1 ;;; help-fns.el --- Complex help functions
3 ;; Copyright (C) 1985, 1986, 1993, 1994, 1998, 1999, 2000, 2001
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 (read-language-name 'tutorial
"Language: " "English")
49 (if (get-language-info current-language-environment
'tutorial
)
50 current-language-environment
53 (setq filename
(get-language-info lang
'tutorial
))
54 (setq file
(expand-file-name (concat "~/" filename
)))
55 (delete-other-windows)
56 (if (get-file-buffer file
)
57 (switch-to-buffer (get-file-buffer file
))
58 (switch-to-buffer (create-file-buffer file
))
59 (setq buffer-file-name file
)
60 (setq default-directory
(expand-file-name "~/"))
61 (setq buffer-auto-save-file-name nil
)
62 (insert-file-contents (expand-file-name filename data-directory
))
63 (goto-char (point-min))
64 (search-forward "\n<<")
66 (delete-region (point) (progn (end-of-line) (point)))
67 (let ((n (- (window-height (selected-window))
68 (count-lines (point-min) (point))
72 ;; Some people get confused by the large gap.
74 (insert "[Middle of page left blank for didactic purposes. "
75 "Text continues below]")
76 (newline (- n
(/ n
2)))))
77 (goto-char (point-min))
78 (set-buffer-modified-p nil
))))
81 (defun locate-library (library &optional nosuffix path interactive-call
)
82 "Show the precise file name of Emacs library LIBRARY.
83 This command searches the directories in `load-path' like `M-x load-library'
84 to find the file that `M-x load-library RET LIBRARY RET' would load.
85 Optional second arg NOSUFFIX non-nil means don't add suffixes `load-suffixes'
86 to the specified name LIBRARY.
88 If the optional third arg PATH is specified, that list of directories
89 is used instead of `load-path'.
91 When called from a program, the file name is normaly returned as a
92 string. When run interactively, the argument INTERACTIVE-CALL is t,
93 and the file name is displayed in the echo area."
94 (interactive (list (read-string "Locate library: ")
98 (dolist (dir (or path load-path
))
99 (dolist (suf (append (unless nosuffix load-suffixes
) '("")))
100 (let ((try (expand-file-name (concat library suf
) dir
)))
101 (and (file-readable-p try
)
102 (null (file-directory-p try
))
105 (message "Library is file %s" (abbreviate-file-name try
)))
106 (throw 'answer try
))))))
108 (message "No library %s in search path" library
))
115 (defun describe-function (function)
116 "Display the full documentation of FUNCTION (a symbol)."
118 (let ((fn (function-called-at-point))
119 (enable-recursive-minibuffers t
)
121 (setq val
(completing-read (if fn
122 (format "Describe function (default %s): " fn
)
123 "Describe function: ")
124 obarray
'fboundp t nil nil
(symbol-name fn
)))
125 (list (if (equal val
"")
128 (message "You didn't specify a function")
129 (help-setup-xref (list #'describe-function function
) (interactive-p))
131 (with-output-to-temp-buffer (help-buffer)
133 ;; Use " is " instead of a colon so that
134 ;; it is easier to get out the function name using forward-sexp.
136 (describe-function-1 function
)
137 (print-help-return-message)
138 (with-current-buffer standard-output
139 ;; Return the text we displayed.
143 (defun describe-function-1 (function)
144 (let* ((def (if (symbolp function
)
145 (symbol-function function
)
148 (beg (if (commandp def
) "an interactive " "a ")))
150 (cond ((or (stringp def
)
154 (if (eq 'unevalled
(cdr (subr-arity def
)))
155 (concat beg
"special form")
156 (concat beg
"built-in function")))
157 ((byte-code-function-p def
)
158 (concat beg
"compiled Lisp function"))
160 (while (symbolp (symbol-function def
))
161 (setq def
(symbol-function def
)))
162 (format "an alias for `%s'" def
))
163 ((eq (car-safe def
) 'lambda
)
164 (concat beg
"Lisp function"))
165 ((eq (car-safe def
) 'macro
)
167 ((eq (car-safe def
) 'autoload
)
168 (setq file-name
(nth 1 def
))
169 (format "%s autoloaded %s"
170 (if (commandp def
) "an interactive" "an")
171 (if (eq (nth 4 def
) 'keymap
) "keymap"
172 (if (nth 4 def
) "Lisp macro" "Lisp function"))
174 ;; perhaps use keymapp here instead
175 ((eq (car-safe def
) 'keymap
)
177 (elts (cdr-safe def
)))
179 (if (char-table-p (car-safe elts
))
182 (setq elts
(cdr-safe elts
)))
188 (with-current-buffer standard-output
191 (if (re-search-backward "alias for `\\([^`']+\\)'" nil t
)
192 (help-xref-button 1 'help-function def
)))))
194 (setq file-name
(symbol-file function
)))
198 ;; We used to add .el to the file name,
199 ;; but that's completely wrong when the user used load-file.
202 ;; Make a hyperlink to the library.
203 (with-current-buffer standard-output
205 (re-search-backward "`\\([^`']+\\)'" nil t
)
206 (help-xref-button 1 'help-function-def function file-name
)))))
209 (when (commandp function
)
210 (let* ((remapped (remap-command function
))
211 (keys (where-is-internal
212 (or remapped function
) overriding-local-map nil nil
)))
214 (princ "It is remapped to `")
215 (princ (symbol-name remapped
))
218 (princ (if remapped
" which is bound to " "It is bound to "))
219 ;; FIXME: This list can be very long (f.ex. for self-insert-command).
220 (princ (mapconcat 'key-description keys
", ")))
221 (when (or remapped keys
)
224 ;; Handle symbols aliased to other symbols.
225 (setq def
(indirect-function def
))
226 ;; If definition is a macro, find the function inside it.
227 (if (eq (car-safe def
) 'macro
)
228 (setq def
(cdr def
)))
229 (let ((arglist (cond ((byte-code-function-p def
)
230 (car (append def nil
)))
231 ((eq (car-safe def
) 'lambda
)
233 ((and (eq (car-safe def
) 'autoload
)
234 (not (eq (nth 4 def
) 'keymap
)))
235 (concat "[Arg list not available until "
236 "function definition is loaded.]"))
238 (cond ((listp arglist
)
239 (princ (cons (if (symbolp function
) function
"anonymous")
240 (mapcar (lambda (arg)
241 (if (memq arg
'(&optional
&rest
))
243 (intern (upcase (symbol-name arg
)))))
249 (let ((doc (documentation function
)))
254 (with-current-buffer standard-output
256 ;; Builtins get the calling sequence at the end of
257 ;; the doc string. Move it to the same place as
258 ;; for other functions.
260 ;; In cases where `function' has been fset to a
261 ;; subr we can't search for function's name in
262 ;; the doc string. Kluge round that using the
263 ;; printed representation. The arg list then
264 ;; shows the wrong function name, but that
265 ;; might be a useful hint.
266 (let* ((rep (prin1-to-string def
))
268 (string-match " \\([^ ]+\\)>$" rep
)
269 (match-string 1 rep
))))
270 (if (looking-at (format "(%s[ )]" (regexp-quote name
)))
271 (let ((start (point-marker)))
272 (goto-char (point-min))
274 (insert-buffer-substring (current-buffer) start
)
276 (delete-region (1- start
) (point-max)))
277 (goto-char (point-min))
280 "[Missing arglist. Please make a bug report.]\n")))
281 (goto-char (point-max)))))
282 (princ "not documented")))))
288 (defun variable-at-point ()
289 "Return the bound variable symbol found around point.
290 Return 0 if there is no such symbol."
292 (with-syntax-table emacs-lisp-mode-syntax-table
294 (or (not (zerop (skip-syntax-backward "_w")))
295 (eq (char-syntax (following-char)) ?w
)
296 (eq (char-syntax (following-char)) ?_
)
298 (skip-chars-forward "'")
299 (let ((obj (read (current-buffer))))
300 (or (and (symbolp obj
) (boundp obj
) obj
)
305 (defun describe-variable (variable &optional buffer
)
306 "Display the full documentation of VARIABLE (a symbol).
307 Returns the documentation as a string, also.
308 If VARIABLE has a buffer-local value in BUFFER (default to the current buffer),
309 it is displayed along with the global value."
311 (let ((v (variable-at-point))
312 (enable-recursive-minibuffers t
)
314 (setq val
(completing-read (if (symbolp v
)
316 "Describe variable (default %s): " v
)
317 "Describe variable: ")
318 obarray
'boundp t nil nil
319 (if (symbolp v
) (symbol-name v
))))
320 (list (if (equal val
"")
322 (unless (bufferp buffer
) (setq buffer
(current-buffer)))
323 (if (not (symbolp variable
))
324 (message "You did not specify a variable")
327 (help-setup-xref (list #'describe-variable variable buffer
)
329 (with-output-to-temp-buffer (help-buffer)
330 (with-current-buffer buffer
332 (if (not (boundp variable
))
336 (let ((val (symbol-value variable
)))
337 (with-current-buffer standard-output
338 (princ "'s value is ")
340 (let ((from (point)))
342 (help-xref-on-pp from
(point))
343 (if (< (point) (+ from
20))
346 (delete-char -
1)))))))
348 (when (local-variable-p variable
)
349 (princ (format "Local in buffer %s; " (buffer-name)))
350 (if (not (default-boundp variable
))
351 (princ "globally void")
352 (let ((val (default-value variable
)))
353 (with-current-buffer standard-output
354 (princ "global value is ")
356 ;; Fixme: pp can take an age if you happen to
357 ;; ask for a very large expression. We should
358 ;; probably print it raw once and check it's a
359 ;; sensible size before prettyprinting. -- fx
360 (let ((from (point)))
362 (help-xref-on-pp from
(point))
363 (if (< (point) (+ from
20))
366 (delete-char -
1)))))))
369 (with-current-buffer standard-output
370 (when (> (count-lines (point-min) (point-max)) 10)
371 ;; Note that setting the syntax table like below
372 ;; makes forward-sexp move over a `'s' at the end
374 (set-syntax-table emacs-lisp-mode-syntax-table
)
375 (goto-char (point-min))
379 (delete-region (point) (progn (end-of-line) (point)))
380 (insert " value is shown below.\n\n")
382 (insert "\n\nValue:"))))
383 ;; Add a note for variables that have been make-var-buffer-local.
384 (when (and (local-variable-if-set-p variable
)
385 (or (not (local-variable-p variable
))
387 (local-variable-if-set-p variable
))))
390 (insert "Automatically becomes buffer-local when set in any fashion.\n"))))
391 (princ "Documentation:")
393 (let ((doc (documentation-property variable
'variable-documentation
)))
394 (princ (or doc
"not documented as a variable.")))
396 ;; Make a link to customize if this variable can be customized.
397 ;; Note, it is not reliable to test only for a custom-type property
398 ;; because those are only present after the var's definition
400 (if (or (get variable
'custom-type
) ; after defcustom
401 (get variable
'custom-loads
) ; from loaddefs.el
402 (get variable
'standard-value
)) ; from cus-start.el
403 (let ((customize-label "customize"))
406 (princ (concat "You can " customize-label
" this variable."))
407 (with-current-buffer standard-output
410 (concat "\\(" customize-label
"\\)") nil t
)
411 (help-xref-button 1 'help-customize-variable variable
)))))
412 ;; Make a hyperlink to the library if appropriate. (Don't
413 ;; change the format of the buffer's initial line in case
414 ;; anything expects the current format.)
415 (let ((file-name (symbol-file variable
)))
416 (when (equal file-name
"loaddefs.el")
417 ;; Find the real def site of the preloaded variable.
420 (find-variable-noselect variable file-name
)
423 (with-current-buffer (car location
)
424 (goto-char (cdr location
))
425 (when (re-search-backward
426 "^;;; Generated autoloads from \\(.*\\)" nil t
)
427 (setq file-name
(match-string 1)))))))
429 (princ "\n\nDefined in `")
432 (with-current-buffer standard-output
434 (re-search-backward "`\\([^`']+\\)'" nil t
)
435 (help-xref-button 1 'help-variable-def
436 variable file-name
)))))
438 (print-help-return-message)
440 (set-buffer standard-output
)
441 ;; Return the text we displayed.
442 (buffer-string))))))))
446 (defun describe-syntax (&optional buffer
)
447 "Describe the syntax specifications in the syntax table of BUFFER.
448 The descriptions are inserted in a help buffer, which is then displayed.
449 BUFFER defaults to the current buffer."
451 (setq buffer
(or buffer
(current-buffer)))
452 (help-setup-xref (list #'describe-syntax buffer
) (interactive-p))
453 (with-output-to-temp-buffer (help-buffer)
454 (let ((table (with-current-buffer buffer
(syntax-table))))
455 (with-current-buffer standard-output
456 (describe-vector table
'internal-describe-syntax-value
)
457 (while (setq table
(char-table-parent table
))
458 (insert "\nThe parent syntax table is:")
459 (describe-vector table
'internal-describe-syntax-value
))))))
461 (defun help-describe-category-set (value)
463 ((null value
) "default")
464 ((char-table-p value
) "deeper char-table ...")
465 (t (condition-case err
466 (category-set-mnemonics value
)
467 (error "invalid"))))))
470 (defun describe-categories (&optional buffer
)
471 "Describe the category specifications in the current category table.
472 The descriptions are inserted in a buffer, which is then displayed."
474 (setq buffer
(or buffer
(current-buffer)))
475 (help-setup-xref (list #'describe-categories buffer
) (interactive-p))
476 (with-output-to-temp-buffer (help-buffer)
477 (let ((table (with-current-buffer buffer
(category-table))))
478 (with-current-buffer standard-output
479 (describe-vector table
'help-describe-category-set
)
480 (let ((docs (char-table-extra-slot table
0)))
481 (if (or (not (vectorp docs
)) (/= (length docs
) 95))
482 (insert "Invalid first extra slot in this char table\n")
483 (insert "Meanings of mnemonic characters are:\n")
485 (let ((elt (aref docs i
)))
487 (insert (+ i ?\
) ": " elt
"\n"))))
488 (while (setq table
(char-table-parent table
))
489 (insert "\nThe parent category table is:")
490 (describe-vector table
'help-describe-category-set
))))))))
494 ;;; help-fns.el ends here