-;; Help commands for Emacs
-;; Copyright (C) 1985, 1986 Free Software Foundation, Inc.
+;;; help.el --- help commands for Emacs
+
+;; Copyright (C) 1985, 1986, 1993, 1994, 1998, 1999, 2000 Free Software Foundation, Inc.
+
+;; Maintainer: FSF
+;; Keywords: help, internal
;; This file is part of GNU Emacs.
;; GNU Emacs is free software; you can redistribute it and/or modify
;; it under the terms of the GNU General Public License as published by
-;; the Free Software Foundation; either version 1, or (at your option)
+;; the Free Software Foundation; either version 2, or (at your option)
;; any later version.
;; GNU Emacs is distributed in the hope that it will be useful,
;; GNU General Public License for more details.
;; You should have received a copy of the GNU General Public License
-;; along with GNU Emacs; see the file COPYING. If not, write to
-;; the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA.
+;; along with GNU Emacs; see the file COPYING. If not, write to the
+;; Free Software Foundation, Inc., 59 Temple Place - Suite 330,
+;; Boston, MA 02111-1307, USA.
+
+;;; Commentary:
+
+;; This code implements GNU Emacs' on-line help system, the one invoked by
+;; `M-x help-for-help'.
+
+;;; Code:
+
+;; Get the macro make-help-screen when this is compiled,
+;; or run interpreted, but not when the compiled code is loaded.
+(eval-when-compile (require 'help-macro))
+(eval-when-compile (require 'view))
-;;;###autoload
(defvar help-map (make-sparse-keymap)
"Keymap for characters following the Help key.")
-(define-key global-map "\C-h" 'help-command)
+(defvar help-mode-map (make-sparse-keymap)
+ "Keymap for help mode.")
+
+(define-key global-map (char-to-string help-char) 'help-command)
+(define-key global-map [help] 'help-command)
+(define-key global-map [f1] 'help-command)
(fset 'help-command help-map)
-(define-key help-map "\C-h" 'help-for-help)
+(define-key help-map (char-to-string help-char) 'help-for-help)
+(define-key help-map [help] 'help-for-help)
+(define-key help-map [f1] 'help-for-help)
(define-key help-map "?" 'help-for-help)
(define-key help-map "\C-c" 'describe-copying)
(define-key help-map "\C-d" 'describe-distribution)
(define-key help-map "\C-w" 'describe-no-warranty)
-(define-key help-map "a" 'command-apropos)
+(define-key help-map "\C-p" 'describe-project)
+(define-key help-map "a" 'apropos-command)
(define-key help-map "b" 'describe-bindings)
(define-key help-map "d" 'describe-function)
(define-key help-map "f" 'describe-function)
+(define-key help-map "F" 'view-emacs-FAQ)
+
(define-key help-map "i" 'info)
+(define-key help-map "4i" 'info-other-window)
+(define-key help-map "\C-f" 'Info-goto-emacs-command-node)
+(define-key help-map "\C-k" 'Info-goto-emacs-key-command-node)
+(define-key help-map "\C-i" 'info-lookup-symbol)
(define-key help-map "l" 'view-lossage)
(define-key help-map "\C-n" 'view-emacs-news)
(define-key help-map "n" 'view-emacs-news)
+(define-key help-map "p" 'finder-by-keyword)
+(autoload 'finder-by-keyword "finder"
+ "Find packages matching a given keyword." t)
+
+(define-key help-map "P" 'view-emacs-problems)
+
(define-key help-map "s" 'describe-syntax)
(define-key help-map "t" 'help-with-tutorial)
(define-key help-map "v" 'describe-variable)
-(defun help-with-tutorial ()
- "Select the Emacs learn-by-doing tutorial."
+(define-key help-map "q" 'help-quit)
+
+(define-key help-mode-map [mouse-2] 'help-follow-mouse)
+(define-key help-mode-map "\C-c\C-b" 'help-go-back)
+(define-key help-mode-map "\C-c\C-c" 'help-follow)
+(define-key help-mode-map "\t" 'help-next-ref)
+(define-key help-mode-map [backtab] 'help-previous-ref)
+(define-key help-mode-map [(shift tab)] 'help-previous-ref)
+;; Documentation only, since we use minor-mode-overriding-map-alist.
+(define-key help-mode-map "\r" 'help-follow)
+
+(defvar help-xref-stack nil
+ "A stack of ways by which to return to help buffers after following xrefs.
+Used by `help-follow' and `help-xref-go-back'.
+An element looks like (POSITION FUNCTION ARGS...), where POSITION is
+`(POINT . BUFFER-NAME)'.
+To use the element, do (apply FUNCTION ARGS) then goto the point in
+the named buffer.")
+(put 'help-xref-stack 'permanent-local t)
+
+(defvar help-xref-stack-item nil
+ "An item for `help-follow' in this buffer to push onto `help-xref-stack'.
+The format is (FUNCTION ARGS...).")
+(put 'help-xref-stack-item 'permanent-local t)
+
+(setq-default help-xref-stack nil help-xref-stack-item nil)
+
+(defcustom help-mode-hook nil
+ "Hook run by `help-mode'."
+ :type 'hook
+ :group 'help)
+
+(defun help-mode ()
+ "Major mode for viewing help text and navigating references in it.
+Entry to this mode runs the normal hook `help-mode-hook'.
+Commands:
+\\{help-mode-map}"
+ (interactive)
+ (kill-all-local-variables)
+ (use-local-map help-mode-map)
+ (setq mode-name "Help")
+ (setq major-mode 'help-mode)
+ (make-local-variable 'font-lock-defaults)
+ (setq font-lock-defaults nil) ; font-lock would defeat xref
+ (view-mode)
+ (make-local-variable 'view-no-disable-on-exit)
+ (setq view-no-disable-on-exit t)
+ ;; `help-make-xrefs' would be run here if not invoked from
+ ;; `help-mode-maybe'.
+ (run-hooks 'help-mode-hook))
+
+(defun help-mode-setup ()
+ (help-mode)
+ (setq buffer-read-only nil))
+
+(add-hook 'temp-buffer-setup-hook 'help-mode-setup)
+
+(defun help-mode-finish ()
+ (when (eq major-mode 'help-mode)
+ ;; View mode's read-only status of existing *Help* buffer is lost
+ ;; by with-output-to-temp-buffer.
+ (toggle-read-only 1)
+ (help-make-xrefs (current-buffer)))
+ (setq view-return-to-alist
+ (list (cons (selected-window) help-return-method))))
+
+(add-hook 'temp-buffer-show-hook 'help-mode-finish)
+
+(defun help-quit ()
+ "Just exit from the Help command's command loop."
(interactive)
- (let ((file (expand-file-name "~/TUTORIAL")))
+ nil)
+
+(defun help-with-tutorial (&optional arg)
+ "Select the Emacs learn-by-doing tutorial.
+If there is a tutorial version written in the language
+of the selected language environment, that version is used.
+If there's no tutorial in that language, `TUTORIAL' is selected.
+With arg, you are asked to choose which language."
+ (interactive "P")
+ (let ((lang (if arg
+ (read-language-name 'tutorial "Language: " "English")
+ (if (get-language-info current-language-environment 'tutorial)
+ current-language-environment
+ "English")))
+ file filename)
+ (setq filename (get-language-info lang 'tutorial))
+ (setq file (expand-file-name (concat "~/" filename)))
(delete-other-windows)
(if (get-file-buffer file)
(switch-to-buffer (get-file-buffer file))
(switch-to-buffer (create-file-buffer file))
(setq buffer-file-name file)
(setq default-directory (expand-file-name "~/"))
- (setq auto-save-file-name nil)
- (insert-file-contents (expand-file-name "TUTORIAL" data-directory))
+ (setq buffer-auto-save-file-name nil)
+ (insert-file-contents (expand-file-name filename data-directory))
(goto-char (point-min))
(search-forward "\n<<")
(beginning-of-line)
(delete-region (point) (progn (end-of-line) (point)))
- (newline (- (window-height (selected-window))
+ (let ((n (- (window-height (selected-window))
(count-lines (point-min) (point))
- 6))
+ 6)))
+ (if (< n 12)
+ (newline n)
+ ;; Some people get confused by the large gap.
+ (newline (/ n 2))
+ (insert "[Middle of page left blank for didactic purposes. "
+ "Text continues below]")
+ (newline (- n (/ n 2)))))
(goto-char (point-min))
(set-buffer-modified-p nil))))
-(defun describe-key-briefly (key)
- "Print the name of the function KEY invokes. KEY is a string."
- (interactive "kDescribe key briefly: ")
- (let ((defn (key-binding key)))
- (if (or (null defn) (integerp defn))
- (message "%s is undefined" (key-description key))
- (message "%s runs the command %s"
- (key-description key)
- (if (symbolp defn) defn (prin1-to-string defn))))))
+(defun mode-line-key-binding (key)
+ "Value is the binding of KEY in the mode line or nil if none."
+ (let (string-info defn)
+ (when (and (eq 'mode-line (aref key 0))
+ (consp (setq string-info (nth 4 (event-start (aref key 1))))))
+ (let* ((string (car string-info))
+ (pos (cdr string-info))
+ (local-map (and (> pos 0)
+ (< pos (length string))
+ (get-text-property pos 'local-map string))))
+ (setq defn (and local-map (lookup-key local-map key)))))
+ defn))
+
+(defun describe-key-briefly (key &optional insert)
+ "Print the name of the function KEY invokes. KEY is a string.
+If INSERT (the prefix arg) is non-nil, insert the message in the buffer."
+ (interactive "kDescribe key briefly: \nP")
+ (save-excursion
+ (let ((modifiers (event-modifiers (aref key 0)))
+ (standard-output (if insert (current-buffer) t))
+ window position)
+ ;; For a mouse button event, go to the button it applies to
+ ;; to get the right key bindings. And go to the right place
+ ;; in case the keymap depends on where you clicked.
+ (if (or (memq 'click modifiers) (memq 'down modifiers)
+ (memq 'drag modifiers))
+ (setq window (posn-window (event-start (aref key 0)))
+ position (posn-point (event-start (aref key 0)))))
+ (if (windowp window)
+ (progn
+ (set-buffer (window-buffer window))
+ (goto-char position)))
+ ;; Ok, now look up the key and name the command.
+ (let ((defn (or (mode-line-key-binding key)
+ (key-binding key)))
+ (key-desc (key-description key)))
+ (if (or (null defn) (integerp defn))
+ (princ (format "%s is undefined" key-desc))
+ (princ (format (if insert
+ "`%s' (`%s')"
+ (if (windowp window)
+ "%s at that spot runs the command %s"
+ "%s runs the command %s"))
+ key-desc
+ (if (symbolp defn) defn (prin1-to-string defn)))))))))
+
+(defvar help-return-method nil
+ "What to do to \"exit\" the help buffer.
+This is a list
+ (WINDOW . t) delete the selected window, go to WINDOW.
+ (WINDOW . quit-window) do quit-window, then select WINDOW.
+ (WINDOW BUF START POINT) display BUF at START, POINT, then select WINDOW.")
(defun print-help-return-message (&optional function)
"Display or return message saying how to restore windows after help command.
Computes a message and applies the optional argument FUNCTION to it.
If FUNCTION is nil, applies `message' to it, thus printing it."
(and (not (get-buffer-window standard-output))
- (funcall (or function 'message)
- (concat
- (substitute-command-keys
- (if (one-window-p t)
- (if pop-up-windows
- "Type \\[delete-other-windows] to remove help window."
- "Type \\[switch-to-buffer] RET to remove help window.")
- "Type \\[switch-to-buffer-other-window] RET to restore the other window."))
- (substitute-command-keys
- " \\[scroll-other-window] to scroll the help.")))))
+ (let ((first-message
+ (cond ((special-display-p (buffer-name standard-output))
+ (setq help-return-method (cons (selected-window) t))
+ ;; If the help output buffer is a special display buffer,
+ ;; don't say anything about how to get rid of it.
+ ;; First of all, the user will do that with the window
+ ;; manager, not with Emacs.
+ ;; Secondly, the buffer has not been displayed yet,
+ ;; so we don't know whether its frame will be selected.
+ nil)
+ ((not (one-window-p t))
+ (setq help-return-method
+ (cons (selected-window) 'quit-window))
+ "Type \\[switch-to-buffer-other-window] RET to restore the other window.")
+ (pop-up-windows
+ (setq help-return-method (cons (selected-window) t))
+ "Type \\[delete-other-windows] to remove help window.")
+ (t
+ (setq help-return-method
+ (list (selected-window) (window-buffer)
+ (window-start) (window-point)))
+ "Type \\[switch-to-buffer] RET to remove help window."))))
+ (funcall (or function 'message)
+ (concat
+ (if first-message
+ (substitute-command-keys first-message))
+ (if first-message " ")
+ ;; If the help buffer will go in a separate frame,
+ ;; it's no use mentioning a command to scroll, so don't.
+ (if (special-display-p (buffer-name standard-output))
+ nil
+ (if (same-window-p (buffer-name standard-output))
+ ;; Say how to scroll this window.
+ (substitute-command-keys
+ "\\[scroll-up] to scroll the help.")
+ ;; Say how to scroll some other window.
+ (substitute-command-keys
+ "\\[scroll-other-window] to scroll the help."))))))))
(defun describe-key (key)
"Display documentation of the function invoked by KEY. KEY is a string."
(interactive "kDescribe key: ")
- (let ((defn (key-binding key)))
- (if (or (null defn) (integerp defn))
- (message "%s is undefined" (key-description key))
- (with-output-to-temp-buffer "*Help*"
- (prin1 defn)
- (princ ":\n")
- (if (documentation defn)
- (princ (documentation defn))
- (princ "not documented"))
- (print-help-return-message)))))
-
-(defun describe-mode (&optional minor)
- "Display documentation of current major mode.
-If optional MINOR is non-nil (or prefix argument is given if interactive),
-display documentation of active minor modes as well.
+ (save-excursion
+ (let ((modifiers (event-modifiers (aref key 0)))
+ window position)
+ ;; For a mouse button event, go to the button it applies to
+ ;; to get the right key bindings. And go to the right place
+ ;; in case the keymap depends on where you clicked.
+ (if (or (memq 'click modifiers) (memq 'down modifiers)
+ (memq 'drag modifiers))
+ (setq window (posn-window (event-start (aref key 0)))
+ position (posn-point (event-start (aref key 0)))))
+ (if (windowp window)
+ (progn
+ (set-buffer (window-buffer window))
+ (goto-char position)))
+ (let ((defn (or (mode-line-key-binding key) (key-binding key))))
+ (if (or (null defn) (integerp defn))
+ (message "%s is undefined" (key-description key))
+ (with-output-to-temp-buffer "*Help*"
+ (princ (key-description key))
+ (if (windowp window)
+ (princ " at that spot"))
+ (princ " runs the command ")
+ (prin1 defn)
+ (princ "\n which is ")
+ (describe-function-1 defn nil (interactive-p))
+ (print-help-return-message)))))))
+
+(defun describe-mode ()
+ "Display documentation of current major mode and minor modes.
+The major mode description comes first, followed by the minor modes,
+each on a separate page.
+
For this to work correctly for a minor mode, the mode's indicator variable
-(listed in `minor-mode-alist') must also be a function whose documentation
+\(listed in `minor-mode-alist') must also be a function whose documentation
describes the minor mode."
(interactive)
(with-output-to-temp-buffer "*Help*"
+ (when minor-mode-alist
+ (princ "The major mode is described first.
+For minor modes, see following pages.\n\n"))
(princ mode-name)
- (princ " Mode:\n")
+ (princ " mode:\n")
(princ (documentation major-mode))
- (let ((minor-modes minor-mode-alist)
- (locals (buffer-local-variables)))
+ (help-setup-xref (list #'help-xref-mode (current-buffer)) (interactive-p))
+ (let ((minor-modes minor-mode-alist))
(while minor-modes
(let* ((minor-mode (car (car minor-modes)))
- (indicator (car (cdr (car minor-modes))))
- (local-binding (assq minor-mode locals)))
+ (indicator (car (cdr (car minor-modes)))))
;; Document a minor mode if it is listed in minor-mode-alist,
;; bound locally in this buffer, non-nil, and has a function
;; definition.
- (if (and local-binding
- (cdr local-binding)
+ (if (and (symbol-value minor-mode)
(fboundp minor-mode))
- (progn
- (princ (format "\n\n\n%s minor mode (indicator%s):\n"
- minor-mode indicator))
+ (let ((pretty-minor-mode minor-mode))
+ (if (string-match "-mode$" (symbol-name minor-mode))
+ (setq pretty-minor-mode
+ (capitalize
+ (substring (symbol-name minor-mode)
+ 0 (match-beginning 0)))))
+ (while (and indicator (symbolp indicator)
+ (boundp indicator)
+ (not (eq indicator (symbol-value indicator))))
+ (setq indicator (symbol-value indicator)))
+ (princ "\n\f\n")
+ (princ (format "%s minor mode (%s):\n"
+ pretty-minor-mode
+ (if indicator
+ (format "indicator%s" indicator)
+ "no indicator")))
(princ (documentation minor-mode)))))
(setq minor-modes (cdr minor-modes))))
(print-help-return-message)))
(expand-file-name "COPYING" data-directory))
(goto-char (point-min)))
+(defun describe-project ()
+ "Display info on the GNU project."
+ (interactive)
+ (find-file-read-only
+ (expand-file-name "GNU" data-directory))
+ (goto-char (point-min)))
+
(defun describe-no-warranty ()
"Display info on all the kinds of warranty Emacs does NOT have."
(interactive)
(search-forward "NO WARRANTY")
(recenter 0)))
-(defun view-emacs-news ()
- "Display info on recent changes to Emacs."
+(defun describe-prefix-bindings ()
+ "Describe the bindings of the prefix used to reach this command.
+The prefix described consists of all but the last event
+of the key sequence that ran this command."
+ (interactive)
+ (let* ((key (this-command-keys)))
+ (describe-bindings
+ (if (stringp key)
+ (substring key 0 (1- (length key)))
+ (let ((prefix (make-vector (1- (length key)) nil))
+ (i 0))
+ (while (< i (length prefix))
+ (aset prefix i (aref key i))
+ (setq i (1+ i)))
+ prefix)))))
+;; Make C-h after a prefix, when not specifically bound,
+;; run describe-prefix-bindings.
+(setq prefix-help-command 'describe-prefix-bindings)
+
+(defun view-emacs-news (&optional arg)
+ "Display info on recent changes to Emacs.
+With numeric argument display information on correspondingly older changes."
+ (interactive "P")
+ (let* ((arg (if arg (prefix-numeric-value arg) 0)))
+ (find-file-read-only
+ (expand-file-name (concat (make-string arg ?O) "NEWS")
+ data-directory))))
+
+(defun view-emacs-FAQ ()
+ "Display the Emacs Frequently Asked Questions (FAQ) file."
(interactive)
- (find-file-read-only (expand-file-name "NEWS" data-directory)))
+;;; (find-file-read-only (expand-file-name "FAQ" data-directory))
+ (info "(efaq)"))
+
+(defun view-emacs-problems ()
+ "Display info on known problems with Emacs and possible workarounds."
+ (interactive)
+ (view-file (expand-file-name "PROBLEMS" data-directory)))
(defun view-lossage ()
"Display last 100 input keystrokes."
(interactive)
(with-output-to-temp-buffer "*Help*"
- (princ (key-description (recent-keys)))
+ (princ (mapconcat (function (lambda (key)
+ (if (or (integerp key)
+ (symbolp key)
+ (listp key))
+ (single-key-description key)
+ (prin1-to-string key nil))))
+ (recent-keys)
+ " "))
(save-excursion
(set-buffer standard-output)
(goto-char (point-min))
(while (progn (move-to-column 50) (not (eobp)))
(search-forward " " nil t)
- (insert "\n")))
+ (insert "\n"))
+ (setq help-xref-stack nil
+ help-xref-stack-item nil))
(print-help-return-message)))
-(defun help-for-help ()
- "You have typed C-h, the help character. Type a Help option:
-
-A command-apropos. Give a substring, and see a list of commands
- (functions interactively callable) that contain
- that substring. See also the apropos command.
-B describe-bindings. Display table of all key bindings.
-C describe-key-briefly. Type a command key sequence;
- it prints the function name that sequence runs.
-F describe-function. Type a function name and get documentation of it.
-I info. The info documentation reader.
-K describe-key. Type a command key sequence;
- it displays the full documentation.
-L view-lossage. Shows last 100 characters you typed.
-M describe-mode. Print documentation of current major mode,
- which describes the commands peculiar to it.
-N view-emacs-news. Shows emacs news file.
-S describe-syntax. Display contents of syntax table, plus explanations
-T help-with-tutorial. Select the Emacs learn-by-doing tutorial.
-V describe-variable. Type name of a variable;
- it displays the variable's documentation and value.
-W where-is. Type command name; it prints which keystrokes
- invoke that command.
-C-c print Emacs copying permission (General Public License).
-C-d print Emacs ordering information.
-C-n print news of recent Emacs changes.
-C-w print information on absence of warranty for GNU Emacs."
- (interactive)
- (message
- "A B C F I K L M N S T V W C-c C-d C-n C-w. Type C-h again for more help: ")
- (let ((char (read-char)))
- (if (or (= char ?\C-h) (= char ??))
- (save-window-excursion
- (switch-to-buffer "*Help*")
- (delete-other-windows)
- (erase-buffer)
- (insert (documentation 'help-for-help))
- (goto-char (point-min))
- (while (memq char '(?\C-h ?? ?\C-v ?\ ?\177 ?\M-v))
- (if (memq char '(?\C-v ?\ ))
- (scroll-up))
- (if (memq char '(?\177 ?\M-v))
- (scroll-down))
- (message "A B C F I K L M N S T V W C-c C-d C-n C-w%s: "
- (if (pos-visible-in-window-p (point-max))
- "" " or Space to scroll"))
- (let ((cursor-in-echo-area t))
- (setq char (read-char))))))
- (let ((defn (cdr (assq (downcase char) (cdr help-map)))))
- (if defn (call-interactively defn) (ding)))))
-
-
-;; Return a function which is called by the list containing point.
-;; If that gives no function, return a function whose name is around point.
-;; If that doesn't give a function, return nil.
+(defalias 'help 'help-for-help)
+(make-help-screen help-for-help
+ "a b c C f F C-f i I k C-k l L m n p s t v w C-c C-d C-n C-p C-w; ? for help:"
+ "You have typed %THIS-KEY%, the help character. Type a Help option:
+\(Use SPC or DEL to scroll through this text. Type \\<help-map>\\[help-quit] to exit the Help command.)
+
+a command-apropos. Give a substring, and see a list of commands
+ (functions interactively callable) that contain
+ that substring. See also the apropos command.
+b describe-bindings. Display table of all key bindings.
+c describe-key-briefly. Type a command key sequence;
+ it prints the function name that sequence runs.
+C describe-coding-system. This describes either a specific coding system
+ (if you type its name) or the coding systems currently in use
+ (if you type just RET).
+f describe-function. Type a function name and get documentation of it.
+C-f Info-goto-emacs-command-node. Type a function name;
+ it takes you to the Info node for that command.
+i info. The info documentation reader.
+I describe-input-method. Describe a specific input method (if you type
+ its name) or the current input method (if you type just RET).
+C-i info-lookup-symbol. Display the definition of a specific symbol
+ as found in the manual for the language this buffer is written in.
+k describe-key. Type a command key sequence;
+ it displays the full documentation.
+C-k Info-goto-emacs-key-command-node. Type a command key sequence;
+ it takes you to the Info node for the command bound to that key.
+l view-lossage. Show last 100 characters you typed.
+L describe-language-environment. This describes either the a
+ specific language environment (if you type its name)
+ or the current language environment (if you type just RET).
+m describe-mode. Print documentation of current minor modes,
+ and the current major mode, including their special commands.
+n view-emacs-news. Display news of recent Emacs changes.
+p finder-by-keyword. Find packages matching a given topic keyword.
+s describe-syntax. Display contents of syntax table, plus explanations
+t help-with-tutorial. Select the Emacs learn-by-doing tutorial.
+v describe-variable. Type name of a variable;
+ it displays the variable's documentation and value.
+w where-is. Type command name; it prints which keystrokes
+ invoke that command.
+
+F Display the frequently asked questions file.
+h Display the HELLO file which illustrates various scripts.
+C-c Display Emacs copying permission (General Public License).
+C-d Display Emacs ordering information.
+C-n Display news of recent Emacs changes.
+C-p Display information about the GNU project.
+C-w Display information on absence of warranty for GNU Emacs."
+ help-map)
+
(defun function-called-at-point ()
- (or (condition-case ()
- (save-excursion
- (save-restriction
- (narrow-to-region (max (point-min) (- (point) 1000)) (point-max))
- (backward-up-list 1)
- (forward-char 1)
- (let (obj)
- (setq obj (read (current-buffer)))
- (and (symbolp obj) (fboundp obj) obj))))
- (error nil))
- (condition-case ()
- (save-excursion
- (forward-sexp -1)
- (skip-chars-forward "'")
- (let ((obj (read (current-buffer))))
- (and (symbolp obj) (fboundp obj) obj)))
- (error nil))))
+ "Return a function around point or else called by the list containing point.
+If that doesn't give a function, return nil."
+ (let ((stab (syntax-table)))
+ (set-syntax-table emacs-lisp-mode-syntax-table)
+ (unwind-protect
+ (or (condition-case ()
+ (save-excursion
+ (or (not (zerop (skip-syntax-backward "_w")))
+ (eq (char-syntax (following-char)) ?w)
+ (eq (char-syntax (following-char)) ?_)
+ (forward-sexp -1))
+ (skip-chars-forward "'")
+ (let ((obj (read (current-buffer))))
+ (and (symbolp obj) (fboundp obj) obj)))
+ (error nil))
+ (condition-case ()
+ (save-excursion
+ (save-restriction
+ (narrow-to-region (max (point-min) (- (point) 1000)) (point-max))
+ ;; Move up to surrounding paren, then after the open.
+ (backward-up-list 1)
+ (forward-char 1)
+ ;; If there is space here, this is probably something
+ ;; other than a real Lisp function call, so ignore it.
+ (if (looking-at "[ \t]")
+ (error "Probably not a Lisp function call"))
+ (let (obj)
+ (setq obj (read (current-buffer)))
+ (and (symbolp obj) (fboundp obj) obj))))
+ (error nil)))
+ (set-syntax-table stab))))
+
+(defvar symbol-file-load-history-loaded nil
+ "Non-nil means we have loaded the file `fns-VERSION.el' in `exec-directory'.
+That file records the part of `load-history' for preloaded files,
+which is cleared out before dumping to make Emacs smaller.")
+
+(defun symbol-file (function)
+ "Return the input source from which FUNCTION was loaded.
+The value is normally a string that was passed to `load':
+either an absolute file name, or a library name
+\(with no directory name and no `.el' or `.elc' at the end).
+It can also be nil, if the definition is not associated with any file."
+ (unless symbol-file-load-history-loaded
+ (load (expand-file-name
+ ;; fns-XX.YY.ZZ.el does not work on DOS filesystem.
+ (if (eq system-type 'ms-dos)
+ "fns.el"
+ (format "fns-%s.el" emacs-version))
+ exec-directory)
+ ;; The file name fns-%s.el already has a .el extension.
+ nil nil t)
+ (setq symbol-file-load-history-loaded t))
+ (let ((files load-history)
+ file functions)
+ (while files
+ (if (memq function (cdr (car files)))
+ (setq file (car (car files)) files nil))
+ (setq files (cdr files)))
+ file))
(defun describe-function (function)
"Display the full documentation of FUNCTION (a symbol)."
(setq val (completing-read (if fn
(format "Describe function (default %s): " fn)
"Describe function: ")
- obarray 'fboundp t))
+ obarray 'fboundp t nil nil (symbol-name fn)))
(list (if (equal val "")
fn (intern val)))))
- (with-output-to-temp-buffer "*Help*"
- (prin1 function)
- (princ ": ")
- (let* ((def (symbol-function function))
- (beg (if (commandp def) "an interactive " "a ")))
- (princ (cond ((stringp def) "a keyboard macro.")
- ((subrp def)
- (concat beg "built-in function."))
- ((compiled-function-p def)
- (concat beg "compiled Lisp function."))
- ((symbolp def)
- (format "alias for `%s'." def))
- ((eq (car-safe def) 'lambda)
- (concat beg "Lisp function."))
- ((eq (car-safe def) 'macro)
- "a Lisp macro.")
- ((eq (car-safe def) 'mocklisp)
- "a mocklisp function.")
- ((eq (car-safe def) 'autoload)
- (format "%sLisp %s to autoload from `%s'."
- beg
- (if (nth 4 def) "macro" "function")
- (nth 1 def)))
- (t "")))
- (terpri))
- (if (documentation function)
- (princ (documentation function))
- (princ "not documented"))
- (print-help-return-message)
- ;; Return the text we displayed.
- (save-excursion (set-buffer standard-output) (buffer-string))))
+ (if function
+ (with-output-to-temp-buffer "*Help*"
+ (prin1 function)
+ ;; Use " is " instead of a colon so that
+ ;; it is easier to get out the function name using forward-sexp.
+ (princ " is ")
+ (describe-function-1 function nil (interactive-p))
+ (print-help-return-message)
+ (save-excursion
+ (set-buffer standard-output)
+ ;; Return the text we displayed.
+ (buffer-string)))
+ (message "You didn't specify a function")))
+
+(defun describe-function-1 (function parens interactive-p)
+ (let* ((def (if (symbolp function)
+ (symbol-function function)
+ function))
+ file-name string need-close
+ (beg (if (commandp def) "an interactive " "a ")))
+ (setq string
+ (cond ((or (stringp def)
+ (vectorp def))
+ "a keyboard macro")
+ ((subrp def)
+ (if (eq 'unevalled (cdr (subr-arity def)))
+ (concat beg "special form")
+ (concat beg "built-in function")))
+ ((byte-code-function-p def)
+ (concat beg "compiled Lisp function"))
+ ((symbolp def)
+ (while (symbolp (symbol-function def))
+ (setq def (symbol-function def)))
+ (format "an alias for `%s'" def))
+ ((eq (car-safe def) 'lambda)
+ (concat beg "Lisp function"))
+ ((eq (car-safe def) 'macro)
+ "a Lisp macro")
+ ((eq (car-safe def) 'mocklisp)
+ "a mocklisp function")
+ ((eq (car-safe def) 'autoload)
+ (setq file-name (nth 1 def))
+ (format "%s autoloaded %s"
+ (if (commandp def) "an interactive" "an")
+ (if (eq (nth 4 def) 'keymap) "keymap"
+ (if (nth 4 def) "Lisp macro" "Lisp function"))
+ ))
+ ;; perhaps use keymapp here instead
+ ((eq (car-safe def) 'keymap)
+ (let ((is-full nil)
+ (elts (cdr-safe def)))
+ (while elts
+ (if (char-table-p (car-safe elts))
+ (setq is-full t
+ elts nil))
+ (setq elts (cdr-safe elts)))
+ (if is-full
+ "a full keymap"
+ "a sparse keymap")))
+ (t "")))
+ (when (and parens (not (equal string "")))
+ (setq need-close t)
+ (princ "("))
+ (princ string)
+ (with-current-buffer "*Help*"
+ (save-excursion
+ (save-match-data
+ (if (re-search-backward "alias for `\\([^`']+\\)'" nil t)
+ (help-xref-button 1 #'describe-function def
+ "mouse-2, RET: describe this function")))))
+ (or file-name
+ (setq file-name (symbol-file function)))
+ (if file-name
+ (progn
+ (princ " in `")
+ ;; We used to add .el to the file name,
+ ;; but that's completely wrong when the user used load-file.
+ (princ file-name)
+ (princ "'")
+ ;; Make a hyperlink to the library.
+ (with-current-buffer "*Help*"
+ (save-excursion
+ (re-search-backward "`\\([^`']+\\)'" nil t)
+ (help-xref-button 1 #'(lambda (arg)
+ (let ((location
+ (find-function-noselect arg)))
+ (pop-to-buffer (car location))
+ (goto-char (cdr location))))
+ function
+ "mouse-2, RET: find function's definition")))))
+ (if need-close (princ ")"))
+ (princ ".")
+ (terpri)
+ ;; Handle symbols aliased to other symbols.
+ (setq def (indirect-function def))
+ ;; If definition is a macro, find the function inside it.
+ (if (eq (car-safe def) 'macro)
+ (setq def (cdr def)))
+ (let ((arglist (cond ((byte-code-function-p def)
+ (car (append def nil)))
+ ((eq (car-safe def) 'lambda)
+ (nth 1 def))
+ ((and (eq (car-safe def) 'autoload)
+ (not (eq (nth 4 def) 'keymap)))
+ (concat "[Arg list not available until "
+ "function definition is loaded.]"))
+ (t t))))
+ (cond ((listp arglist)
+ (princ (cons (if (symbolp function) function "anonymous")
+ (mapcar (lambda (arg)
+ (if (memq arg '(&optional &rest))
+ arg
+ (intern (upcase (symbol-name arg)))))
+ arglist)))
+ (terpri))
+ ((stringp arglist)
+ (princ arglist)
+ (terpri))))
+ (let ((doc (documentation function)))
+ (if doc
+ (progn (terpri)
+ (princ doc)
+ (if (subrp (symbol-function function))
+ (with-current-buffer standard-output
+ (beginning-of-line)
+ ;; Builtins get the calling sequence at the end of
+ ;; the doc string. Move it to the same place as
+ ;; for other functions.
+
+ ;; In cases where `function' has been fset to a
+ ;; subr we can't search for function's name in
+ ;; the doc string. Kluge round that using the
+ ;; printed representation. The arg list then
+ ;; shows the wrong function name, but that
+ ;; might be a useful hint.
+ (let* ((rep (prin1-to-string def))
+ (name (progn
+ (string-match " \\([^ ]+\\)>$" rep)
+ (match-string 1 rep))))
+ (if (looking-at (format "(%s[ )]" name))
+ (let ((start (point-marker)))
+ (goto-char (point-min))
+ (forward-paragraph)
+ (insert-buffer-substring (current-buffer) start)
+ (insert ?\n)
+ (delete-region (1- start) (point-max)))
+ (goto-char (point-min))
+ (forward-paragraph)
+ (insert
+ "[Missing arglist. Please make a bug report.]\n")))
+ (goto-char (point-max))))
+ (help-setup-xref (list #'describe-function function)
+ interactive-p))
+ (princ "not documented")))))
(defun variable-at-point ()
+ "Return the bound variable symbol found around point.
+Return 0 if there is no such symbol."
(condition-case ()
- (save-excursion
- (forward-sexp -1)
- (skip-chars-forward "'")
- (let ((obj (read (current-buffer))))
- (and (symbolp obj) (boundp obj) obj)))
- (error nil)))
+ (let ((stab (syntax-table)))
+ (unwind-protect
+ (save-excursion
+ (set-syntax-table emacs-lisp-mode-syntax-table)
+ (or (not (zerop (skip-syntax-backward "_w")))
+ (eq (char-syntax (following-char)) ?w)
+ (eq (char-syntax (following-char)) ?_)
+ (forward-sexp -1))
+ (skip-chars-forward "'")
+ (let ((obj (read (current-buffer))))
+ (or (and (symbolp obj) (boundp obj) obj)
+ 0)))
+ (set-syntax-table stab)))
+ (error 0)))
+
+(defun help-xref-on-pp (from to)
+ "Add xrefs for symbols in `pp's output between FROM and TO."
+ (let ((ost (syntax-table)))
+ (unwind-protect
+ (save-excursion
+ (save-restriction
+ (set-syntax-table emacs-lisp-mode-syntax-table)
+ (narrow-to-region from to)
+ (goto-char (point-min))
+ (while (not (eobp))
+ (cond
+ ((looking-at "\"") (forward-sexp 1))
+ ((looking-at "#<") (search-forward ">" nil 'move))
+ ((looking-at "\\(\\(\\sw\\|\\s_\\)+\\)")
+ (let* ((sym (intern-soft
+ (buffer-substring (match-beginning 1)
+ (match-end 1))))
+ (fn (cond ((fboundp sym) #'describe-function)
+ ((or (memq sym '(t nil))
+ (keywordp sym))
+ nil)
+ ((and sym (boundp sym))
+ #'describe-variable))))
+ (when fn (help-xref-button 1 fn sym)))
+ (goto-char (match-end 1)))
+ (t (forward-char 1))))))
+ (set-syntax-table ost))))
(defun describe-variable (variable)
"Display the full documentation of VARIABLE (a symbol).
(let ((v (variable-at-point))
(enable-recursive-minibuffers t)
val)
- (setq val (completing-read (if v
- (format "Describe variable (default %s): " v)
+ (setq val (completing-read (if (symbolp v)
+ (format
+ "Describe variable (default %s): " v)
"Describe variable: ")
- obarray 'boundp t))
+ obarray 'boundp t nil nil
+ (if (symbolp v) (symbol-name v))))
(list (if (equal val "")
v (intern val)))))
- (with-output-to-temp-buffer "*Help*"
- (prin1 variable)
- (princ "'s value is ")
- (if (not (boundp variable))
- (princ "void.")
- (prin1 (symbol-value variable)))
- (terpri) (terpri)
- (princ "Documentation:")
- (terpri)
- (let ((doc (documentation-property variable 'variable-documentation)))
- (if doc
- (princ (substitute-command-keys doc))
- (princ "not documented as a variable.")))
- (print-help-return-message)
- ;; Return the text we displayed.
- (save-excursion (set-buffer standard-output) (buffer-string))))
-
-(defun command-apropos (string)
- "Like apropos but lists only symbols that are names of commands
-\(interactively callable functions). Argument REGEXP is a regular expression
-that is matched against command symbol names. Returns list of symbols and
-documentation found."
- (interactive "sCommand apropos (regexp): ")
- (let ((message
- (let ((standard-output (get-buffer-create "*Help*")))
- (print-help-return-message 'identity))))
- (apropos string 'commandp)
- (and message (message message))))
-
-(defun locate-library (library &optional nosuffix)
- "Show the full path name of Emacs library LIBRARY.
+ (if (symbolp variable)
+ (let (valvoid)
+ (with-output-to-temp-buffer "*Help*"
+ (prin1 variable)
+ (if (not (boundp variable))
+ (progn
+ (princ " is void")
+ (setq valvoid t))
+ (let ((val (symbol-value variable)))
+ (with-current-buffer standard-output
+ (princ "'s value is ")
+ (terpri)
+ (let ((from (point)))
+ (pp val)
+ (help-xref-on-pp from (point))))))
+ (terpri)
+ (if (local-variable-p variable)
+ (progn
+ (princ (format "Local in buffer %s; " (buffer-name)))
+ (if (not (default-boundp variable))
+ (princ "globally void")
+ (let ((val (default-value variable)))
+ (with-current-buffer standard-output
+ (princ "global value is ")
+ (terpri)
+ (let ((from (point)))
+ (pp val)
+ (help-xref-on-pp from (point))))))
+ (terpri)))
+ (terpri)
+ (save-current-buffer
+ (set-buffer standard-output)
+ (if (> (count-lines (point-min) (point-max)) 10)
+ (progn
+ ;; Note that setting the syntax table like below
+ ;; makes forward-sexp move over a `'s' at the end
+ ;; of a symbol.
+ (set-syntax-table emacs-lisp-mode-syntax-table)
+ (goto-char (point-min))
+ (if valvoid
+ (forward-line 1)
+ (forward-sexp 1)
+ (delete-region (point) (progn (end-of-line) (point)))
+ (insert " value is shown below.\n\n")
+ (save-excursion
+ (insert "\n\nValue:"))))))
+ (princ "Documentation:")
+ (terpri)
+ (let ((doc (documentation-property variable 'variable-documentation)))
+ (princ (or doc "not documented as a variable.")))
+ (help-setup-xref (list #'describe-variable variable) (interactive-p))
+
+ ;; Make a link to customize if this variable can be customized.
+ ;; Note, it is not reliable to test only for a custom-type property
+ ;; because those are only present after the var's definition
+ ;; has been loaded.
+ (if (or (get variable 'custom-type) ; after defcustom
+ (get variable 'custom-loads) ; from loaddefs.el
+ (get variable 'standard-value)) ; from cus-start.el
+ (let ((customize-label "customize"))
+ (terpri)
+ (terpri)
+ (princ (concat "You can " customize-label " this variable."))
+ (with-current-buffer "*Help*"
+ (save-excursion
+ (re-search-backward
+ (concat "\\(" customize-label "\\)") nil t)
+ (help-xref-button 1 (lambda (v)
+ (if help-xref-stack
+ (pop help-xref-stack))
+ (customize-variable v))
+ variable
+ "mouse-2, RET: customize variable")))))
+ ;; Make a hyperlink to the library if appropriate. (Don't
+ ;; change the format of the buffer's initial line in case
+ ;; anything expects the current format.)
+ (let ((file-name (symbol-file variable)))
+ (when file-name
+ (princ "\n\nDefined in `")
+ (princ file-name)
+ (princ "'.")
+ (with-current-buffer "*Help*"
+ (save-excursion
+ (re-search-backward "`\\([^`']+\\)'" nil t)
+ (help-xref-button
+ 1 (lambda (arg)
+ (let ((location
+ (find-variable-noselect arg)))
+ (pop-to-buffer (car location))
+ (goto-char (cdr location))))
+ variable "mouse-2, RET: find variable's definition")))))
+
+ (print-help-return-message)
+ (save-excursion
+ (set-buffer standard-output)
+ ;; Return the text we displayed.
+ (buffer-string))))
+ (message "You did not specify a variable")))
+
+(defun describe-bindings (&optional prefix buffer)
+ "Show a list of all defined keys, and their definitions.
+We put that list in a buffer, and display the buffer.
+
+The optional argument PREFIX, if non-nil, should be a key sequence;
+then we display only bindings that start with that prefix.
+The optional argument BUFFER specifies which buffer's bindings
+to display (default, the current buffer)."
+ (interactive "P")
+ (or buffer (setq buffer (current-buffer)))
+ (with-current-buffer buffer
+ (describe-bindings-internal nil prefix))
+ (with-current-buffer "*Help*"
+ (help-setup-xref (list #'describe-bindings prefix buffer)
+ (interactive-p))))
+
+(defun where-is (definition &optional insert)
+ "Print message listing key sequences that invoke the command DEFINITION.
+Argument is a command definition, usually a symbol with a function definition.
+If INSERT (the prefix arg) is non-nil, insert the message in the buffer."
+ (interactive
+ (let ((fn (function-called-at-point))
+ (enable-recursive-minibuffers t)
+ val)
+ (setq val (completing-read (if fn
+ (format "Where is command (default %s): " fn)
+ "Where is command: ")
+ obarray 'commandp t))
+ (list (if (equal val "")
+ fn (intern val))
+ current-prefix-arg)))
+ (let* ((keys (where-is-internal definition overriding-local-map nil nil))
+ (keys1 (mapconcat 'key-description keys ", "))
+ (standard-output (if insert (current-buffer) t)))
+ (if insert
+ (if (> (length keys1) 0)
+ (princ (format "%s (%s)" keys1 definition))
+ (princ (format "M-x %s RET" definition)))
+ (if (> (length keys1) 0)
+ (princ (format "%s is on %s" definition keys1))
+ (princ (format "%s is not on any key" definition)))))
+ nil)
+
+(defun locate-library (library &optional nosuffix path interactive-call)
+ "Show the precise file name of Emacs library LIBRARY.
This command searches the directories in `load-path' like `M-x load-library'
to find the file that `M-x load-library RET LIBRARY RET' would load.
Optional second arg NOSUFFIX non-nil means don't add suffixes `.elc' or `.el'
-to the specified name LIBRARY (a la calling `load' instead of `load-library')."
- (interactive "sLocate library: ")
- (catch 'answer
- (mapcar
- '(lambda (dir)
- (mapcar
- '(lambda (suf)
+to the specified name LIBRARY.
+
+If the optional third arg PATH is specified, that list of directories
+is used instead of `load-path'.
+
+When called from a program, the file name is normaly returned as a
+string. When run interactively, the argument INTERACTIVE-CALL is t,
+and the file name is displayed in the echo area."
+ (interactive (list (read-string "Locate library: ")
+ nil nil
+ t))
+ (let (result)
+ (catch 'answer
+ (mapc
+ (lambda (dir)
+ (mapc
+ (lambda (suf)
(let ((try (expand-file-name (concat library suf) dir)))
(and (file-readable-p try)
(null (file-directory-p try))
(progn
- (message "Library is file %s" try)
+ (setq result try)
(throw 'answer try)))))
- (if nosuffix '("") '(".elc" ".el" ""))))
- load-path)
- (message "No library %s in search path" library)
- nil))
+ (if nosuffix
+ '("")
+ '(".elc" ".el" "")
+;;; load doesn't handle this yet.
+;;; (let ((basic '(".elc" ".el" ""))
+;;; (compressed '(".Z" ".gz" "")))
+;;; ;; If autocompression mode is on,
+;;; ;; consider all combinations of library suffixes
+;;; ;; and compression suffixes.
+;;; (if (rassq 'jka-compr-handler file-name-handler-alist)
+;;; (apply 'nconc
+;;; (mapcar (lambda (compelt)
+;;; (mapcar (lambda (baselt)
+;;; (concat baselt compelt))
+;;; basic))
+;;; compressed))
+;;; basic))
+ )))
+ (or path load-path)))
+ (and interactive-call
+ (if result
+ (message "Library is file %s" result)
+ (message "No library %s in search path" library)))
+ result))
+
+\f
+;;; Grokking cross-reference information in doc strings and
+;;; hyperlinking it.
+
+;; This may have some scope for extension and the same or something
+;; similar should be done for widget doc strings, which currently use
+;; another mechanism.
+
+(defcustom help-highlight-p t
+ "*If non-nil, `help-make-xrefs' highlight cross-references.
+Under a window system it highlights them with face defined by
+`help-highlight-face'."
+ :group 'help
+ :version "20.3"
+ :type 'boolean)
+
+(defcustom help-highlight-face 'underline
+ "Face used by `help-make-xrefs' to highlight cross-references.
+Must be previously-defined."
+ :group 'help
+ :version "20.3"
+ :type 'face)
+
+(defvar help-back-label (purecopy "[back]")
+ "Label to use by `help-make-xrefs' for the go-back reference.")
+
+(defconst help-xref-symbol-regexp
+ (purecopy (concat "\\(\\<\\(\\(variable\\|option\\)\\|"
+ "\\(function\\|command\\)\\|"
+ "\\(face\\)\\|"
+ "\\(symbol\\)\\)\\s-+\\)?"
+ ;; Note starting with word-syntax character:
+ "`\\(\\sw\\(\\sw\\|\\s_\\)+\\)'"))
+ "Regexp matching doc string references to symbols.
+
+The words preceding the quoted symbol can be used in doc strings to
+distinguish references to variables, functions and symbols.")
+
+(defconst help-xref-info-regexp
+ (purecopy "\\<[Ii]nfo[ \t\n]+node[ \t\n]+`\\([^']+\\)'")
+ "Regexp matching doc string references to an Info node.")
+
+(defun help-setup-xref (item interactive-p)
+ "Invoked from commands using the \"*Help*\" buffer to install some xref info.
+
+ITEM is a (FUNCTION . ARGS) pair appropriate for recreating the help
+buffer after following a reference. INTERACTIVE-P is non-nil if the
+calling command was invoked interactively. In this case the stack of
+items for help buffer \"back\" buttons is cleared."
+ (if interactive-p
+ (setq help-xref-stack nil))
+ (setq help-xref-stack-item item))
+
+(defvar help-xref-following nil
+ "Non-nil when following a help cross-reference.")
+
+(defun help-make-xrefs (&optional buffer)
+ "Parse and hyperlink documentation cross-references in the given BUFFER.
+
+Find cross-reference information in a buffer and, if
+`help-highlight-p' is non-nil, highlight it with face defined by
+`help-highlight-face'; activate such cross references for selection
+with `help-follow'. Cross-references have the canonical form `...'
+and the type of reference may be disambiguated by the preceding
+word(s) used in `help-xref-symbol-regexp'.
+
+A special reference `back' is made to return back through a stack of
+help buffers. Variable `help-back-label' specifies the text for
+that."
+ (interactive "b")
+ (save-excursion
+ (set-buffer (or buffer (current-buffer)))
+ (goto-char (point-min))
+ ;; Skip the header-type info, though it might be useful to parse
+ ;; it at some stage (e.g. "function in `library'").
+ (forward-paragraph)
+ (let ((old-modified (buffer-modified-p)))
+ (let ((stab (syntax-table))
+ (case-fold-search t)
+ (inhibit-read-only t))
+ (set-syntax-table emacs-lisp-mode-syntax-table)
+ ;; The following should probably be abstracted out.
+ (unwind-protect
+ (progn
+ ;; Info references
+ (save-excursion
+ (while (re-search-forward help-xref-info-regexp nil t)
+ (let ((data (match-string 1)))
+ (save-match-data
+ (unless (string-match "^([^)]+)" data)
+ (setq data (concat "(emacs)" data))))
+ (help-xref-button 1 #'info data
+ "mouse-2, RET: read this Info node"))))
+ ;; Quoted symbols
+ (save-excursion
+ (while (re-search-forward help-xref-symbol-regexp nil t)
+ (let* ((data (match-string 7))
+ (sym (intern-soft data)))
+ (if sym
+ (cond
+ ((match-string 3) ; `variable' &c
+ (and (boundp sym) ; `variable' doesn't ensure
+ ; it's actually bound
+ (help-xref-button
+ 7 #'describe-variable sym
+ "mouse-2, RET: describe this variable")))
+ ((match-string 4) ; `function' &c
+ (and (fboundp sym) ; similarly
+ (help-xref-button
+ 7 #'describe-function sym
+ "mouse-2, RET: describe this function")))
+ ((match-string 5) ; `face'
+ (and (facep sym)
+ (help-xref-button 7 #'describe-face sym
+ "mouse-2, RET: describe this face")))
+ ((match-string 6)) ; nothing for symbol
+ ((and (boundp sym) (fboundp sym))
+ ;; We can't intuit whether to use the
+ ;; variable or function doc -- supply both.
+ (help-xref-button
+ 7 #'help-xref-interned sym
+ "mouse-2, RET: describe this symbol"))
+ ((boundp sym)
+ (help-xref-button
+ 7 #'describe-variable sym
+ "mouse-2, RET: describe this variable"))
+ ((fboundp sym)
+ (help-xref-button
+ 7 #'describe-function sym
+ "mouse-2, RET: describe this function"))
+ ((facep sym)
+ (help-xref-button
+ 7 #'describe-face sym)))))))
+ ;; An obvious case of a key substitution:
+ (save-excursion
+ (while (re-search-forward
+ ;; Assume command name is only word characters
+ ;; and dashes to get things like `use M-x foo.'.
+ "\\<M-x\\s-+\\(\\sw\\(\\sw\\|-\\)+\\)" nil t)
+ (let ((sym (intern-soft (match-string 1))))
+ (if (fboundp sym)
+ (help-xref-button
+ 1 #'describe-function sym
+ "mouse-2, RET: describe this command")))))
+ ;; Look for commands in whole keymap substitutions:
+ (save-excursion
+ ;; Make sure to find the first keymap.
+ (goto-char (point-min))
+ ;; Find a header and the column at which the command
+ ;; name will be found.
+ (while (re-search-forward "^key +binding\n\\(-+ +\\)-+\n\n"
+ nil t)
+ (let ((col (- (match-end 1) (match-beginning 1))))
+ (while
+ ;; Ignore single blank lines in table, but not
+ ;; double ones, which should terminate it.
+ (and (not (looking-at "\n\\s-*\n"))
+ (progn
+ (and (eolp) (forward-line))
+ (end-of-line)
+ (skip-chars-backward "^\t\n")
+ (if (and (>= (current-column) col)
+ (looking-at "\\(\\sw\\|-\\)+$"))
+ (let ((sym (intern-soft (match-string 0))))
+ (if (fboundp sym)
+ (help-xref-button
+ 0 #'describe-function sym
+ "mouse-2, RET: describe this function"))))
+ (zerop (forward-line)))))))))
+ (set-syntax-table stab))
+ ;; Make a back-reference in this buffer if appropriate.
+ (when (and help-xref-following help-xref-stack)
+ (goto-char (point-max))
+ (save-excursion
+ (insert "\n\n" help-back-label))
+ ;; Just to provide the match data:
+ (looking-at (concat "\n\n\\(" (regexp-quote help-back-label) "\\)"))
+ (help-xref-button 1 #'help-xref-go-back (current-buffer))))
+ ;; View mode steals RET from us.
+ (set (make-local-variable 'minor-mode-overriding-map-alist)
+ (list (cons 'view-mode
+ (let ((map (make-sparse-keymap)))
+ (set-keymap-parent map view-mode-map)
+ (define-key map "\r" 'help-follow)
+ map))))
+ (set-buffer-modified-p old-modified))))
+
+(defun help-xref-button (match-number function data &optional help-echo)
+ "Make a hyperlink for cross-reference text previously matched.
+
+MATCH-NUMBER is the subexpression of interest in the last matched
+regexp. FUNCTION is a function to invoke when the button is
+activated, applied to DATA. DATA may be a single value or a list.
+See `help-make-xrefs'.
+If optional arg HELP-ECHO is supplied, it is used as a help string."
+ ;; Don't mung properties we've added specially in some instances.
+ (unless (get-text-property (match-beginning match-number) 'help-xref)
+ (add-text-properties (match-beginning match-number)
+ (match-end match-number)
+ (list 'mouse-face 'highlight
+ 'help-xref (cons function
+ (if (listp data)
+ data
+ (list data)))))
+ (if help-echo
+ (put-text-property (match-beginning match-number)
+ (match-end match-number)
+ 'help-echo help-echo))
+ (if help-highlight-p
+ (put-text-property (match-beginning match-number)
+ (match-end match-number)
+ 'face help-highlight-face))))
+
+\f
+;; Additional functions for (re-)creating types of help buffers.
+(defun help-xref-interned (symbol)
+ "Follow a hyperlink which appeared to be an arbitrary interned SYMBOL.
+
+Both variable and function documentation are extracted into a single
+help buffer."
+ (let ((fdoc (when (fboundp symbol) (describe-function symbol)))
+ (facedoc (when (facep symbol) (describe-face symbol))))
+ (when (or (boundp symbol) (not fdoc))
+ (describe-variable symbol)
+ ;; We now have a help buffer on the variable. Insert the function
+ ;; text before it.
+ (when (or fdoc facedoc)
+ (with-current-buffer "*Help*"
+ (goto-char (point-min))
+ (let ((inhibit-read-only t))
+ (when fdoc
+ (insert fdoc "\n\n"))
+ (when facedoc
+ (insert (make-string 30 ?-) "\n\n" (symbol-name symbol)
+ " is also a " "face." "\n\n" facedoc "\n\n"))
+ (insert (make-string 30 ?-) "\n\n" (symbol-name symbol)
+ " is also a " "variable." "\n\n"))
+ (help-setup-xref (list #'help-xref-interned symbol) nil))))))
+
+(defun help-xref-mode (buffer)
+ "Do a `describe-mode' for the specified BUFFER."
+ (save-excursion
+ (set-buffer buffer)
+ (describe-mode)))
+\f
+;;; Navigation/hyperlinking with xrefs
+
+(defun help-follow-mouse (click)
+ "Follow the cross-reference that you click on."
+ (interactive "e")
+ (let* ((start (event-start click))
+ (window (car start))
+ (pos (car (cdr start))))
+ (with-current-buffer (window-buffer window)
+ (help-follow pos))))
+
+(defun help-xref-go-back (buffer)
+ "From BUFFER, go back to previous help buffer text using `help-xref-stack'."
+ (let (item position method args)
+ (with-current-buffer buffer
+ (when help-xref-stack
+ (setq help-xref-stack (cdr help-xref-stack)) ; due to help-follow
+ (setq item (pop help-xref-stack)
+ position (car item)
+ method (cadr item)
+ args (cddr item))))
+ (apply method args)
+ ;; We assume that the buffer we just recreated has the saved name,
+ ;; which might not always be true.
+ (when (get-buffer (cdr position))
+ (with-current-buffer (cdr position)
+ (goto-char (car position))))))
+
+(defun help-go-back ()
+ "Invoke the [back] button (if any) in the Help mode buffer."
+ (interactive)
+ (help-follow (1- (point-max))))
+
+(defun help-follow (&optional pos)
+ "Follow cross-reference at POS, defaulting to point.
+
+For the cross-reference format, see `help-make-xrefs'."
+ (interactive "d")
+ (unless pos
+ (setq pos (point)))
+ (let* ((help-data
+ (or (and (not (= pos (point-max)))
+ (get-text-property pos 'help-xref))
+ (and (not (= pos (point-min)))
+ (get-text-property (1- pos) 'help-xref))
+ ;; check if the symbol under point is a function or variable
+ (let ((sym
+ (intern
+ (save-excursion
+ (goto-char pos) (skip-syntax-backward "w_")
+ (buffer-substring (point)
+ (progn (skip-syntax-forward "w_")
+ (point)))))))
+ (when (or (boundp sym) (fboundp sym))
+ (list #'help-xref-interned sym)))))
+ (method (car help-data))
+ (args (cdr help-data)))
+ (when help-data
+ (setq help-xref-stack (cons (cons (cons pos (buffer-name))
+ help-xref-stack-item)
+ help-xref-stack))
+ (setq help-xref-stack-item nil)
+ ;; There is a reference at point. Follow it.
+ (let ((help-xref-following t))
+ (apply method args)))))
+
+;; For tabbing through buffer.
+(defun help-next-ref ()
+ "Find the next help cross-reference in the buffer."
+ (interactive)
+ (let (pos)
+ (while (not pos)
+ (if (get-text-property (point) 'help-xref) ; move off reference
+ (goto-char (or (next-single-property-change (point) 'help-xref)
+ (point))))
+ (cond ((setq pos (next-single-property-change (point) 'help-xref))
+ (if pos (goto-char pos)))
+ ((bobp)
+ (message "No cross references in the buffer.")
+ (setq pos t))
+ (t ; be circular
+ (goto-char (point-min)))))))
+
+(defun help-previous-ref ()
+ "Find the previous help cross-reference in the buffer."
+ (interactive)
+ (let (pos)
+ (while (not pos)
+ (if (get-text-property (point) 'help-xref) ; move off reference
+ (goto-char (or (previous-single-property-change (point) 'help-xref)
+ (point))))
+ (cond ((setq pos (previous-single-property-change (point) 'help-xref))
+ (if pos (goto-char pos)))
+ ((bobp)
+ (message "No cross references in the buffer.")
+ (setq pos t))
+ (t ; be circular
+ (goto-char (point-max)))))))
+
+\f
+;;; Automatic resizing of temporary buffers.
+
+(defcustom temp-buffer-resize-mode nil
+ "Non-nil means resize windows displaying temporary buffers.
+This makes the window the right height for its contents, but never
+more than `temp-buffer-max-height' nor less than `window-min-height'.
+This applies to `help', `apropos' and `completion' buffers, and some others.
+
+Setting this variable directly does not take effect;
+use either \\[customize] or the function `temp-buffer-resize-mode'."
+ :get (lambda (symbol)
+ (and (memq 'resize-temp-buffer-window temp-buffer-show-hook) t))
+ :set (lambda (symbol value)
+ (temp-buffer-resize-mode (if value 1 -1)))
+ :initialize 'custom-initialize-default
+ :type 'boolean
+ :group 'help
+ :version "20.4")
+
+(defcustom temp-buffer-max-height (lambda (buffer) (/ (- (frame-height) 2) 2))
+ "*Maximum height of a window displaying a temporary buffer.
+This is the maximum height (in text lines) which `resize-temp-buffer-window'
+will give to a window displaying a temporary buffer.
+It can also be a function which will be called with the object corresponding
+to the buffer to be displayed as argument and should return an integer
+positive number."
+ :type '(choice integer function)
+ :group 'help
+ :version "20.4")
+
+(defun temp-buffer-resize-mode (arg)
+ "Toggle the mode which that makes windows smaller for temporary buffers.
+With prefix argument ARG, turn the resizing of windows displaying temporary
+buffers on if ARG is positive or off otherwise.
+See the documentation of the variable `temp-buffer-resize-mode' for
+more information."
+ (interactive "P")
+ (let ((turn-it-on
+ (if (null arg)
+ (not (memq 'resize-temp-buffer-window temp-buffer-show-hook))
+ (> (prefix-numeric-value arg) 0))))
+ (if turn-it-on
+ (progn
+ ;; `help-mode-maybe' may add a `back' button and thus increase the
+ ;; text size, so `resize-temp-buffer-window' must be run *after* it.
+ (add-hook 'temp-buffer-show-hook 'resize-temp-buffer-window 'append)
+ (setq temp-buffer-resize-mode t))
+ (remove-hook 'temp-buffer-show-hook 'resize-temp-buffer-window)
+ (setq temp-buffer-resize-mode nil))))
+
+(defun resize-temp-buffer-window ()
+ "Resize the current window to fit its contents.
+Will not make it higher than `temp-buffer-max-height' nor smaller than
+`window-min-height'. Do nothing if it is the only window on its frame, if it
+is not as wide as the frame or if some of the window's contents are scrolled
+out of view."
+ (unless (or (one-window-p 'nomini)
+ (not (pos-visible-in-window-p (point-min)))
+ (/= (frame-width) (window-width)))
+ (let* ((max-height (if (functionp temp-buffer-max-height)
+ (funcall temp-buffer-max-height (current-buffer))
+ temp-buffer-max-height))
+ (win-height (1- (window-height)))
+ (min-height (1- window-min-height))
+ (text-height (count-screen-lines))
+ (new-height (max (min text-height max-height) min-height)))
+ (enlarge-window (- new-height win-height)))))
+
+;; `help-manyarg-func-alist' is defined primitively (in doc.c).
+;; New primitives with `MANY' or `UNEVALLED' arglists should be added
+;; to this alist.
+;; The parens and function name are redundant, but it's messy to add
+;; them in `documentation'.
+(defconst help-manyarg-func-alist
+ (purecopy
+ '((list . "(list &rest OBJECTS)")
+ (vector . "(vector &rest OBJECTS)")
+ (make-byte-code . "(make-byte-code &rest ELEMENTS)")
+ (call-process
+ . "(call-process PROGRAM &optional INFILE BUFFER DISPLAY &rest ARGS)")
+ (call-process-region
+ . "(call-process-region START END PROGRAM &optional DELETE BUFFER DISPLAY &rest ARGS)")
+ (string . "(string &rest CHARACTERS)")
+ (+ . "(+ &rest NUMBERS-OR-MARKERS)")
+ (- . "(- &optional NUMBER-OR-MARKER &rest MORE-NUMBERS-OR-MARKERS)")
+ (* . "(* &rest NUMBERS-OR-MARKERS)")
+ (/ . "(/ DIVIDEND DIVISOR &rest DIVISORS)")
+ (max . "(max NUMBER-OR-MARKER &rest NUMBERS-OR-MARKERS)")
+ (min . "(min NUMBER-OR-MARKER &rest NUMBERS-OR-MARKERS)")
+ (logand . "(logand &rest INTS-OR-MARKERS)")
+ (logior . "(logior &rest INTS-OR-MARKERS)")
+ (logxor . "(logxor &rest INTS-OR-MARKERS)")
+ (encode-time
+ . "(encode-time SECOND MINUTE HOUR DAY MONTH YEAR &optional ZONE)")
+ (insert . "(insert &rest ARGS)")
+ (insert-before-markers . "(insert-before-markers &rest ARGS)")
+ (message . "(message STRING &rest ARGUMENTS)")
+ (message-box . "(message-box STRING &rest ARGUMENTS)")
+ (message-or-box . "(message-or-box STRING &rest ARGUMENTS)")
+ (propertize . "(propertize STRING &rest PROPERTIES)")
+ (format . "(format STRING &rest OBJECTS)")
+ (apply . "(apply FUNCTION &rest ARGUMENTS)")
+ (run-hooks . "(run-hooks &rest HOOKS)")
+ (run-hook-with-args . "(run-hook-with-args HOOK &rest ARGS)")
+ (run-hook-with-args-until-failure
+ . "(run-hook-with-args-until-failure HOOK &rest ARGS)")
+ (run-hook-with-args-until-success
+ . "(run-hook-with-args-until-success HOOK &rest ARGS)")
+ (funcall . "(funcall FUNCTION &rest ARGUMENTS)")
+ (append . "(append &rest SEQUENCES)")
+ (concat . "(concat &rest SEQUENCES)")
+ (vconcat . "(vconcat vconcat)")
+ (nconc . "(nconc &rest LISTS)")
+ (widget-apply . "(widget-apply WIDGET PROPERTY &rest ARGS)")
+ (make-hash-table . "(make-hash-table &rest KEYWORD-ARGS)")
+ (insert-string . "(insert-string &rest ARGS)")
+ (start-process . "(start-process NAME BUFFER PROGRAM &rest PROGRAM-ARGS)")
+ (setq-default . "(setq-default SYMBOL VALUE [SYMBOL VALUE...])")
+ (save-excursion . "(save-excursion &rest BODY)")
+ (save-current-buffer . "(save-current-buffer &rest BODY)")
+ (save-restriction . "(save-restriction &rest BODY)")
+ (or . "(or CONDITIONS ...)")
+ (and . "(and CONDITIONS ...)")
+ (if . "(if COND THEN ELSE...)")
+ (cond . "(cond CLAUSES...)")
+ (progn . "(progn BODY ...)")
+ (prog1 . "(prog1 FIRST BODY...)")
+ (prog2 . "(prog2 X Y BODY...)")
+ (setq . "(setq SYM VAL SYM VAL ...)")
+ (quote . "(quote ARG)")
+ (function . "(function ARG)")
+ (defun . "(defun NAME ARGLIST [DOCSTRING] BODY...)")
+ (defmacro . "(defmacro NAME ARGLIST [DOCSTRING] BODY...)")
+ (defvar . "(defvar SYMBOL [INITVALUE DOCSTRING])")
+ (defconst . "(defconst SYMBOL INITVALUE [DOCSTRING])")
+ (let* . "(let* VARLIST BODY...)")
+ (let . "(let VARLIST BODY...)")
+ (while . "(while TEST BODY...)")
+ (catch . "(catch TAG BODY...)")
+ (unwind-protect . "(unwind-protect BODYFORM UNWINDFORMS...)")
+ (condition-case . "(condition-case VAR BODYFORM HANDLERS...)")
+ (track-mouse . "(track-mouse BODY ...)")
+ (ml-if . "(ml-if COND THEN ELSE...)")
+ (ml-provide-prefix-argument . "(ml-provide-prefix-argument ARG1 ARG2)")
+ (with-output-to-temp-buffer
+ . "(with-output-to-temp-buffer BUFFNAME BODY ...)")
+ (save-window-excursion . "(save-window-excursion BODY ...)"))))
+
+;;; help.el ends here