Commit cde56121 authored by Martin Rudalics's avatar Martin Rudalics
Browse files

(help-window, help-window-point-marker): New variables.

(help-window-select): New option.
(with-help-window): New macro for displaying help windows.
(help-window-display-message, help-window-setup-finish)
(help-window-setup): New functions used for setting up help windows.
(print-help-return-message): Reset help-window to nil.
(view-lossage): Use with-help-window instead of
with-output-to-temp-buffer and move help-window-point-marker after
inserted text.
(describe-bindings, describe-key, describe-mode): Use
with-help-window instead of with-output-to-temp-buffer.
parent 78ddc123
......@@ -38,6 +38,26 @@
(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 `print-help-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)
......@@ -124,6 +144,8 @@ 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
......@@ -431,7 +453,7 @@ is specified by the variable `message-log-max'."
To record all your input on a file, use `open-dribble-file'."
(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)
......@@ -443,8 +465,9 @@ To record all your input on a file, use `open-dribble-file'."
(while (progn (move-to-column 50) (not (eobp)))
(when (search-forward " " nil t)
(delete-char -1))
(insert "\n")))
(insert "\n"))
;; jidanni wants to see the last keystrokes immediately.
(set-marker help-window-point-marker (point)))))
;; Key bindings
......@@ -475,7 +498,7 @@ The optional argument PREFIX, if non-nil, should be a key sequence;
then we display only bindings that start with that prefix."
(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)))))
......@@ -719,7 +742,7 @@ temporarily enables it to allow getting help on disabled items and buttons."
(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
......@@ -755,8 +778,7 @@ runs the command %S
ev-type mouse-msg
(describe-function-1 defn-up-tricky)))
(describe-function-1 defn-up-tricky)))))))
(defun describe-mode (&optional buffer)
"Display documentation of current major mode and minor modes.
......@@ -773,7 +795,7 @@ whose documentation describes the minor mode."
;; 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
......@@ -841,8 +863,7 @@ whose documentation describes the minor mode."
(insert (format-mode-line mode))
(add-text-properties start (point) '(face bold)))))
(princ " mode:\n")
(princ (documentation major-mode)))
(princ (documentation major-mode))))))
(defun describe-minor-mode (minor-mode)
......@@ -975,6 +996,248 @@ out of view."
;;; 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
(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."))))
(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
(let ((number-of-windows
(length (window-list (window-frame window) 'no-mini window))))
((eq window (selected-window))
;; The help window is the selected window, probably the
;; `pop-up-windows' nil case.
(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.
(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"))
((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.
(if reuse
;; Offer `display-buffer' for consistency with
;; `print-help-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)
(if reuse
"Type \"q\" to restore this window"
"Type \"q\" to delete this window") window)))
;; 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)
(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.
(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))
;; `view-return-to-alist' has an entry for the help window.
((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.
help-buffer (cons help-window
(cons (selected-window) (cddr view-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.
help-buffer (cons help-window
(cons (selected-window) (cdr help-entry))))
(help-window-setup-finish help-window t))
;; The help window is new but `view-return-to-alist' had an
;; entry for it. This should never happen.
help-buffer (cons help-window
(cons (selected-window) 'quit-window)))
(help-window-setup-finish help-window t))))
;; `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.
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.
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.
help-buffer (cons help-window
(cons (selected-window) 'keep-frame)))
(help-window-setup-finish help-window nil 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.
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 `print-help-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."
(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))
(let (list)
(lambda (window)
(push (list window (window-buffer window)
(window-start window) (window-point window))
'no-mini t)
;; We set `help-window' to t in order 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)
(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' by "plain" `with-output-to-temp-buffer'.
(setq help-window nil)))
(provide 'help)
;; arch-tag: cf427352-27e9-49b7-9a6f-741ebab02423
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