1 ;;; help-fns.el --- Complex help functions -*- lexical-binding: t -*-
3 ;; Copyright (C) 1985-1986, 1993-1994, 1998-2012
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, where USAGE info
69 is a string describing the argument list of DEF, such as
70 \"(apply FUNCTION &rest ARGUMENTS)\".
71 DEF is the function whose usage we're looking for in DOCSTRING."
72 ;; Functions can get the calling sequence at the end of the doc string.
73 ;; In cases where `function' has been fset to a subr we can't search for
74 ;; function's name in the doc string so we use `fn' as the anonymous
75 ;; function name instead.
76 (when (and docstring (string-match "\n\n(fn\\(\\( .*\\)?)\\)\\'" docstring))
78 ;; Replace `fn' with the actual function name.
79 (if (consp def) "anonymous" def)
80 (match-string 1 docstring))
81 (unless (zerop (match-beginning 0))
82 (substring docstring 0 (match-beginning 0))))))
84 ;; FIXME: Move to subr.el?
85 (defun help-add-fundoc-usage (docstring arglist)
86 "Add the usage info to DOCSTRING.
87 If DOCSTRING already has a usage info, then just return it unchanged.
88 The usage info is built from ARGLIST. DOCSTRING can be nil.
89 ARGLIST can also be t or a string of the form \"(FUN ARG1 ARG2 ...)\"."
90 (unless (stringp docstring) (setq docstring ""))
91 (if (or (string-match "\n\n(fn\\(\\( .*\\)?)\\)\\'" docstring)
95 (if (string-match "\n?\n\\'" docstring)
96 (if (< (- (match-end 0) (match-beginning 0)) 2) "\n" "")
98 (if (and (stringp arglist)
99 (string-match "\\`([^ ]+\\(.*\\))\\'" arglist))
100 (concat "(fn" (match-string 1 arglist) ")")
101 (format "%S" (help-make-usage 'fn arglist))))))
103 ;; FIXME: Move to subr.el?
104 (defun help-function-arglist (def &optional preserve-names)
105 "Return a formal argument list for the function DEF.
106 IF PRESERVE-NAMES is non-nil, return a formal arglist that uses
107 the same names as used in the original source code, when possible."
108 ;; Handle symbols aliased to other symbols.
109 (if (and (symbolp def) (fboundp def)) (setq def (indirect-function def)))
110 ;; If definition is a macro, find the function inside it.
111 (if (eq (car-safe def) 'macro) (setq def (cdr def)))
113 ((and (byte-code-function-p def) (listp (aref def 0))) (aref def 0))
114 ((eq (car-safe def) 'lambda) (nth 1 def))
115 ((eq (car-safe def) 'closure) (nth 2 def))
116 ((or (and (byte-code-function-p def) (integerp (aref def 0)))
118 (or (when preserve-names
119 (let* ((doc (condition-case nil (documentation def) (error nil)))
120 (docargs (if doc (car (help-split-fundoc doc nil))))
122 (cdar (read-from-string (downcase docargs)))))
125 (dolist (arg arglist)
126 (unless (and (symbolp arg)
127 (let ((name (symbol-name arg)))
128 (if (eq (aref name 0) ?&)
129 (memq arg '(&rest &optional))
130 (not (string-match "\\." name)))))
132 (when valid arglist)))
133 (let* ((args-desc (if (not (subrp def))
135 (let ((a (subr-arity def)))
137 (if (numberp (cdr a))
140 (max (lsh args-desc -8))
141 (min (logand args-desc 127))
142 (rest (logand args-desc 128))
145 (push (intern (concat "arg" (number-to-string (1+ i)))) arglist))
147 (push '&optional arglist)
148 (dotimes (i (- max min))
149 (push (intern (concat "arg" (number-to-string (+ 1 i min))))
151 (unless (zerop rest) (push '&rest arglist) (push 'rest arglist))
152 (nreverse arglist))))
153 ((and (eq (car-safe def) 'autoload) (not (eq (nth 4 def) 'keymap)))
154 "[Arg list not available until function definition is loaded.]")
157 ;; FIXME: Move to subr.el?
158 (defun help-make-usage (function arglist)
159 (cons (if (symbolp function) function 'anonymous)
160 (mapcar (lambda (arg)
161 (if (not (symbolp arg)) arg
162 (let ((name (symbol-name arg)))
164 ((string-match "\\`&" name) arg)
165 ((string-match "\\`_" name)
166 (intern (upcase (substring name 1))))
167 (t (intern (upcase name)))))))
170 ;; Could be this, if we make symbol-file do the work below.
171 ;; (defun help-C-file-name (subr-or-var kind)
172 ;; "Return the name of the C file where SUBR-OR-VAR is defined.
173 ;; KIND should be `var' for a variable or `subr' for a subroutine."
174 ;; (symbol-file (if (symbolp subr-or-var) subr-or-var
175 ;; (subr-name subr-or-var))
176 ;; (if (eq kind 'var) 'defvar 'defun)))
178 (defun help-C-file-name (subr-or-var kind)
179 "Return the name of the C file where SUBR-OR-VAR is defined.
180 KIND should be `var' for a variable or `subr' for a subroutine."
181 (let ((docbuf (get-buffer-create " *DOC*"))
182 (name (if (eq 'var kind)
183 (concat "V" (symbol-name subr-or-var))
184 (concat "F" (subr-name subr-or-var)))))
185 (with-current-buffer docbuf
186 (goto-char (point-min))
188 (insert-file-contents-literally
189 (expand-file-name internal-doc-file-name doc-directory)))
190 (let ((file (catch 'loop
192 (let ((pnt (search-forward (concat "
\1f" name "\n"))))
193 (re-search-backward "
\1fS\\(.*\\)")
194 (let ((file (match-string 1)))
195 (if (member file build-files)
197 (goto-char pnt))))))))
198 (if (string-match "^ns.*\\(\\.o\\|obj\\)\\'" file)
199 (setq file (replace-match ".m" t t file 1))
200 (if (string-match "\\.\\(o\\|obj\\)\\'" file)
201 (setq file (replace-match ".c" t t file))))
202 (if (string-match "\\.\\(c\\|m\\)\\'" file)
206 (defcustom help-downcase-arguments nil
207 "If non-nil, argument names in *Help* buffers are downcased."
212 (defun help-highlight-arg (arg)
213 "Highlight ARG as an argument name for a *Help* buffer.
214 Return ARG in face `help-argument-name'; ARG is also downcased
215 if the variable `help-downcase-arguments' is non-nil."
216 (propertize (if help-downcase-arguments (downcase arg) arg)
217 'face 'help-argument-name))
219 (defun help-do-arg-highlight (doc args)
220 (with-syntax-table (make-syntax-table emacs-lisp-mode-syntax-table)
221 (modify-syntax-entry ?\- "w")
223 (setq doc (replace-regexp-in-string
224 ;; This is heuristic, but covers all common cases
226 (concat "\\<" ; beginning of word
227 "\\(?:[a-z-]*-\\)?" ; for xxx-ARG
231 "\\(?:es\\|s\\|th\\)?" ; for ARGth, ARGs
232 "\\(?:-[a-z0-9-]+\\)?" ; for ARG-xxx, ARG-n
233 "\\(?:-[{([<`\"].*?\\)?"; for ARG-{x}, (x), <x>, [x], `x'
235 (help-highlight-arg arg)
239 (defun help-highlight-arguments (usage doc &rest args)
240 (when (and usage (string-match "^(" usage))
243 (goto-char (point-min))
244 (let ((case-fold-search nil)
245 (next (not (or args (looking-at "\\["))))
247 ;; Make a list of all arguments
248 (skip-chars-forward "^ ")
250 (or opt (not (looking-at " &")) (setq opt t))
251 (if (not (re-search-forward " \\([\\[(]*\\)\\([^] &)\.]+\\)" nil t))
253 (setq args (cons (match-string 2) args))
254 (when (and opt (string= (match-string 1) "("))
255 ;; A pesky CL-style optional argument with default value,
256 ;; so let's skip over it
257 (search-backward "(")
258 (goto-char (scan-sexps (point) 1)))))
259 ;; Highlight arguments in the USAGE string
260 (setq usage (help-do-arg-highlight (buffer-string) args))
261 ;; Highlight arguments in the DOC string
262 (setq doc (and doc (help-do-arg-highlight doc args))))))
263 ;; Return value is like the one from help-split-fundoc, but highlighted
266 ;; The following function was compiled from the former functions
267 ;; `describe-simplify-lib-file-name' and `find-source-lisp-file' with
268 ;; some excerpts from `describe-function-1' and `describe-variable'.
269 ;; The only additional twists provided are (1) locate the defining file
270 ;; for autoloaded functions, and (2) give preference to files in the
271 ;; "install directory" (directories found via `load-path') rather than
272 ;; to files in the "compile directory" (directories found by searching
273 ;; the loaddefs.el file). We autoload it because it's also used by
274 ;; `describe-face' (instead of `describe-simplify-lib-file-name').
277 (defun find-lisp-object-file-name (object type)
278 "Guess the file that defined the Lisp object OBJECT, of type TYPE.
279 OBJECT should be a symbol associated with a function, variable, or face;
280 alternatively, it can be a function definition.
281 If TYPE is `defvar', search for a variable definition.
282 If TYPE is `defface', search for a face definition.
283 If TYPE is the value returned by `symbol-function' for a function symbol,
284 search for a function definition.
286 The return value is the absolute name of a readable file where OBJECT is
287 defined. If several such files exist, preference is given to a file
288 found via `load-path'. The return value can also be `C-source', which
289 means that OBJECT is a function or variable defined in C. If no
290 suitable file is found, return nil."
291 (let* ((autoloaded (eq (car-safe type) 'autoload))
292 (file-name (or (and autoloaded (nth 1 type))
294 object (if (memq type (list 'defvar 'defface))
299 ;; An autoloaded function: Locate the file since `symbol-function'
300 ;; has only returned a bare string here.
302 (locate-file file-name load-path '(".el" ".elc") 'readable)))
303 ((and (stringp file-name)
304 (string-match "[.]*loaddefs.el\\'" file-name))
305 ;; An autoloaded variable or face. Visit loaddefs.el in a buffer
306 ;; and try to extract the defining file. The following form is
307 ;; from `describe-function-1' and `describe-variable'.
310 (find-function-search-for-symbol object nil file-name)
313 (with-current-buffer (car location)
314 (goto-char (cdr location))
315 (when (re-search-backward
316 "^;;; Generated autoloads from \\(.*\\)" nil t)
319 (file-name-sans-extension
320 (match-string-no-properties 1))
321 load-path '(".el" ".elc") 'readable))))))))
324 ((and (not file-name) (subrp type))
325 ;; A built-in function. The form is from `describe-function-1'.
326 (if (get-buffer " *DOC*")
327 (help-C-file-name type 'subr)
329 ((and (not file-name) (symbolp object)
330 (integerp (get object 'variable-documentation)))
331 ;; A variable defined in C. The form is from `describe-variable'.
332 (if (get-buffer " *DOC*")
333 (help-C-file-name object 'var)
335 ((not (stringp file-name))
336 ;; If we don't have a file-name string by now, we lost.
338 ;; Now, `file-name' should have become an absolute file name.
339 ;; For files loaded from ~/.emacs.elc, try ~/.emacs.
341 (and (string-equal file-name
342 (expand-file-name ".emacs.elc" "~"))
343 (file-readable-p (setq fn (expand-file-name ".emacs" "~")))
345 ;; When the Elisp source file can be found in the install
346 ;; directory, return the name of that file.
348 (if (string-match "[.]elc\\'" file-name)
349 (substring-no-properties file-name 0 -1)
351 (or (and (file-readable-p lib-name) lib-name)
352 ;; The library might be compressed.
353 (and (file-readable-p (concat lib-name ".gz")) lib-name))))
354 ((let* ((lib-name (file-name-nondirectory file-name))
355 ;; The next form is from `describe-simplify-lib-file-name'.
357 ;; Try converting the absolute file name to a library
358 ;; name, convert that back to a file name and see if we
359 ;; get the original one. If so, they are equivalent.
360 (if (equal file-name (locate-file lib-name load-path '("")))
361 (if (string-match "[.]elc\\'" lib-name)
362 (substring-no-properties lib-name 0 -1)
365 ;; The next three forms are from `find-source-lisp-file'.
366 (elc-file (locate-file
368 (if (string-match "\\.el\\'" file-name)
371 load-path nil 'readable))
374 (insert-file-contents-literally elc-file nil 0 256)
377 (string-match ";;; from file \\(.*\\.el\\)" str)
378 (match-string 1 str))))
379 (and src-file (file-readable-p src-file) src-file))))))
381 (declare-function ad-get-advice-info "advice" (function))
384 (defun describe-function-1 (function)
385 (let* ((advised (and (symbolp function) (featurep 'advice)
386 (ad-get-advice-info function)))
387 ;; If the function is advised, use the symbol that has the
388 ;; real definition, if that symbol is already set up.
391 (let ((origname (cdr (assq 'origname advised))))
392 (and (fboundp origname) origname)))
394 ;; Get the real definition.
395 (def (if (symbolp real-function)
396 (symbol-function real-function)
399 (beg (if (commandp def) "an interactive " "a "))
400 (pt1 (with-current-buffer (help-buffer) (point)))
403 (cond ((or (stringp def) (vectorp def))
406 (if (eq 'unevalled (cdr (subr-arity def)))
407 (concat beg "special form")
408 (concat beg "built-in function")))
409 ((byte-code-function-p def)
410 (concat beg "compiled Lisp function"))
412 (while (and (fboundp def)
413 (symbolp (symbol-function def)))
414 (setq def (symbol-function def)))
415 ;; Handle (defalias 'foo 'bar), where bar is undefined.
416 (or (fboundp def) (setq errtype 'alias))
417 (format "an alias for `%s'" def))
418 ((eq (car-safe def) 'lambda)
419 (concat beg "Lisp function"))
420 ((eq (car-safe def) 'macro)
422 ((eq (car-safe def) 'closure)
423 (concat beg "Lisp closure"))
424 ((eq (car-safe def) 'autoload)
425 (format "%s autoloaded %s"
426 (if (commandp def) "an interactive" "an")
427 (if (eq (nth 4 def) 'keymap) "keymap"
428 (if (nth 4 def) "Lisp macro" "Lisp function"))))
431 (elts (cdr-safe def)))
433 (if (char-table-p (car-safe elts))
436 (setq elts (cdr-safe elts)))
442 (if (eq errtype 'alias)
443 (princ ",\nwhich is not defined. Please make a bug report.")
444 (with-current-buffer standard-output
447 (when (re-search-backward "alias for `\\([^`']+\\)'" nil t)
448 (help-xref-button 1 'help-function def)))))
450 (setq file-name (find-lisp-object-file-name function def))
453 ;; We used to add .el to the file name,
454 ;; but that's completely wrong when the user used load-file.
455 (princ (if (eq file-name 'C-source)
457 (file-name-nondirectory file-name)))
459 ;; Make a hyperlink to the library.
460 (with-current-buffer standard-output
462 (re-search-backward "`\\([^`']+\\)'" nil t)
463 (help-xref-button 1 'help-function-def function file-name))))
465 (with-current-buffer (help-buffer)
466 (fill-region-as-paragraph (save-excursion (goto-char pt1) (forward-line 0) (point))
469 (when (commandp function)
470 (let ((pt2 (with-current-buffer (help-buffer) (point)))
471 (remapped (command-remapping function)))
472 (unless (memq remapped '(ignore undefined))
473 (let ((keys (where-is-internal
474 (or remapped function) overriding-local-map nil nil))
476 (if (and (eq function 'self-insert-command)
477 (vectorp (car-safe keys))
478 (consp (aref (car keys) 0)))
479 (princ "It is bound to many ordinary text characters.\n")
480 ;; Which non-control non-meta keys run this command?
482 (if (member (event-modifiers (aref key 0)) '(nil (shift)))
483 (push key non-modified-keys)))
485 (princ "It is remapped to `")
486 (princ (symbol-name remapped))
490 (princ (if remapped ", which is bound to " "It is bound to "))
491 ;; If lots of ordinary text characters run this command,
492 ;; don't mention them one by one.
493 (if (< (length non-modified-keys) 10)
494 (princ (mapconcat 'key-description keys ", "))
495 (dolist (key non-modified-keys)
496 (setq keys (delq key keys)))
499 (princ (mapconcat 'key-description keys ", "))
500 (princ ", and many ordinary text characters"))
501 (princ "many ordinary text characters"))))
502 (when (or remapped keys non-modified-keys)
506 (with-current-buffer (help-buffer)
507 (fill-region-as-paragraph pt2 (point))
508 (unless (looking-back "\n\n")
510 ;; Note that list* etc do not get this property until
511 ;; cl-hack-byte-compiler runs, after bytecomp is loaded.
512 (when (and (symbolp function)
513 (eq (get function 'byte-compile)
514 'cl-byte-compile-compiler-macro))
515 (princ "This function has a compiler macro")
516 (let ((lib (get function 'compiler-macro-file)))
518 (princ (format " in `%s'" lib))
519 (with-current-buffer standard-output
521 (re-search-backward "`\\([^`']+\\)'" nil t)
522 (help-xref-button 1 'help-function-cmacro function lib)))))
524 (let* ((advertised (gethash def advertised-signature-table t))
525 (arglist (if (listp advertised)
526 advertised (help-function-arglist def)))
527 (doc (condition-case err (documentation function)
528 (error (format "No Doc! %S" err))))
529 (usage (help-split-fundoc doc function)))
530 (with-current-buffer standard-output
531 ;; If definition is a keymap, skip arglist note.
532 (unless (keymapp function)
533 (if usage (setq doc (cdr usage)))
535 ((and usage (not (listp advertised))) (car usage))
537 (format "%S" (help-make-usage function arglist)))
538 ((stringp arglist) arglist)
539 ;; Maybe the arglist is in the docstring of a symbol
540 ;; this one is aliased to.
541 ((let ((fun real-function))
542 (while (and (symbolp fun)
543 (setq fun (symbol-function fun))
544 (not (setq usage (help-split-fundoc
551 (format "\nMacro: %s" (format-kbd-macro def)))
552 (t "[Missing arglist. Please make a bug report.]")))
553 (high (help-highlight-arguments use doc)))
554 (let ((fill-begin (point)))
555 (insert (car high) "\n")
556 (fill-region fill-begin (point)))
557 (setq doc (cdr high))))
559 ;; If this is a derived mode, link to the parent.
560 (let ((parent-mode (and (symbolp real-function)
562 'derived-mode-parent))))
564 (with-current-buffer standard-output
565 (insert "\nParent mode: `")
567 (insert (format "%s" parent-mode))
568 (make-text-button beg (point)
570 'help-args (list parent-mode))))
573 (let* ((obsolete (and
574 ;; function might be a lambda construct.
576 (get function 'byte-obsolete-info)))
577 (use (car obsolete)))
579 (princ "\nThis function is obsolete")
580 (when (nth 2 obsolete)
581 (insert (format " since %s" (nth 2 obsolete))))
582 (insert (cond ((stringp use) (concat ";\n" use))
583 (use (format ";\nuse `%s' instead." use))
587 (or doc "Not documented."))))))))
593 (defun variable-at-point (&optional any-symbol)
594 "Return the bound variable symbol found at or before point.
595 Return 0 if there is no such symbol.
596 If ANY-SYMBOL is non-nil, don't insist the symbol be bound."
597 (with-syntax-table emacs-lisp-mode-syntax-table
598 (or (condition-case ()
600 (skip-chars-forward "'")
601 (or (not (zerop (skip-syntax-backward "_w")))
602 (eq (char-syntax (following-char)) ?w)
603 (eq (char-syntax (following-char)) ?_)
605 (skip-chars-forward "'")
606 (let ((obj (read (current-buffer))))
607 (and (symbolp obj) (boundp obj) obj)))
609 (let* ((str (find-tag-default))
610 (sym (if str (intern-soft str))))
611 (if (and sym (or any-symbol (boundp sym)))
614 (when (and str (string-match "\\`\\W*\\(.*?\\)\\W*\\'" str))
615 (setq sym (intern-soft (match-string 1 str)))
616 (and (or any-symbol (boundp sym)) sym)))))
619 (defun describe-variable-custom-version-info (variable)
620 (let ((custom-version (get variable 'custom-version))
621 (cpv (get variable 'custom-package-version))
625 (format "This variable was introduced, or its default value was changed, in\nversion %s of Emacs.\n"
628 (let* ((package (car-safe cpv))
629 (version (if (listp (cdr-safe cpv))
632 (pkg-versions (assq package customize-package-emacs-version-alist))
633 (emacsv (cdr (assoc version pkg-versions))))
634 (if (and package version)
636 (format (concat "This variable was introduced, or its default value was changed, in\nversion %s of the %s package"
638 (format " that is part of Emacs %s" emacsv))
640 version package))))))
644 (defun describe-variable (variable &optional buffer frame)
645 "Display the full documentation of VARIABLE (a symbol).
646 Returns the documentation as a string, also.
647 If VARIABLE has a buffer-local value in BUFFER or FRAME
648 \(default to the current buffer and current frame),
649 it is displayed along with the global value."
651 (let ((v (variable-at-point))
652 (enable-recursive-minibuffers t)
654 (setq val (completing-read (if (symbolp v)
656 "Describe variable (default %s): " v)
657 "Describe variable: ")
660 (or (get vv 'variable-documentation)
661 (and (boundp vv) (not (keywordp vv)))))
663 (if (symbolp v) (symbol-name v))))
664 (list (if (equal val "")
667 (unless (buffer-live-p buffer) (setq buffer (current-buffer)))
668 (unless (frame-live-p frame) (setq frame (selected-frame)))
669 (if (not (symbolp variable))
670 (message "You did not specify a variable")
672 (let ((valvoid (not (with-current-buffer buffer (boundp variable))))
673 val val-start-pos locus)
674 ;; Extract the value before setting up the output buffer,
675 ;; in case `buffer' *is* the output buffer.
677 (with-selected-frame frame
678 (with-current-buffer buffer
679 (setq val (symbol-value variable)
680 locus (variable-binding-locus variable)))))
681 (help-setup-xref (list #'describe-variable variable buffer)
682 (called-interactively-p 'interactive))
683 (with-help-window (help-buffer)
684 (with-current-buffer buffer
686 (setq file-name (find-lisp-object-file-name variable 'defvar))
690 (princ " is a variable defined in `")
691 (princ (if (eq file-name 'C-source)
693 (file-name-nondirectory file-name)))
695 (with-current-buffer standard-output
697 (re-search-backward "`\\([^`']+\\)'" nil t)
698 (help-xref-button 1 'help-variable-def
699 variable file-name)))
701 (princ "It is void as a variable.")
704 (princ " is void as a variable.")
707 (with-current-buffer standard-output
708 (setq val-start-pos (point))
710 (let ((from (point)))
713 (if (< (point) (+ 68 (line-beginning-position 0)))
714 (delete-region from (1+ from))
715 (delete-region (1- from) from))
716 (let* ((sv (get variable 'standard-value))
717 (origval (and (consp sv)
720 (error :help-eval-error)))))
721 (when (and (consp sv)
722 (not (equal origval val))
723 (not (equal origval :help-eval-error)))
724 (princ "\nOriginal value was \n")
727 (if (< (point) (+ from 20))
728 (delete-region (1- from) from)))))))
733 (princ (format "%socal in buffer %s; "
734 (if (get variable 'permanent-local)
738 (princ (format "It is a frame-local variable; ")))
739 ((terminal-live-p locus)
740 (princ (format "It is a terminal-local variable; ")))
742 (princ (format "It is local to %S" locus))))
743 (if (not (default-boundp variable))
744 (princ "globally void")
745 (let ((val (default-value variable)))
746 (with-current-buffer standard-output
747 (princ "global value is ")
749 ;; Fixme: pp can take an age if you happen to
750 ;; ask for a very large expression. We should
751 ;; probably print it raw once and check it's a
752 ;; sensible size before prettyprinting. -- fx
753 (let ((from (point)))
755 ;; See previous comment for this function.
756 ;; (help-xref-on-pp from (point))
757 (if (< (point) (+ from 20))
758 (delete-region (1- from) from))))))
761 ;; If the value is large, move it to the end.
762 (with-current-buffer standard-output
763 (when (> (count-lines (point-min) (point-max)) 10)
764 ;; Note that setting the syntax table like below
765 ;; makes forward-sexp move over a `'s' at the end
767 (set-syntax-table emacs-lisp-mode-syntax-table)
768 (goto-char val-start-pos)
769 ;; The line below previously read as
770 ;; (delete-region (point) (progn (end-of-line) (point)))
771 ;; which suppressed display of the buffer local value for
773 (when (looking-at "value is") (replace-match ""))
775 (insert "\n\nValue:")
776 (set (make-local-variable 'help-button-cache)
778 (insert "value is shown ")
779 (insert-button "below"
780 'action help-button-cache
782 'help-echo "mouse-2, RET: show value")
786 (let* ((alias (condition-case nil
787 (indirect-variable variable)
789 (obsolete (get variable 'byte-obsolete-variable))
791 (safe-var (get variable 'safe-local-variable))
792 (doc (or (documentation-property variable 'variable-documentation)
793 (documentation-property alias 'variable-documentation)))
795 ;; Add a note for variables that have been make-var-buffer-local.
796 (when (and (local-variable-if-set-p variable)
797 (or (not (local-variable-p variable))
799 (local-variable-if-set-p variable))))
801 (princ " Automatically becomes buffer-local when set in any fashion.\n"))
803 ;; Mention if it's an alias
804 (unless (eq alias variable)
806 (princ (format " This variable is an alias for `%s'.\n" alias)))
810 (princ " This variable is obsolete")
812 (princ (format " since %s" (nth 2 obsolete))))
813 (princ (cond ((stringp use) (concat ";\n " use))
814 (use (format ";\n use `%s' instead." (car obsolete)))
818 (when (member (cons variable val) file-local-variables-alist)
820 (if (member (cons variable val) dir-local-variables-alist)
821 (let ((file (and (buffer-file-name)
822 (not (file-remote-p (buffer-file-name)))
823 (dir-locals-find-file
824 (buffer-file-name))))
826 (princ " This variable is a directory local variable")
828 (if (consp file) ; result from cache
829 ;; If the cache element has an mtime, we
830 ;; assume it came from a file.
832 (setq file (expand-file-name
833 dir-locals-file (car file)))
834 ;; Otherwise, assume it was set directly.
835 (setq type "directory")))
836 (princ (format "\n from the %s \"%s\"" type file)))
838 (princ " This variable is a file local variable.\n")))
840 (when (memq variable ignored-local-variables)
842 (princ " This variable is ignored when used as a file local \
845 ;; Can be both risky and safe, eg auto-fill-function.
846 (when (risky-local-variable-p variable)
848 (princ " This variable is potentially risky when used as a \
849 file local variable.\n")
850 (when (assq variable safe-local-variable-values)
851 (princ " However, you have added it to \
852 `safe-local-variable-values'.\n")))
856 (princ " This variable is safe as a file local variable ")
857 (princ "if its value\n satisfies the predicate ")
858 (princ (if (byte-code-function-p safe-var)
859 "which is byte-compiled expression.\n"
860 (format "`%s'.\n" safe-var))))
862 (if extra-line (terpri))
863 (princ "Documentation:\n")
864 (with-current-buffer standard-output
865 (insert (or doc "Not documented as a variable."))))
867 ;; Make a link to customize if this variable can be customized.
868 (when (custom-variable-p variable)
869 (let ((customize-label "customize"))
872 (princ (concat "You can " customize-label " this variable."))
873 (with-current-buffer standard-output
876 (concat "\\(" customize-label "\\)") nil t)
877 (help-xref-button 1 'help-customize-variable variable))))
878 ;; Note variable's version or package version
879 (let ((output (describe-variable-custom-version-info variable)))
885 (with-current-buffer standard-output
886 ;; Return the text we displayed.
887 (buffer-string))))))))
891 (defun describe-syntax (&optional buffer)
892 "Describe the syntax specifications in the syntax table of BUFFER.
893 The descriptions are inserted in a help buffer, which is then displayed.
894 BUFFER defaults to the current buffer."
896 (setq buffer (or buffer (current-buffer)))
897 (help-setup-xref (list #'describe-syntax buffer)
898 (called-interactively-p 'interactive))
899 (with-help-window (help-buffer)
900 (let ((table (with-current-buffer buffer (syntax-table))))
901 (with-current-buffer standard-output
902 (describe-vector table 'internal-describe-syntax-value)
903 (while (setq table (char-table-parent table))
904 (insert "\nThe parent syntax table is:")
905 (describe-vector table 'internal-describe-syntax-value))))))
907 (defun help-describe-category-set (value)
909 ((null value) "default")
910 ((char-table-p value) "deeper char-table ...")
911 (t (condition-case nil
912 (category-set-mnemonics value)
913 (error "invalid"))))))
916 (defun describe-categories (&optional buffer)
917 "Describe the category specifications in the current category table.
918 The descriptions are inserted in a buffer, which is then displayed.
919 If BUFFER is non-nil, then describe BUFFER's category table instead.
920 BUFFER should be a buffer or a buffer name."
922 (setq buffer (or buffer (current-buffer)))
923 (help-setup-xref (list #'describe-categories buffer)
924 (called-interactively-p 'interactive))
925 (with-help-window (help-buffer)
926 (let* ((table (with-current-buffer buffer (category-table)))
927 (docs (char-table-extra-slot table 0)))
928 (if (or (not (vectorp docs)) (/= (length docs) 95))
929 (error "Invalid first extra slot in this category table\n"))
930 (with-current-buffer standard-output
931 (insert "Legend of category mnemonics (see the tail for the longer description)\n")
932 (let ((pos (point)) (items 0) lines n)
934 (if (aref docs i) (setq items (1+ items))))
935 (setq lines (1+ (/ (1- items) 4)))
938 (let ((elt (aref docs i)))
940 (string-match ".*" elt)
941 (setq elt (match-string 0 elt))
942 (if (>= (length elt) 17)
943 (setq elt (concat (substring elt 0 14) "...")))
944 (if (< (point) (point-max))
945 (move-to-column (* 20 (/ n lines)) t))
946 (insert (+ i ?\s) ?: elt)
947 (if (< (point) (point-max))
951 (if (= (% n lines) 0)
953 (goto-char (point-max))
955 "character(s)\tcategory mnemonics\n"
956 "------------\t------------------")
957 (describe-vector table 'help-describe-category-set)
958 (insert "Legend of category mnemonics:\n")
960 (let ((elt (aref docs i)))
962 (if (string-match "\n" elt)
963 (setq elt (substring elt (match-end 0))))
964 (insert (+ i ?\s) ": " elt "\n"))))
965 (while (setq table (char-table-parent table))
966 (insert "\nThe parent category table is:")
967 (describe-vector table 'help-describe-category-set))))))
970 ;;; Replacements for old lib-src/ programs. Don't seem especially useful.
972 ;; Replaces lib-src/digest-doc.c.
974 (defun doc-file-to-man (file)
975 "Produce an nroff buffer containing the doc-strings from the DOC file."
976 (interactive (list (read-file-name "Name of DOC file: " doc-directory
977 internal-doc-file-name t)))
978 (or (file-readable-p file)
979 (error "Cannot read file `%s'" file))
980 (pop-to-buffer (generate-new-buffer "*man-doc*"))
981 (setq buffer-undo-list t)
982 (insert ".TH \"Command Summary for GNU Emacs\"\n"
983 ".AU Richard M. Stallman\n")
984 (insert-file-contents file)
986 (while (search-forward "
\1f" nil 'move)
988 (delete-region (1- (point)) (line-end-position))
994 (insert (if (looking-at "F") "Function " "Variable "))
997 (insert ".DS L\n"))))
999 (setq buffer-undo-list nil)
1002 ;; Replaces lib-src/sorted-doc.c.
1004 (defun doc-file-to-info (file)
1005 "Produce a texinfo buffer with sorted doc-strings from the DOC file."
1006 (interactive (list (read-file-name "Name of DOC file: " doc-directory
1007 internal-doc-file-name t)))
1008 (or (file-readable-p file)
1009 (error "Cannot read file `%s'" file))
1010 (let ((i 0) type name doc alist)
1012 (insert-file-contents file)
1013 ;; The characters "@{}" need special treatment.
1014 (while (re-search-forward "[@{}]" nil t)
1018 (goto-char (point-min))
1019 (while (search-forward "
\1f" nil t)
1020 (unless (looking-at "S")
1021 (setq type (char-after)
1022 name (buffer-substring (1+ (point)) (line-end-position))
1023 doc (buffer-substring (line-beginning-position 2)
1024 (if (search-forward "
\1f" nil 'move)
1027 alist (cons (list name type doc) alist))
1028 (backward-char 1))))
1029 (pop-to-buffer (generate-new-buffer "*info-doc*"))
1030 (setq buffer-undo-list t)
1031 ;; Write the output header.
1032 (insert "\\input texinfo @c -*-texinfo-*-\n"
1033 "@setfilename emacsdoc.info\n"
1034 "@settitle Command Summary for GNU Emacs\n"
1037 "@unnumbered Command Summary for GNU Emacs\n\n"
1040 "@global@let@ITEM@item\n"
1041 "@def@item{@filbreak@vskip5pt@ITEM}\n"
1042 "@font@tensy cmsy10 scaled @magstephalf\n"
1043 "@font@teni cmmi10 scaled @magstephalf\n"
1044 "@def\\{{@tensy@char110}}\n" ; this backslash goes with cmr10
1045 "@def|{{@tensy@char106}}\n"
1046 "@def@{{{@tensy@char102}}\n"
1047 "@def@}{{@tensy@char103}}\n"
1048 "@def<{{@teni@char62}}\n"
1049 "@def>{{@teni@char60}}\n"
1052 "@tableindent-0.2in\n"
1054 ;; Sort the array by name; within each name, by type (functions first).
1055 (setq alist (sort alist (lambda (e1 e2)
1056 (if (string-equal (car e1) (car e2))
1057 (<= (cadr e1) (cadr e2))
1058 (string-lessp (car e1) (car e2))))))
1059 ;; Print each function.
1062 (if (char-equal (cadr e) ?\F) "Function" "Variable")
1063 " @code{" (car e) "}\n@display\n"
1066 ;; Try to avoid a save size overflow in the TeX output routine.
1067 (if (zerop (setq i (% (1+ i) 100)))
1068 (insert "\n@end table\n@table @asis\n")))
1069 (insert "@end table\n"
1071 (setq buffer-undo-list nil)
1076 ;;; help-fns.el ends here