1 ;;; help-fns.el --- Complex help functions
3 ;; Copyright (C) 1985, 1986, 1993, 1994, 1998, 1999, 2000, 2001, 2002
4 ;; 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 2, 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., 59 Temple Place - Suite 330,
24 ;; Boston, MA 02111-1307, 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
40 (defun help-with-tutorial (&optional arg
)
41 "Select the Emacs learn-by-doing tutorial.
42 If there is a tutorial version written in the language
43 of the selected language environment, that version is used.
44 If there's no tutorial in that language, `TUTORIAL' is selected.
45 With ARG, you are asked to choose which language."
48 (let ((minibuffer-setup-hook minibuffer-setup-hook
))
49 (add-hook 'minibuffer-setup-hook
50 'minibuffer-completion-help
)
51 (read-language-name 'tutorial
"Language: " "English"))
52 (if (get-language-info current-language-environment
'tutorial
)
53 current-language-environment
56 (setq filename
(get-language-info lang
'tutorial
))
57 (setq file
(expand-file-name (concat "~/" filename
)))
58 (delete-other-windows)
59 (if (get-file-buffer file
)
60 (switch-to-buffer (get-file-buffer file
))
61 (switch-to-buffer (create-file-buffer file
))
62 (setq buffer-file-name file
)
63 (setq default-directory
(expand-file-name "~/"))
64 (setq buffer-auto-save-file-name nil
)
65 (insert-file-contents (expand-file-name filename data-directory
))
66 (goto-char (point-min))
67 (search-forward "\n<<")
69 ;; Convert the <<...>> line to the proper [...] line,
70 ;; or just delete the <<...>> line if a [...] line follows.
71 (cond ((save-excursion
74 (delete-region (point) (progn (forward-line 1) (point))))
75 ((looking-at "<<Blank lines inserted.*>>")
76 (replace-match "[Middle of page left blank for didactic purposes. Text continues below]"))
83 (let ((n (- (window-height (selected-window))
84 (count-lines (point-min) (point))
88 ;; For a short gap, we don't need the [...] line,
90 (delete-region (point) (progn (end-of-line) (point)))
92 ;; Some people get confused by the large gap.
95 ;; Skip the [...] line (don't delete it).
97 (newline (- n
(/ n
2)))))
98 (goto-char (point-min))
99 (set-buffer-modified-p nil
))))
102 (defun locate-library (library &optional nosuffix path interactive-call
)
103 "Show the precise file name of Emacs library LIBRARY.
104 This command searches the directories in `load-path' like `\\[load-library]'
105 to find the file that `\\[load-library] RET LIBRARY RET' would load.
106 Optional second arg NOSUFFIX non-nil means don't add suffixes `load-suffixes'
107 to the specified name LIBRARY.
109 If the optional third arg PATH is specified, that list of directories
110 is used instead of `load-path'.
112 When called from a program, the file name is normaly returned as a
113 string. When run interactively, the argument INTERACTIVE-CALL is t,
114 and the file name is displayed in the echo area."
115 (interactive (list (completing-read "Locate library: "
116 'locate-file-completion
117 (cons load-path load-suffixes
))
120 (let ((file (locate-file library
122 (append (unless nosuffix load-suffixes
) '("")))))
125 (message "Library is file %s" (abbreviate-file-name file
))
126 (message "No library %s in search path" library
)))
133 (defun describe-function (function)
134 "Display the full documentation of FUNCTION (a symbol)."
136 (let ((fn (function-called-at-point))
137 (enable-recursive-minibuffers t
)
139 (setq val
(completing-read (if fn
140 (format "Describe function (default %s): " fn
)
141 "Describe function: ")
142 obarray
'fboundp t nil nil
(symbol-name fn
)))
143 (list (if (equal val
"")
146 (message "You didn't specify a function")
147 (help-setup-xref (list #'describe-function function
) (interactive-p))
149 (with-output-to-temp-buffer (help-buffer)
151 ;; Use " is " instead of a colon so that
152 ;; it is easier to get out the function name using forward-sexp.
154 (describe-function-1 function
)
155 (print-help-return-message)
156 (with-current-buffer standard-output
157 ;; Return the text we displayed.
160 (defun help-split-fundoc (doc def
)
161 "Split a function docstring DOC into the actual doc and the usage info.
162 Return (USAGE . DOC) or nil if there's no usage info.
163 DEF is the function whose usage we're looking for in DOC."
164 ;; Functions can get the calling sequence at the end of the doc string.
165 ;; In cases where `function' has been fset to a subr we can't search for
166 ;; function's name in the doc string so we use `fn' as the anonymous
167 ;; function name instead.
168 (when (and doc
(string-match "\n\n(fn\\(\\( .*\\)?)\\)\\'" doc
))
169 (cons (format "(%s%s"
170 ;; Replace `fn' with the actual function name.
171 (if (consp def
) "anonymous" def
)
172 (match-string 1 doc
))
173 (substring doc
0 (match-beginning 0)))))
175 (defun help-add-fundoc-usage (doc arglist
)
176 "Add the usage info to the docstring DOC.
177 If DOC already has a usage info, then just return DOC unchanged.
178 The usage info is built from ARGLIST. DOC can be nil."
179 (unless (stringp doc
) (setq doc
"Not documented"))
180 (if (string-match "\n\n(fn\\(\\( .*\\)?)\\)\\'" doc
)
183 (if (string-match "\n?\n\\'" doc
)
184 (if (< (- (match-end 0) (match-beginning 0)) 2) "\n")
186 (help-make-usage 'fn arglist
))))
188 (defun help-function-arglist (def)
189 ;; Handle symbols aliased to other symbols.
190 (if (and (symbolp def
) (fboundp def
)) (setq def
(indirect-function def
)))
191 ;; If definition is a macro, find the function inside it.
192 (if (eq (car-safe def
) 'macro
) (setq def
(cdr def
)))
194 ((byte-code-function-p def
) (aref def
0))
195 ((eq (car-safe def
) 'lambda
) (nth 1 def
))
196 ((and (eq (car-safe def
) 'autoload
) (not (eq (nth 4 def
) 'keymap
)))
197 "[Arg list not available until function definition is loaded.]")
200 (defun help-make-usage (function arglist
)
201 (cons (if (symbolp function
) function
'anonymous
)
202 (mapcar (lambda (arg)
203 (if (not (symbolp arg
))
204 (if (and (consp arg
) (symbolp (car arg
)))
205 ;; CL style default values for optional args.
206 (cons (intern (upcase (symbol-name (car arg
))))
209 (let ((name (symbol-name arg
)))
210 (if (string-match "\\`&" name
) arg
211 (intern (upcase name
))))))
215 (defun describe-function-1 (function)
216 (let* ((def (if (symbolp function
)
217 (symbol-function function
)
220 (beg (if (commandp def
) "an interactive " "a ")))
222 (cond ((or (stringp def
)
226 (if (eq 'unevalled
(cdr (subr-arity def
)))
227 (concat beg
"special form")
228 (concat beg
"built-in function")))
229 ((byte-code-function-p def
)
230 (concat beg
"compiled Lisp function"))
232 (while (symbolp (symbol-function def
))
233 (setq def
(symbol-function def
)))
234 (format "an alias for `%s'" def
))
235 ((eq (car-safe def
) 'lambda
)
236 (concat beg
"Lisp function"))
237 ((eq (car-safe def
) 'macro
)
239 ((eq (car-safe def
) 'autoload
)
240 (setq file-name
(nth 1 def
))
241 (format "%s autoloaded %s"
242 (if (commandp def
) "an interactive" "an")
243 (if (eq (nth 4 def
) 'keymap
) "keymap"
244 (if (nth 4 def
) "Lisp macro" "Lisp function"))
248 (elts (cdr-safe def
)))
250 (if (char-table-p (car-safe elts
))
253 (setq elts
(cdr-safe elts
)))
259 (with-current-buffer standard-output
262 (if (re-search-backward "alias for `\\([^`']+\\)'" nil t
)
263 (help-xref-button 1 'help-function def
)))))
265 (setq file-name
(symbol-file function
)))
266 (when (equal file-name
"loaddefs.el")
267 ;; Find the real def site of the preloaded function.
268 ;; This is necessary only for defaliases.
271 (find-function-search-for-symbol function nil
"loaddefs.el")
274 (with-current-buffer (car location
)
275 (goto-char (cdr location
))
276 (when (re-search-backward
277 "^;;; Generated autoloads from \\(.*\\)" nil t
)
278 (setq file-name
(match-string 1)))))))
282 ;; We used to add .el to the file name,
283 ;; but that's completely wrong when the user used load-file.
286 ;; Make a hyperlink to the library.
287 (with-current-buffer standard-output
289 (re-search-backward "`\\([^`']+\\)'" nil t
)
290 (help-xref-button 1 'help-function-def function file-name
)))))
293 (when (commandp function
)
294 (let* ((remapped (remap-command function
))
295 (keys (where-is-internal
296 (or remapped function
) overriding-local-map nil nil
)))
298 (princ "It is remapped to `")
299 (princ (symbol-name remapped
))
302 (princ (if remapped
" which is bound to " "It is bound to "))
303 ;; FIXME: This list can be very long (f.ex. for self-insert-command).
304 (princ (mapconcat 'key-description keys
", ")))
305 (when (or remapped keys
)
308 (let* ((arglist (help-function-arglist def
))
309 (doc (documentation function
))
310 (usage (help-split-fundoc doc function
)))
311 ;; If definition is a keymap, skip arglist note.
312 (unless (keymapp def
)
314 (usage (setq doc
(cdr usage
)) (car usage
))
315 ((listp arglist
) (help-make-usage function arglist
))
316 ((stringp arglist
) arglist
)
317 ;; Maybe the arglist is in the docstring of the alias.
318 ((let ((fun function
))
319 (while (and (symbolp fun
)
320 (setq fun
(symbol-function fun
))
321 (not (setq usage
(help-split-fundoc
326 (t "[Missing arglist. Please make a bug report.]")))
329 ;; function might be a lambda construct.
331 (get function
'byte-obsolete-info
))))
334 (princ "This function is obsolete")
335 (if (nth 2 obsolete
) (princ (format " since %s" (nth 2 obsolete
))))
337 (princ (if (stringp (car obsolete
)) (car obsolete
)
338 (format "use `%s' instead." (car obsolete
))))
341 (princ (or doc
"Not documented.")))))
347 (defun variable-at-point ()
348 "Return the bound variable symbol found around point.
349 Return 0 if there is no such symbol."
351 (with-syntax-table emacs-lisp-mode-syntax-table
353 (or (not (zerop (skip-syntax-backward "_w")))
354 (eq (char-syntax (following-char)) ?w
)
355 (eq (char-syntax (following-char)) ?_
)
357 (skip-chars-forward "'")
358 (let ((obj (read (current-buffer))))
359 (or (and (symbolp obj
) (boundp obj
) obj
)
364 (defun describe-variable (variable &optional buffer
)
365 "Display the full documentation of VARIABLE (a symbol).
366 Returns the documentation as a string, also.
367 If VARIABLE has a buffer-local value in BUFFER (default to the current buffer),
368 it is displayed along with the global value."
370 (let ((v (variable-at-point))
371 (enable-recursive-minibuffers t
)
373 (setq val
(completing-read (if (symbolp v
)
375 "Describe variable (default %s): " v
)
376 "Describe variable: ")
377 obarray
'boundp t nil nil
378 (if (symbolp v
) (symbol-name v
))))
379 (list (if (equal val
"")
381 (unless (buffer-live-p buffer
) (setq buffer
(current-buffer)))
382 (if (not (symbolp variable
))
383 (message "You did not specify a variable")
385 (let* ((valvoid (not (with-current-buffer buffer
(boundp variable
))))
386 ;; Extract the value before setting up the output buffer,
387 ;; in case `buffer' *is* the output buffer.
388 (val (unless valvoid
(buffer-local-value variable buffer
))))
389 (help-setup-xref (list #'describe-variable variable buffer
)
391 (with-output-to-temp-buffer (help-buffer)
392 (with-current-buffer buffer
396 (with-current-buffer standard-output
397 (princ "'s value is ")
399 (let ((from (point)))
401 (help-xref-on-pp from
(point))
402 (if (< (point) (+ from
20))
403 (delete-region (1- from
) from
)))))
405 (when (local-variable-p variable
)
406 (princ (format "Local in buffer %s; " (buffer-name)))
407 (if (not (default-boundp variable
))
408 (princ "globally void")
409 (let ((val (default-value variable
)))
410 (with-current-buffer standard-output
411 (princ "global value is ")
413 ;; Fixme: pp can take an age if you happen to
414 ;; ask for a very large expression. We should
415 ;; probably print it raw once and check it's a
416 ;; sensible size before prettyprinting. -- fx
417 (let ((from (point)))
419 (help-xref-on-pp from
(point))
420 (if (< (point) (+ from
20))
421 (delete-region (1- from
) from
))))))
424 (with-current-buffer standard-output
425 (when (> (count-lines (point-min) (point-max)) 10)
426 ;; Note that setting the syntax table like below
427 ;; makes forward-sexp move over a `'s' at the end
429 (set-syntax-table emacs-lisp-mode-syntax-table
)
430 (goto-char (point-min))
434 (delete-region (point) (progn (end-of-line) (point)))
435 (insert " value is shown below.\n\n")
437 (insert "\n\nValue:"))))
438 ;; Add a note for variables that have been make-var-buffer-local.
439 (when (and (local-variable-if-set-p variable
)
440 (or (not (local-variable-p variable
))
442 (local-variable-if-set-p variable
))))
445 (insert "Automatically becomes buffer-local when set in any fashion.\n"))))
446 ;; Mention if it's an alias
447 (let* ((alias (condition-case nil
448 (indirect-variable variable
)
450 (obsolete (get variable
'byte-obsolete-variable
))
451 (doc (or (documentation-property variable
'variable-documentation
)
452 (documentation-property alias
'variable-documentation
))))
453 (unless (eq alias variable
)
454 (princ (format "This variable is an alias for `%s'." alias
))
458 (princ "This variable is obsolete")
459 (if (cdr obsolete
) (princ (format " since %s" (cdr obsolete
))))
461 (princ (if (stringp (car obsolete
)) (car obsolete
)
462 (format "use `%s' instead." (car obsolete
))))
465 (princ (or doc
"Not documented as a variable.")))
466 ;; Make a link to customize if this variable can be customized.
467 ;; Note, it is not reliable to test only for a custom-type property
468 ;; because those are only present after the var's definition
470 (if (or (get variable
'custom-type
) ; after defcustom
471 (get variable
'custom-loads
) ; from loaddefs.el
472 (get variable
'standard-value
)) ; from cus-start.el
473 (let ((customize-label "customize"))
476 (princ (concat "You can " customize-label
" this variable."))
477 (with-current-buffer standard-output
480 (concat "\\(" customize-label
"\\)") nil t
)
481 (help-xref-button 1 'help-customize-variable variable
)))))
482 ;; Make a hyperlink to the library if appropriate. (Don't
483 ;; change the format of the buffer's initial line in case
484 ;; anything expects the current format.)
485 (let ((file-name (symbol-file (cons 'defvar variable
))))
486 (when (equal file-name
"loaddefs.el")
487 ;; Find the real def site of the preloaded variable.
490 (find-variable-noselect variable file-name
)
493 (with-current-buffer (car location
)
494 (goto-char (cdr location
))
495 (when (re-search-backward
496 "^;;; Generated autoloads from \\(.*\\)" nil t
)
497 (setq file-name
(match-string 1)))))))
499 (princ "\n\nDefined in `")
502 (with-current-buffer standard-output
504 (re-search-backward "`\\([^`']+\\)'" nil t
)
505 (help-xref-button 1 'help-variable-def
506 variable file-name
)))))
508 (print-help-return-message)
510 (set-buffer standard-output
)
511 ;; Return the text we displayed.
512 (buffer-string))))))))
516 (defun describe-syntax (&optional buffer
)
517 "Describe the syntax specifications in the syntax table of BUFFER.
518 The descriptions are inserted in a help buffer, which is then displayed.
519 BUFFER defaults to the current buffer."
521 (setq buffer
(or buffer
(current-buffer)))
522 (help-setup-xref (list #'describe-syntax buffer
) (interactive-p))
523 (with-output-to-temp-buffer (help-buffer)
524 (let ((table (with-current-buffer buffer
(syntax-table))))
525 (with-current-buffer standard-output
526 (describe-vector table
'internal-describe-syntax-value
)
527 (while (setq table
(char-table-parent table
))
528 (insert "\nThe parent syntax table is:")
529 (describe-vector table
'internal-describe-syntax-value
))))))
531 (defun help-describe-category-set (value)
533 ((null value
) "default")
534 ((char-table-p value
) "deeper char-table ...")
535 (t (condition-case err
536 (category-set-mnemonics value
)
537 (error "invalid"))))))
540 (defun describe-categories (&optional buffer
)
541 "Describe the category specifications in the current category table.
542 The descriptions are inserted in a buffer, which is then displayed."
544 (setq buffer
(or buffer
(current-buffer)))
545 (help-setup-xref (list #'describe-categories buffer
) (interactive-p))
546 (with-output-to-temp-buffer (help-buffer)
547 (let ((table (with-current-buffer buffer
(category-table))))
548 (with-current-buffer standard-output
549 (describe-vector table
'help-describe-category-set
)
550 (let ((docs (char-table-extra-slot table
0)))
551 (if (or (not (vectorp docs
)) (/= (length docs
) 95))
552 (insert "Invalid first extra slot in this char table\n")
553 (insert "Meanings of mnemonic characters are:\n")
555 (let ((elt (aref docs i
)))
557 (insert (+ i ?\
) ": " elt
"\n"))))
558 (while (setq table
(char-table-parent table
))
559 (insert "\nThe parent category table is:")
560 (describe-vector table
'help-describe-category-set
))))))))
564 ;;; help-fns.el ends here