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)))
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 "
\1f" name "\n"))))
147 (re-search-backward "
\1fS\\(.*\\)")
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 (defcustom help-downcase-arguments nil
161 "If non-nil, argument names in *Help* buffers are downcased."
166 (defun help-highlight-arg (arg)
167 "Highlight ARG as an argument name for a *Help* buffer.
168 Return ARG in face `help-argument-name'; ARG is also downcased
169 if the variable `help-downcase-arguments' is non-nil."
170 (propertize (if help-downcase-arguments (downcase arg) arg)
171 'face 'help-argument-name))
173 (defun help-do-arg-highlight (doc args)
174 (with-syntax-table (make-syntax-table emacs-lisp-mode-syntax-table)
175 (modify-syntax-entry ?\- "w")
176 (dolist (arg args doc)
177 (setq doc (replace-regexp-in-string
178 ;; This is heuristic, but covers all common cases
180 (concat "\\<" ; beginning of word
181 "\\(?:[a-z-]*-\\)?" ; for xxx-ARG
185 "\\(?:es\\|s\\|th\\)?" ; for ARGth, ARGs
186 "\\(?:-[a-z0-9-]+\\)?" ; for ARG-xxx, ARG-n
187 "\\(?:-[{([<`\"].*?\\)?"; for ARG-{x}, (x), <x>, [x], `x'
189 (help-highlight-arg arg)
192 (defun help-highlight-arguments (usage doc &rest args)
196 (goto-char (point-min))
197 (let ((case-fold-search nil)
198 (next (not (or args (looking-at "\\["))))
200 ;; Make a list of all arguments
201 (skip-chars-forward "^ ")
203 (or opt (not (looking-at " &")) (setq opt t))
204 (if (not (re-search-forward " \\([\\[(]*\\)\\([^] &)\.]+\\)" nil t))
206 (setq args (cons (match-string 2) args))
207 (when (and opt (string= (match-string 1) "("))
208 ;; A pesky CL-style optional argument with default value,
209 ;; so let's skip over it
210 (search-backward "(")
211 (goto-char (scan-sexps (point) 1)))))
212 ;; Highlight aguments in the USAGE string
213 (setq usage (help-do-arg-highlight (buffer-string) args))
214 ;; Highlight arguments in the DOC string
215 (setq doc (and doc (help-do-arg-highlight doc args))))))
216 ;; Return value is like the one from help-split-fundoc, but highlighted
219 ;; The following function was compiled from the former functions
220 ;; `describe-simplify-lib-file-name' and `find-source-lisp-file' with
221 ;; some excerpts from `describe-function-1' and `describe-variable'.
222 ;; The only additional twists provided are (1) locate the defining file
223 ;; for autoloaded functions, and (2) give preference to files in the
224 ;; "install directory" (directories found via `load-path') rather than
225 ;; to files in the "compile directory" (directories found by searching
226 ;; the loaddefs.el file). We autoload it because it's also used by
227 ;; `describe-face' (instead of `describe-simplify-lib-file-name').
230 (defun find-lisp-object-file-name (object type)
231 "Guess the file that defined the Lisp object OBJECT, of type TYPE.
232 OBJECT should be a symbol associated with a function, variable, or face;
233 alternatively, it can be a function definition.
234 If TYPE is `defvar', search for a variable definition.
235 If TYPE is `defface', search for a face definition.
236 If TYPE is the value returned by `symbol-function' for a function symbol,
237 search for a function definition.
239 The return value is the absolute name of a readable file where OBJECT is
240 defined. If several such files exist, preference is given to a file
241 found via `load-path'. The return value can also be `C-source', which
242 means that OBJECT is a function or variable defined in C. If no
243 suitable file is found, return nil."
244 (let* ((autoloaded (eq (car-safe type) 'autoload))
245 (file-name (or (and autoloaded (nth 1 type))
247 object (if (memq type (list 'defvar 'defface))
252 ;; An autoloaded function: Locate the file since `symbol-function'
253 ;; has only returned a bare string here.
255 (locate-file file-name load-path '(".el" ".elc") 'readable)))
256 ((and (stringp file-name)
257 (string-match "[.]*loaddefs.el\\'" file-name))
258 ;; An autoloaded variable or face. Visit loaddefs.el in a buffer
259 ;; and try to extract the defining file. The following form is
260 ;; from `describe-function-1' and `describe-variable'.
263 (find-function-search-for-symbol object nil file-name)
266 (with-current-buffer (car location)
267 (goto-char (cdr location))
268 (when (re-search-backward
269 "^;;; Generated autoloads from \\(.*\\)" nil t)
272 (file-name-sans-extension
273 (match-string-no-properties 1))
274 load-path '(".el" ".elc") '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.
291 ;; Now, `file-name' should have become an absolute file name.
292 ;; For files loaded from ~/.emacs.elc, try ~/.emacs.
294 (and (string-equal file-name
295 (expand-file-name ".emacs.elc" "~"))
296 (file-readable-p (setq fn (expand-file-name ".emacs" "~")))
298 ;; When the Elisp source file can be found in the install
299 ;; directory, return the name of that file.
301 (if (string-match "[.]elc\\'" file-name)
302 (substring-no-properties file-name 0 -1)
304 (or (and (file-readable-p lib-name) lib-name)
305 ;; The library might be compressed.
306 (and (file-readable-p (concat lib-name ".gz")) lib-name))))
307 ((let* ((lib-name (file-name-nondirectory file-name))
308 ;; The next form is from `describe-simplify-lib-file-name'.
310 ;; Try converting the absolute file name to a library
311 ;; name, convert that back to a file name and see if we
312 ;; get the original one. If so, they are equivalent.
313 (if (equal file-name (locate-file lib-name load-path '("")))
314 (if (string-match "[.]elc\\'" lib-name)
315 (substring-no-properties lib-name 0 -1)
318 ;; The next three forms are from `find-source-lisp-file'.
319 (elc-file (locate-file
321 (if (string-match "\\.el\\'" file-name)
324 load-path nil 'readable))
327 (insert-file-contents-literally elc-file nil 0 256)
330 (string-match ";;; from file \\(.*\\.el\\)" str)
331 (match-string 1 str))))
332 (and src-file (file-readable-p src-file) src-file))))))
334 (declare-function ad-get-advice-info "advice" (function))
337 (defun describe-function-1 (function)
338 (let* ((advised (and (symbolp function) (featurep 'advice)
339 (ad-get-advice-info function)))
340 ;; If the function is advised, use the symbol that has the
341 ;; real definition, if that symbol is already set up.
344 (let ((origname (cdr (assq 'origname advised))))
345 (and (fboundp origname) origname)))
347 ;; Get the real definition.
348 (def (if (symbolp real-function)
349 (symbol-function real-function)
352 (beg (if (commandp def) "an interactive " "a "))
353 (pt1 (with-current-buffer (help-buffer) (point)))
356 (cond ((or (stringp def)
360 (if (eq 'unevalled (cdr (subr-arity def)))
361 (concat beg "special form")
362 (concat beg "built-in function")))
363 ((byte-code-function-p def)
364 (concat beg "compiled Lisp function"))
366 (while (and (fboundp def)
367 (symbolp (symbol-function def)))
368 (setq def (symbol-function def)))
369 ;; Handle (defalias 'foo 'bar), where bar is undefined.
370 (or (fboundp def) (setq errtype 'alias))
371 (format "an alias for `%s'" def))
372 ((eq (car-safe def) 'lambda)
373 (concat beg "Lisp function"))
374 ((eq (car-safe def) 'macro)
376 ((eq (car-safe def) 'autoload)
377 (format "%s autoloaded %s"
378 (if (commandp def) "an interactive" "an")
379 (if (eq (nth 4 def) 'keymap) "keymap"
380 (if (nth 4 def) "Lisp macro" "Lisp function"))))
383 (elts (cdr-safe def)))
385 (if (char-table-p (car-safe elts))
388 (setq elts (cdr-safe elts)))
394 (if (eq errtype 'alias)
395 (princ ",\nwhich is not defined. Please make a bug report.")
396 (with-current-buffer standard-output
399 (when (re-search-backward "alias for `\\([^`']+\\)'" nil t)
400 (help-xref-button 1 'help-function def)))))
402 (setq file-name (find-lisp-object-file-name function def))
405 ;; We used to add .el to the file name,
406 ;; but that's completely wrong when the user used load-file.
407 (princ (if (eq file-name 'C-source)
409 (file-name-nondirectory file-name)))
411 ;; Make a hyperlink to the library.
412 (with-current-buffer standard-output
414 (re-search-backward "`\\([^`']+\\)'" nil t)
415 (help-xref-button 1 'help-function-def function file-name))))
417 (with-current-buffer (help-buffer)
418 (fill-region-as-paragraph (save-excursion (goto-char pt1) (forward-line 0) (point))
421 (when (commandp function)
422 (let ((pt2 (with-current-buffer (help-buffer) (point)))
423 (remapped (command-remapping function)))
424 (unless (memq remapped '(ignore undefined))
425 (let ((keys (where-is-internal
426 (or remapped function) overriding-local-map nil nil))
428 (if (and (eq function 'self-insert-command)
429 (vectorp (car-safe keys))
430 (consp (aref (car keys) 0)))
431 (princ "It is bound to many ordinary text characters.\n")
432 ;; Which non-control non-meta keys run this command?
434 (if (member (event-modifiers (aref key 0)) '(nil (shift)))
435 (push key non-modified-keys)))
437 (princ "It is remapped to `")
438 (princ (symbol-name remapped))
442 (princ (if remapped ", which is bound to " "It is bound to "))
443 ;; If lots of ordinary text characters run this command,
444 ;; don't mention them one by one.
445 (if (< (length non-modified-keys) 10)
446 (princ (mapconcat 'key-description keys ", "))
447 (dolist (key non-modified-keys)
448 (setq keys (delq key keys)))
451 (princ (mapconcat 'key-description keys ", "))
452 (princ ", and many ordinary text characters"))
453 (princ "many ordinary text characters"))))
454 (when (or remapped keys non-modified-keys)
458 (with-current-buffer (help-buffer)
459 (fill-region-as-paragraph pt2 (point))
460 (unless (looking-back "\n\n")
462 ;; Note that list* etc do not get this property until
463 ;; cl-hack-byte-compiler runs, after bytecomp is loaded.
464 (when (and (symbolp function)
465 (eq (get function 'byte-compile)
466 'cl-byte-compile-compiler-macro))
467 (princ "This function has a compiler macro")
468 (let ((lib (get function 'compiler-macro-file)))
470 (princ (format " in `%s'" lib))
471 (with-current-buffer standard-output
473 (re-search-backward "`\\([^`']+\\)'" nil t)
474 (help-xref-button 1 'help-function-cmacro function lib)))))
476 (let* ((advertised (gethash def advertised-signature-table t))
477 (arglist (if (listp advertised)
478 advertised (help-function-arglist def)))
479 (doc (documentation function))
480 (usage (help-split-fundoc doc function)))
481 (with-current-buffer standard-output
482 ;; If definition is a keymap, skip arglist note.
483 (unless (keymapp function)
484 (if usage (setq doc (cdr usage)))
486 ((and usage (not (listp advertised))) (car usage))
488 (format "%S" (help-make-usage function arglist)))
489 ((stringp arglist) arglist)
490 ;; Maybe the arglist is in the docstring of a symbol
491 ;; this one is aliased to.
492 ((let ((fun real-function))
493 (while (and (symbolp fun)
494 (setq fun (symbol-function fun))
495 (not (setq usage (help-split-fundoc
502 (format "\nMacro: %s" (format-kbd-macro def)))
503 (t "[Missing arglist. Please make a bug report.]")))
504 (high (help-highlight-arguments use doc)))
505 (let ((fill-begin (point)))
506 (insert (car high) "\n")
507 (fill-region fill-begin (point)))
508 (setq doc (cdr high))))
509 (let* ((obsolete (and
510 ;; function might be a lambda construct.
512 (get function 'byte-obsolete-info)))
513 (use (car obsolete)))
515 (princ "\nThis function is obsolete")
516 (when (nth 2 obsolete)
517 (insert (format " since %s" (nth 2 obsolete))))
518 (insert (cond ((stringp use) (concat ";\n" use))
519 (use (format ";\nuse `%s' instead." use))
523 (or doc "Not documented."))))))))
529 (defun variable-at-point (&optional any-symbol)
530 "Return the bound variable symbol found at or before point.
531 Return 0 if there is no such symbol.
532 If ANY-SYMBOL is non-nil, don't insist the symbol be bound."
533 (with-syntax-table emacs-lisp-mode-syntax-table
534 (or (condition-case ()
536 (or (not (zerop (skip-syntax-backward "_w")))
537 (eq (char-syntax (following-char)) ?w)
538 (eq (char-syntax (following-char)) ?_)
540 (skip-chars-forward "'")
541 (let ((obj (read (current-buffer))))
542 (and (symbolp obj) (boundp obj) obj)))
544 (let* ((str (find-tag-default))
545 (sym (if str (intern-soft str))))
546 (if (and sym (or any-symbol (boundp sym)))
549 (when (and str (string-match "\\`\\W*\\(.*?\\)\\W*\\'" str))
550 (setq sym (intern-soft (match-string 1 str)))
551 (and (or any-symbol (boundp sym)) sym)))))
554 (defun describe-variable-custom-version-info (variable)
555 (let ((custom-version (get variable 'custom-version))
556 (cpv (get variable 'custom-package-version))
560 (format "This variable was introduced, or its default value was changed, in\nversion %s of Emacs.\n"
563 (let* ((package (car-safe cpv))
564 (version (if (listp (cdr-safe cpv))
567 (pkg-versions (assq package customize-package-emacs-version-alist))
568 (emacsv (cdr (assoc version pkg-versions))))
569 (if (and package version)
571 (format (concat "This variable was introduced, or its default value was changed, in\nversion %s of the %s package"
573 (format " that is part of Emacs %s" emacsv))
575 version package))))))
579 (defun describe-variable (variable &optional buffer frame)
580 "Display the full documentation of VARIABLE (a symbol).
581 Returns the documentation as a string, also.
582 If VARIABLE has a buffer-local value in BUFFER or FRAME
583 \(default to the current buffer and current frame),
584 it is displayed along with the global value."
586 (let ((v (variable-at-point))
587 (enable-recursive-minibuffers t)
589 (setq val (completing-read (if (symbolp v)
591 "Describe variable (default %s): " v)
592 "Describe variable: ")
596 (get vv 'variable-documentation)))
598 (if (symbolp v) (symbol-name v))))
599 (list (if (equal val "")
602 (unless (buffer-live-p buffer) (setq buffer (current-buffer)))
603 (unless (frame-live-p frame) (setq frame (selected-frame)))
604 (if (not (symbolp variable))
605 (message "You did not specify a variable")
607 (let ((valvoid (not (with-current-buffer buffer (boundp variable))))
608 val val-start-pos locus)
609 ;; Extract the value before setting up the output buffer,
610 ;; in case `buffer' *is* the output buffer.
612 (with-selected-frame frame
613 (with-current-buffer buffer
614 (setq val (symbol-value variable)
615 locus (variable-binding-locus variable)))))
616 (help-setup-xref (list #'describe-variable variable buffer)
617 (called-interactively-p 'interactive))
618 (with-help-window (help-buffer)
619 (with-current-buffer buffer
621 (setq file-name (find-lisp-object-file-name variable 'defvar))
625 (princ " is a variable defined in `")
626 (princ (if (eq file-name 'C-source)
628 (file-name-nondirectory file-name)))
630 (with-current-buffer standard-output
632 (re-search-backward "`\\([^`']+\\)'" nil t)
633 (help-xref-button 1 'help-variable-def
634 variable file-name)))
636 (princ "It is void as a variable.")
639 (princ " is void as a variable.")
642 (with-current-buffer standard-output
643 (setq val-start-pos (point))
645 (let ((from (point)))
648 (if (< (point) (+ 68 (line-beginning-position 0)))
649 (delete-region from (1+ from))
650 (delete-region (1- from) from))
651 (let* ((sv (get variable 'standard-value))
652 (origval (and (consp sv)
655 (error :help-eval-error)))))
656 (when (and (consp sv)
657 (not (equal origval val))
658 (not (equal origval :help-eval-error)))
659 (princ "\nOriginal value was \n")
662 (if (< (point) (+ from 20))
663 (delete-region (1- from) from)))))))
667 (princ (format "%socal in buffer %s; "
668 (if (get variable 'permanent-local)
671 (princ (format "It is a frame-local variable; ")))
672 (if (not (default-boundp variable))
673 (princ "globally void")
674 (let ((val (default-value variable)))
675 (with-current-buffer standard-output
676 (princ "global value is ")
678 ;; Fixme: pp can take an age if you happen to
679 ;; ask for a very large expression. We should
680 ;; probably print it raw once and check it's a
681 ;; sensible size before prettyprinting. -- fx
682 (let ((from (point)))
684 ;; See previous comment for this function.
685 ;; (help-xref-on-pp from (point))
686 (if (< (point) (+ from 20))
687 (delete-region (1- from) from))))))
690 ;; If the value is large, move it to the end.
691 (with-current-buffer standard-output
692 (when (> (count-lines (point-min) (point-max)) 10)
693 ;; Note that setting the syntax table like below
694 ;; makes forward-sexp move over a `'s' at the end
696 (set-syntax-table emacs-lisp-mode-syntax-table)
697 (goto-char val-start-pos)
698 ;; The line below previously read as
699 ;; (delete-region (point) (progn (end-of-line) (point)))
700 ;; which suppressed display of the buffer local value for
702 (when (looking-at "value is") (replace-match ""))
704 (insert "\n\nValue:")
705 (set (make-local-variable 'help-button-cache)
707 (insert "value is shown ")
708 (insert-button "below"
709 'action help-button-cache
711 'help-echo "mouse-2, RET: show value")
715 (let* ((alias (condition-case nil
716 (indirect-variable variable)
718 (obsolete (get variable 'byte-obsolete-variable))
720 (safe-var (get variable 'safe-local-variable))
721 (doc (or (documentation-property variable 'variable-documentation)
722 (documentation-property alias 'variable-documentation)))
724 ;; Add a note for variables that have been make-var-buffer-local.
725 (when (and (local-variable-if-set-p variable)
726 (or (not (local-variable-p variable))
728 (local-variable-if-set-p variable))))
730 (princ " Automatically becomes buffer-local when set in any fashion.\n"))
732 ;; Mention if it's an alias
733 (unless (eq alias variable)
735 (princ (format " This variable is an alias for `%s'.\n" alias)))
739 (princ " This variable is obsolete")
740 (if (cdr obsolete) (princ (format " since %s" (cdr obsolete))))
741 (princ (cond ((stringp use) (concat ";\n " use))
742 (use (format ";\n use `%s' instead." (car obsolete)))
746 (when (member (cons variable val) file-local-variables-alist)
748 (if (member (cons variable val) dir-local-variables-alist)
749 (let ((file (and (buffer-file-name)
750 (not (file-remote-p (buffer-file-name)))
751 (dir-locals-find-file (buffer-file-name)))))
752 (princ " This variable is a directory local variable")
754 (princ (concat "\n from the file \""
760 (princ " This variable is a file local variable.\n")))
762 (when (memq variable ignored-local-variables)
764 (princ " This variable is ignored when used as a file local \
767 ;; Can be both risky and safe, eg auto-fill-function.
768 (when (risky-local-variable-p variable)
770 (princ " This variable is potentially risky when used as a \
771 file local variable.\n")
772 (when (assq variable safe-local-variable-values)
773 (princ " However, you have added it to \
774 `safe-local-variable-values'.\n")))
778 (princ " This variable is safe as a file local variable ")
779 (princ "if its value\n satisfies the predicate ")
780 (princ (if (byte-code-function-p safe-var)
781 "which is byte-compiled expression.\n"
782 (format "`%s'.\n" safe-var))))
784 (if extra-line (terpri))
785 (princ "Documentation:\n")
786 (with-current-buffer standard-output
787 (insert (or doc "Not documented as a variable."))))
789 ;; Make a link to customize if this variable can be customized.
790 (when (custom-variable-p variable)
791 (let ((customize-label "customize"))
794 (princ (concat "You can " customize-label " this variable."))
795 (with-current-buffer standard-output
798 (concat "\\(" customize-label "\\)") nil t)
799 (help-xref-button 1 'help-customize-variable variable))))
800 ;; Note variable's version or package version
801 (let ((output (describe-variable-custom-version-info variable)))
807 (with-current-buffer standard-output
808 ;; Return the text we displayed.
809 (buffer-string))))))))
813 (defun describe-syntax (&optional buffer)
814 "Describe the syntax specifications in the syntax table of BUFFER.
815 The descriptions are inserted in a help buffer, which is then displayed.
816 BUFFER defaults to the current buffer."
818 (setq buffer (or buffer (current-buffer)))
819 (help-setup-xref (list #'describe-syntax buffer)
820 (called-interactively-p 'interactive))
821 (with-help-window (help-buffer)
822 (let ((table (with-current-buffer buffer (syntax-table))))
823 (with-current-buffer standard-output
824 (describe-vector table 'internal-describe-syntax-value)
825 (while (setq table (char-table-parent table))
826 (insert "\nThe parent syntax table is:")
827 (describe-vector table 'internal-describe-syntax-value))))))
829 (defun help-describe-category-set (value)
831 ((null value) "default")
832 ((char-table-p value) "deeper char-table ...")
833 (t (condition-case err
834 (category-set-mnemonics value)
835 (error "invalid"))))))
838 (defun describe-categories (&optional buffer)
839 "Describe the category specifications in the current category table.
840 The descriptions are inserted in a buffer, which is then displayed.
841 If BUFFER is non-nil, then describe BUFFER's category table instead.
842 BUFFER should be a buffer or a buffer name."
844 (setq buffer (or buffer (current-buffer)))
845 (help-setup-xref (list #'describe-categories buffer)
846 (called-interactively-p 'interactive))
847 (with-help-window (help-buffer)
848 (let* ((table (with-current-buffer buffer (category-table)))
849 (docs (char-table-extra-slot table 0)))
850 (if (or (not (vectorp docs)) (/= (length docs) 95))
851 (error "Invalid first extra slot in this category table\n"))
852 (with-current-buffer standard-output
853 (insert "Legend of category mnemonics (see the tail for the longer description)\n")
854 (let ((pos (point)) (items 0) lines n)
856 (if (aref docs i) (setq items (1+ items))))
857 (setq lines (1+ (/ (1- items) 4)))
860 (let ((elt (aref docs i)))
862 (string-match ".*" elt)
863 (setq elt (match-string 0 elt))
864 (if (>= (length elt) 17)
865 (setq elt (concat (substring elt 0 14) "...")))
866 (if (< (point) (point-max))
867 (move-to-column (* 20 (/ n lines)) t))
868 (insert (+ i ?\s) ?: elt)
869 (if (< (point) (point-max))
873 (if (= (% n lines) 0)
875 (goto-char (point-max))
877 "character(s)\tcategory mnemonics\n"
878 "------------\t------------------")
879 (describe-vector table 'help-describe-category-set)
880 (insert "Legend of category mnemonics:\n")
882 (let ((elt (aref docs i)))
884 (if (string-match "\n" elt)
885 (setq elt (substring elt (match-end 0))))
886 (insert (+ i ?\s) ": " elt "\n"))))
887 (while (setq table (char-table-parent table))
888 (insert "\nThe parent category table is:")
889 (describe-vector table 'help-describe-category-set))))))
892 ;;; Replacements for old lib-src/ programs. Don't seem especially useful.
894 ;; Replaces lib-src/digest-doc.c.
896 (defun doc-file-to-man (file)
897 "Produce an nroff buffer containing the doc-strings from the DOC file."
898 (interactive (list (read-file-name "Name of DOC file: " doc-directory
899 internal-doc-file-name t)))
900 (or (file-readable-p file)
901 (error "Cannot read file `%s'" file))
902 (pop-to-buffer (generate-new-buffer "*man-doc*"))
903 (setq buffer-undo-list t)
904 (insert ".TH \"Command Summary for GNU Emacs\"\n"
905 ".AU Richard M. Stallman\n")
906 (insert-file-contents file)
908 (while (search-forward "
\1f" nil 'move)
910 (delete-region (1- (point)) (line-end-position))
916 (insert (if (looking-at "F") "Function " "Variable "))
919 (insert ".DS L\n"))))
921 (setq buffer-undo-list nil)
924 ;; Replaces lib-src/sorted-doc.c.
926 (defun doc-file-to-info (file)
927 "Produce a texinfo buffer with sorted doc-strings from the DOC file."
928 (interactive (list (read-file-name "Name of DOC file: " doc-directory
929 internal-doc-file-name t)))
930 (or (file-readable-p file)
931 (error "Cannot read file `%s'" file))
932 (let ((i 0) type name doc alist)
934 (insert-file-contents file)
935 ;; The characters "@{}" need special treatment.
936 (while (re-search-forward "[@{}]" nil t)
940 (goto-char (point-min))
941 (while (search-forward "
\1f" nil t)
942 (unless (looking-at "S")
943 (setq type (char-after)
944 name (buffer-substring (1+ (point)) (line-end-position))
945 doc (buffer-substring (line-beginning-position 2)
946 (if (search-forward "
\1f" nil 'move)
949 alist (cons (list name type doc) alist))
951 (pop-to-buffer (generate-new-buffer "*info-doc*"))
952 (setq buffer-undo-list t)
953 ;; Write the output header.
954 (insert "\\input texinfo @c -*-texinfo-*-\n"
955 "@setfilename emacsdoc.info\n"
956 "@settitle Command Summary for GNU Emacs\n"
959 "@unnumbered Command Summary for GNU Emacs\n\n"
962 "@global@let@ITEM@item\n"
963 "@def@item{@filbreak@vskip5pt@ITEM}\n"
964 "@font@tensy cmsy10 scaled @magstephalf\n"
965 "@font@teni cmmi10 scaled @magstephalf\n"
966 "@def\\{{@tensy@char110}}\n" ; this backslash goes with cmr10
967 "@def|{{@tensy@char106}}\n"
968 "@def@{{{@tensy@char102}}\n"
969 "@def@}{{@tensy@char103}}\n"
970 "@def<{{@teni@char62}}\n"
971 "@def>{{@teni@char60}}\n"
974 "@tableindent-0.2in\n"
976 ;; Sort the array by name; within each name, by type (functions first).
977 (setq alist (sort alist (lambda (e1 e2)
978 (if (string-equal (car e1) (car e2))
979 (<= (cadr e1) (cadr e2))
980 (string-lessp (car e1) (car e2))))))
981 ;; Print each function.
984 (if (char-equal (cadr e) ?\F) "Function" "Variable")
985 " @code{" (car e) "}\n@display\n"
988 ;; Try to avoid a save size overflow in the TeX output routine.
989 (if (zerop (setq i (% (1+ i) 100)))
990 (insert "\n@end table\n@table @asis\n")))
991 (insert "@end table\n"
993 (setq buffer-undo-list nil)
998 ;;; help-fns.el ends here