1 ;;; help-fns.el --- Complex help functions -*- lexical-binding: t -*-
3 ;; Copyright (C) 1985-1986, 1993-1994, 1998-2014 Free Software
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 (symbolp def) def "anonymous")
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 ~/.foo.elc, try ~/.foo.
340 ;; This applies to config files like ~/.emacs,
341 ;; which people sometimes compile.
343 (and (string-match "\\`\\..*\\.elc\\'"
344 (file-name-nondirectory file-name))
345 (string-equal (file-name-directory file-name)
346 (file-name-as-directory (expand-file-name "~")))
347 (file-readable-p (setq fn (file-name-sans-extension file-name)))
349 ;; When the Elisp source file can be found in the install
350 ;; directory, return the name of that file.
352 (if (string-match "[.]elc\\'" file-name)
353 (substring-no-properties file-name 0 -1)
355 (or (and (file-readable-p lib-name) lib-name)
356 ;; The library might be compressed.
357 (and (file-readable-p (concat lib-name ".gz")) lib-name))))
358 ((let* ((lib-name (file-name-nondirectory file-name))
359 ;; The next form is from `describe-simplify-lib-file-name'.
361 ;; Try converting the absolute file name to a library
362 ;; name, convert that back to a file name and see if we
363 ;; get the original one. If so, they are equivalent.
364 (if (equal file-name (locate-file lib-name load-path '("")))
365 (if (string-match "[.]elc\\'" lib-name)
366 (substring-no-properties lib-name 0 -1)
369 ;; The next three forms are from `find-source-lisp-file'.
370 (elc-file (locate-file
372 (if (string-match "\\.el\\'" file-name)
375 load-path nil 'readable))
378 (insert-file-contents-literally elc-file nil 0 256)
381 (string-match ";;; from file \\(.*\\.el\\)" str)
382 (match-string 1 str))))
383 (and src-file (file-readable-p src-file) src-file))))))
385 (defun help-fns--key-bindings (function)
386 (when (commandp function)
387 (let ((pt2 (with-current-buffer standard-output (point)))
388 (remapped (command-remapping function)))
389 (unless (memq remapped '(ignore undefined))
390 (let ((keys (where-is-internal
391 (or remapped function) overriding-local-map nil nil))
393 (if (and (eq function 'self-insert-command)
394 (vectorp (car-safe keys))
395 (consp (aref (car keys) 0)))
396 (princ "It is bound to many ordinary text characters.\n")
397 ;; Which non-control non-meta keys run this command?
399 (if (member (event-modifiers (aref key 0)) '(nil (shift)))
400 (push key non-modified-keys)))
402 (princ "Its keys are remapped to ")
403 (princ (if (symbolp remapped)
404 (concat "`" (symbol-name remapped) "'")
405 "an anonymous command"))
410 "Without this remapping, it would be bound to "
412 ;; If lots of ordinary text characters run this command,
413 ;; don't mention them one by one.
414 (if (< (length non-modified-keys) 10)
415 (princ (mapconcat 'key-description keys ", "))
416 (dolist (key non-modified-keys)
417 (setq keys (delq key keys)))
420 (princ (mapconcat 'key-description keys ", "))
421 (princ ", and many ordinary text characters"))
422 (princ "many ordinary text characters"))))
423 (when (or remapped keys non-modified-keys)
427 (with-current-buffer standard-output
428 (fill-region-as-paragraph pt2 (point))
429 (unless (looking-back "\n\n")
432 (defun help-fns--compiler-macro (function)
433 (let ((handler (function-get function 'compiler-macro)))
435 (insert "\nThis function has a compiler macro")
436 (if (symbolp handler)
438 (insert (format " `%s'" handler))
440 (re-search-backward "`\\([^`']+\\)'" nil t)
441 (help-xref-button 1 'help-function handler)))
442 ;; FIXME: Obsolete since 24.4.
443 (let ((lib (get function 'compiler-macro-file)))
445 (insert (format " in `%s'" lib))
447 (re-search-backward "`\\([^`']+\\)'" nil t)
448 (help-xref-button 1 'help-function-cmacro function lib)))))
451 (defun help-fns--signature (function doc real-def real-function)
452 (unless (keymapp function) ; If definition is a keymap, skip arglist note.
453 (let* ((advertised (gethash real-def advertised-signature-table t))
454 (arglist (if (listp advertised)
455 advertised (help-function-arglist real-def)))
456 (usage (help-split-fundoc doc function)))
457 (if usage (setq doc (cdr usage)))
459 ((and usage (not (listp advertised))) (car usage))
461 (format "%S" (help-make-usage function arglist)))
462 ((stringp arglist) arglist)
463 ;; Maybe the arglist is in the docstring of a symbol
464 ;; this one is aliased to.
465 ((let ((fun real-function))
466 (while (and (symbolp fun)
467 (setq fun (symbol-function fun))
468 (not (setq usage (help-split-fundoc
473 ((or (stringp real-def)
475 (format "\nMacro: %s" (format-kbd-macro real-def)))
476 (t "[Missing arglist. Please make a bug report.]")))
477 (high (help-highlight-arguments use doc)))
478 (let ((fill-begin (point)))
479 (insert (car high) "\n")
480 (fill-region fill-begin (point)))
483 (defun help-fns--parent-mode (function)
484 ;; If this is a derived mode, link to the parent.
485 (let ((parent-mode (and (symbolp function)
487 'derived-mode-parent))))
489 (insert "\nParent mode: `")
491 (insert (format "%s" parent-mode))
492 (make-text-button beg (point)
494 'help-args (list parent-mode)))
497 (defun help-fns--obsolete (function)
498 ;; Ignore lambda constructs, keyboard macros, etc.
499 (let* ((obsolete (and (symbolp function)
500 (get function 'byte-obsolete-info)))
501 (use (car obsolete)))
504 (if (eq (car-safe (symbol-function function)) 'macro)
508 (when (nth 2 obsolete)
509 (insert (format " since %s" (nth 2 obsolete))))
510 (insert (cond ((stringp use) (concat ";\n" use))
511 (use (format ";\nuse `%s' instead." use))
515 ;; We could use `symbol-file' but this is a wee bit more efficient.
516 (defun help-fns--autoloaded-p (function file)
517 "Return non-nil if FUNCTION has previously been autoloaded.
518 FILE is the file where FUNCTION was probably defined."
519 (let* ((file (file-name-sans-extension (file-truename file)))
520 (load-hist load-history)
521 (target (cons t function))
523 (while (and load-hist (not found))
524 (and (caar load-hist)
525 (equal (file-name-sans-extension (caar load-hist)) file)
526 (setq found (member target (cdar load-hist))))
527 (setq load-hist (cdr load-hist)))
531 (defun describe-function-1 (function)
532 (let* ((advised (and (symbolp function)
534 (advice--p (advice--symbol-function function))))
535 ;; If the function is advised, use the symbol that has the
536 ;; real definition, if that symbol is already set up.
539 (let* ((advised-fn (advice--cdr
540 (advice--symbol-function function))))
541 (while (advice--p advised-fn)
542 (setq advised-fn (advice--cdr advised-fn)))
545 ;; Get the real definition.
546 (def (if (symbolp real-function)
547 (symbol-function real-function)
549 (aliased (or (symbolp def)
550 ;; Advised & aliased function.
551 (and advised (symbolp real-function))))
553 (aliased (let ((f real-function))
554 (while (and (fboundp f)
555 (symbolp (symbol-function f)))
556 (setq f (symbol-function f)))
558 ((subrp def) (intern (subr-name def)))
560 (file-name (find-lisp-object-file-name function def))
561 (pt1 (with-current-buffer (help-buffer) (point)))
562 (beg (if (and (or (byte-code-function-p def)
564 (memq (car-safe def) '(macro lambda closure)))
566 (help-fns--autoloaded-p function file-name))
568 "an interactive autoloaded "
570 (if (commandp def) "an interactive " "a "))))
572 ;; Print what kind of function-like object FUNCTION is.
573 (princ (cond ((or (stringp def) (vectorp def))
576 (if (eq 'unevalled (cdr (subr-arity def)))
577 (concat beg "special form")
578 (concat beg "built-in function")))
579 ;; Aliases are Lisp functions, so we need to check
580 ;; aliases before functions.
582 (format "an alias for `%s'" real-def))
583 ((or (eq (car-safe def) 'macro)
584 ;; For advised macros, def is a lambda
585 ;; expression or a byte-code-function-p, so we
586 ;; need to check macros before functions.
588 (concat beg "Lisp macro"))
589 ((byte-code-function-p def)
590 (concat beg "compiled Lisp function"))
591 ((eq (car-safe def) 'lambda)
592 (concat beg "Lisp function"))
593 ((eq (car-safe def) 'closure)
594 (concat beg "Lisp closure"))
596 (format "%s autoloaded %s"
597 (if (commandp def) "an interactive" "an")
598 (if (eq (nth 4 def) 'keymap) "keymap"
599 (if (nth 4 def) "Lisp macro" "Lisp function"))))
602 (elts (cdr-safe def)))
604 (if (char-table-p (car-safe elts))
607 (setq elts (cdr-safe elts)))
608 (concat beg (if is-full "keymap" "sparse keymap"))))
611 (if (and aliased (not (fboundp real-def)))
612 (princ ",\nwhich is not defined. Please make a bug report.")
613 (with-current-buffer standard-output
616 (when (re-search-backward "alias for `\\([^`']+\\)'" nil t)
617 (help-xref-button 1 'help-function real-def)))))
621 ;; We used to add .el to the file name,
622 ;; but that's completely wrong when the user used load-file.
623 (princ (if (eq file-name 'C-source)
625 (file-name-nondirectory file-name)))
627 ;; Make a hyperlink to the library.
628 (with-current-buffer standard-output
630 (re-search-backward "`\\([^`']+\\)'" nil t)
631 (help-xref-button 1 'help-function-def function file-name))))
633 (with-current-buffer (help-buffer)
634 (fill-region-as-paragraph (save-excursion (goto-char pt1) (forward-line 0) (point))
638 (let* ((doc-raw (documentation function t))
639 ;; If the function is autoloaded, and its docstring has
640 ;; key substitution constructs, load the library.
642 (and (autoloadp real-def) doc-raw
643 help-enable-auto-load
644 (string-match "\\([^\\]=\\|[^=]\\|\\`\\)\\\\[[{<]"
646 (load (cadr real-def) t))
647 (substitute-command-keys doc-raw))))
649 (help-fns--key-bindings function)
650 (with-current-buffer standard-output
651 (setq doc (help-fns--signature function doc real-def real-function))
653 (help-fns--compiler-macro function)
654 (help-fns--parent-mode function)
655 (help-fns--obsolete function)
658 (or doc "Not documented.")))))))
664 (defun variable-at-point (&optional any-symbol)
665 "Return the bound variable symbol found at or before point.
666 Return 0 if there is no such symbol.
667 If ANY-SYMBOL is non-nil, don't insist the symbol be bound."
668 (with-syntax-table emacs-lisp-mode-syntax-table
669 (or (condition-case ()
671 (skip-chars-forward "'")
672 (or (not (zerop (skip-syntax-backward "_w")))
673 (eq (char-syntax (following-char)) ?w)
674 (eq (char-syntax (following-char)) ?_)
676 (skip-chars-forward "'")
677 (let ((obj (read (current-buffer))))
678 (and (symbolp obj) (boundp obj) obj)))
680 (let* ((str (find-tag-default))
681 (sym (if str (intern-soft str))))
682 (if (and sym (or any-symbol (boundp sym)))
685 (when (and str (string-match "\\`\\W*\\(.*?\\)\\W*\\'" str))
686 (setq sym (intern-soft (match-string 1 str)))
687 (and (or any-symbol (boundp sym)) sym)))))
690 (defun describe-variable-custom-version-info (variable)
691 (let ((custom-version (get variable 'custom-version))
692 (cpv (get variable 'custom-package-version))
696 (format "This variable was introduced, or its default value was changed, in\nversion %s of Emacs.\n"
699 (let* ((package (car-safe cpv))
700 (version (if (listp (cdr-safe cpv))
703 (pkg-versions (assq package customize-package-emacs-version-alist))
704 (emacsv (cdr (assoc version pkg-versions))))
705 (if (and package version)
707 (format (concat "This variable was introduced, or its default value was changed, in\nversion %s of the %s package"
709 (format " that is part of Emacs %s" emacsv))
711 version package))))))
715 (defun describe-variable (variable &optional buffer frame)
716 "Display the full documentation of VARIABLE (a symbol).
717 Returns the documentation as a string, also.
718 If VARIABLE has a buffer-local value in BUFFER or FRAME
719 \(default to the current buffer and current frame),
720 it is displayed along with the global value."
722 (let ((v (variable-at-point))
723 (enable-recursive-minibuffers t)
725 (setq val (completing-read (if (symbolp v)
727 "Describe variable (default %s): " v)
728 "Describe variable: ")
731 (or (get vv 'variable-documentation)
732 (and (boundp vv) (not (keywordp vv)))))
734 (if (symbolp v) (symbol-name v))))
735 (list (if (equal val "")
738 (unless (buffer-live-p buffer) (setq buffer (current-buffer)))
739 (unless (frame-live-p frame) (setq frame (selected-frame)))
740 (if (not (symbolp variable))
741 (message "You did not specify a variable")
743 (let ((valvoid (not (with-current-buffer buffer (boundp variable))))
744 (permanent-local (get variable 'permanent-local))
745 val val-start-pos locus)
746 ;; Extract the value before setting up the output buffer,
747 ;; in case `buffer' *is* the output buffer.
749 (with-selected-frame frame
750 (with-current-buffer buffer
751 (setq val (symbol-value variable)
752 locus (variable-binding-locus variable)))))
753 (help-setup-xref (list #'describe-variable variable buffer)
754 (called-interactively-p 'interactive))
755 (with-help-window (help-buffer)
756 (with-current-buffer buffer
758 (setq file-name (find-lisp-object-file-name variable 'defvar))
762 (princ " is a variable defined in `")
763 (princ (if (eq file-name 'C-source)
765 (file-name-nondirectory file-name)))
767 (with-current-buffer standard-output
769 (re-search-backward "`\\([^`']+\\)'" nil t)
770 (help-xref-button 1 'help-variable-def
771 variable file-name)))
773 (princ "It is void as a variable.")
776 (princ " is void as a variable.")
779 (with-current-buffer standard-output
780 (setq val-start-pos (point))
783 (line-beg (line-beginning-position))
785 (let ((print-quoted t))
786 (prin1-to-string val))))
787 (if (< (+ (length print-rep) (point) (- line-beg)) 68)
791 (if (< (point) (+ 68 (line-beginning-position 0)))
792 (delete-region from (1+ from))
793 (delete-region (1- from) from)))
794 (let* ((sv (get variable 'standard-value))
795 (origval (and (consp sv)
798 (error :help-eval-error)))))
799 (when (and (consp sv)
800 (not (equal origval val))
801 (not (equal origval :help-eval-error)))
802 (princ "\nOriginal value was \n")
805 (if (< (point) (+ from 20))
806 (delete-region (1- from) from)))))))
811 (princ (format "Local in buffer %s; "
812 (buffer-name buffer))))
814 (princ (format "It is a frame-local variable; ")))
815 ((terminal-live-p locus)
816 (princ (format "It is a terminal-local variable; ")))
818 (princ (format "It is local to %S" locus))))
819 (if (not (default-boundp variable))
820 (princ "globally void")
821 (let ((global-val (default-value variable)))
822 (with-current-buffer standard-output
823 (princ "global value is ")
824 (if (eq val global-val)
827 ;; Fixme: pp can take an age if you happen to
828 ;; ask for a very large expression. We should
829 ;; probably print it raw once and check it's a
830 ;; sensible size before prettyprinting. -- fx
831 (let ((from (point)))
833 ;; See previous comment for this function.
834 ;; (help-xref-on-pp from (point))
835 (if (< (point) (+ from 20))
836 (delete-region (1- from) from)))))))
839 ;; If the value is large, move it to the end.
840 (with-current-buffer standard-output
841 (when (> (count-lines (point-min) (point-max)) 10)
842 ;; Note that setting the syntax table like below
843 ;; makes forward-sexp move over a `'s' at the end
845 (set-syntax-table emacs-lisp-mode-syntax-table)
846 (goto-char val-start-pos)
847 ;; The line below previously read as
848 ;; (delete-region (point) (progn (end-of-line) (point)))
849 ;; which suppressed display of the buffer local value for
851 (when (looking-at "value is") (replace-match ""))
853 (insert "\n\nValue:")
854 (set (make-local-variable 'help-button-cache)
856 (insert "value is shown ")
857 (insert-button "below"
858 'action help-button-cache
860 'help-echo "mouse-2, RET: show value")
864 (let* ((alias (condition-case nil
865 (indirect-variable variable)
867 (obsolete (get variable 'byte-obsolete-variable))
869 (safe-var (get variable 'safe-local-variable))
870 (doc (or (documentation-property
871 variable 'variable-documentation)
872 (documentation-property
873 alias 'variable-documentation)))
876 ;; Mention if it's a local variable.
878 ((and (local-variable-if-set-p variable)
879 (or (not (local-variable-p variable))
881 (local-variable-if-set-p variable))))
883 (princ " Automatically becomes ")
885 (princ "permanently "))
886 (princ "buffer-local when set.\n"))
887 ((not permanent-local))
890 (princ " This variable's buffer-local value is permanent.\n"))
893 (princ " This variable's value is permanent \
894 if it is given a local binding.\n")))
896 ;; Mention if it's an alias.
897 (unless (eq alias variable)
899 (princ (format " This variable is an alias for `%s'.\n" alias)))
903 (princ " This variable is obsolete")
905 (princ (format " since %s" (nth 2 obsolete))))
906 (princ (cond ((stringp use) (concat ";\n " use))
907 (use (format ";\n use `%s' instead." (car obsolete)))
911 (when (member (cons variable val) file-local-variables-alist)
913 (if (member (cons variable val) dir-local-variables-alist)
914 (let ((file (and (buffer-file-name)
915 (not (file-remote-p (buffer-file-name)))
916 (dir-locals-find-file
917 (buffer-file-name))))
919 (princ " This variable's value is directory-local")
923 (if (consp file) ; result from cache
924 ;; If the cache element has an mtime, we
925 ;; assume it came from a file.
927 (setq file (expand-file-name
928 dir-locals-file (car file)))
929 ;; Otherwise, assume it was set directly.
930 (setq dir-file nil)))
933 "for the directory\n `"))
934 (with-current-buffer standard-output
936 file 'type 'help-dir-local-var-def
937 'help-args (list variable file)))
939 (princ " This variable's value is file-local.\n")))
941 (when (memq variable ignored-local-variables)
943 (princ " This variable is ignored as a file-local \
946 ;; Can be both risky and safe, eg auto-fill-function.
947 (when (risky-local-variable-p variable)
949 (princ " This variable may be risky if used as a \
950 file-local variable.\n")
951 (when (assq variable safe-local-variable-values)
952 (princ " However, you have added it to \
953 `safe-local-variable-values'.\n")))
957 (princ " This variable is safe as a file local variable ")
958 (princ "if its value\n satisfies the predicate ")
959 (princ (if (byte-code-function-p safe-var)
960 "which is a byte-compiled expression.\n"
961 (format "`%s'.\n" safe-var))))
963 (if extra-line (terpri))
964 (princ "Documentation:\n")
965 (with-current-buffer standard-output
966 (insert (or doc "Not documented as a variable."))))
968 ;; Make a link to customize if this variable can be customized.
969 (when (custom-variable-p variable)
970 (let ((customize-label "customize"))
973 (princ (concat "You can " customize-label " this variable."))
974 (with-current-buffer standard-output
977 (concat "\\(" customize-label "\\)") nil t)
978 (help-xref-button 1 'help-customize-variable variable))))
979 ;; Note variable's version or package version
980 (let ((output (describe-variable-custom-version-info variable)))
986 (with-current-buffer standard-output
987 ;; Return the text we displayed.
988 (buffer-string))))))))
992 (defun describe-syntax (&optional buffer)
993 "Describe the syntax specifications in the syntax table of BUFFER.
994 The descriptions are inserted in a help buffer, which is then displayed.
995 BUFFER defaults to the current buffer."
997 (setq buffer (or buffer (current-buffer)))
998 (help-setup-xref (list #'describe-syntax buffer)
999 (called-interactively-p 'interactive))
1000 (with-help-window (help-buffer)
1001 (let ((table (with-current-buffer buffer (syntax-table))))
1002 (with-current-buffer standard-output
1003 (describe-vector table 'internal-describe-syntax-value)
1004 (while (setq table (char-table-parent table))
1005 (insert "\nThe parent syntax table is:")
1006 (describe-vector table 'internal-describe-syntax-value))))))
1008 (defun help-describe-category-set (value)
1010 ((null value) "default")
1011 ((char-table-p value) "deeper char-table ...")
1012 (t (condition-case nil
1013 (category-set-mnemonics value)
1014 (error "invalid"))))))
1017 (defun describe-categories (&optional buffer)
1018 "Describe the category specifications in the current category table.
1019 The descriptions are inserted in a buffer, which is then displayed.
1020 If BUFFER is non-nil, then describe BUFFER's category table instead.
1021 BUFFER should be a buffer or a buffer name."
1023 (setq buffer (or buffer (current-buffer)))
1024 (help-setup-xref (list #'describe-categories buffer)
1025 (called-interactively-p 'interactive))
1026 (with-help-window (help-buffer)
1027 (let* ((table (with-current-buffer buffer (category-table)))
1028 (docs (char-table-extra-slot table 0)))
1029 (if (or (not (vectorp docs)) (/= (length docs) 95))
1030 (error "Invalid first extra slot in this category table\n"))
1031 (with-current-buffer standard-output
1032 (insert "Legend of category mnemonics (see the tail for the longer description)\n")
1033 (let ((pos (point)) (items 0) lines n)
1035 (if (aref docs i) (setq items (1+ items))))
1036 (setq lines (1+ (/ (1- items) 4)))
1039 (let ((elt (aref docs i)))
1041 (string-match ".*" elt)
1042 (setq elt (match-string 0 elt))
1043 (if (>= (length elt) 17)
1044 (setq elt (concat (substring elt 0 14) "...")))
1045 (if (< (point) (point-max))
1046 (move-to-column (* 20 (/ n lines)) t))
1047 (insert (+ i ?\s) ?: elt)
1048 (if (< (point) (point-max))
1052 (if (= (% n lines) 0)
1053 (goto-char pos))))))
1054 (goto-char (point-max))
1056 "character(s)\tcategory mnemonics\n"
1057 "------------\t------------------")
1058 (describe-vector table 'help-describe-category-set)
1059 (insert "Legend of category mnemonics:\n")
1061 (let ((elt (aref docs i)))
1063 (if (string-match "\n" elt)
1064 (setq elt (substring elt (match-end 0))))
1065 (insert (+ i ?\s) ": " elt "\n"))))
1066 (while (setq table (char-table-parent table))
1067 (insert "\nThe parent category table is:")
1068 (describe-vector table 'help-describe-category-set))))))
1071 ;;; Replacements for old lib-src/ programs. Don't seem especially useful.
1073 ;; Replaces lib-src/digest-doc.c.
1075 (defun doc-file-to-man (file)
1076 "Produce an nroff buffer containing the doc-strings from the DOC file."
1077 (interactive (list (read-file-name "Name of DOC file: " doc-directory
1078 internal-doc-file-name t)))
1079 (or (file-readable-p file)
1080 (error "Cannot read file `%s'" file))
1081 (pop-to-buffer (generate-new-buffer "*man-doc*"))
1082 (setq buffer-undo-list t)
1083 (insert ".TH \"Command Summary for GNU Emacs\"\n"
1084 ".AU Richard M. Stallman\n")
1085 (insert-file-contents file)
1087 (while (search-forward "
\1f" nil 'move)
1088 (if (looking-at "S")
1089 (delete-region (1- (point)) (line-end-position))
1095 (insert (if (looking-at "F") "Function " "Variable "))
1098 (insert ".DS L\n"))))
1100 (setq buffer-undo-list nil)
1103 ;; Replaces lib-src/sorted-doc.c.
1105 (defun doc-file-to-info (file)
1106 "Produce a texinfo buffer with sorted doc-strings from the DOC file."
1107 (interactive (list (read-file-name "Name of DOC file: " doc-directory
1108 internal-doc-file-name t)))
1109 (or (file-readable-p file)
1110 (error "Cannot read file `%s'" file))
1111 (let ((i 0) type name doc alist)
1113 (insert-file-contents file)
1114 ;; The characters "@{}" need special treatment.
1115 (while (re-search-forward "[@{}]" nil t)
1119 (goto-char (point-min))
1120 (while (search-forward "
\1f" nil t)
1121 (unless (looking-at "S")
1122 (setq type (char-after)
1123 name (buffer-substring (1+ (point)) (line-end-position))
1124 doc (buffer-substring (line-beginning-position 2)
1125 (if (search-forward "
\1f" nil 'move)
1128 alist (cons (list name type doc) alist))
1129 (backward-char 1))))
1130 (pop-to-buffer (generate-new-buffer "*info-doc*"))
1131 (setq buffer-undo-list t)
1132 ;; Write the output header.
1133 (insert "\\input texinfo @c -*-texinfo-*-\n"
1134 "@setfilename emacsdoc.info\n"
1135 "@settitle Command Summary for GNU Emacs\n"
1138 "@unnumbered Command Summary for GNU Emacs\n\n"
1141 "@global@let@ITEM@item\n"
1142 "@def@item{@filbreak@vskip5pt@ITEM}\n"
1143 "@font@tensy cmsy10 scaled @magstephalf\n"
1144 "@font@teni cmmi10 scaled @magstephalf\n"
1145 "@def\\{{@tensy@char110}}\n" ; this backslash goes with cmr10
1146 "@def|{{@tensy@char106}}\n"
1147 "@def@{{{@tensy@char102}}\n"
1148 "@def@}{{@tensy@char103}}\n"
1149 "@def<{{@teni@char62}}\n"
1150 "@def>{{@teni@char60}}\n"
1153 "@tableindent-0.2in\n"
1155 ;; Sort the array by name; within each name, by type (functions first).
1156 (setq alist (sort alist (lambda (e1 e2)
1157 (if (string-equal (car e1) (car e2))
1158 (<= (cadr e1) (cadr e2))
1159 (string-lessp (car e1) (car e2))))))
1160 ;; Print each function.
1163 (if (char-equal (cadr e) ?\F) "Function" "Variable")
1164 " @code{" (car e) "}\n@display\n"
1167 ;; Try to avoid a save size overflow in the TeX output routine.
1168 (if (zerop (setq i (% (1+ i) 100)))
1169 (insert "\n@end table\n@table @asis\n")))
1170 (insert "@end table\n"
1172 (setq buffer-undo-list nil)
1177 ;;; help-fns.el ends here