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 (unless (zerop (match-beginning 0))
80 (substring docstring 0 (match-beginning 0))))))
82 ;; FIXME: Move to subr.el?
83 (defun help-add-fundoc-usage (docstring arglist)
84 "Add the usage info to DOCSTRING.
85 If DOCSTRING already has a usage info, then just return it unchanged.
86 The usage info is built from ARGLIST. DOCSTRING can be nil.
87 ARGLIST can also be t or a string of the form \"(FUN ARG1 ARG2 ...)\"."
88 (unless (stringp docstring) (setq docstring ""))
89 (if (or (string-match "\n\n(fn\\(\\( .*\\)?)\\)\\'" docstring)
93 (if (string-match "\n?\n\\'" docstring)
94 (if (< (- (match-end 0) (match-beginning 0)) 2) "\n" "")
96 (if (and (stringp arglist)
97 (string-match "\\`([^ ]+\\(.*\\))\\'" arglist))
98 (concat "(fn" (match-string 1 arglist) ")")
99 (format "%S" (help-make-usage 'fn arglist))))))
101 ;; FIXME: Move to subr.el?
102 (defun help-function-arglist (def)
103 ;; Handle symbols aliased to other symbols.
104 (if (and (symbolp def) (fboundp def)) (setq def (indirect-function def)))
105 ;; If definition is a macro, find the function inside it.
106 (if (eq (car-safe def) 'macro) (setq def (cdr def)))
107 ;; and do the same for interpreted closures
108 (if (eq (car-safe def) 'closure) (setq def (cddr def)))
110 ((and (byte-code-function-p def) (integerp (aref def 0)))
111 (let* ((args-desc (aref def 0))
112 (max (lsh args-desc -8))
113 (min (logand args-desc 127))
114 (rest (logand args-desc 128))
117 (push (intern (concat "arg" (number-to-string (1+ i)))) arglist))
119 (push '&optional arglist)
120 (dotimes (i (- max min))
121 (push (intern (concat "arg" (number-to-string (+ 1 i min))))
123 (unless (zerop rest) (push '&rest arglist) (push 'rest arglist))
125 ((byte-code-function-p def) (aref def 0))
126 ((eq (car-safe def) 'lambda) (nth 1 def))
128 (let ((arity (subr-arity def))
130 (dotimes (i (car arity))
131 (push (intern (concat "arg" (number-to-string (1+ i)))) arglist))
133 ((not (numberp (cdr arglist)))
134 (push '&rest arglist)
135 (push 'rest arglist))
136 ((< (car arity) (cdr arity))
137 (push '&optional arglist)
138 (dotimes (i (- (cdr arity) (car arity)))
139 (push (intern (concat "arg" (number-to-string
140 (+ 1 i (car arity)))))
143 ((and (eq (car-safe def) 'autoload) (not (eq (nth 4 def) 'keymap)))
144 "[Arg list not available until function definition is loaded.]")
147 ;; FIXME: Move to subr.el?
148 (defun help-make-usage (function arglist)
149 (cons (if (symbolp function) function 'anonymous)
150 (mapcar (lambda (arg)
151 (if (not (symbolp arg))
152 (if (and (consp arg) (symbolp (car arg)))
153 ;; CL style default values for optional args.
154 (cons (intern (upcase (symbol-name (car arg))))
157 (let ((name (symbol-name arg)))
159 ((string-match "\\`&" name) arg)
160 ((string-match "\\`_" name)
161 (intern (upcase (substring name 1))))
162 (t (intern (upcase name)))))))
165 ;; Could be this, if we make symbol-file do the work below.
166 ;; (defun help-C-file-name (subr-or-var kind)
167 ;; "Return the name of the C file where SUBR-OR-VAR is defined.
168 ;; KIND should be `var' for a variable or `subr' for a subroutine."
169 ;; (symbol-file (if (symbolp subr-or-var) subr-or-var
170 ;; (subr-name subr-or-var))
171 ;; (if (eq kind 'var) 'defvar 'defun)))
173 (defun help-C-file-name (subr-or-var kind)
174 "Return the name of the C file where SUBR-OR-VAR is defined.
175 KIND should be `var' for a variable or `subr' for a subroutine."
176 (let ((docbuf (get-buffer-create " *DOC*"))
177 (name (if (eq 'var kind)
178 (concat "V" (symbol-name subr-or-var))
179 (concat "F" (subr-name subr-or-var)))))
180 (with-current-buffer docbuf
181 (goto-char (point-min))
183 (insert-file-contents-literally
184 (expand-file-name internal-doc-file-name doc-directory)))
185 (let ((file (catch 'loop
187 (let ((pnt (search-forward (concat "
\1f" name "\n"))))
188 (re-search-backward "
\1fS\\(.*\\)")
189 (let ((file (match-string 1)))
190 (if (member file build-files)
192 (goto-char pnt))))))))
193 (if (string-match "^ns.*\\(\\.o\\|obj\\)\\'" file)
194 (setq file (replace-match ".m" t t file 1))
195 (if (string-match "\\.\\(o\\|obj\\)\\'" file)
196 (setq file (replace-match ".c" t t file))))
197 (if (string-match "\\.\\(c\\|m\\)\\'" file)
201 (defcustom help-downcase-arguments nil
202 "If non-nil, argument names in *Help* buffers are downcased."
207 (defun help-highlight-arg (arg)
208 "Highlight ARG as an argument name for a *Help* buffer.
209 Return ARG in face `help-argument-name'; ARG is also downcased
210 if the variable `help-downcase-arguments' is non-nil."
211 (propertize (if help-downcase-arguments (downcase arg) arg)
212 'face 'help-argument-name))
214 (defun help-do-arg-highlight (doc args)
215 (with-syntax-table (make-syntax-table emacs-lisp-mode-syntax-table)
216 (modify-syntax-entry ?\- "w")
217 (dolist (arg args doc)
218 (setq doc (replace-regexp-in-string
219 ;; This is heuristic, but covers all common cases
221 (concat "\\<" ; beginning of word
222 "\\(?:[a-z-]*-\\)?" ; for xxx-ARG
226 "\\(?:es\\|s\\|th\\)?" ; for ARGth, ARGs
227 "\\(?:-[a-z0-9-]+\\)?" ; for ARG-xxx, ARG-n
228 "\\(?:-[{([<`\"].*?\\)?"; for ARG-{x}, (x), <x>, [x], `x'
230 (help-highlight-arg arg)
233 (defun help-highlight-arguments (usage doc &rest args)
234 (when (and usage (string-match "^(" usage))
237 (goto-char (point-min))
238 (let ((case-fold-search nil)
239 (next (not (or args (looking-at "\\["))))
241 ;; Make a list of all arguments
242 (skip-chars-forward "^ ")
244 (or opt (not (looking-at " &")) (setq opt t))
245 (if (not (re-search-forward " \\([\\[(]*\\)\\([^] &)\.]+\\)" nil t))
247 (setq args (cons (match-string 2) args))
248 (when (and opt (string= (match-string 1) "("))
249 ;; A pesky CL-style optional argument with default value,
250 ;; so let's skip over it
251 (search-backward "(")
252 (goto-char (scan-sexps (point) 1)))))
253 ;; Highlight aguments in the USAGE string
254 (setq usage (help-do-arg-highlight (buffer-string) args))
255 ;; Highlight arguments in the DOC string
256 (setq doc (and doc (help-do-arg-highlight doc args))))))
257 ;; Return value is like the one from help-split-fundoc, but highlighted
260 ;; The following function was compiled from the former functions
261 ;; `describe-simplify-lib-file-name' and `find-source-lisp-file' with
262 ;; some excerpts from `describe-function-1' and `describe-variable'.
263 ;; The only additional twists provided are (1) locate the defining file
264 ;; for autoloaded functions, and (2) give preference to files in the
265 ;; "install directory" (directories found via `load-path') rather than
266 ;; to files in the "compile directory" (directories found by searching
267 ;; the loaddefs.el file). We autoload it because it's also used by
268 ;; `describe-face' (instead of `describe-simplify-lib-file-name').
271 (defun find-lisp-object-file-name (object type)
272 "Guess the file that defined the Lisp object OBJECT, of type TYPE.
273 OBJECT should be a symbol associated with a function, variable, or face;
274 alternatively, it can be a function definition.
275 If TYPE is `defvar', search for a variable definition.
276 If TYPE is `defface', search for a face definition.
277 If TYPE is the value returned by `symbol-function' for a function symbol,
278 search for a function definition.
280 The return value is the absolute name of a readable file where OBJECT is
281 defined. If several such files exist, preference is given to a file
282 found via `load-path'. The return value can also be `C-source', which
283 means that OBJECT is a function or variable defined in C. If no
284 suitable file is found, return nil."
285 (let* ((autoloaded (eq (car-safe type) 'autoload))
286 (file-name (or (and autoloaded (nth 1 type))
288 object (if (memq type (list 'defvar 'defface))
293 ;; An autoloaded function: Locate the file since `symbol-function'
294 ;; has only returned a bare string here.
296 (locate-file file-name load-path '(".el" ".elc") 'readable)))
297 ((and (stringp file-name)
298 (string-match "[.]*loaddefs.el\\'" file-name))
299 ;; An autoloaded variable or face. Visit loaddefs.el in a buffer
300 ;; and try to extract the defining file. The following form is
301 ;; from `describe-function-1' and `describe-variable'.
304 (find-function-search-for-symbol object nil file-name)
307 (with-current-buffer (car location)
308 (goto-char (cdr location))
309 (when (re-search-backward
310 "^;;; Generated autoloads from \\(.*\\)" nil t)
313 (file-name-sans-extension
314 (match-string-no-properties 1))
315 load-path '(".el" ".elc") 'readable))))))))
318 ((and (not file-name) (subrp type))
319 ;; A built-in function. The form is from `describe-function-1'.
320 (if (get-buffer " *DOC*")
321 (help-C-file-name type 'subr)
323 ((and (not file-name) (symbolp object)
324 (integerp (get object 'variable-documentation)))
325 ;; A variable defined in C. The form is from `describe-variable'.
326 (if (get-buffer " *DOC*")
327 (help-C-file-name object 'var)
329 ((not (stringp file-name))
330 ;; If we don't have a file-name string by now, we lost.
332 ;; Now, `file-name' should have become an absolute file name.
333 ;; For files loaded from ~/.emacs.elc, try ~/.emacs.
335 (and (string-equal file-name
336 (expand-file-name ".emacs.elc" "~"))
337 (file-readable-p (setq fn (expand-file-name ".emacs" "~")))
339 ;; When the Elisp source file can be found in the install
340 ;; directory, return the name of that file.
342 (if (string-match "[.]elc\\'" file-name)
343 (substring-no-properties file-name 0 -1)
345 (or (and (file-readable-p lib-name) lib-name)
346 ;; The library might be compressed.
347 (and (file-readable-p (concat lib-name ".gz")) lib-name))))
348 ((let* ((lib-name (file-name-nondirectory file-name))
349 ;; The next form is from `describe-simplify-lib-file-name'.
351 ;; Try converting the absolute file name to a library
352 ;; name, convert that back to a file name and see if we
353 ;; get the original one. If so, they are equivalent.
354 (if (equal file-name (locate-file lib-name load-path '("")))
355 (if (string-match "[.]elc\\'" lib-name)
356 (substring-no-properties lib-name 0 -1)
359 ;; The next three forms are from `find-source-lisp-file'.
360 (elc-file (locate-file
362 (if (string-match "\\.el\\'" file-name)
365 load-path nil 'readable))
368 (insert-file-contents-literally elc-file nil 0 256)
371 (string-match ";;; from file \\(.*\\.el\\)" str)
372 (match-string 1 str))))
373 (and src-file (file-readable-p src-file) src-file))))))
375 (declare-function ad-get-advice-info "advice" (function))
378 (defun describe-function-1 (function)
379 (let* ((advised (and (symbolp function) (featurep 'advice)
380 (ad-get-advice-info function)))
381 ;; If the function is advised, use the symbol that has the
382 ;; real definition, if that symbol is already set up.
385 (let ((origname (cdr (assq 'origname advised))))
386 (and (fboundp origname) origname)))
388 ;; Get the real definition.
389 (def (if (symbolp real-function)
390 (symbol-function real-function)
393 (beg (if (commandp def) "an interactive " "a "))
394 (pt1 (with-current-buffer (help-buffer) (point)))
397 (cond ((or (stringp def) (vectorp def))
400 (if (eq 'unevalled (cdr (subr-arity def)))
401 (concat beg "special form")
402 (concat beg "built-in function")))
403 ((byte-code-function-p def)
404 (concat beg "compiled Lisp function"))
406 (while (and (fboundp def)
407 (symbolp (symbol-function def)))
408 (setq def (symbol-function def)))
409 ;; Handle (defalias 'foo 'bar), where bar is undefined.
410 (or (fboundp def) (setq errtype 'alias))
411 (format "an alias for `%s'" def))
412 ((eq (car-safe def) 'lambda)
413 (concat beg "Lisp function"))
414 ((eq (car-safe def) 'macro)
416 ((eq (car-safe def) 'closure)
417 (concat beg "Lisp closure"))
418 ((eq (car-safe def) 'autoload)
419 (format "%s autoloaded %s"
420 (if (commandp def) "an interactive" "an")
421 (if (eq (nth 4 def) 'keymap) "keymap"
422 (if (nth 4 def) "Lisp macro" "Lisp function"))))
425 (elts (cdr-safe def)))
427 (if (char-table-p (car-safe elts))
430 (setq elts (cdr-safe elts)))
436 (if (eq errtype 'alias)
437 (princ ",\nwhich is not defined. Please make a bug report.")
438 (with-current-buffer standard-output
441 (when (re-search-backward "alias for `\\([^`']+\\)'" nil t)
442 (help-xref-button 1 'help-function def)))))
444 (setq file-name (find-lisp-object-file-name function def))
447 ;; We used to add .el to the file name,
448 ;; but that's completely wrong when the user used load-file.
449 (princ (if (eq file-name 'C-source)
451 (file-name-nondirectory file-name)))
453 ;; Make a hyperlink to the library.
454 (with-current-buffer standard-output
456 (re-search-backward "`\\([^`']+\\)'" nil t)
457 (help-xref-button 1 'help-function-def function file-name))))
459 (with-current-buffer (help-buffer)
460 (fill-region-as-paragraph (save-excursion (goto-char pt1) (forward-line 0) (point))
463 (when (commandp function)
464 (let ((pt2 (with-current-buffer (help-buffer) (point)))
465 (remapped (command-remapping function)))
466 (unless (memq remapped '(ignore undefined))
467 (let ((keys (where-is-internal
468 (or remapped function) overriding-local-map nil nil))
470 (if (and (eq function 'self-insert-command)
471 (vectorp (car-safe keys))
472 (consp (aref (car keys) 0)))
473 (princ "It is bound to many ordinary text characters.\n")
474 ;; Which non-control non-meta keys run this command?
476 (if (member (event-modifiers (aref key 0)) '(nil (shift)))
477 (push key non-modified-keys)))
479 (princ "It is remapped to `")
480 (princ (symbol-name remapped))
484 (princ (if remapped ", which is bound to " "It is bound to "))
485 ;; If lots of ordinary text characters run this command,
486 ;; don't mention them one by one.
487 (if (< (length non-modified-keys) 10)
488 (princ (mapconcat 'key-description keys ", "))
489 (dolist (key non-modified-keys)
490 (setq keys (delq key keys)))
493 (princ (mapconcat 'key-description keys ", "))
494 (princ ", and many ordinary text characters"))
495 (princ "many ordinary text characters"))))
496 (when (or remapped keys non-modified-keys)
500 (with-current-buffer (help-buffer)
501 (fill-region-as-paragraph pt2 (point))
502 (unless (looking-back "\n\n")
504 ;; Note that list* etc do not get this property until
505 ;; cl-hack-byte-compiler runs, after bytecomp is loaded.
506 (when (and (symbolp function)
507 (eq (get function 'byte-compile)
508 'cl-byte-compile-compiler-macro))
509 (princ "This function has a compiler macro")
510 (let ((lib (get function 'compiler-macro-file)))
512 (princ (format " in `%s'" lib))
513 (with-current-buffer standard-output
515 (re-search-backward "`\\([^`']+\\)'" nil t)
516 (help-xref-button 1 'help-function-cmacro function lib)))))
518 (let* ((advertised (gethash def advertised-signature-table t))
519 (arglist (if (listp advertised)
520 advertised (help-function-arglist def)))
521 (doc (condition-case err (documentation function)
522 (error (format "No Doc! %S" err))))
523 (usage (help-split-fundoc doc function)))
524 (with-current-buffer standard-output
525 ;; If definition is a keymap, skip arglist note.
526 (unless (keymapp function)
527 (if usage (setq doc (cdr usage)))
529 ((and usage (not (listp advertised))) (car usage))
531 (format "%S" (help-make-usage function arglist)))
532 ((stringp arglist) arglist)
533 ;; Maybe the arglist is in the docstring of a symbol
534 ;; this one is aliased to.
535 ((let ((fun real-function))
536 (while (and (symbolp fun)
537 (setq fun (symbol-function fun))
538 (not (setq usage (help-split-fundoc
545 (format "\nMacro: %s" (format-kbd-macro def)))
546 (t "[Missing arglist. Please make a bug report.]")))
547 (high (help-highlight-arguments use doc)))
548 (let ((fill-begin (point)))
549 (insert (car high) "\n")
550 (fill-region fill-begin (point)))
551 (setq doc (cdr high))))
552 (let* ((obsolete (and
553 ;; function might be a lambda construct.
555 (get function 'byte-obsolete-info)))
556 (use (car obsolete)))
558 (princ "\nThis function is obsolete")
559 (when (nth 2 obsolete)
560 (insert (format " since %s" (nth 2 obsolete))))
561 (insert (cond ((stringp use) (concat ";\n" use))
562 (use (format ";\nuse `%s' instead." use))
566 (or doc "Not documented."))))))))
572 (defun variable-at-point (&optional any-symbol)
573 "Return the bound variable symbol found at or before point.
574 Return 0 if there is no such symbol.
575 If ANY-SYMBOL is non-nil, don't insist the symbol be bound."
576 (with-syntax-table emacs-lisp-mode-syntax-table
577 (or (condition-case ()
579 (or (not (zerop (skip-syntax-backward "_w")))
580 (eq (char-syntax (following-char)) ?w)
581 (eq (char-syntax (following-char)) ?_)
583 (skip-chars-forward "'")
584 (let ((obj (read (current-buffer))))
585 (and (symbolp obj) (boundp obj) obj)))
587 (let* ((str (find-tag-default))
588 (sym (if str (intern-soft str))))
589 (if (and sym (or any-symbol (boundp sym)))
592 (when (and str (string-match "\\`\\W*\\(.*?\\)\\W*\\'" str))
593 (setq sym (intern-soft (match-string 1 str)))
594 (and (or any-symbol (boundp sym)) sym)))))
597 (defun describe-variable-custom-version-info (variable)
598 (let ((custom-version (get variable 'custom-version))
599 (cpv (get variable 'custom-package-version))
603 (format "This variable was introduced, or its default value was changed, in\nversion %s of Emacs.\n"
606 (let* ((package (car-safe cpv))
607 (version (if (listp (cdr-safe cpv))
610 (pkg-versions (assq package customize-package-emacs-version-alist))
611 (emacsv (cdr (assoc version pkg-versions))))
612 (if (and package version)
614 (format (concat "This variable was introduced, or its default value was changed, in\nversion %s of the %s package"
616 (format " that is part of Emacs %s" emacsv))
618 version package))))))
622 (defun describe-variable (variable &optional buffer frame)
623 "Display the full documentation of VARIABLE (a symbol).
624 Returns the documentation as a string, also.
625 If VARIABLE has a buffer-local value in BUFFER or FRAME
626 \(default to the current buffer and current frame),
627 it is displayed along with the global value."
629 (let ((v (variable-at-point))
630 (enable-recursive-minibuffers t)
632 (setq val (completing-read (if (symbolp v)
634 "Describe variable (default %s): " v)
635 "Describe variable: ")
638 (or (special-variable-p vv)
639 (get vv 'variable-documentation)))
641 (if (symbolp v) (symbol-name v))))
642 (list (if (equal val "")
645 (unless (buffer-live-p buffer) (setq buffer (current-buffer)))
646 (unless (frame-live-p frame) (setq frame (selected-frame)))
647 (if (not (symbolp variable))
648 (message "You did not specify a variable")
650 (let ((valvoid (not (with-current-buffer buffer (boundp variable))))
651 val val-start-pos locus)
652 ;; Extract the value before setting up the output buffer,
653 ;; in case `buffer' *is* the output buffer.
655 (with-selected-frame frame
656 (with-current-buffer buffer
657 (setq val (symbol-value variable)
658 locus (variable-binding-locus variable)))))
659 (help-setup-xref (list #'describe-variable variable buffer)
660 (called-interactively-p 'interactive))
661 (with-help-window (help-buffer)
662 (with-current-buffer buffer
664 (setq file-name (find-lisp-object-file-name variable 'defvar))
668 (princ " is a variable defined in `")
669 (princ (if (eq file-name 'C-source)
671 (file-name-nondirectory file-name)))
673 (with-current-buffer standard-output
675 (re-search-backward "`\\([^`']+\\)'" nil t)
676 (help-xref-button 1 'help-variable-def
677 variable file-name)))
679 (princ "It is void as a variable.")
682 (princ " is void as a variable.")
685 (with-current-buffer standard-output
686 (setq val-start-pos (point))
688 (let ((from (point)))
691 (if (< (point) (+ 68 (line-beginning-position 0)))
692 (delete-region from (1+ from))
693 (delete-region (1- from) from))
694 (let* ((sv (get variable 'standard-value))
695 (origval (and (consp sv)
698 (error :help-eval-error)))))
699 (when (and (consp sv)
700 (not (equal origval val))
701 (not (equal origval :help-eval-error)))
702 (princ "\nOriginal value was \n")
705 (if (< (point) (+ from 20))
706 (delete-region (1- from) from)))))))
710 (princ (format "%socal in buffer %s; "
711 (if (get variable 'permanent-local)
714 (princ (format "It is a frame-local variable; ")))
715 (if (not (default-boundp variable))
716 (princ "globally void")
717 (let ((val (default-value variable)))
718 (with-current-buffer standard-output
719 (princ "global value is ")
721 ;; Fixme: pp can take an age if you happen to
722 ;; ask for a very large expression. We should
723 ;; probably print it raw once and check it's a
724 ;; sensible size before prettyprinting. -- fx
725 (let ((from (point)))
727 ;; See previous comment for this function.
728 ;; (help-xref-on-pp from (point))
729 (if (< (point) (+ from 20))
730 (delete-region (1- from) from))))))
733 ;; If the value is large, move it to the end.
734 (with-current-buffer standard-output
735 (when (> (count-lines (point-min) (point-max)) 10)
736 ;; Note that setting the syntax table like below
737 ;; makes forward-sexp move over a `'s' at the end
739 (set-syntax-table emacs-lisp-mode-syntax-table)
740 (goto-char val-start-pos)
741 ;; The line below previously read as
742 ;; (delete-region (point) (progn (end-of-line) (point)))
743 ;; which suppressed display of the buffer local value for
745 (when (looking-at "value is") (replace-match ""))
747 (insert "\n\nValue:")
748 (set (make-local-variable 'help-button-cache)
750 (insert "value is shown ")
751 (insert-button "below"
752 'action help-button-cache
754 'help-echo "mouse-2, RET: show value")
758 (let* ((alias (condition-case nil
759 (indirect-variable variable)
761 (obsolete (get variable 'byte-obsolete-variable))
763 (safe-var (get variable 'safe-local-variable))
764 (doc (or (documentation-property variable 'variable-documentation)
765 (documentation-property alias 'variable-documentation)))
767 ;; Add a note for variables that have been make-var-buffer-local.
768 (when (and (local-variable-if-set-p variable)
769 (or (not (local-variable-p variable))
771 (local-variable-if-set-p variable))))
773 (princ " Automatically becomes buffer-local when set in any fashion.\n"))
775 ;; Mention if it's an alias
776 (unless (eq alias variable)
778 (princ (format " This variable is an alias for `%s'.\n" alias)))
782 (princ " This variable is obsolete")
783 (if (cdr obsolete) (princ (format " since %s" (cdr obsolete))))
784 (princ (cond ((stringp use) (concat ";\n " use))
785 (use (format ";\n use `%s' instead." (car obsolete)))
789 (when (member (cons variable val) file-local-variables-alist)
791 (if (member (cons variable val) dir-local-variables-alist)
792 (let ((file (and (buffer-file-name)
793 (not (file-remote-p (buffer-file-name)))
794 (dir-locals-find-file
795 (buffer-file-name))))
797 (princ " This variable is a directory local variable")
799 (if (consp file) ; result from cache
800 ;; If the cache element has an mtime, we
801 ;; assume it came from a file.
803 (setq file (expand-file-name
804 dir-locals-file (car file)))
805 ;; Otherwise, assume it was set directly.
806 (setq type "directory")))
807 (princ (format "\n from the %s \"%s\"" type file)))
809 (princ " This variable is a file local variable.\n")))
811 (when (memq variable ignored-local-variables)
813 (princ " This variable is ignored when used as a file local \
816 ;; Can be both risky and safe, eg auto-fill-function.
817 (when (risky-local-variable-p variable)
819 (princ " This variable is potentially risky when used as a \
820 file local variable.\n")
821 (when (assq variable safe-local-variable-values)
822 (princ " However, you have added it to \
823 `safe-local-variable-values'.\n")))
827 (princ " This variable is safe as a file local variable ")
828 (princ "if its value\n satisfies the predicate ")
829 (princ (if (byte-code-function-p safe-var)
830 "which is byte-compiled expression.\n"
831 (format "`%s'.\n" safe-var))))
833 (if extra-line (terpri))
834 (princ "Documentation:\n")
835 (with-current-buffer standard-output
836 (insert (or doc "Not documented as a variable."))))
838 ;; Make a link to customize if this variable can be customized.
839 (when (custom-variable-p variable)
840 (let ((customize-label "customize"))
843 (princ (concat "You can " customize-label " this variable."))
844 (with-current-buffer standard-output
847 (concat "\\(" customize-label "\\)") nil t)
848 (help-xref-button 1 'help-customize-variable variable))))
849 ;; Note variable's version or package version
850 (let ((output (describe-variable-custom-version-info variable)))
856 (with-current-buffer standard-output
857 ;; Return the text we displayed.
858 (buffer-string))))))))
862 (defun describe-syntax (&optional buffer)
863 "Describe the syntax specifications in the syntax table of BUFFER.
864 The descriptions are inserted in a help buffer, which is then displayed.
865 BUFFER defaults to the current buffer."
867 (setq buffer (or buffer (current-buffer)))
868 (help-setup-xref (list #'describe-syntax buffer)
869 (called-interactively-p 'interactive))
870 (with-help-window (help-buffer)
871 (let ((table (with-current-buffer buffer (syntax-table))))
872 (with-current-buffer standard-output
873 (describe-vector table 'internal-describe-syntax-value)
874 (while (setq table (char-table-parent table))
875 (insert "\nThe parent syntax table is:")
876 (describe-vector table 'internal-describe-syntax-value))))))
878 (defun help-describe-category-set (value)
880 ((null value) "default")
881 ((char-table-p value) "deeper char-table ...")
882 (t (condition-case err
883 (category-set-mnemonics value)
884 (error "invalid"))))))
887 (defun describe-categories (&optional buffer)
888 "Describe the category specifications in the current category table.
889 The descriptions are inserted in a buffer, which is then displayed.
890 If BUFFER is non-nil, then describe BUFFER's category table instead.
891 BUFFER should be a buffer or a buffer name."
893 (setq buffer (or buffer (current-buffer)))
894 (help-setup-xref (list #'describe-categories buffer)
895 (called-interactively-p 'interactive))
896 (with-help-window (help-buffer)
897 (let* ((table (with-current-buffer buffer (category-table)))
898 (docs (char-table-extra-slot table 0)))
899 (if (or (not (vectorp docs)) (/= (length docs) 95))
900 (error "Invalid first extra slot in this category table\n"))
901 (with-current-buffer standard-output
902 (insert "Legend of category mnemonics (see the tail for the longer description)\n")
903 (let ((pos (point)) (items 0) lines n)
905 (if (aref docs i) (setq items (1+ items))))
906 (setq lines (1+ (/ (1- items) 4)))
909 (let ((elt (aref docs i)))
911 (string-match ".*" elt)
912 (setq elt (match-string 0 elt))
913 (if (>= (length elt) 17)
914 (setq elt (concat (substring elt 0 14) "...")))
915 (if (< (point) (point-max))
916 (move-to-column (* 20 (/ n lines)) t))
917 (insert (+ i ?\s) ?: elt)
918 (if (< (point) (point-max))
922 (if (= (% n lines) 0)
924 (goto-char (point-max))
926 "character(s)\tcategory mnemonics\n"
927 "------------\t------------------")
928 (describe-vector table 'help-describe-category-set)
929 (insert "Legend of category mnemonics:\n")
931 (let ((elt (aref docs i)))
933 (if (string-match "\n" elt)
934 (setq elt (substring elt (match-end 0))))
935 (insert (+ i ?\s) ": " elt "\n"))))
936 (while (setq table (char-table-parent table))
937 (insert "\nThe parent category table is:")
938 (describe-vector table 'help-describe-category-set))))))
941 ;;; Replacements for old lib-src/ programs. Don't seem especially useful.
943 ;; Replaces lib-src/digest-doc.c.
945 (defun doc-file-to-man (file)
946 "Produce an nroff buffer containing the doc-strings from the DOC file."
947 (interactive (list (read-file-name "Name of DOC file: " doc-directory
948 internal-doc-file-name t)))
949 (or (file-readable-p file)
950 (error "Cannot read file `%s'" file))
951 (pop-to-buffer (generate-new-buffer "*man-doc*"))
952 (setq buffer-undo-list t)
953 (insert ".TH \"Command Summary for GNU Emacs\"\n"
954 ".AU Richard M. Stallman\n")
955 (insert-file-contents file)
957 (while (search-forward "
\1f" nil 'move)
959 (delete-region (1- (point)) (line-end-position))
965 (insert (if (looking-at "F") "Function " "Variable "))
968 (insert ".DS L\n"))))
970 (setq buffer-undo-list nil)
973 ;; Replaces lib-src/sorted-doc.c.
975 (defun doc-file-to-info (file)
976 "Produce a texinfo buffer with sorted doc-strings from the DOC file."
977 (interactive (list (read-file-name "Name of DOC file: " doc-directory
978 internal-doc-file-name t)))
979 (or (file-readable-p file)
980 (error "Cannot read file `%s'" file))
981 (let ((i 0) type name doc alist)
983 (insert-file-contents file)
984 ;; The characters "@{}" need special treatment.
985 (while (re-search-forward "[@{}]" nil t)
989 (goto-char (point-min))
990 (while (search-forward "
\1f" nil t)
991 (unless (looking-at "S")
992 (setq type (char-after)
993 name (buffer-substring (1+ (point)) (line-end-position))
994 doc (buffer-substring (line-beginning-position 2)
995 (if (search-forward "
\1f" nil 'move)
998 alist (cons (list name type doc) alist))
1000 (pop-to-buffer (generate-new-buffer "*info-doc*"))
1001 (setq buffer-undo-list t)
1002 ;; Write the output header.
1003 (insert "\\input texinfo @c -*-texinfo-*-\n"
1004 "@setfilename emacsdoc.info\n"
1005 "@settitle Command Summary for GNU Emacs\n"
1008 "@unnumbered Command Summary for GNU Emacs\n\n"
1011 "@global@let@ITEM@item\n"
1012 "@def@item{@filbreak@vskip5pt@ITEM}\n"
1013 "@font@tensy cmsy10 scaled @magstephalf\n"
1014 "@font@teni cmmi10 scaled @magstephalf\n"
1015 "@def\\{{@tensy@char110}}\n" ; this backslash goes with cmr10
1016 "@def|{{@tensy@char106}}\n"
1017 "@def@{{{@tensy@char102}}\n"
1018 "@def@}{{@tensy@char103}}\n"
1019 "@def<{{@teni@char62}}\n"
1020 "@def>{{@teni@char60}}\n"
1023 "@tableindent-0.2in\n"
1025 ;; Sort the array by name; within each name, by type (functions first).
1026 (setq alist (sort alist (lambda (e1 e2)
1027 (if (string-equal (car e1) (car e2))
1028 (<= (cadr e1) (cadr e2))
1029 (string-lessp (car e1) (car e2))))))
1030 ;; Print each function.
1033 (if (char-equal (cadr e) ?\F) "Function" "Variable")
1034 " @code{" (car e) "}\n@display\n"
1037 ;; Try to avoid a save size overflow in the TeX output routine.
1038 (if (zerop (setq i (% (1+ i) 100)))
1039 (insert "\n@end table\n@table @asis\n")))
1040 (insert "@end table\n"
1042 (setq buffer-undo-list nil)
1047 ;;; help-fns.el ends here