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 (autoloadp def) (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 (autoloadp type))
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))
383 (defun help-fns--key-bindings (function)
384 (when (commandp function)
385 (let ((pt2 (with-current-buffer standard-output (point)))
386 (remapped (command-remapping function)))
387 (unless (memq remapped '(ignore undefined))
388 (let ((keys (where-is-internal
389 (or remapped function) overriding-local-map nil nil))
391 (if (and (eq function 'self-insert-command)
392 (vectorp (car-safe keys))
393 (consp (aref (car keys) 0)))
394 (princ "It is bound to many ordinary text characters.\n")
395 ;; Which non-control non-meta keys run this command?
397 (if (member (event-modifiers (aref key 0)) '(nil (shift)))
398 (push key non-modified-keys)))
400 (princ "Its keys are remapped to ")
401 (princ (if (symbolp remapped)
402 (concat "`" (symbol-name remapped) "'")
403 "an anonymous command"))
408 "Without this remapping, it would be bound to "
410 ;; If lots of ordinary text characters run this command,
411 ;; don't mention them one by one.
412 (if (< (length non-modified-keys) 10)
413 (princ (mapconcat 'key-description keys ", "))
414 (dolist (key non-modified-keys)
415 (setq keys (delq key keys)))
418 (princ (mapconcat 'key-description keys ", "))
419 (princ ", and many ordinary text characters"))
420 (princ "many ordinary text characters"))))
421 (when (or remapped keys non-modified-keys)
425 (with-current-buffer standard-output
426 (fill-region-as-paragraph pt2 (point))
427 (unless (looking-back "\n\n")
430 (defun help-fns--compiler-macro (function)
431 (let ((handler (function-get function 'compiler-macro)))
433 (insert "\nThis function has a compiler macro")
434 (let ((lib (get function 'compiler-macro-file)))
435 ;; FIXME: rather than look at the compiler-macro-file property,
436 ;; just look at `handler' itself.
438 (insert (format " in `%s'" lib))
440 (re-search-backward "`\\([^`']+\\)'" nil t)
441 (help-xref-button 1 'help-function-cmacro function lib))))
444 (defun help-fns--signature (function doc real-def real-function)
445 (unless (keymapp function) ; If definition is a keymap, skip arglist note.
446 (let* ((advertised (gethash real-def advertised-signature-table t))
447 (arglist (if (listp advertised)
448 advertised (help-function-arglist real-def)))
449 (usage (help-split-fundoc doc function)))
450 (if usage (setq doc (cdr usage)))
452 ((and usage (not (listp advertised))) (car usage))
454 (format "%S" (help-make-usage function arglist)))
455 ((stringp arglist) arglist)
456 ;; Maybe the arglist is in the docstring of a symbol
457 ;; this one is aliased to.
458 ((let ((fun real-function))
459 (while (and (symbolp fun)
460 (setq fun (symbol-function fun))
461 (not (setq usage (help-split-fundoc
466 ((or (stringp real-def)
468 (format "\nMacro: %s" (format-kbd-macro real-def)))
469 (t "[Missing arglist. Please make a bug report.]")))
470 (high (help-highlight-arguments use doc)))
471 (let ((fill-begin (point)))
472 (insert (car high) "\n")
473 (fill-region fill-begin (point)))
476 (defun help-fns--parent-mode (function)
477 ;; If this is a derived mode, link to the parent.
478 (let ((parent-mode (and (symbolp function)
480 'derived-mode-parent))))
482 (insert "\nParent mode: `")
484 (insert (format "%s" parent-mode))
485 (make-text-button beg (point)
487 'help-args (list parent-mode)))
490 (defun help-fns--obsolete (function)
491 ;; Ignore lambda constructs, keyboard macros, etc.
492 (let* ((obsolete (and (symbolp function)
493 (get function 'byte-obsolete-info)))
494 (use (car obsolete)))
497 (if (eq (car-safe (symbol-function 'with-current-buffer))
502 (when (nth 2 obsolete)
503 (insert (format " since %s" (nth 2 obsolete))))
504 (insert (cond ((stringp use) (concat ";\n" use))
505 (use (format ";\nuse `%s' instead." use))
509 ;; We could use `symbol-file' but this is a wee bit more efficient.
510 (defun help-fns--autoloaded-p (function file)
511 "Return non-nil if FUNCTION has previously been autoloaded.
512 FILE is the file where FUNCTION was probably defined."
513 (let* ((file (file-name-sans-extension (file-truename file)))
514 (load-hist load-history)
515 (target (cons t function))
517 (while (and load-hist (not found))
518 (and (caar load-hist)
519 (equal (file-name-sans-extension (caar load-hist)) file)
520 (setq found (member target (cdar load-hist))))
521 (setq load-hist (cdr load-hist)))
525 (defun describe-function-1 (function)
526 (let* ((advised (and (symbolp function) (featurep 'advice)
527 (ad-get-advice-info function)))
528 ;; If the function is advised, use the symbol that has the
529 ;; real definition, if that symbol is already set up.
532 (let ((origname (cdr (assq 'origname advised))))
533 (and (fboundp origname) origname)))
535 ;; Get the real definition.
536 (def (if (symbolp real-function)
537 (symbol-function real-function)
539 (aliased (symbolp def))
540 (real-def (if aliased
542 (while (and (fboundp f)
543 (symbolp (symbol-function f)))
544 (setq f (symbol-function f)))
547 (file-name (find-lisp-object-file-name function def))
548 (pt1 (with-current-buffer (help-buffer) (point)))
549 (beg (if (and (or (byte-code-function-p def)
551 (memq (car-safe def) '(macro lambda closure)))
553 (help-fns--autoloaded-p function file-name))
555 "an interactive autoloaded "
557 (if (commandp def) "an interactive " "a "))))
559 ;; Print what kind of function-like object FUNCTION is.
560 (princ (cond ((or (stringp def) (vectorp def))
563 (if (eq 'unevalled (cdr (subr-arity def)))
564 (concat beg "special form")
565 (concat beg "built-in function")))
566 ((byte-code-function-p def)
567 (concat beg "compiled Lisp function"))
569 (format "an alias for `%s'" real-def))
570 ((eq (car-safe def) 'lambda)
571 (concat beg "Lisp function"))
572 ((eq (car-safe def) 'macro)
573 (concat beg "Lisp macro"))
574 ((eq (car-safe def) 'closure)
575 (concat beg "Lisp closure"))
577 (format "%s autoloaded %s"
578 (if (commandp def) "an interactive" "an")
579 (if (eq (nth 4 def) 'keymap) "keymap"
580 (if (nth 4 def) "Lisp macro" "Lisp function"))))
583 (elts (cdr-safe def)))
585 (if (char-table-p (car-safe elts))
588 (setq elts (cdr-safe elts)))
589 (concat beg (if is-full "keymap" "sparse keymap"))))
592 (if (and aliased (not (fboundp real-def)))
593 (princ ",\nwhich is not defined. Please make a bug report.")
594 (with-current-buffer standard-output
597 (when (re-search-backward "alias for `\\([^`']+\\)'" nil t)
598 (help-xref-button 1 'help-function real-def)))))
602 ;; We used to add .el to the file name,
603 ;; but that's completely wrong when the user used load-file.
604 (princ (if (eq file-name 'C-source)
606 (file-name-nondirectory file-name)))
608 ;; Make a hyperlink to the library.
609 (with-current-buffer standard-output
611 (re-search-backward "`\\([^`']+\\)'" nil t)
612 (help-xref-button 1 'help-function-def function file-name))))
614 (with-current-buffer (help-buffer)
615 (fill-region-as-paragraph (save-excursion (goto-char pt1) (forward-line 0) (point))
619 (let* ((doc-raw (condition-case err
620 (documentation function t)
621 (error (format "No Doc! %S" err))))
622 ;; If the function is autoloaded, and its docstring has
623 ;; key substitution constructs, load the library.
625 (and (autoloadp real-def)
626 help-enable-auto-load
627 (string-match "\\([^\\]=\\|[^=]\\|\\`\\)\\\\[[{<]"
629 (load (cadr real-def) t))
630 (substitute-command-keys doc-raw))))
632 (help-fns--key-bindings function)
633 (with-current-buffer standard-output
634 (setq doc (help-fns--signature function doc real-def real-function))
636 (help-fns--compiler-macro function)
637 (help-fns--parent-mode function)
638 (help-fns--obsolete function)
641 (or doc "Not documented.")))))))
647 (defun variable-at-point (&optional any-symbol)
648 "Return the bound variable symbol found at or before point.
649 Return 0 if there is no such symbol.
650 If ANY-SYMBOL is non-nil, don't insist the symbol be bound."
651 (with-syntax-table emacs-lisp-mode-syntax-table
652 (or (condition-case ()
654 (skip-chars-forward "'")
655 (or (not (zerop (skip-syntax-backward "_w")))
656 (eq (char-syntax (following-char)) ?w)
657 (eq (char-syntax (following-char)) ?_)
659 (skip-chars-forward "'")
660 (let ((obj (read (current-buffer))))
661 (and (symbolp obj) (boundp obj) obj)))
663 (let* ((str (find-tag-default))
664 (sym (if str (intern-soft str))))
665 (if (and sym (or any-symbol (boundp sym)))
668 (when (and str (string-match "\\`\\W*\\(.*?\\)\\W*\\'" str))
669 (setq sym (intern-soft (match-string 1 str)))
670 (and (or any-symbol (boundp sym)) sym)))))
673 (defun describe-variable-custom-version-info (variable)
674 (let ((custom-version (get variable 'custom-version))
675 (cpv (get variable 'custom-package-version))
679 (format "This variable was introduced, or its default value was changed, in\nversion %s of Emacs.\n"
682 (let* ((package (car-safe cpv))
683 (version (if (listp (cdr-safe cpv))
686 (pkg-versions (assq package customize-package-emacs-version-alist))
687 (emacsv (cdr (assoc version pkg-versions))))
688 (if (and package version)
690 (format (concat "This variable was introduced, or its default value was changed, in\nversion %s of the %s package"
692 (format " that is part of Emacs %s" emacsv))
694 version package))))))
698 (defun describe-variable (variable &optional buffer frame)
699 "Display the full documentation of VARIABLE (a symbol).
700 Returns the documentation as a string, also.
701 If VARIABLE has a buffer-local value in BUFFER or FRAME
702 \(default to the current buffer and current frame),
703 it is displayed along with the global value."
705 (let ((v (variable-at-point))
706 (enable-recursive-minibuffers t)
708 (setq val (completing-read (if (symbolp v)
710 "Describe variable (default %s): " v)
711 "Describe variable: ")
714 (or (get vv 'variable-documentation)
715 (and (boundp vv) (not (keywordp vv)))))
717 (if (symbolp v) (symbol-name v))))
718 (list (if (equal val "")
721 (unless (buffer-live-p buffer) (setq buffer (current-buffer)))
722 (unless (frame-live-p frame) (setq frame (selected-frame)))
723 (if (not (symbolp variable))
724 (message "You did not specify a variable")
726 (let ((valvoid (not (with-current-buffer buffer (boundp variable))))
727 (permanent-local (get variable 'permanent-local))
728 val val-start-pos locus)
729 ;; Extract the value before setting up the output buffer,
730 ;; in case `buffer' *is* the output buffer.
732 (with-selected-frame frame
733 (with-current-buffer buffer
734 (setq val (symbol-value variable)
735 locus (variable-binding-locus variable)))))
736 (help-setup-xref (list #'describe-variable variable buffer)
737 (called-interactively-p 'interactive))
738 (with-help-window (help-buffer)
739 (with-current-buffer buffer
741 (setq file-name (find-lisp-object-file-name variable 'defvar))
745 (princ " is a variable defined in `")
746 (princ (if (eq file-name 'C-source)
748 (file-name-nondirectory file-name)))
750 (with-current-buffer standard-output
752 (re-search-backward "`\\([^`']+\\)'" nil t)
753 (help-xref-button 1 'help-variable-def
754 variable file-name)))
756 (princ "It is void as a variable.")
759 (princ " is void as a variable.")
762 (with-current-buffer standard-output
763 (setq val-start-pos (point))
766 (line-beg (line-beginning-position))
768 (let ((print-quoted t))
769 (prin1-to-string val))))
770 (if (< (+ (length print-rep) (point) (- line-beg)) 68)
774 (if (< (point) (+ 68 (line-beginning-position 0)))
775 (delete-region from (1+ from))
776 (delete-region (1- from) from)))
777 (let* ((sv (get variable 'standard-value))
778 (origval (and (consp sv)
781 (error :help-eval-error)))))
782 (when (and (consp sv)
783 (not (equal origval val))
784 (not (equal origval :help-eval-error)))
785 (princ "\nOriginal value was \n")
788 (if (< (point) (+ from 20))
789 (delete-region (1- from) from)))))))
794 (princ (format "Local in buffer %s; "
797 (princ (format "It is a frame-local variable; ")))
798 ((terminal-live-p locus)
799 (princ (format "It is a terminal-local variable; ")))
801 (princ (format "It is local to %S" locus))))
802 (if (not (default-boundp variable))
803 (princ "globally void")
804 (let ((global-val (default-value variable)))
805 (with-current-buffer standard-output
806 (princ "global value is ")
807 (if (eq val global-val)
810 ;; Fixme: pp can take an age if you happen to
811 ;; ask for a very large expression. We should
812 ;; probably print it raw once and check it's a
813 ;; sensible size before prettyprinting. -- fx
814 (let ((from (point)))
816 ;; See previous comment for this function.
817 ;; (help-xref-on-pp from (point))
818 (if (< (point) (+ from 20))
819 (delete-region (1- from) from)))))))
822 ;; If the value is large, move it to the end.
823 (with-current-buffer standard-output
824 (when (> (count-lines (point-min) (point-max)) 10)
825 ;; Note that setting the syntax table like below
826 ;; makes forward-sexp move over a `'s' at the end
828 (set-syntax-table emacs-lisp-mode-syntax-table)
829 (goto-char val-start-pos)
830 ;; The line below previously read as
831 ;; (delete-region (point) (progn (end-of-line) (point)))
832 ;; which suppressed display of the buffer local value for
834 (when (looking-at "value is") (replace-match ""))
836 (insert "\n\nValue:")
837 (set (make-local-variable 'help-button-cache)
839 (insert "value is shown ")
840 (insert-button "below"
841 'action help-button-cache
843 'help-echo "mouse-2, RET: show value")
847 (let* ((alias (condition-case nil
848 (indirect-variable variable)
850 (obsolete (get variable 'byte-obsolete-variable))
852 (safe-var (get variable 'safe-local-variable))
853 (doc (condition-case err
854 (or (documentation-property
855 variable 'variable-documentation)
856 (documentation-property
857 alias 'variable-documentation))
858 (error (format "Doc not found: %S" err))))
861 ;; Mention if it's a local variable.
863 ((and (local-variable-if-set-p variable)
864 (or (not (local-variable-p variable))
866 (local-variable-if-set-p variable))))
868 (princ " Automatically becomes ")
870 (princ "permanently "))
871 (princ "buffer-local when set.\n"))
872 ((not permanent-local))
874 (princ " This variable's buffer-local value is permanent.\n"))
876 (princ " This variable's value is permanent \
877 if it is given a local binding.\n")))
879 ;; Mention if it's an alias.
880 (unless (eq alias variable)
882 (princ (format " This variable is an alias for `%s'.\n" alias)))
886 (princ " This variable is obsolete")
888 (princ (format " since %s" (nth 2 obsolete))))
889 (princ (cond ((stringp use) (concat ";\n " use))
890 (use (format ";\n use `%s' instead." (car obsolete)))
894 (when (member (cons variable val) file-local-variables-alist)
896 (if (member (cons variable val) dir-local-variables-alist)
897 (let ((file (and (buffer-file-name)
898 (not (file-remote-p (buffer-file-name)))
899 (dir-locals-find-file
900 (buffer-file-name))))
902 (princ " This variable's value is directory-local")
906 (if (consp file) ; result from cache
907 ;; If the cache element has an mtime, we
908 ;; assume it came from a file.
910 (setq file (expand-file-name
911 dir-locals-file (car file)))
912 ;; Otherwise, assume it was set directly.
913 (setq dir-file nil)))
916 "for the directory\n `"))
917 (with-current-buffer standard-output
919 file 'type 'help-dir-local-var-def
920 'help-args (list variable file)))
922 (princ " This variable's value is file-local.\n")))
924 (when (memq variable ignored-local-variables)
926 (princ " This variable is ignored as a file-local \
929 ;; Can be both risky and safe, eg auto-fill-function.
930 (when (risky-local-variable-p variable)
932 (princ " This variable may be risky if used as a \
933 file-local variable.\n")
934 (when (assq variable safe-local-variable-values)
935 (princ " However, you have added it to \
936 `safe-local-variable-values'.\n")))
940 (princ " This variable is safe as a file local variable ")
941 (princ "if its value\n satisfies the predicate ")
942 (princ (if (byte-code-function-p safe-var)
943 "which is a byte-compiled expression.\n"
944 (format "`%s'.\n" safe-var))))
946 (if extra-line (terpri))
947 (princ "Documentation:\n")
948 (with-current-buffer standard-output
949 (insert (or doc "Not documented as a variable."))))
951 ;; Make a link to customize if this variable can be customized.
952 (when (custom-variable-p variable)
953 (let ((customize-label "customize"))
956 (princ (concat "You can " customize-label " this variable."))
957 (with-current-buffer standard-output
960 (concat "\\(" customize-label "\\)") nil t)
961 (help-xref-button 1 'help-customize-variable variable))))
962 ;; Note variable's version or package version
963 (let ((output (describe-variable-custom-version-info variable)))
969 (with-current-buffer standard-output
970 ;; Return the text we displayed.
971 (buffer-string))))))))
975 (defun describe-syntax (&optional buffer)
976 "Describe the syntax specifications in the syntax table of BUFFER.
977 The descriptions are inserted in a help buffer, which is then displayed.
978 BUFFER defaults to the current buffer."
980 (setq buffer (or buffer (current-buffer)))
981 (help-setup-xref (list #'describe-syntax buffer)
982 (called-interactively-p 'interactive))
983 (with-help-window (help-buffer)
984 (let ((table (with-current-buffer buffer (syntax-table))))
985 (with-current-buffer standard-output
986 (describe-vector table 'internal-describe-syntax-value)
987 (while (setq table (char-table-parent table))
988 (insert "\nThe parent syntax table is:")
989 (describe-vector table 'internal-describe-syntax-value))))))
991 (defun help-describe-category-set (value)
993 ((null value) "default")
994 ((char-table-p value) "deeper char-table ...")
995 (t (condition-case nil
996 (category-set-mnemonics value)
997 (error "invalid"))))))
1000 (defun describe-categories (&optional buffer)
1001 "Describe the category specifications in the current category table.
1002 The descriptions are inserted in a buffer, which is then displayed.
1003 If BUFFER is non-nil, then describe BUFFER's category table instead.
1004 BUFFER should be a buffer or a buffer name."
1006 (setq buffer (or buffer (current-buffer)))
1007 (help-setup-xref (list #'describe-categories buffer)
1008 (called-interactively-p 'interactive))
1009 (with-help-window (help-buffer)
1010 (let* ((table (with-current-buffer buffer (category-table)))
1011 (docs (char-table-extra-slot table 0)))
1012 (if (or (not (vectorp docs)) (/= (length docs) 95))
1013 (error "Invalid first extra slot in this category table\n"))
1014 (with-current-buffer standard-output
1015 (insert "Legend of category mnemonics (see the tail for the longer description)\n")
1016 (let ((pos (point)) (items 0) lines n)
1018 (if (aref docs i) (setq items (1+ items))))
1019 (setq lines (1+ (/ (1- items) 4)))
1022 (let ((elt (aref docs i)))
1024 (string-match ".*" elt)
1025 (setq elt (match-string 0 elt))
1026 (if (>= (length elt) 17)
1027 (setq elt (concat (substring elt 0 14) "...")))
1028 (if (< (point) (point-max))
1029 (move-to-column (* 20 (/ n lines)) t))
1030 (insert (+ i ?\s) ?: elt)
1031 (if (< (point) (point-max))
1035 (if (= (% n lines) 0)
1036 (goto-char pos))))))
1037 (goto-char (point-max))
1039 "character(s)\tcategory mnemonics\n"
1040 "------------\t------------------")
1041 (describe-vector table 'help-describe-category-set)
1042 (insert "Legend of category mnemonics:\n")
1044 (let ((elt (aref docs i)))
1046 (if (string-match "\n" elt)
1047 (setq elt (substring elt (match-end 0))))
1048 (insert (+ i ?\s) ": " elt "\n"))))
1049 (while (setq table (char-table-parent table))
1050 (insert "\nThe parent category table is:")
1051 (describe-vector table 'help-describe-category-set))))))
1054 ;;; Replacements for old lib-src/ programs. Don't seem especially useful.
1056 ;; Replaces lib-src/digest-doc.c.
1058 (defun doc-file-to-man (file)
1059 "Produce an nroff buffer containing the doc-strings from the DOC file."
1060 (interactive (list (read-file-name "Name of DOC file: " doc-directory
1061 internal-doc-file-name t)))
1062 (or (file-readable-p file)
1063 (error "Cannot read file `%s'" file))
1064 (pop-to-buffer (generate-new-buffer "*man-doc*"))
1065 (setq buffer-undo-list t)
1066 (insert ".TH \"Command Summary for GNU Emacs\"\n"
1067 ".AU Richard M. Stallman\n")
1068 (insert-file-contents file)
1070 (while (search-forward "
\1f" nil 'move)
1071 (if (looking-at "S")
1072 (delete-region (1- (point)) (line-end-position))
1078 (insert (if (looking-at "F") "Function " "Variable "))
1081 (insert ".DS L\n"))))
1083 (setq buffer-undo-list nil)
1086 ;; Replaces lib-src/sorted-doc.c.
1088 (defun doc-file-to-info (file)
1089 "Produce a texinfo buffer with sorted doc-strings from the DOC file."
1090 (interactive (list (read-file-name "Name of DOC file: " doc-directory
1091 internal-doc-file-name t)))
1092 (or (file-readable-p file)
1093 (error "Cannot read file `%s'" file))
1094 (let ((i 0) type name doc alist)
1096 (insert-file-contents file)
1097 ;; The characters "@{}" need special treatment.
1098 (while (re-search-forward "[@{}]" nil t)
1102 (goto-char (point-min))
1103 (while (search-forward "
\1f" nil t)
1104 (unless (looking-at "S")
1105 (setq type (char-after)
1106 name (buffer-substring (1+ (point)) (line-end-position))
1107 doc (buffer-substring (line-beginning-position 2)
1108 (if (search-forward "
\1f" nil 'move)
1111 alist (cons (list name type doc) alist))
1112 (backward-char 1))))
1113 (pop-to-buffer (generate-new-buffer "*info-doc*"))
1114 (setq buffer-undo-list t)
1115 ;; Write the output header.
1116 (insert "\\input texinfo @c -*-texinfo-*-\n"
1117 "@setfilename emacsdoc.info\n"
1118 "@settitle Command Summary for GNU Emacs\n"
1121 "@unnumbered Command Summary for GNU Emacs\n\n"
1124 "@global@let@ITEM@item\n"
1125 "@def@item{@filbreak@vskip5pt@ITEM}\n"
1126 "@font@tensy cmsy10 scaled @magstephalf\n"
1127 "@font@teni cmmi10 scaled @magstephalf\n"
1128 "@def\\{{@tensy@char110}}\n" ; this backslash goes with cmr10
1129 "@def|{{@tensy@char106}}\n"
1130 "@def@{{{@tensy@char102}}\n"
1131 "@def@}{{@tensy@char103}}\n"
1132 "@def<{{@teni@char62}}\n"
1133 "@def>{{@teni@char60}}\n"
1136 "@tableindent-0.2in\n"
1138 ;; Sort the array by name; within each name, by type (functions first).
1139 (setq alist (sort alist (lambda (e1 e2)
1140 (if (string-equal (car e1) (car e2))
1141 (<= (cadr e1) (cadr e2))
1142 (string-lessp (car e1) (car e2))))))
1143 ;; Print each function.
1146 (if (char-equal (cadr e) ?\F) "Function" "Variable")
1147 " @code{" (car e) "}\n@display\n"
1150 ;; Try to avoid a save size overflow in the TeX output routine.
1151 (if (zerop (setq i (% (1+ i) 100)))
1152 (insert "\n@end table\n@table @asis\n")))
1153 (insert "@end table\n"
1155 (setq buffer-undo-list nil)
1160 ;;; help-fns.el ends here