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 "
\1f" name "\n"))))
148 (re-search-backward "
\1fS\\(.*\\)")
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 (defcustom help-downcase-arguments nil
162 "If non-nil, argument names in *Help* buffers are downcased."
167 (defun help-highlight-arg (arg)
168 "Highlight ARG as an argument name for a *Help* buffer.
169 Return ARG in face `help-argument-name'; ARG is also downcased
170 if the variable `help-downcase-arguments' is non-nil."
171 (propertize (if help-downcase-arguments (downcase arg) arg)
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-highlight-arg 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 (file-name-sans-extension
274 (match-string-no-properties 1))
275 load-path '(".el" ".elc") 'readable))))))))
278 ((and (not file-name) (subrp type))
279 ;; A built-in function. The form is from `describe-function-1'.
280 (if (get-buffer " *DOC*")
281 (help-C-file-name type 'subr)
283 ((and (not file-name) (symbolp object)
284 (integerp (get object 'variable-documentation)))
285 ;; A variable defined in C. The form is from `describe-variable'.
286 (if (get-buffer " *DOC*")
287 (help-C-file-name object 'var)
289 ((not (stringp file-name))
290 ;; If we don't have a file-name string by now, we lost.
293 (if (string-match "[.]elc\\'" file-name)
294 (substring-no-properties file-name 0 -1)
296 ;; When the Elisp source file can be found in the install
297 ;; directory return the name of that file - `file-name' should
298 ;; have become an absolute file name ny now.
299 (or (and (file-readable-p lib-name) lib-name)
300 ;; The library might be compressed.
301 (and (file-readable-p (concat lib-name ".gz")) lib-name))))
302 ((let* ((lib-name (file-name-nondirectory file-name))
303 ;; The next form is from `describe-simplify-lib-file-name'.
305 ;; Try converting the absolute file name to a library
306 ;; name, convert that back to a file name and see if we
307 ;; get the original one. If so, they are equivalent.
308 (if (equal file-name (locate-file lib-name load-path '("")))
309 (if (string-match "[.]elc\\'" lib-name)
310 (substring-no-properties lib-name 0 -1)
313 ;; The next three forms are from `find-source-lisp-file'.
314 (elc-file (locate-file
316 (if (string-match "\\.el\\'" file-name)
319 load-path nil 'readable))
322 (insert-file-contents-literally elc-file nil 0 256)
325 (string-match ";;; from file \\(.*\\.el\\)" str)
326 (match-string 1 str))))
327 (and src-file (file-readable-p src-file) src-file))))))
329 (declare-function ad-get-advice-info "advice" (function))
332 (defun describe-function-1 (function)
333 (let* ((advised (and (symbolp function) (featurep 'advice)
334 (ad-get-advice-info function)))
335 ;; If the function is advised, use the symbol that has the
336 ;; real definition, if that symbol is already set up.
339 (let ((origname (cdr (assq 'origname advised))))
340 (and (fboundp origname) origname)))
342 ;; Get the real definition.
343 (def (if (symbolp real-function)
344 (symbol-function real-function)
347 (beg (if (commandp def) "an interactive " "a "))
348 (pt1 (with-current-buffer (help-buffer) (point)))
351 (cond ((or (stringp def)
355 (if (eq 'unevalled (cdr (subr-arity def)))
356 (concat beg "special form")
357 (concat beg "built-in function")))
358 ((byte-code-function-p def)
359 (concat beg "compiled Lisp function"))
361 (while (and (fboundp def)
362 (symbolp (symbol-function def)))
363 (setq def (symbol-function def)))
364 ;; Handle (defalias 'foo 'bar), where bar is undefined.
365 (or (fboundp def) (setq errtype 'alias))
366 (format "an alias for `%s'" def))
367 ((eq (car-safe def) 'lambda)
368 (concat beg "Lisp function"))
369 ((eq (car-safe def) 'macro)
371 ((eq (car-safe def) 'autoload)
372 (format "%s autoloaded %s"
373 (if (commandp def) "an interactive" "an")
374 (if (eq (nth 4 def) 'keymap) "keymap"
375 (if (nth 4 def) "Lisp macro" "Lisp function"))))
378 (elts (cdr-safe def)))
380 (if (char-table-p (car-safe elts))
383 (setq elts (cdr-safe elts)))
389 (if (eq errtype 'alias)
390 (princ ",\nwhich is not defined. Please make a bug report.")
391 (with-current-buffer standard-output
394 (when (re-search-backward "alias for `\\([^`']+\\)'" nil t)
395 (help-xref-button 1 'help-function def)))))
397 (setq file-name (find-lisp-object-file-name function def))
400 ;; We used to add .el to the file name,
401 ;; but that's completely wrong when the user used load-file.
402 (princ (if (eq file-name 'C-source)
404 (file-name-nondirectory file-name)))
406 ;; Make a hyperlink to the library.
407 (with-current-buffer standard-output
409 (re-search-backward "`\\([^`']+\\)'" nil t)
410 (help-xref-button 1 'help-function-def function file-name))))
412 (with-current-buffer (help-buffer)
413 (fill-region-as-paragraph (save-excursion (goto-char pt1) (forward-line 0) (point))
416 (when (commandp function)
417 (let ((pt2 (with-current-buffer (help-buffer) (point)))
418 (remapped (command-remapping function)))
419 (unless (memq remapped '(ignore undefined))
420 (let ((keys (where-is-internal
421 (or remapped function) overriding-local-map nil nil))
423 (if (and (eq function 'self-insert-command)
424 (vectorp (car-safe keys))
425 (consp (aref (car keys) 0)))
426 (princ "It is bound to many ordinary text characters.\n")
427 ;; Which non-control non-meta keys run this command?
429 (if (member (event-modifiers (aref key 0)) '(nil (shift)))
430 (push key non-modified-keys)))
432 (princ "It is remapped to `")
433 (princ (symbol-name remapped))
437 (princ (if remapped ", which is bound to " "It is bound to "))
438 ;; If lots of ordinary text characters run this command,
439 ;; don't mention them one by one.
440 (if (< (length non-modified-keys) 10)
441 (princ (mapconcat 'key-description keys ", "))
442 (dolist (key non-modified-keys)
443 (setq keys (delq key keys)))
446 (princ (mapconcat 'key-description keys ", "))
447 (princ ", and many ordinary text characters"))
448 (princ "many ordinary text characters"))))
449 (when (or remapped keys non-modified-keys)
453 (with-current-buffer (help-buffer)
454 (fill-region-as-paragraph pt2 (point))
455 (unless (looking-back "\n\n")
457 ;; Note that list* etc do not get this property until
458 ;; cl-hack-byte-compiler runs, after bytecomp is loaded.
459 (when (eq (get function 'byte-compile) 'cl-byte-compile-compiler-macro)
460 (princ "This function has a compiler macro")
461 (let ((lib (get function 'compiler-macro-file)))
463 (princ (format " in `%s'" lib))
464 (with-current-buffer standard-output
466 (re-search-backward "`\\([^`']+\\)'" nil t)
467 (help-xref-button 1 'help-function-cmacro function lib)))))
469 (let* ((arglist (help-function-arglist def))
470 (doc (documentation function))
471 (usage (help-split-fundoc doc function)))
472 (with-current-buffer standard-output
473 ;; If definition is a keymap, skip arglist note.
474 (unless (keymapp function)
476 (usage (setq doc (cdr usage)) (car usage))
478 (format "%S" (help-make-usage function arglist)))
479 ((stringp arglist) arglist)
480 ;; Maybe the arglist is in the docstring of a symbol
481 ;; this one is aliased to.
482 ((let ((fun real-function))
483 (while (and (symbolp fun)
484 (setq fun (symbol-function fun))
485 (not (setq usage (help-split-fundoc
492 (format "\nMacro: %s" (format-kbd-macro def)))
493 (t "[Missing arglist. Please make a bug report.]")))
494 (high (help-highlight-arguments use doc)))
495 (let ((fill-begin (point)))
496 (insert (car high) "\n")
497 (fill-region fill-begin (point)))
498 (setq doc (cdr high))))
499 (let* ((obsolete (and
500 ;; function might be a lambda construct.
502 (get function 'byte-obsolete-info)))
503 (use (car obsolete)))
505 (princ "\nThis function is obsolete")
506 (when (nth 2 obsolete)
507 (insert (format " since %s" (nth 2 obsolete))))
508 (insert (cond ((stringp use) (concat ";\n" use))
509 (use (format ";\nuse `%s' instead." use))
513 (or doc "Not documented."))))))))
519 (defun variable-at-point (&optional any-symbol)
520 "Return the bound variable symbol found at or before point.
521 Return 0 if there is no such symbol.
522 If ANY-SYMBOL is non-nil, don't insist the symbol be bound."
523 (with-syntax-table emacs-lisp-mode-syntax-table
524 (or (condition-case ()
526 (or (not (zerop (skip-syntax-backward "_w")))
527 (eq (char-syntax (following-char)) ?w)
528 (eq (char-syntax (following-char)) ?_)
530 (skip-chars-forward "'")
531 (let ((obj (read (current-buffer))))
532 (and (symbolp obj) (boundp obj) obj)))
534 (let* ((str (find-tag-default))
535 (sym (if str (intern-soft str))))
536 (if (and sym (or any-symbol (boundp sym)))
539 (when (and str (string-match "\\`\\W*\\(.*?\\)\\W*\\'" str))
540 (setq sym (intern-soft (match-string 1 str)))
541 (and (or any-symbol (boundp sym)) sym)))))
544 (defun describe-variable-custom-version-info (variable)
545 (let ((custom-version (get variable 'custom-version))
546 (cpv (get variable 'custom-package-version))
550 (format "This variable was introduced, or its default value was changed, in\nversion %s of Emacs.\n"
553 (let* ((package (car-safe cpv))
554 (version (if (listp (cdr-safe cpv))
557 (pkg-versions (assq package customize-package-emacs-version-alist))
558 (emacsv (cdr (assoc version pkg-versions))))
559 (if (and package version)
561 (format (concat "This variable was introduced, or its default value was changed, in\nversion %s of the %s package"
563 (format " that is part of Emacs %s" emacsv))
565 version package))))))
569 (defun describe-variable (variable &optional buffer frame)
570 "Display the full documentation of VARIABLE (a symbol).
571 Returns the documentation as a string, also.
572 If VARIABLE has a buffer-local value in BUFFER or FRAME
573 \(default to the current buffer and current frame),
574 it is displayed along with the global value."
576 (let ((v (variable-at-point))
577 (enable-recursive-minibuffers t)
579 (setq val (completing-read (if (symbolp v)
581 "Describe variable (default %s): " v)
582 "Describe variable: ")
586 (get vv 'variable-documentation)))
588 (if (symbolp v) (symbol-name v))))
589 (list (if (equal val "")
592 (unless (buffer-live-p buffer) (setq buffer (current-buffer)))
593 (unless (frame-live-p frame) (setq frame (selected-frame)))
594 (if (not (symbolp variable))
595 (message "You did not specify a variable")
597 (let ((valvoid (not (with-current-buffer buffer (boundp variable))))
598 val val-start-pos locus)
599 ;; Extract the value before setting up the output buffer,
600 ;; in case `buffer' *is* the output buffer.
602 (with-selected-frame frame
603 (with-current-buffer buffer
604 (setq val (symbol-value variable)
605 locus (variable-binding-locus variable)))))
606 (help-setup-xref (list #'describe-variable variable buffer)
608 (with-help-window (help-buffer)
609 (with-current-buffer buffer
611 (setq file-name (find-lisp-object-file-name variable 'defvar))
615 (princ " is a variable defined in `")
616 (princ (if (eq file-name 'C-source)
618 (file-name-nondirectory file-name)))
620 (with-current-buffer standard-output
622 (re-search-backward "`\\([^`']+\\)'" nil t)
623 (help-xref-button 1 'help-variable-def
624 variable file-name)))
626 (princ "It is void as a variable.")
629 (princ " is void as a variable.")
633 (with-current-buffer standard-output
634 (setq val-start-pos (point))
637 (let ((from (point)))
639 ;; Hyperlinks in variable's value are quite frequently
640 ;; inappropriate e.g C-h v <RET> features <RET>
641 ;; (help-xref-on-pp from (point))
642 (if (< (point) (+ from 20))
643 (delete-region (1- from) from)))))
648 (princ (format "%socal in buffer %s; "
649 (if (get variable 'permanent-local)
652 (princ (format "It is a frame-local variable; ")))
653 (if (not (default-boundp variable))
654 (princ "globally void")
655 (let ((val (default-value variable)))
656 (with-current-buffer standard-output
657 (princ "global value is ")
659 ;; Fixme: pp can take an age if you happen to
660 ;; ask for a very large expression. We should
661 ;; probably print it raw once and check it's a
662 ;; sensible size before prettyprinting. -- fx
663 (let ((from (point)))
665 ;; See previous comment for this function.
666 ;; (help-xref-on-pp from (point))
667 (if (< (point) (+ from 20))
668 (delete-region (1- from) from))))))
671 ;; If the value is large, move it to the end.
672 (with-current-buffer standard-output
673 (when (> (count-lines (point-min) (point-max)) 10)
674 ;; Note that setting the syntax table like below
675 ;; makes forward-sexp move over a `'s' at the end
677 (set-syntax-table emacs-lisp-mode-syntax-table)
678 (goto-char val-start-pos)
679 ;; The line below previously read as
680 ;; (delete-region (point) (progn (end-of-line) (point)))
681 ;; which suppressed display of the buffer local value for
683 (when (looking-at "value is") (replace-match ""))
685 (insert "\n\nValue:")
686 (set (make-local-variable 'help-button-cache)
688 (insert "value is shown ")
689 (insert-button "below"
690 'action help-button-cache
692 'help-echo "mouse-2, RET: show value")
696 (let* ((alias (condition-case nil
697 (indirect-variable variable)
699 (obsolete (get variable 'byte-obsolete-variable))
701 (safe-var (get variable 'safe-local-variable))
702 (doc (or (documentation-property variable 'variable-documentation)
703 (documentation-property alias 'variable-documentation)))
705 ;; Add a note for variables that have been make-var-buffer-local.
706 (when (and (local-variable-if-set-p variable)
707 (or (not (local-variable-p variable))
709 (local-variable-if-set-p variable))))
711 (princ " Automatically becomes buffer-local when set in any fashion.\n"))
713 ;; Mention if it's an alias
714 (unless (eq alias variable)
716 (princ (format " This variable is an alias for `%s'.\n" alias)))
720 (princ " This variable is obsolete")
721 (if (cdr obsolete) (princ (format " since %s" (cdr obsolete))))
722 (princ (cond ((stringp use) (concat ";\n " use))
723 (use (format ";\n use `%s' instead." (car obsolete)))
727 (when (member (cons variable val) file-local-variables-alist)
729 (if (member (cons variable val) dir-local-variables-alist)
730 (let ((file (and (buffer-file-name)
731 (not (file-remote-p (buffer-file-name)))
732 (dir-locals-find-file (buffer-file-name)))))
733 (princ " This variable is a directory local variable")
735 (princ (concat "\n from the file \""
741 (princ " This variable is a file local variable.\n")))
743 (when (memq variable ignored-local-variables)
745 (princ " This variable is ignored when used as a file local \
748 ;; Can be both risky and safe, eg auto-fill-function.
749 (when (risky-local-variable-p variable)
751 (princ " This variable is potentially risky when used as a \
752 file local variable.\n")
753 (when (assq variable safe-local-variable-values)
754 (princ " However, you have added it to \
755 `safe-local-variable-values'.\n")))
759 (princ " This variable is safe as a file local variable ")
760 (princ "if its value\n satisfies the predicate ")
761 (princ (if (byte-code-function-p safe-var)
762 "which is byte-compiled expression.\n"
763 (format "`%s'.\n" safe-var))))
765 (if extra-line (terpri))
766 (princ "Documentation:\n")
767 (with-current-buffer standard-output
768 (insert (or doc "Not documented as a variable."))))
770 ;; Make a link to customize if this variable can be customized.
771 (when (custom-variable-p variable)
772 (let ((customize-label "customize"))
775 (princ (concat "You can " customize-label " this variable."))
776 (with-current-buffer standard-output
779 (concat "\\(" customize-label "\\)") nil t)
780 (help-xref-button 1 'help-customize-variable variable))))
781 ;; Note variable's version or package version
782 (let ((output (describe-variable-custom-version-info variable)))
789 (set-buffer standard-output)
790 ;; Return the text we displayed.
791 (buffer-string))))))))
795 (defun describe-syntax (&optional buffer)
796 "Describe the syntax specifications in the syntax table of BUFFER.
797 The descriptions are inserted in a help buffer, which is then displayed.
798 BUFFER defaults to the current buffer."
800 (setq buffer (or buffer (current-buffer)))
801 (help-setup-xref (list #'describe-syntax buffer) (interactive-p))
802 (with-help-window (help-buffer)
803 (let ((table (with-current-buffer buffer (syntax-table))))
804 (with-current-buffer standard-output
805 (describe-vector table 'internal-describe-syntax-value)
806 (while (setq table (char-table-parent table))
807 (insert "\nThe parent syntax table is:")
808 (describe-vector table 'internal-describe-syntax-value))))))
810 (defun help-describe-category-set (value)
812 ((null value) "default")
813 ((char-table-p value) "deeper char-table ...")
814 (t (condition-case err
815 (category-set-mnemonics value)
816 (error "invalid"))))))
819 (defun describe-categories (&optional buffer)
820 "Describe the category specifications in the current category table.
821 The descriptions are inserted in a buffer, which is then displayed.
822 If BUFFER is non-nil, then describe BUFFER's category table instead.
823 BUFFER should be a buffer or a buffer name."
825 (setq buffer (or buffer (current-buffer)))
826 (help-setup-xref (list #'describe-categories buffer) (interactive-p))
827 (with-help-window (help-buffer)
828 (let* ((table (with-current-buffer buffer (category-table)))
829 (docs (char-table-extra-slot table 0)))
830 (if (or (not (vectorp docs)) (/= (length docs) 95))
831 (error "Invalid first extra slot in this category table\n"))
832 (with-current-buffer standard-output
833 (insert "Legend of category mnemonics (see the tail for the longer description)\n")
834 (let ((pos (point)) (items 0) lines n)
836 (if (aref docs i) (setq items (1+ items))))
837 (setq lines (1+ (/ (1- items) 4)))
840 (let ((elt (aref docs i)))
842 (string-match ".*" elt)
843 (setq elt (match-string 0 elt))
844 (if (>= (length elt) 17)
845 (setq elt (concat (substring elt 0 14) "...")))
846 (if (< (point) (point-max))
847 (move-to-column (* 20 (/ n lines)) t))
848 (insert (+ i ?\s) ?: elt)
849 (if (< (point) (point-max))
853 (if (= (% n lines) 0)
855 (goto-char (point-max))
857 "character(s)\tcategory mnemonics\n"
858 "------------\t------------------")
859 (describe-vector table 'help-describe-category-set)
860 (insert "Legend of category mnemonics:\n")
862 (let ((elt (aref docs i)))
864 (if (string-match "\n" elt)
865 (setq elt (substring elt (match-end 0))))
866 (insert (+ i ?\s) ": " elt "\n"))))
867 (while (setq table (char-table-parent table))
868 (insert "\nThe parent category table is:")
869 (describe-vector table 'help-describe-category-set))))))
873 ;; arch-tag: 9e10331c-ae81-4d13-965d-c4819aaab0b3
874 ;;; help-fns.el ends here