1 ;;; help-fns.el --- Complex help functions
3 ;; Copyright (C) 1985, 1986, 1993, 1994, 1998, 1999, 2000, 2001,
4 ;; 2002, 2003, 2004, 2005, 2006, 2007 Free Software Foundation, Inc.
7 ;; Keywords: help, internal
9 ;; This file is part of GNU Emacs.
11 ;; GNU Emacs is free software; you can redistribute it and/or modify
12 ;; it under the terms of the GNU General Public License as published by
13 ;; the Free Software Foundation; either version 3, or (at your option)
16 ;; GNU Emacs is distributed in the hope that it will be useful,
17 ;; but WITHOUT ANY WARRANTY; without even the implied warranty of
18 ;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
19 ;; GNU General Public License for more details.
21 ;; You should have received a copy of the GNU General Public License
22 ;; along with GNU Emacs; see the file COPYING. If not, write to the
23 ;; Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
24 ;; Boston, MA 02110-1301, USA.
28 ;; This file contains those help commands which are complicated, and
29 ;; which may not be used in every session. For example
30 ;; `describe-function' will probably be heavily used when doing elisp
31 ;; programming, but not if just editing C files. Simpler help commands
41 (defun describe-function (function)
42 "Display the full documentation of FUNCTION (a symbol)."
44 (let ((fn (function-called-at-point))
45 (enable-recursive-minibuffers t
)
47 (setq val
(completing-read (if fn
48 (format "Describe function (default %s): " fn
)
49 "Describe function: ")
50 obarray
'fboundp t nil nil
51 (and fn
(symbol-name fn
))))
52 (list (if (equal val
"")
55 (message "You didn't specify a function")
56 (help-setup-xref (list #'describe-function function
) (interactive-p))
58 (with-output-to-temp-buffer (help-buffer)
60 ;; Use " is " instead of a colon so that
61 ;; it is easier to get out the function name using forward-sexp.
63 (describe-function-1 function
)
64 (print-help-return-message)
65 (with-current-buffer standard-output
66 ;; Return the text we displayed.
69 (defun help-split-fundoc (docstring def
)
70 "Split a function DOCSTRING into the actual doc and the usage info.
71 Return (USAGE . DOC) or nil if there's no usage info.
72 DEF is the function whose usage we're looking for in DOCSTRING."
73 ;; Functions can get the calling sequence at the end of the doc string.
74 ;; In cases where `function' has been fset to a subr we can't search for
75 ;; function's name in the doc string so we use `fn' as the anonymous
76 ;; function name instead.
77 (when (and docstring
(string-match "\n\n(fn\\(\\( .*\\)?)\\)\\'" docstring
))
79 ;; Replace `fn' with the actual function name.
80 (if (consp def
) "anonymous" def
)
81 (match-string 1 docstring
))
82 (substring docstring
0 (match-beginning 0)))))
84 (defun help-add-fundoc-usage (docstring arglist
)
85 "Add the usage info to DOCSTRING.
86 If DOCSTRING already has a usage info, then just return it unchanged.
87 The usage info is built from ARGLIST. DOCSTRING can be nil.
88 ARGLIST can also be t or a string of the form \"(FUN ARG1 ARG2 ...)\"."
89 (unless (stringp docstring
) (setq docstring
"Not documented"))
90 (if (or (string-match "\n\n(fn\\(\\( .*\\)?)\\)\\'" docstring
) (eq arglist t
))
93 (if (string-match "\n?\n\\'" docstring
)
94 (if (< (- (match-end 0) (match-beginning 0)) 2) "\n" "")
96 (if (and (stringp arglist
)
97 (string-match "\\`([^ ]+\\(.*\\))\\'" arglist
))
98 (concat "(fn" (match-string 1 arglist
) ")")
99 (format "%S" (help-make-usage 'fn arglist
))))))
101 (defun help-function-arglist (def)
102 ;; Handle symbols aliased to other symbols.
103 (if (and (symbolp def
) (fboundp def
)) (setq def
(indirect-function def
)))
104 ;; If definition is a macro, find the function inside it.
105 (if (eq (car-safe def
) 'macro
) (setq def
(cdr def
)))
107 ((byte-code-function-p def
) (aref def
0))
108 ((eq (car-safe def
) 'lambda
) (nth 1 def
))
109 ((and (eq (car-safe def
) 'autoload
) (not (eq (nth 4 def
) 'keymap
)))
110 "[Arg list not available until function definition is loaded.]")
113 (defun help-make-usage (function arglist
)
114 (cons (if (symbolp function
) function
'anonymous
)
115 (mapcar (lambda (arg)
116 (if (not (symbolp arg
))
117 (if (and (consp arg
) (symbolp (car arg
)))
118 ;; CL style default values for optional args.
119 (cons (intern (upcase (symbol-name (car arg
))))
122 (let ((name (symbol-name arg
)))
123 (if (string-match "\\`&" name
) arg
124 (intern (upcase name
))))))
127 ;; Could be this, if we make symbol-file do the work below.
128 ;; (defun help-C-file-name (subr-or-var kind)
129 ;; "Return the name of the C file where SUBR-OR-VAR is defined.
130 ;; KIND should be `var' for a variable or `subr' for a subroutine."
131 ;; (symbol-file (if (symbolp subr-or-var) subr-or-var
132 ;; (subr-name subr-or-var))
133 ;; (if (eq kind 'var) 'defvar 'defun)))
135 (defun help-C-file-name (subr-or-var kind
)
136 "Return the name of the C file where SUBR-OR-VAR is defined.
137 KIND should be `var' for a variable or `subr' for a subroutine."
138 (let ((docbuf (get-buffer-create " *DOC*"))
139 (name (if (eq 'var kind
)
140 (concat "V" (symbol-name subr-or-var
))
141 (concat "F" (subr-name subr-or-var
)))))
142 (with-current-buffer docbuf
143 (goto-char (point-min))
145 (insert-file-contents-literally
146 (expand-file-name internal-doc-file-name doc-directory
)))
147 (let ((file (catch 'loop
149 (let ((pnt (search-forward (concat "\x1f" name
"\n"))))
150 (re-search-backward "\x1fS\\(.*\\)")
151 (let ((file (match-string 1)))
152 (if (member file build-files
)
154 (goto-char pnt
))))))))
155 (if (string-match "\\.\\(o\\|obj\\)\\'" file
)
156 (setq file
(replace-match ".c" t t file
)))
157 (if (string-match "\\.c\\'" file
)
161 (defface help-argument-name
'((((supports :slant italic
)) :inherit italic
))
162 "Face to highlight argument names in *Help* buffers."
165 (defun help-default-arg-highlight (arg)
166 "Default function to highlight arguments in *Help* buffers.
167 It returns ARG in face `help-argument-name'; ARG is also
168 downcased if it displays differently than the default
169 face (according to `face-differs-from-default-p')."
170 (propertize (if (face-differs-from-default-p 'help-argument-name
)
173 'face
'help-argument-name
))
175 (defun help-do-arg-highlight (doc args
)
176 (with-syntax-table (make-syntax-table emacs-lisp-mode-syntax-table
)
177 (modify-syntax-entry ?\-
"w")
178 (dolist (arg args doc
)
179 (setq doc
(replace-regexp-in-string
180 ;; This is heuristic, but covers all common cases
182 (concat "\\<" ; beginning of word
183 "\\(?:[a-z-]*-\\)?" ; for xxx-ARG
187 "\\(?:es\\|s\\|th\\)?" ; for ARGth, ARGs
188 "\\(?:-[a-z0-9-]+\\)?" ; for ARG-xxx, ARG-n
189 "\\(?:-[{([<`\"].*?\\)?"; for ARG-{x}, (x), <x>, [x], `x'
191 (help-default-arg-highlight arg
)
194 (defun help-highlight-arguments (usage doc
&rest args
)
198 (goto-char (point-min))
199 (let ((case-fold-search nil
)
200 (next (not (or args
(looking-at "\\["))))
202 ;; Make a list of all arguments
203 (skip-chars-forward "^ ")
205 (or opt
(not (looking-at " &")) (setq opt t
))
206 (if (not (re-search-forward " \\([\\[(]*\\)\\([^] &)\.]+\\)" nil t
))
208 (setq args
(cons (match-string 2) args
))
209 (when (and opt
(string= (match-string 1) "("))
210 ;; A pesky CL-style optional argument with default value,
211 ;; so let's skip over it
212 (search-backward "(")
213 (goto-char (scan-sexps (point) 1)))))
214 ;; Highlight aguments in the USAGE string
215 (setq usage
(help-do-arg-highlight (buffer-string) args
))
216 ;; Highlight arguments in the DOC string
217 (setq doc
(and doc
(help-do-arg-highlight doc args
))))))
218 ;; Return value is like the one from help-split-fundoc, but highlighted
222 (defun describe-simplify-lib-file-name (file)
223 "Simplify a library name FILE to a relative name, and make it a source file."
225 ;; Try converting the absolute file name to a library name.
226 (let ((libname (file-name-nondirectory file
)))
227 ;; Now convert that back to a file name and see if we get
228 ;; the original one. If so, they are equivalent.
229 (if (equal file
(locate-file libname load-path
'("")))
230 (if (string-match "[.]elc\\'" libname
)
231 (substring libname
0 -
1)
235 (defun find-source-lisp-file (file-name)
236 (let* ((elc-file (locate-file (concat file-name
237 (if (string-match "\\.el" file-name
)
241 (str (if (and elc-file
(file-readable-p elc-file
))
243 (insert-file-contents-literally elc-file nil
0 256)
246 (string-match ";;; from file \\(.*\\.el\\)" str
)
247 (match-string 1 str
))))
248 (if (and src-file
(file-readable-p src-file
))
253 (defun describe-function-1 (function)
254 (let* ((def (if (symbolp function
)
255 (symbol-function function
)
258 (beg (if (commandp def
) "an interactive " "a ")))
260 (cond ((or (stringp def
)
264 (if (eq 'unevalled
(cdr (subr-arity def
)))
265 (concat beg
"special form")
266 (concat beg
"built-in function")))
267 ((byte-code-function-p def
)
268 (concat beg
"compiled Lisp function"))
270 (while (symbolp (symbol-function def
))
271 (setq def
(symbol-function def
)))
272 (format "an alias for `%s'" def
))
273 ((eq (car-safe def
) 'lambda
)
274 (concat beg
"Lisp function"))
275 ((eq (car-safe def
) 'macro
)
277 ((eq (car-safe def
) 'autoload
)
278 (setq file-name
(nth 1 def
))
279 (format "%s autoloaded %s"
280 (if (commandp def
) "an interactive" "an")
281 (if (eq (nth 4 def
) 'keymap
) "keymap"
282 (if (nth 4 def
) "Lisp macro" "Lisp function"))
286 (elts (cdr-safe def
)))
288 (if (char-table-p (car-safe elts
))
291 (setq elts
(cdr-safe elts
)))
297 (with-current-buffer standard-output
300 (if (re-search-backward "alias for `\\([^`']+\\)'" nil t
)
301 (help-xref-button 1 'help-function def
)))))
303 (setq file-name
(symbol-file function
'defun
)))
304 (setq file-name
(describe-simplify-lib-file-name file-name
))
305 (when (equal file-name
"loaddefs.el")
306 ;; Find the real def site of the preloaded function.
307 ;; This is necessary only for defaliases.
310 (find-function-search-for-symbol function nil
"loaddefs.el")
313 (with-current-buffer (car location
)
314 (goto-char (cdr location
))
315 (when (re-search-backward
316 "^;;; Generated autoloads from \\(.*\\)" nil t
)
317 (setq file-name
(match-string 1)))))))
318 (when (and (null file-name
) (subrp def
))
319 ;; Find the C source file name.
320 (setq file-name
(if (get-buffer " *DOC*")
321 (help-C-file-name def
'subr
)
325 ;; We used to add .el to the file name,
326 ;; but that's completely wrong when the user used load-file.
327 (princ (if (eq file-name
'C-source
) "C source code" file-name
))
329 ;; See if lisp files are present where they where installed from.
330 (if (not (eq file-name
'C-source
))
331 (setq file-name
(find-source-lisp-file file-name
)))
333 ;; Make a hyperlink to the library.
334 (with-current-buffer standard-output
336 (re-search-backward "`\\([^`']+\\)'" nil t
)
337 (help-xref-button 1 'help-function-def function file-name
))))
340 (when (commandp function
)
341 (if (and (eq function
'self-insert-command
)
342 (eq (key-binding "a") 'self-insert-command
)
343 (eq (key-binding "b") 'self-insert-command
)
344 (eq (key-binding "c") 'self-insert-command
))
345 (princ "It is bound to many ordinary text characters.\n")
346 (let* ((remapped (command-remapping function
))
347 (keys (where-is-internal
348 (or remapped function
) overriding-local-map nil nil
))
350 ;; Which non-control non-meta keys run this command?
352 (if (member (event-modifiers (aref key
0)) '(nil (shift)))
353 (push key non-modified-keys
)))
355 (princ "It is remapped to `")
356 (princ (symbol-name remapped
))
360 (princ (if remapped
" which is bound to " "It is bound to "))
361 ;; If lots of ordinary text characters run this command,
362 ;; don't mention them one by one.
363 (if (< (length non-modified-keys
) 10)
364 (princ (mapconcat 'key-description keys
", "))
365 (dolist (key non-modified-keys
)
366 (setq keys
(delq key keys
)))
369 (princ (mapconcat 'key-description keys
", "))
370 (princ ", and many ordinary text characters"))
371 (princ "many ordinary text characters"))))
372 (when (or remapped keys non-modified-keys
)
375 (let* ((arglist (help-function-arglist def
))
376 (doc (documentation function
))
377 (usage (help-split-fundoc doc function
)))
378 (with-current-buffer standard-output
379 ;; If definition is a keymap, skip arglist note.
380 (unless (keymapp def
)
382 (usage (setq doc
(cdr usage
)) (car usage
))
384 (format "%S" (help-make-usage function arglist
)))
385 ((stringp arglist
) arglist
)
386 ;; Maybe the arglist is in the docstring of the alias.
387 ((let ((fun function
))
388 (while (and (symbolp fun
)
389 (setq fun
(symbol-function fun
))
390 (not (setq usage
(help-split-fundoc
397 (format "\nMacro: %s" (format-kbd-macro def
)))
398 (t "[Missing arglist. Please make a bug report.]")))
399 (high (help-highlight-arguments use doc
)))
400 (let ((fill-begin (point)))
401 (insert (car high
) "\n")
402 (fill-region fill-begin
(point)))
403 (setq doc
(cdr high
))))
405 ;; function might be a lambda construct.
407 (get function
'byte-obsolete-info
))))
409 (princ "\nThis function is obsolete")
410 (when (nth 2 obsolete
)
411 (insert (format " since %s" (nth 2 obsolete
))))
413 (if (stringp (car obsolete
)) (car obsolete
)
414 (format "use `%s' instead." (car obsolete
)))
417 (or doc
"Not documented.")))))))
423 (defun variable-at-point (&optional any-symbol
)
424 "Return the bound variable symbol found at or before point.
425 Return 0 if there is no such symbol.
426 If ANY-SYMBOL is non-nil, don't insist the symbol be bound."
427 (or (condition-case ()
428 (with-syntax-table emacs-lisp-mode-syntax-table
430 (or (not (zerop (skip-syntax-backward "_w")))
431 (eq (char-syntax (following-char)) ?w
)
432 (eq (char-syntax (following-char)) ?_
)
434 (skip-chars-forward "'")
435 (let ((obj (read (current-buffer))))
436 (and (symbolp obj
) (boundp obj
) obj
))))
438 (let* ((str (find-tag-default))
439 (sym (if str
(intern-soft str
))))
440 (if (and sym
(or any-symbol
(boundp sym
)))
443 (when (and str
(string-match "\\`\\W*\\(.*?\\)\\W*\\'" str
))
444 (setq sym
(intern-soft (match-string 1 str
)))
445 (and (or any-symbol
(boundp sym
)) sym
)))))
449 (defun describe-variable (variable &optional buffer frame
)
450 "Display the full documentation of VARIABLE (a symbol).
451 Returns the documentation as a string, also.
452 If VARIABLE has a buffer-local value in BUFFER or FRAME
453 \(default to the current buffer and current frame),
454 it is displayed along with the global value."
456 (let ((v (variable-at-point))
457 (enable-recursive-minibuffers t
)
459 (setq val
(completing-read (if (symbolp v
)
461 "Describe variable (default %s): " v
)
462 "Describe variable: ")
466 (get vv
'variable-documentation
)))
468 (if (symbolp v
) (symbol-name v
))))
469 (list (if (equal val
"")
471 (unless (buffer-live-p buffer
) (setq buffer
(current-buffer)))
472 (unless (frame-live-p frame
) (setq frame
(selected-frame)))
473 (if (not (symbolp variable
))
474 (message "You did not specify a variable")
476 (let ((valvoid (not (with-current-buffer buffer
(boundp variable
))))
477 val val-start-pos locus
)
478 ;; Extract the value before setting up the output buffer,
479 ;; in case `buffer' *is* the output buffer.
481 (with-selected-frame frame
482 (with-current-buffer buffer
483 (setq val
(symbol-value variable
)
484 locus
(variable-binding-locus variable
)))))
485 (help-setup-xref (list #'describe-variable variable buffer
)
487 (with-output-to-temp-buffer (help-buffer)
488 (with-current-buffer buffer
490 ;; Make a hyperlink to the library if appropriate. (Don't
491 ;; change the format of the buffer's initial line in case
492 ;; anything expects the current format.)
493 (let ((file-name (symbol-file variable
'defvar
)))
494 (setq file-name
(describe-simplify-lib-file-name file-name
))
495 (when (equal file-name
"loaddefs.el")
496 ;; Find the real def site of the preloaded variable.
499 (find-variable-noselect variable file-name
)
502 (with-current-buffer (car location
)
504 (goto-char (cdr location
)))
505 (when (re-search-backward
506 "^;;; Generated autoloads from \\(.*\\)" nil t
)
507 (setq file-name
(match-string 1)))))))
508 (when (and (null file-name
)
509 (integerp (get variable
'variable-documentation
)))
510 ;; It's a variable not defined in Elisp but in C.
512 (if (get-buffer " *DOC*")
513 (help-C-file-name variable
'var
)
517 (princ " is a variable defined in `")
518 (princ (if (eq file-name
'C-source
) "C source code" file-name
))
520 (with-current-buffer standard-output
522 (re-search-backward "`\\([^`']+\\)'" nil t
)
523 (help-xref-button 1 'help-variable-def
524 variable file-name
)))
526 (princ "It is void as a variable.")
529 (princ " is void as a variable.")
533 (with-current-buffer standard-output
534 (setq val-start-pos
(point))
537 (let ((from (point)))
539 ;; Hyperlinks in variable's value are quite frequently
540 ;; inappropriate e.g C-h v <RET> features <RET>
541 ;; (help-xref-on-pp from (point))
542 (if (< (point) (+ from
20))
543 (delete-region (1- from
) from
)))))
548 (princ (format "%socal in buffer %s; "
549 (if (get variable
'permanent-local
)
552 (princ (format "It is a frame-local variable; ")))
553 (if (not (default-boundp variable
))
554 (princ "globally void")
555 (let ((val (default-value variable
)))
556 (with-current-buffer standard-output
557 (princ "global value is ")
559 ;; Fixme: pp can take an age if you happen to
560 ;; ask for a very large expression. We should
561 ;; probably print it raw once and check it's a
562 ;; sensible size before prettyprinting. -- fx
563 (let ((from (point)))
565 ;; See previous comment for this function.
566 ;; (help-xref-on-pp from (point))
567 (if (< (point) (+ from
20))
568 (delete-region (1- from
) from
)))))))
570 ;; If the value is large, move it to the end.
571 (with-current-buffer standard-output
572 (when (> (count-lines (point-min) (point-max)) 10)
573 ;; Note that setting the syntax table like below
574 ;; makes forward-sexp move over a `'s' at the end
576 (set-syntax-table emacs-lisp-mode-syntax-table
)
577 (goto-char val-start-pos
)
578 ;; The line below previously read as
579 ;; (delete-region (point) (progn (end-of-line) (point)))
580 ;; which suppressed display of the buffer local value for
582 (when (looking-at "value is") (replace-match ""))
584 (insert "\n\nValue:")
585 (set (make-local-variable 'help-button-cache
)
587 (insert "value is shown ")
588 (insert-button "below"
589 'action help-button-cache
591 'help-echo
"mouse-2, RET: show value")
595 (let* ((alias (condition-case nil
596 (indirect-variable variable
)
598 (obsolete (get variable
'byte-obsolete-variable
))
599 (safe-var (get variable
'safe-local-variable
))
600 (doc (or (documentation-property variable
'variable-documentation
)
601 (documentation-property alias
'variable-documentation
)))
603 ;; Add a note for variables that have been make-var-buffer-local.
604 (when (and (local-variable-if-set-p variable
)
605 (or (not (local-variable-p variable
))
607 (local-variable-if-set-p variable
))))
609 (princ " Automatically becomes buffer-local when set in any fashion.\n"))
611 ;; Mention if it's an alias
612 (unless (eq alias variable
)
614 (princ (format " This variable is an alias for `%s'.\n" alias
)))
618 (princ " This variable is obsolete")
619 (if (cdr obsolete
) (princ (format " since %s" (cdr obsolete
))))
621 (princ (if (stringp (car obsolete
)) (car obsolete
)
622 (format "use `%s' instead." (car obsolete
))))
626 (princ " This variable is safe as a file local variable ")
627 (princ "if its value\n satisfies the predicate ")
628 (princ (if (byte-code-function-p safe-var
)
629 "which is byte-compiled expression.\n"
630 (format "`%s'.\n" safe-var
))))
632 (if extra-line
(terpri))
633 (princ "Documentation:\n")
634 (with-current-buffer standard-output
635 (insert (or doc
"Not documented as a variable."))))
636 ;; Make a link to customize if this variable can be customized.
637 (if (custom-variable-p variable
)
638 (let ((customize-label "customize"))
641 (princ (concat "You can " customize-label
" this variable."))
642 (with-current-buffer standard-output
645 (concat "\\(" customize-label
"\\)") nil t
)
646 (help-xref-button 1 'help-customize-variable variable
)))))
647 (print-help-return-message)
649 (set-buffer standard-output
)
650 ;; Return the text we displayed.
651 (buffer-string))))))))
655 (defun describe-syntax (&optional buffer
)
656 "Describe the syntax specifications in the syntax table of BUFFER.
657 The descriptions are inserted in a help buffer, which is then displayed.
658 BUFFER defaults to the current buffer."
660 (setq buffer
(or buffer
(current-buffer)))
661 (help-setup-xref (list #'describe-syntax buffer
) (interactive-p))
662 (with-output-to-temp-buffer (help-buffer)
663 (let ((table (with-current-buffer buffer
(syntax-table))))
664 (with-current-buffer standard-output
665 (describe-vector table
'internal-describe-syntax-value
)
666 (while (setq table
(char-table-parent table
))
667 (insert "\nThe parent syntax table is:")
668 (describe-vector table
'internal-describe-syntax-value
))))))
670 (defun help-describe-category-set (value)
672 ((null value
) "default")
673 ((char-table-p value
) "deeper char-table ...")
674 (t (condition-case err
675 (category-set-mnemonics value
)
676 (error "invalid"))))))
679 (defun describe-categories (&optional buffer
)
680 "Describe the category specifications in the current category table.
681 The descriptions are inserted in a buffer, which is then displayed.
682 If BUFFER is non-nil, then describe BUFFER's category table instead.
683 BUFFER should be a buffer or a buffer name."
685 (setq buffer
(or buffer
(current-buffer)))
686 (help-setup-xref (list #'describe-categories buffer
) (interactive-p))
687 (with-output-to-temp-buffer (help-buffer)
688 (let ((table (with-current-buffer buffer
(category-table))))
689 (with-current-buffer standard-output
690 (describe-vector table
'help-describe-category-set
)
691 (let ((docs (char-table-extra-slot table
0)))
692 (if (or (not (vectorp docs
)) (/= (length docs
) 95))
693 (insert "Invalid first extra slot in this char table\n")
694 (insert "Meanings of mnemonic characters are:\n")
696 (let ((elt (aref docs i
)))
698 (insert (+ i ?\s
) ": " elt
"\n"))))
699 (while (setq table
(char-table-parent table
))
700 (insert "\nThe parent category table is:")
701 (describe-vector table
'help-describe-category-set
))))))))
705 ;; arch-tag: 9e10331c-ae81-4d13-965d-c4819aaab0b3
706 ;;; help-fns.el ends here