;;; help.el --- help commands for Emacs
;; Copyright (C) 1985, 1986, 1993, 1994, 1998, 1999, 2000, 2001, 2002,
-;; 2003, 2004, 2005, 2006, 2007 Free Software Foundation, Inc.
+;; 2003, 2004, 2005, 2006, 2007, 2008, 2009 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
+;; 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 2, or (at your option)
-;; any later version.
+;; the Free Software Foundation, either version 3 of the License, or
+;; (at your option) any later version.
;; GNU Emacs is distributed in the hope that it will be useful,
;; but WITHOUT ANY WARRANTY; without even the implied warranty of
;; 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, Inc., 51 Franklin Street, Fifth Floor,
-;; Boston, MA 02110-1301, USA.
+;; along with GNU Emacs. If not, see <http://www.gnu.org/licenses/>.
;;; Commentary:
(add-hook 'temp-buffer-setup-hook 'help-mode-setup)
(add-hook 'temp-buffer-show-hook 'help-mode-finish)
+;; The variable `help-window' below is used by `help-mode-finish' to
+;; communicate the window displaying help (the "help window") to the
+;; macro `with-help-window'. The latter sets `help-window' to t before
+;; invoking `with-output-to-temp-buffer'. If and only if `help-window'
+;; is eq to t, `help-mode-finish' (called by `temp-buffer-setup-hook')
+;; sets `help-window' to the window selected by `display-buffer'.
+;; Exiting `with-help-window' and calling `help-print-return-message'
+;; reset `help-window' to nil.
+(defvar help-window nil
+ "Window chosen for displaying help.")
+
+;; `help-window-point-marker' is a marker you can move to a valid
+;; position of the buffer shown in the help window in order to override
+;; the standard positioning mechanism (`point-min') chosen by
+;; `with-output-to-temp-buffer'. `with-help-window' has this point
+;; nowhere before exiting. Currently used by `view-lossage' to assert
+;; that the last keystrokes are always visible.
+(defvar help-window-point-marker (make-marker)
+ "Marker to override default `window-point' of `help-window'.")
+
(defvar help-map
(let ((map (make-sparse-keymap)))
(define-key map (char-to-string help-char) 'help-for-help)
(define-key map "." 'display-local-help)
(define-key map "?" 'help-for-help)
+ (define-key map "\C-a" 'about-emacs)
(define-key map "\C-c" 'describe-copying)
- (define-key map "\C-d" 'describe-distribution)
- (define-key map "\C-e" 'view-emacs-problems)
+ (define-key map "\C-d" 'view-emacs-debugging)
+ (define-key map "\C-e" 'view-external-packages)
(define-key map "\C-f" 'view-emacs-FAQ)
(define-key map "\C-m" 'view-order-manuals)
(define-key map "\C-n" 'view-emacs-news)
- (define-key map "\C-p" 'describe-project)
- (define-key map "\C-t" 'view-todo)
+ (define-key map "\C-o" 'describe-distribution)
+ (define-key map "\C-p" 'view-emacs-problems)
+ (define-key map "\C-t" 'view-emacs-todo)
(define-key map "\C-w" 'describe-no-warranty)
;; This does not fit the pattern, but it is natural given the C-\ command.
(define-key map "d" 'apropos-documentation)
(define-key map "e" 'view-echo-area-messages)
(define-key map "f" 'describe-function)
+ (define-key map "g" 'describe-gnu-project)
(define-key map "h" 'view-hello-file)
(define-key map "i" 'info)
(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)
+(define-obsolete-function-alias 'print-help-return-message 'help-print-return-message "23.2")
+(defun help-print-return-message (&optional function)
"Display or return message saying how to restore windows after help command.
This function assumes that `standard-output' is the help buffer.
It computes a message, and applies the optional argument FUNCTION to it.
If FUNCTION is nil, it applies `message', thus displaying the message.
In addition, this function sets up `help-return-method', which see, that
specifies what to do when the user exits the help buffer."
+ ;; Reset `help-window' here to avoid confusing `help-mode-finish'.
+ (setq help-window nil)
(and (not (get-buffer-window standard-output))
(let ((first-message
(cond ((or
(defalias 'help-for-help 'help-for-help-internal)
;; It can't find this, but nobody will look.
(make-help-screen help-for-help-internal
- "a b c C e f F i I k C-k l L m p r s t v w C-c C-d C-f C-n C-p C-t C-w . or ? :"
+ (purecopy "Type a help option: [abcCdefFgiIkKlLmnprstvw.] C-[cdefmnoptw] or ?")
+ ;; Don't purecopy this one, because it's not evaluated (it's
+ ;; directly used as a docstring in a function definition, so it'll
+ ;; be moved to the DOC file anyway: no need for purecopying it).
"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. Type a list of words or a regexp; it shows a list of
- commands whose names match. See also the apropos command.
-b describe-bindings. Display a table of all key bindings.
-c describe-key-briefly. Type a key sequence;
- it displays the command name run by that key sequence.
-C describe-coding-system. Type the name of the coding system to describe,
- or just RET to describe the ones currently in use.
-d apropos-documentation. Type a pattern (a list of words or a regexp), and
- it shows a list of functions, variables, and other items whose
- documentation matches that pattern. See also the apropos command.
-e view-echo-area-messages. Go to the buffer that logs echo-area messages.
-f describe-function. Type a function name and you see its documentation.
-F Info-goto-emacs-command-node. Type a command name;
- it goes to the on-line manual's section that describes the command.
-h Display the HELLO file which illustrates various scripts.
-i info. The Info documentation reader: read on-line manuals.
-I describe-input-method. Describe a specific input method (if you type
- its name) or the current input method (if you type just RET).
-k describe-key. Type a key sequence;
- it displays the full documentation for that key sequence.
-K Info-goto-emacs-key-command-node. Type a key sequence;
- it goes to the on-line manual's section that describes
- the command bound to that key.
-l view-lossage. Show last 100 characters you typed.
-L describe-language-environment. This describes either a
- specific language environment (if you type its name)
- or the current language environment (if you type just RET).
-m describe-mode. Display 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.
-r info-emacs-manual. Display the Emacs manual in Info mode.
-s describe-syntax. Display contents of syntax table, plus explanations.
-S info-lookup-symbol. Type a symbol; it goes to that symbol in the
- on-line manual for the programming language used in this buffer.
-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 a command name; it displays which keystrokes
- invoke that command.
-. display-local-help. Display any available local help at point
- in the echo area.
-
-C-c Display Emacs copying permission (GNU General Public License).
-C-d Display Emacs ordering information.
-C-e Display info about Emacs problems.
-C-f Display the Emacs FAQ.
-C-m Display how to order printed Emacs manuals.
-C-n Display news of recent Emacs changes.
-C-p Display information about the GNU project.
-C-t Display the Emacs TODO list.
-C-w Display information on absence of warranty for GNU Emacs."
+a PATTERN Show commands whose name matches the PATTERN (a list of words
+ or a regexp). See also the `apropos' command.
+b Display all key bindings.
+c KEYS Display the command name run by the given key sequence.
+C CODING Describe the given coding system, or RET for current ones.
+d PATTERN Show a list of functions, variables, and other items whose
+ documentation matches the PATTERN (a list of words or a regexp).
+e Go to the *Messages* buffer which logs echo-area messages.
+f FUNCTION Display documentation for the given function.
+F COMMAND Show the on-line manual's section that describes the command.
+g Display information about the GNU project.
+h Display the HELLO file which illustrates various scripts.
+i Start the Info documentation reader: read on-line manuals.
+I METHOD Describe a specific input method, or RET for current.
+k KEYS Display the full documentation for the key sequence.
+K KEYS Show the on-line manual's section for the command bound to KEYS.
+l Show last 300 input keystrokes (lossage).
+L LANG-ENV Describes a specific language environment, or RET for current.
+m Display documentation of current minor modes and current major mode,
+ including their special commands.
+n Display news of recent Emacs changes.
+p TOPIC Find packages matching a given topic keyword.
+r Display the Emacs manual in Info mode.
+s Display contents of current syntax table, plus explanations.
+S SYMBOL Show the section for the given symbol in the on-line manual
+ for the programming language used in this buffer.
+t Start the Emacs learn-by-doing tutorial.
+v VARIABLE Display the given variable's documentation and value.
+w COMMAND Display which keystrokes invoke the given command (where-is).
+. Display any available local help at point in the echo area.
+
+C-a Information about Emacs.
+C-c Emacs copying permission (GNU General Public License).
+C-d Instructions for debugging GNU Emacs.
+C-e External packages and information about Emacs.
+C-f Emacs FAQ.
+C-m How to order printed Emacs manuals.
+C-n News of recent Emacs changes.
+C-o Emacs ordering and distribution information.
+C-p Info about known Emacs problems.
+C-t Emacs TODO list.
+C-w Information on absence of warranty for GNU Emacs."
help-map)
\f
(defun function-called-at-point ()
"Return a function around point or else called by the list containing point.
If that doesn't give a function, return nil."
- (or (with-syntax-table emacs-lisp-mode-syntax-table
- (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 (read (current-buffer))))
- (and (symbolp obj) (fboundp obj) obj))))
- (error nil))))
- (let* ((str (find-tag-default))
- (sym (if str (intern-soft str))))
- (if (and sym (fboundp sym))
- sym
- (save-match-data
- (when (and str (string-match "\\`\\W*\\(.*?\\)\\W*\\'" str))
- (setq sym (intern-soft (match-string 1 str)))
- (and (fboundp sym) sym)))))))
+ (with-syntax-table emacs-lisp-mode-syntax-table
+ (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 (read (current-buffer))))
+ (and (symbolp obj) (fboundp obj) obj))))
+ (error nil))
+ (let* ((str (find-tag-default))
+ (sym (if str (intern-soft str))))
+ (if (and sym (fboundp sym))
+ sym
+ (save-match-data
+ (when (and str (string-match "\\`\\W*\\(.*?\\)\\W*\\'" str))
+ (setq sym (intern-soft (match-string 1 str)))
+ (and (fboundp sym) sym))))))))
\f
;;; `User' help functions
+(defun view-help-file (file &optional dir)
+ (view-file (expand-file-name file (or dir data-directory)))
+ (goto-address-mode 1)
+ (goto-char (point-min)))
+
(defun describe-distribution ()
"Display info on how to obtain the latest version of GNU Emacs."
(interactive)
- (view-file (expand-file-name "DISTRIB" data-directory)))
+ (view-help-file "DISTRIB"))
(defun describe-copying ()
"Display info on how you may redistribute copies of GNU Emacs."
(interactive)
- (view-file (expand-file-name "COPYING" data-directory))
- (goto-char (point-min)))
+ (view-help-file "COPYING"))
-(defun describe-project ()
+(defun describe-gnu-project ()
"Display info on the GNU project."
(interactive)
- (view-file (expand-file-name "THE-GNU-PROJECT" data-directory))
- (goto-char (point-min)))
+ (view-help-file "THE-GNU-PROJECT"))
+
+(define-obsolete-function-alias 'describe-project 'describe-gnu-project "22.2")
(defun describe-no-warranty ()
"Display info on all the kinds of warranty Emacs does NOT have."
(when (consp version)
(let* ((all-versions
(let (res)
- (mapcar
+ (mapc
(lambda (file)
(with-temp-buffer
(insert-file-contents
(beginning-of-line)
(point)))))))
-
-(defun view-todo (&optional arg)
+(defun view-emacs-todo (&optional arg)
"Display the Emacs TODO list."
(interactive "P")
- (view-file (expand-file-name "TODO" data-directory)))
+ (view-help-file "TODO"))
+
+(define-obsolete-function-alias 'view-todo 'view-emacs-todo "22.2")
+
(defun view-echo-area-messages ()
"View the log of recent echo-area messages: the `*Messages*' buffer.
(defun view-order-manuals ()
"Display the Emacs ORDERS file."
(interactive)
- (view-file (expand-file-name "ORDERS" data-directory))
- (goto-address))
+ (view-help-file "ORDERS"))
(defun view-emacs-FAQ ()
"Display the Emacs Frequently Asked Questions (FAQ) file."
(defun view-emacs-problems ()
"Display info on known problems with Emacs and possible workarounds."
(interactive)
- (view-file (expand-file-name "PROBLEMS" data-directory)))
+ (view-help-file "PROBLEMS"))
+
+(defun view-emacs-debugging ()
+ "Display info on how to debug Emacs problems."
+ (interactive)
+ (view-help-file "DEBUG"))
+
+(defun view-external-packages ()
+ "Display external packages and information about Emacs."
+ (interactive)
+ (view-help-file "MORE.STUFF"))
(defun view-lossage ()
- "Display last 100 input keystrokes.
+ "Display last 300 input keystrokes.
To record all your input on a file, use `open-dribble-file'."
(interactive)
(help-setup-xref (list #'view-lossage) (interactive-p))
- (with-output-to-temp-buffer (help-buffer)
+ (with-help-window (help-buffer)
(princ (mapconcat (lambda (key)
(if (or (integerp key) (symbolp key) (listp key))
(single-key-description key)
(while (progn (move-to-column 50) (not (eobp)))
(when (search-forward " " nil t)
(delete-char -1))
- (insert "\n")))
- (print-help-return-message)))
+ (insert "\n"))
+ ;; jidanni wants to see the last keystrokes immediately.
+ (set-marker help-window-point-marker (point)))))
\f
;; Key bindings
then we display only bindings that start with that prefix."
(interactive)
(let ((buf (current-buffer)))
- (with-output-to-temp-buffer "*Help*"
+ (with-help-window "*Help*"
(with-current-buffer standard-output
(describe-buffer-bindings buf prefix menus)))))
(setq sequence (vector up-event))
(aset sequence 0 'mouse-1)
(setq defn-up-tricky (key-binding sequence nil nil (event-start up-event))))))
- (with-output-to-temp-buffer (help-buffer)
+ (with-help-window (help-buffer)
(princ (help-key-description key untranslated))
(princ (format "\
-%s runs the command %S
- which is "
+%s runs the command %S, which is "
mouse-msg defn))
(describe-function-1 defn)
(when up-event
----------------- up-event %s----------------
-<%S>%s%s runs the command %S
- which is "
+<%S>%s%s runs the command %S, which is "
(if mouse-1-tricky "(short click) " "")
ev-type mouse-msg
(if mouse-1-remapped
- " is remapped to <mouse-2>\nwhich" "")
+ " is remapped to <mouse-2>, which" "")
defn-up))
(describe-function-1 defn-up))
(unless (or (null defn-up-tricky)
----------------- up-event (long click) ----------------
Pressing <%S>%s for longer than %d milli-seconds
-runs the command %S
- which is "
+runs the command %S, which is "
ev-type mouse-msg
mouse-1-click-follows-link
defn-up-tricky))
- (describe-function-1 defn-up-tricky)))
- (print-help-return-message)))))
+ (describe-function-1 defn-up-tricky)))))))
\f
(defun describe-mode (&optional buffer)
"Display documentation of current major mode and minor modes.
(interactive-p))
;; For the sake of help-do-xref and help-xref-go-back,
;; don't switch buffers before calling `help-buffer'.
- (with-output-to-temp-buffer (help-buffer)
+ (with-help-window (help-buffer)
(with-current-buffer buffer
(let (minor-modes)
;; Older packages do not register in minor-mode-list but only in
(let ((mode mode-name))
(with-current-buffer standard-output
(let ((start (point)))
- (insert (format-mode-line mode))
+ (insert (format-mode-line mode nil nil buffer))
(add-text-properties start (point) '(face bold)))))
(princ " mode:\n")
- (princ (documentation major-mode)))
- (print-help-return-message))))
+ (princ (documentation major-mode))))))
(defun describe-minor-mode (minor-mode)
(remove-hook 'temp-buffer-show-hook 'resize-temp-buffer-window)))
(defun resize-temp-buffer-window ()
- "Resize the current window to fit its contents.
+ "Resize the selected 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)))
+ (not (window-full-width-p)))
(fit-window-to-buffer
(selected-window)
(if (functionp temp-buffer-max-height)
temp-buffer-max-height))))
\f
+;;; help-window
+
+(defcustom help-window-select 'other
+ "Non-nil means select help window for viewing.
+Choices are:
+ never (nil) Select help window only if there is no other window
+ on its frame.
+ other Select help window unless the selected window is the
+ only other window on its frame.
+ always (t) Always select the help window.
+
+This option has effect if and only if the help window was created
+by `with-help-window'"
+ :type '(choice (const :tag "never (nil)" nil)
+ (const :tag "other" other)
+ (const :tag "always (t)" t))
+ :group 'help
+ :version "23.1")
+
+(defun help-window-display-message (quit-part window &optional other)
+ "Display message telling how to quit and scroll help window.
+QUIT-PART is a string telling how to quit the help window WINDOW.
+Optional argument OTHER non-nil means return text telling how to
+scroll the \"other\" window."
+ (let ((scroll-part
+ (cond
+ ((pos-visible-in-window-p
+ (with-current-buffer (window-buffer window)
+ (point-max)) window)
+ ;; Buffer end is visible.
+ ".")
+ (other ", \\[scroll-other-window] to scroll help.")
+ (t ", \\[scroll-up] to scroll help."))))
+ (message "%s"
+ (substitute-command-keys (concat quit-part scroll-part)))))
+
+(defun help-window-setup-finish (window &optional reuse keep-frame)
+ "Finish setting up help window WINDOW.
+Select WINDOW according to the value of `help-window-select'.
+Display message telling how to scroll and eventually quit WINDOW.
+
+Optional argument REUSE non-nil means WINDOW has been reused \(by
+`display-buffer'\) for displaying help. Optional argument
+KEEP-FRAME non-nil means that quitting must no delete the frame
+of WINDOW."
+ (let ((number-of-windows
+ (length (window-list (window-frame window) 'no-mini window))))
+ (cond
+ ((eq window (selected-window))
+ ;; The help window is the selected window, probably the
+ ;; `pop-up-windows' nil case.
+ (help-window-display-message
+ (if reuse
+ "Type \"q\" to restore this window"
+ ;; This should not be taken.
+ "Type \"q\" to quit") window))
+ ((= number-of-windows 1)
+ ;; The help window is alone on a frame and not the selected
+ ;; window, could be the `pop-up-frames' t case.
+ (help-window-display-message
+ (cond
+ (keep-frame "Type \"q\" to delete this window")
+ (reuse "Type \"q\" to restore this window")
+ (view-remove-frame-by-deleting "Type \"q\" to delete this frame")
+ (t "Type \"q\" to iconify this frame"))
+ window))
+ ((and (= number-of-windows 2)
+ (eq (window-frame window) (window-frame (selected-window))))
+ ;; There are two windows on the help window's frame and the other
+ ;; window is the selected one.
+ (if (memq help-window-select '(nil other))
+ ;; Do not select the help window.
+ (help-window-display-message
+ (if reuse
+ ;; Offer `display-buffer' for consistency with
+ ;; `help-print-return-message'. This is hardly TRT when
+ ;; the other window and the selected window display the
+ ;; same buffer but has been handled this way ever since.
+ "Type \\[display-buffer] RET to restore the other window"
+ ;; The classic "two windows" configuration.
+ "Type \\[delete-other-windows] to delete the help window")
+ window t)
+ ;; Select help window and tell how to quit.
+ (select-window window)
+ (help-window-display-message
+ (if reuse
+ "Type \"q\" to restore this window"
+ "Type \"q\" to delete this window") window)))
+ (help-window-select
+ ;; Issuing a message with 3 or more windows on the same frame
+ ;; without selecting the help window doesn't make any sense.
+ (select-window window)
+ (help-window-display-message
+ (if reuse
+ "Type \"q\" to restore this window"
+ "Type \"q\" to delete this window") window)))))
+
+(defun help-window-setup (list-of-frames list-of-window-tuples)
+ "Set up help window.
+LIST-OF-FRAMES and LIST-OF-WINDOW-TUPLES are the lists of frames
+and window quadruples built by `with-help-window'. The help
+window itself is specified by the variable `help-window'."
+ (let* ((help-buffer (window-buffer help-window))
+ ;; `help-buffer' now denotes the help window's buffer.
+ (view-entry
+ (assq help-window
+ (buffer-local-value 'view-return-to-alist help-buffer)))
+ (help-entry (assq help-window list-of-window-tuples)))
+
+ ;; Handle `help-window-point-marker'.
+ (when (eq (marker-buffer help-window-point-marker) help-buffer)
+ (set-window-point help-window help-window-point-marker)
+ ;; Reset `help-window-point-marker'.
+ (set-marker help-window-point-marker nil))
+
+ (cond
+ (view-entry
+ ;; `view-return-to-alist' has an entry for the help window.
+ (cond
+ ((eq help-window (selected-window))
+ ;; The help window is the selected window, probably because the
+ ;; user followed a backward/forward button or a cross reference.
+ ;; In this case just purge stale entries from
+ ;; `view-return-to-alist' but leave the entry alone and don't
+ ;; display a message.
+ (view-return-to-alist-update help-buffer))
+ ((and help-entry (eq (cadr help-entry) help-buffer))
+ ;; The help window was not selected but displayed the help
+ ;; buffer. In this case reuse existing exit information but try
+ ;; to get back to the selected window when quitting. Don't
+ ;; display a message since the user must have seen one before.
+ (view-return-to-alist-update
+ help-buffer (cons help-window
+ (cons (selected-window) (cddr view-entry)))))
+ (help-entry
+ ;; The help window was not selected, did display the help buffer
+ ;; earlier, but displayed another buffer when help was invoked.
+ ;; Set up things so that quitting will show that buffer again.
+ (view-return-to-alist-update
+ help-buffer (cons help-window
+ (cons (selected-window) (cdr help-entry))))
+ (help-window-setup-finish help-window t))
+ (t
+ ;; The help window is new but `view-return-to-alist' had an
+ ;; entry for it. This should never happen.
+ (view-return-to-alist-update
+ help-buffer (cons help-window
+ (cons (selected-window) 'quit-window)))
+ (help-window-setup-finish help-window t))))
+ (help-entry
+ ;; `view-return-to-alist' does not have an entry for help window
+ ;; but `list-of-window-tuples' does. Hence `display-buffer' must
+ ;; have reused an existing window.
+ (if (eq (cadr help-entry) help-buffer)
+ ;; The help window displayed `help-buffer' before but no
+ ;; `view-return-to-alist' entry was found probably because the
+ ;; user manually switched to the help buffer. Set up things
+ ;; for `quit-window' although `view-exit-action' should be
+ ;; able to handle this case all by itself.
+ (progn
+ (view-return-to-alist-update
+ help-buffer (cons help-window
+ (cons (selected-window) 'quit-window)))
+ (help-window-setup-finish help-window t))
+ ;; The help window displayed another buffer before. Set up
+ ;; things in a way that quitting can orderly show that buffer
+ ;; again. The window-start and window-point information from
+ ;; `list-of-window-tuples' provide the necessary information.
+ (view-return-to-alist-update
+ help-buffer (cons help-window
+ (cons (selected-window) (cdr help-entry))))
+ (help-window-setup-finish help-window t)))
+ ((memq (window-frame help-window) list-of-frames)
+ ;; The help window is a new window on an existing frame. This
+ ;; case must be handled specially by `help-window-setup-finish'
+ ;; and `view-mode-exit' to ascertain that quitting does _not_
+ ;; inadvertently delete the frame.
+ (view-return-to-alist-update
+ help-buffer (cons help-window
+ (cons (selected-window) 'keep-frame)))
+ (help-window-setup-finish help-window nil t))
+ (t
+ ;; The help window is shown on a new frame. In this case quitting
+ ;; shall handle both, the help window _and_ its frame. We changed
+ ;; the default of `view-remove-frame-by-deleting' to t in order to
+ ;; intuitively DTRT here.
+ (view-return-to-alist-update
+ help-buffer (cons help-window (cons (selected-window) t)))
+ (help-window-setup-finish help-window)))))
+
+;; `with-help-window' is a wrapper for `with-output-to-temp-buffer'
+;; providing the following additional twists:
+
+;; (1) Issue more accurate messages telling how to scroll and quit the
+;; help window.
+
+;; (2) Make `view-mode-exit' DTRT in more cases.
+
+;; (3) An option (customizable via `help-window-select') to select the
+;; help window automatically.
+
+;; (4) A marker (`help-window-point-marker') to move point in the help
+;; window to an arbitrary buffer position.
+
+;; Note: It's usually always wrong to use `help-print-return-message' in
+;; the body of `with-help-window'.
+(defmacro with-help-window (buffer-name &rest body)
+ "Display buffer BUFFER-NAME in a help window evaluating BODY.
+Select help window if the actual value of the user option
+`help-window-select' says so. Return last value in BODY."
+ (declare (indent 1) (debug t))
+ ;; Bind list-of-frames to `frame-list' and list-of-window-tuples to a
+ ;; list of one <window window-buffer window-start window-point> tuple
+ ;; for each live window.
+ `(let ((list-of-frames (frame-list))
+ (list-of-window-tuples
+ (let (list)
+ (walk-windows
+ (lambda (window)
+ (push (list window (window-buffer window)
+ (window-start window) (window-point window))
+ list))
+ 'no-mini t)
+ list)))
+ ;; Make `help-window' t to trigger `help-mode-finish' to set
+ ;; `help-window' to the actual help window.
+ (setq help-window t)
+ ;; Make `help-window-point-marker' point nowhere (the only place
+ ;; where this should be set to a buffer position is within BODY).
+ (set-marker help-window-point-marker nil)
+ (prog1
+ ;; Return value returned by `with-output-to-temp-buffer'.
+ (with-output-to-temp-buffer ,buffer-name
+ (progn ,@body))
+ (when (windowp help-window)
+ ;; Set up help window.
+ (help-window-setup list-of-frames list-of-window-tuples))
+ ;; Reset `help-window' to nil to avoid confusing future calls of
+ ;; `help-mode-finish' with plain `with-output-to-temp-buffer'.
+ (setq help-window nil))))
+\f
(provide 'help)
;; arch-tag: cf427352-27e9-49b7-9a6f-741ebab02423
HCoop / bpt / emacs.git / blobdiff