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))
130 (with-output-to-temp-buffer (help-buffer)
132 ;; Use " is " instead of a colon so that
133 ;; it is easier to get out the function name using forward-sexp.
135 (describe-function-1 function
)
136 (print-help-return-message)
137 (with-current-buffer standard-output
138 ;; Return the text we displayed.
142 (defun describe-function-1 (function)
143 (let* ((def (if (symbolp function
)
144 (symbol-function function
)
147 (beg (if (commandp def
) "an interactive " "a ")))
149 (cond ((or (stringp def
)
153 (if (eq 'unevalled
(cdr (subr-arity def
)))
154 (concat beg
"special form")
155 (concat beg
"built-in function")))
156 ((byte-code-function-p def
)
157 (concat beg
"compiled Lisp function"))
159 (while (symbolp (symbol-function def
))
160 (setq def
(symbol-function def
)))
161 (format "an alias for `%s'" def
))
162 ((eq (car-safe def
) 'lambda
)
163 (concat beg
"Lisp function"))
164 ((eq (car-safe def
) 'macro
)
166 ((eq (car-safe def
) 'autoload
)
167 (setq file-name
(nth 1 def
))
168 (format "%s autoloaded %s"
169 (if (commandp def
) "an interactive" "an")
170 (if (eq (nth 4 def
) 'keymap
) "keymap"
171 (if (nth 4 def
) "Lisp macro" "Lisp function"))
173 ;; perhaps use keymapp here instead
174 ((eq (car-safe def
) 'keymap
)
176 (elts (cdr-safe def
)))
178 (if (char-table-p (car-safe elts
))
181 (setq elts
(cdr-safe elts
)))
187 (with-current-buffer standard-output
190 (if (re-search-backward "alias for `\\([^`']+\\)'" nil t
)
191 (help-xref-button 1 'help-function def
)))))
193 (setq file-name
(symbol-file function
)))
197 ;; We used to add .el to the file name,
198 ;; but that's completely wrong when the user used load-file.
201 ;; Make a hyperlink to the library.
202 (with-current-buffer standard-output
204 (re-search-backward "`\\([^`']+\\)'" nil t
)
205 (help-xref-button 1 'help-function-def function file-name
)))))
208 (when (commandp function
)
209 (let ((keys (where-is-internal
210 function overriding-local-map nil nil
)))
212 (princ "It is bound to ")
213 ;; FIXME: This list can be very long (f.ex. for self-insert-command).
214 (princ (mapconcat 'key-description keys
", "))
217 ;; Handle symbols aliased to other symbols.
218 (setq def
(indirect-function def
))
219 ;; If definition is a macro, find the function inside it.
220 (if (eq (car-safe def
) 'macro
)
221 (setq def
(cdr def
)))
222 (let ((arglist (cond ((byte-code-function-p def
)
223 (car (append def nil
)))
224 ((eq (car-safe def
) 'lambda
)
226 ((and (eq (car-safe def
) 'autoload
)
227 (not (eq (nth 4 def
) 'keymap
)))
228 (concat "[Arg list not available until "
229 "function definition is loaded.]"))
231 (cond ((listp arglist
)
232 (princ (cons (if (symbolp function
) function
"anonymous")
233 (mapcar (lambda (arg)
234 (if (memq arg
'(&optional
&rest
))
236 (intern (upcase (symbol-name arg
)))))
242 (let ((doc (documentation function
)))
247 (with-current-buffer standard-output
249 ;; Builtins get the calling sequence at the end of
250 ;; the doc string. Move it to the same place as
251 ;; for other functions.
253 ;; In cases where `function' has been fset to a
254 ;; subr we can't search for function's name in
255 ;; the doc string. Kluge round that using the
256 ;; printed representation. The arg list then
257 ;; shows the wrong function name, but that
258 ;; might be a useful hint.
259 (let* ((rep (prin1-to-string def
))
261 (string-match " \\([^ ]+\\)>$" rep
)
262 (match-string 1 rep
))))
263 (if (looking-at (format "(%s[ )]" (regexp-quote name
)))
264 (let ((start (point-marker)))
265 (goto-char (point-min))
267 (insert-buffer-substring (current-buffer) start
)
269 (delete-region (1- start
) (point-max)))
270 (goto-char (point-min))
273 "[Missing arglist. Please make a bug report.]\n")))
274 (goto-char (point-max)))))
275 (princ "not documented")))))
281 (defun variable-at-point ()
282 "Return the bound variable symbol found around point.
283 Return 0 if there is no such symbol."
285 (with-syntax-table emacs-lisp-mode-syntax-table
287 (or (not (zerop (skip-syntax-backward "_w")))
288 (eq (char-syntax (following-char)) ?w
)
289 (eq (char-syntax (following-char)) ?_
)
291 (skip-chars-forward "'")
292 (let ((obj (read (current-buffer))))
293 (or (and (symbolp obj
) (boundp obj
) obj
)
298 (defun describe-variable (variable &optional buffer
)
299 "Display the full documentation of VARIABLE (a symbol).
300 Returns the documentation as a string, also.
301 If VARIABLE has a buffer-local value in BUFFER (default to the current buffer),
302 it is displayed along with the global value."
304 (let ((v (variable-at-point))
305 (enable-recursive-minibuffers t
)
307 (setq val
(completing-read (if (symbolp v
)
309 "Describe variable (default %s): " v
)
310 "Describe variable: ")
311 obarray
'boundp t nil nil
312 (if (symbolp v
) (symbol-name v
))))
313 (list (if (equal val
"")
315 (unless (bufferp buffer
) (setq buffer
(current-buffer)))
316 (if (not (symbolp variable
))
317 (message "You did not specify a variable")
319 (help-setup-xref (list #'describe-variable variable buffer
)
321 (with-output-to-temp-buffer (help-buffer)
322 (with-current-buffer buffer
324 (if (not (boundp variable
))
328 (let ((val (symbol-value variable
)))
329 (with-current-buffer standard-output
330 (princ "'s value is ")
332 (let ((from (point)))
334 (help-xref-on-pp from
(point))
335 (if (< (point) (+ from
20))
338 (delete-char -
1)))))))
340 (when (local-variable-p variable
)
341 (princ (format "Local in buffer %s; " (buffer-name)))
342 (if (not (default-boundp variable
))
343 (princ "globally void")
344 (let ((val (default-value variable
)))
345 (with-current-buffer standard-output
346 (princ "global value is ")
348 ;; Fixme: pp can take an age if you happen to
349 ;; ask for a very large expression. We should
350 ;; probably print it raw once and check it's a
351 ;; sensible size before prettyprinting. -- fx
352 (let ((from (point)))
354 (help-xref-on-pp from
(point))
355 (if (< (point) (+ from
20))
358 (delete-char -
1)))))))
361 (with-current-buffer standard-output
362 (when (> (count-lines (point-min) (point-max)) 10)
363 ;; Note that setting the syntax table like below
364 ;; makes forward-sexp move over a `'s' at the end
366 (set-syntax-table emacs-lisp-mode-syntax-table
)
367 (goto-char (point-min))
371 (delete-region (point) (progn (end-of-line) (point)))
372 (insert " value is shown below.\n\n")
374 (insert "\n\nValue:"))))
375 ;; Add a note for variables that have been make-var-buffer-local.
376 (when (and (local-variable-if-set-p variable
)
377 (or (not (local-variable-p variable
))
379 (local-variable-if-set-p variable
))))
382 (insert "Automatically becomes buffer-local when set in any fashion.\n"))))
383 (princ "Documentation:")
385 (let ((doc (documentation-property variable
'variable-documentation
)))
386 (princ (or doc
"not documented as a variable.")))
388 ;; Make a link to customize if this variable can be customized.
389 ;; Note, it is not reliable to test only for a custom-type property
390 ;; because those are only present after the var's definition
392 (if (or (get variable
'custom-type
) ; after defcustom
393 (get variable
'custom-loads
) ; from loaddefs.el
394 (get variable
'standard-value
)) ; from cus-start.el
395 (let ((customize-label "customize"))
398 (princ (concat "You can " customize-label
" this variable."))
399 (with-current-buffer standard-output
402 (concat "\\(" customize-label
"\\)") nil t
)
403 (help-xref-button 1 'help-customize-variable variable
)))))
404 ;; Make a hyperlink to the library if appropriate. (Don't
405 ;; change the format of the buffer's initial line in case
406 ;; anything expects the current format.)
407 (let ((file-name (symbol-file variable
)))
408 (when (equal file-name
"loaddefs.el")
409 ;; Find the real def site of the preloaded variable.
412 (find-variable-noselect variable file-name
)
415 (with-current-buffer (car location
)
416 (goto-char (cdr location
))
417 (when (re-search-backward
418 "^;;; Generated autoloads from \\(.*\\)" nil t
)
419 (setq file-name
(match-string 1)))))))
421 (princ "\n\nDefined in `")
424 (with-current-buffer standard-output
426 (re-search-backward "`\\([^`']+\\)'" nil t
)
427 (help-xref-button 1 'help-variable-def
428 variable file-name
)))))
430 (print-help-return-message)
432 (set-buffer standard-output
)
433 ;; Return the text we displayed.
434 (buffer-string)))))))
438 (defun describe-syntax (&optional buffer
)
439 "Describe the syntax specifications in the syntax table of BUFFER.
440 The descriptions are inserted in a help buffer, which is then displayed.
441 BUFFER defaults to the current buffer."
443 (setq buffer
(or buffer
(current-buffer)))
444 (help-setup-xref (list #'describe-syntax buffer
) (interactive-p))
445 (with-output-to-temp-buffer (help-buffer)
446 (let ((table (with-current-buffer buffer
(syntax-table))))
447 (with-current-buffer standard-output
448 (describe-vector table
'internal-describe-syntax-value
)
449 (while (setq table
(char-table-parent table
))
450 (insert "\nThe parent syntax table is:")
451 (describe-vector table
'internal-describe-syntax-value
))))))
453 (defun help-describe-category-set (value)
455 ((null value
) "default")
456 ((char-table-p value
) "deeper char-table ...")
457 (t (condition-case err
458 (category-set-mnemonics value
)
459 (error "invalid"))))))
462 (defun describe-categories (&optional buffer
)
463 "Describe the category specifications in the current category table.
464 The descriptions are inserted in a buffer, which is then displayed."
466 (setq buffer
(or buffer
(current-buffer)))
467 (help-setup-xref (list #'describe-categories buffer
) (interactive-p))
468 (with-output-to-temp-buffer (help-buffer)
469 (let ((table (with-current-buffer buffer
(category-table))))
470 (with-current-buffer standard-output
471 (describe-vector table
'help-describe-category-set
)
472 (let ((docs (char-table-extra-slot table
0)))
473 (if (or (not (vectorp docs
)) (/= (length docs
) 95))
474 (insert "Invalid first extra slot in this char table\n")
475 (insert "Meanings of mnemonic characters are:\n")
477 (let ((elt (aref docs i
)))
479 (insert (+ i ?\
) ": " elt
"\n"))))
480 (while (setq table
(char-table-parent table
))
481 (insert "\nThe parent category table is:")
482 (describe-vector table
'help-describe-category-set
))))))))
486 ;;; help-fns.el ends here