded function: Locate the file since `symbol-function'
251 ;; has only returned a bare string here.
253 (locate-file file-name load-path
'(".el" ".elc") 'readable
)))
254 ((and (stringp file-name
)
255 (string-match "[.]*loaddefs.el\\'" file-name
))
256 ;; An autoloaded variable or face. Visit loaddefs.el in a buffer
257 ;; and try to extract the defining file. The following form is
258 ;; from `describe-function-1' and `describe-variable'.
261 (find-function-search-for-symbol object nil file-name
)
264 (with-current-buffer (car location
)
265 (goto-char (cdr location
))
266 (when (re-search-backward
267 "^;;; Generated autoloads from \\(.*\\)" nil t
)
270 (file-name-sans-extension
271 (match-string-no-properties 1))
272 load-path
'(".el" ".elc") 'readable
))))))))
275 ((and (not file-name
) (subrp type
))
276 ;; A built-in function. The form is from `describe-function-1'.
277 (if (get-buffer " *DOC*")
278 (help-C-file-name type
'subr
)
280 ((and (not file-name
) (symbolp object
)
281 (integerp (get object
'variable-documentation
)))
282 ;; A variable defined in C. The form is from `describe-variable'.
283 (if (get-buffer " *DOC*")
284 (help-C-file-name object
'var
)
286 ((not (stringp file-name
))
287 ;; If we don't have a file-name string by now, we lost.
290 (if (string-match "[.]elc\\'" file-name
)
291 (substring-no-properties file-name
0 -
1)
293 ;; When the Elisp source file can be found in the install
294 ;; directory return the name of that file - `file-name' should
295 ;; have become an absolute file name ny now.
296 (or (and (file-readable-p lib-name
) lib-name
)
297 ;; The library might be compressed.
298 (and (file-readable-p (concat lib-name
".gz")) lib-name
))))
299 ((let* ((lib-name (file-name-nondirectory file-name
))
300 ;; The next form is from `describe-simplify-lib-file-name'.
302 ;; Try converting the absolute file name to a library
303 ;; name, convert that back to a file name and see if we
304 ;; get the original one. If so, they are equivalent.
305 (if (equal file-name
(locate-file lib-name load-path
'("")))
306 (if (string-match "[.]elc\\'" lib-name
)
307 (substring-no-properties lib-name
0 -
1)
310 ;; The next three forms are from `find-source-lisp-file'.
311 (elc-file (locate-file
313 (if (string-match "\\.el\\'" file-name
)
316 load-path nil
'readable
))
319 (insert-file-contents-literally elc-file nil
0 256)
322 (string-match ";;; from file \\(.*\\.el\\)" str
)
323 (match-string 1 str
))))
324 (and src-file
(file-readable-p src-file
) src-file
))))))
326 (declare-function ad-get-advice-info
"advice" (function))
329 (defun describe-function-1 (function)
330 (let* ((advised (and (symbolp function
) (featurep 'advice
)
331 (ad-get-advice-info function
)))
332 ;; If the function is advised, use the symbol that has the
333 ;; real definition, if that symbol is already set up.
336 (let ((origname (cdr (assq 'origname advised
))))
337 (and (fboundp origname
) origname
)))
339 ;; Get the real definition.
340 (def (if (symbolp real-function
)
341 (symbol-function real-function
)
344 (beg (if (commandp def
) "an interactive " "a "))
345 (pt1 (with-current-buffer (help-buffer) (point)))
348 (cond ((or (stringp def
)
352 (if (eq 'unevalled
(cdr (subr-arity def
)))
353 (concat beg
"special form")
354 (concat beg
"built-in function")))
355 ((byte-code-function-p def
)
356 (concat beg
"compiled Lisp function"))
358 (while (and (fboundp def
)
359 (symbolp (symbol-function def
)))
360 (setq def
(symbol-function def
)))
361 ;; Handle (defalias 'foo 'bar), where bar is undefined.
362 (or (fboundp def
) (setq errtype
'alias
))
363 (format "an alias for `%s'" def
))
364 ((eq (car-safe def
) 'lambda
)
365 (concat beg
"Lisp function"))
366 ((eq (car-safe def
) 'macro
)
368 ((eq (car-safe def
) 'autoload
)
369 (format "%s autoloaded %s"
370 (if (commandp def
) "an interactive" "an")
371 (if (eq (nth 4 def
) 'keymap
) "keymap"
372 (if (nth 4 def
) "Lisp macro" "Lisp function"))))
375 (elts (cdr-safe def
)))
377 (if (char-table-p (car-safe elts
))
380 (setq elts
(cdr-safe elts
)))
386 (if (eq errtype
'alias
)
387 (princ ",\nwhich is not defined. Please make a bug report.")
388 (with-current-buffer standard-output
391 (when (re-search-backward "alias for `\\([^`']+\\)'" nil t
)
392 (help-xref-button 1 'help-function def
)))))
394 (setq file-name
(find-lisp-object-file-name function def
))
397 ;; We used to add .el to the file name,
398 ;; but that's completely wrong when the user used load-file.
399 (princ (if (eq file-name
'C-source
)
401 (file-name-nondirectory 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 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 (remapped (command-remapping function
)))
416 (unless (memq remapped
'(ignore undefined
))
417 (let ((keys (where-is-internal
418 (or remapped function
) overriding-local-map nil nil
))
420 (if (and (eq function
'self-insert-command
)
421 (vectorp (car-safe keys
))
422 (consp (aref (car keys
) 0)))
423 (princ "It is bound to many ordinary text characters.\n")
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
)
450 (with-current-buffer (help-buffer)
451 (fill-region-as-paragraph pt2
(point))
452 (unless (looking-back "\n\n")
454 ;; Note that list* etc do not get this property until
455 ;; cl-hack-byte-compiler runs, after bytecomp is loaded.
456 (when (eq (get function
'byte-compile
) 'cl-byte-compile-compiler-macro
)
457 (princ "This function has a compiler macro")
458 (let ((lib (get function
'compiler-macro-file
)))
460 (princ (format " in `%s'" lib
))
461 (with-current-buffer standard-output
463 (re-search-backward "`\\([^`']+\\)'" nil t
)
464 (help-xref-button 1 'help-function-cmacro function lib
)))))
466 (let* ((arglist (help-function-arglist def
))
467 (doc (documentation function
))
468 (usage (help-split-fundoc doc function
)))
469 (with-current-buffer standard-output
470 ;; If definition is a keymap, skip arglist note.
471 (unless (keymapp function
)
473 (usage (setq doc
(cdr usage
)) (car usage
))
475 (format "%S" (help-make-usage function arglist
)))
476 ((stringp arglist
) arglist
)
477 ;; Maybe the arglist is in the docstring of a symbol
478 ;; this one is aliased to.
479 ((let ((fun real-function
))
480 (while (and (symbolp fun
)
481 (setq fun
(symbol-function fun
))
482 (not (setq usage
(help-split-fundoc
489 (format "\nMacro: %s" (format-kbd-macro def
)))
490 (t "[Missing arglist. Please make a bug report.]")))
491 (high (help-highlight-arguments use doc
)))
492 (let ((fill-begin (point)))
493 (insert (car high
) "\n")
494 (fill-region fill-begin
(point)))
495 (setq doc
(cdr high
))))
496 (let* ((obsolete (and
497 ;; function might be a lambda construct.
499 (get function
'byte-obsolete-info
)))
500 (use (car obsolete
)))
502 (princ "\nThis function is obsolete")
503 (when (nth 2 obsolete
)
504 (insert (format " since %s" (nth 2 obsolete
))))
505 (insert (cond ((stringp use
) (concat ";\n" use
))
506 (use (format ";\nuse `%s' instead." use
))
510 (or doc
"Not documented."))))))))
516 (defun variable-at-point (&optional any-symbol
)
517 "Return the bound variable symbol found at or before point.
518 Return 0 if there is no such symbol.
519 If ANY-SYMBOL is non-nil, don't insist the symbol be bound."
520 (with-syntax-table emacs-lisp-mode-syntax-table
521 (or (condition-case ()
523 (or (not (zerop (skip-syntax-backward "_w")))
524 (eq (char-syntax (following-char)) ?w
)
525 (eq (char-syntax (following-char)) ?_
)
527 (skip-chars-forward "'")
528 (let ((obj (read (current-buffer))))
529 (and (symbolp obj
) (boundp obj
) obj
)))
531 (let* ((str (find-tag-default))
532 (sym (if str
(intern-soft str
))))
533 (if (and sym
(or any-symbol
(boundp sym
)))
536 (when (and str
(string-match "\\`\\W*\\(.*?\\)\\W*\\'" str
))
537 (setq sym
(intern-soft (match-string 1 str
)))
538 (and (or any-symbol
(boundp sym
)) sym
)))))
541 (defun describe-variable-custom-version-info (variable)
542 (let ((custom-version (get variable
'custom-version
))
543 (cpv (get variable
'custom-package-version
))
547 (format "This variable was introduced, or its default value was changed, in\nversion %s of Emacs.\n"
550 (let* ((package (car-safe cpv
))
551 (version (if (listp (cdr-safe cpv
))
554 (pkg-versions (assq package customize-package-emacs-version-alist
))
555 (emacsv (cdr (assoc version pkg-versions
))))
556 (if (and package version
)
558 (format (concat "This variable was introduced, or its default value was changed, in\nversion %s of the %s package"
560 (format " that is part of Emacs %s" emacsv
))
562 version package
))))))
566 (defun describe-variable (variable &optional buffer frame
)
567 "Display the full documentation of VARIABLE (a symbol).
568 Returns the documentation as a string, also.
569 If VARIABLE has a buffer-local value in BUFFER or FRAME
570 \(default to the current buffer and current frame),
571 it is displayed along with the global value."
573 (let ((v (variable-at-point))
574 (enable-recursive-minibuffers t
)
576 (setq val
(completing-read (if (symbolp v
)
578 "Describe variable (default %s): " v
)
579 "Describe variable: ")
583 (get vv
'variable-documentation
)))
585 (if (symbolp v
) (symbol-name v
))))
586 (list (if (equal val
"")
589 (unless (buffer-live-p buffer
) (setq buffer
(current-buffer)))
590 (unless (frame-live-p frame
) (setq frame
(selected-frame)))
591 (if (not (symbolp variable
))
592 (message "You did not specify a variable")
594 (let ((valvoid (not (with-current-buffer buffer
(boundp variable
))))
595 val val-start-pos locus
)
596 ;; Extract the value before setting up the output buffer,
597 ;; in case `buffer' *is* the output buffer.
599 (with-selected-frame frame
600 (with-current-buffer buffer
601 (setq val
(symbol-value variable
)
602 locus
(variable-binding-locus variable
)))))
603 (help-setup-xref (list #'describe-variable variable buffer
)
605 (with-help-window (help-buffer)
606 (with-current-buffer buffer
608 (setq file-name
(find-lisp-object-file-name variable
'defvar
))
612 (princ " is a variable defined in `")
613 (princ (if (eq file-name
'C-source
)
615 (file-name-nondirectory file-name
)))
617 (with-current-buffer standard-output
619 (re-search-backward "`\\([^`']+\\)'" nil t
)
620 (help-xref-button 1 'help-variable-def
621 variable file-name
)))
623 (princ "It is void as a variable.")
626 (princ " is void as a variable.")
630 (with-current-buffer standard-output
631 (setq val-start-pos
(point))
634 (let ((from (point)))
636 ;; Hyperlinks in variable's value are quite frequently
637 ;; inappropriate e.g C-h v <RET> features <RET>
638 ;; (help-xref-on-pp from (point))
639 (if (< (point) (+ from
20))
640 (delete-region (1- from
) from
)))))
645 (princ (format "%socal in buffer %s; "
646 (if (get variable
'permanent-local
)
649 (princ (format "It is a frame-local variable; ")))
650 (if (not (default-boundp variable
))
651 (princ "globally void")
652 (let ((val (default-value variable
)))
653 (with-current-buffer standard-output
654 (princ "global value is ")
656 ;; Fixme: pp can take an age if you happen to
657 ;; ask for a very large expression. We should
658 ;; probably print it raw once and check it's a
659 ;; sensible size before prettyprinting. -- fx
660 (let ((from (point)))
662 ;; See previous comment for this function.
663 ;; (help-xref-on-pp from (point))
664 (if (< (point) (+ from
20))
665 (delete-region (1- from
) from
))))))
668 ;; If the value is large, move it to the end.
669 (with-current-buffer standard-output
670 (when (> (count-lines (point-min) (point-max)) 10)
671 ;; Note that setting the syntax table like below
672 ;; makes forward-sexp move over a `'s' at the end
674 (set-syntax-table emacs-lisp-mode-syntax-table
)
675 (goto-char val-start-pos
)
676 ;; The line below previously read as
677 ;; (delete-region (point) (progn (end-of-line) (point)))
678 ;; which suppressed display of the buffer local value for
680 (when (looking-at "value is") (replace-match ""))
682 (insert "\n\nValue:")
683 (set (make-local-variable 'help-button-cache
)
685 (insert "value is shown ")
686 (insert-button "below"
687 'action help-button-cache
689 'help-echo
"mouse-2, RET: show value")
693 (let* ((alias (condition-case nil
694 (indirect-variable variable
)
696 (obsolete (get variable
'byte-obsolete-variable
))
698 (safe-var (get variable
'safe-local-variable
))
699 (doc (or (documentation-property variable
'variable-documentation
)
700 (documentation-property alias
'variable-documentation
)))
702 ;; Add a note for variables that have been make-var-buffer-local.
703 (when (and (local-variable-if-set-p variable
)
704 (or (not (local-variable-p variable
))
706 (local-variable-if-set-p variable
))))
708 (princ " Automatically becomes buffer-local when set in any fashion.\n"))
710 ;; Mention if it's an alias
711 (unless (eq alias variable
)
713 (princ (format " This variable is an alias for `%s'.\n" alias
)))
717 (princ " This variable is obsolete")
718 (if (cdr obsolete
) (princ (format " since %s" (cdr obsolete
))))
719 (princ (cond ((stringp use
) (concat ";\n " use
))
720 (use (format ";\n use `%s' instead." (car obsolete
)))
724 (when (member (cons variable val
) file-local-variables-alist
)
726 (if (member (cons variable val
) dir-local-variables-alist
)
727 (let ((file (and (buffer-file-name)
728 (not (file-remote-p (buffer-file-name)))
729 (dir-locals-find-file (buffer-file-name)))))
730 (princ " This variable is a directory local variable")
732 (princ (concat "\n from the file \""
738 (princ " This variable is a file local variable.\n")))
740 (when (memq variable ignored-local-variables
)
742 (princ " This variable is ignored when used as a file local \
745 ;; Can be both risky and safe, eg auto-fill-function.
746 (when (risky-local-variable-p variable
)
748 (princ " This variable is potentially risky when used as a \
749 file local variable.\n")
750 (when (assq variable safe-local-variable-values
)
751 (princ " However, you have added it to \
752 `safe-local-variable-values'.\n")))
756 (princ " This variable is safe as a file local variable ")
757 (princ "if its value\n satisfies the predicate ")
758 (princ (if (byte-code-function-p safe-var
)
759 "which is byte-compiled expression.\n"
760 (format "`%s'.\n" safe-var
))))
762 (if extra-line
(terpri))
763 (princ "Documentation:\n")
764 (with-current-buffer standard-output
765 (insert (or doc
"Not documented as a variable."))))
767 ;; Make a link to customize if this variable can be customized.
768 (when (custom-variable-p variable
)
769 (let ((customize-label "customize"))
772 (princ (concat "You can " customize-label
" this variable."))
773 (with-current-buffer standard-output
776 (concat "\\(" customize-label
"\\)") nil t
)
777 (help-xref-button 1 'help-customize-variable variable
))))
778 ;; Note variable's version or package version
779 (let ((output (describe-variable-custom-version-info variable
)))
786 (set-buffer standard-output
)
787 ;; Return the text we displayed.
788 (buffer-string))))))))
792 (defun describe-syntax (&optional buffer
)
793 "Describe the syntax specifications in the syntax table of BUFFER.
794 The descriptions are inserted in a help buffer, which is then displayed.
795 BUFFER defaults to the current buffer."
797 (setq buffer
(or buffer
(current-buffer)))
798 (help-setup-xref (list #'describe-syntax buffer
) (interactive-p))
799 (with-help-window (help-buffer)
800 (let ((table (with-current-buffer buffer
(syntax-table))))
801 (with-current-buffer standard-output
802 (describe-vector table
'internal-describe-syntax-value
)
803 (while (setq table
(char-table-parent table
))
804 (insert "\nThe parent syntax table is:")
805 (describe-vector table
'internal-describe-syntax-value
))))))
807 (defun help-describe-category-set (value)
809 ((null value
) "default")
810 ((char-table-p value
) "deeper char-table ...")
811 (t (condition-case err
812 (category-set-mnemonics value
)
813 (error "invalid"))))))
816 (defun describe-categories (&optional buffer
)
817 "Describe the category specifications in the current category table.
818 The descriptions are inserted in a buffer, which is then displayed.
819 If BUFFER is non-nil, then describe BUFFER's category table instead.
820 BUFFER should be a buffer or a buffer name."
822 (setq buffer
(or buffer
(current-buffer)))
823 (help-setup-xref (list #'describe-categories buffer
) (interactive-p))
824 (with-help-window (help-buffer)
825 (let* ((table (with-current-buffer buffer
(category-table)))
826 (docs (char-table-extra-slot table
0)))
827 (if (or (not (vectorp docs
)) (/= (length docs
) 95))
828 (error "Invalid first extra slot in this category table\n"))
829 (with-current-buffer standard-output
830 (insert "Legend of category mnemonics (see the tail for the longer description)\n")
831 (let ((pos (point)) (items 0) lines n
)
833 (if (aref docs i
) (setq items
(1+ items
))))
834 (setq lines
(1+ (/ (1- items
) 4)))
837 (let ((elt (aref docs i
)))
839 (string-match ".*" elt
)
840 (setq elt
(match-string 0 elt
))
841 (if (>= (length elt
) 17)
842 (setq elt
(concat (substring elt
0 14) "...")))
843 (if (< (point) (point-max))
844 (move-to-column (* 20 (/ n lines
)) t
))
845 (insert (+ i ?\s
) ?
: elt
)
846 (if (< (point) (point-max))
850 (if (= (% n lines
) 0)
852 (goto-char (point-max))
854 "character(s)\tcategory mnemonics\n"
855 "------------\t------------------")
856 (describe-vector table
'help-describe-category-set
)
857 (insert "Legend of category mnemonics:\n")
859 (let ((elt (aref docs i
)))
861 (if (string-match "\n" elt
)
862 (setq elt
(substring elt
(match-end 0))))
863 (insert (+ i ?\s
) ": " elt
"\n"))))
864 (while (setq table
(char-table-parent table
))
865 (insert "\nThe parent category table is:")
866 (describe-vector table
'help-describe-category-set
))))))
870 ;; arch-tag: 9e10331c-ae81-4d13-965d-c4819aaab0b3
871 ;;; help-fns.el ends here