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comparison lisp/mode-motion.el @ 428:3ecd8885ac67 r21-2-22

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Import from CVS: tag r21-2-22
author cvs
date Mon, 13 Aug 2007 11:28:15 +0200
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427:0a0253eac470 428:3ecd8885ac67
1 ;;; mode-motion.el --- Mode-specific mouse-highlighting of text.
2
3 ;; Copyright (C) 1992, 1993, 1997 Free Software Foundation, Inc.
4
5 ;; Maintainer: XEmacs Development Team
6 ;; Keywords: internal, mouse, dumped
7
8 ;; This file is part of XEmacs.
9
10 ;; XEmacs is free software; you can redistribute it and/or modify it
11 ;; under the terms of the GNU General Public License as published by
12 ;; the Free Software Foundation; either version 2, or (at your option)
13 ;; any later version.
14
15 ;; XEmacs is distributed in the hope that it will be useful, but
16 ;; WITHOUT ANY WARRANTY; without even the implied warranty of
17 ;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
18 ;; General Public License for more details.
19
20 ;; You should have received a copy of the GNU General Public License
21 ;; along with XEmacs; see the file COPYING. If not, write to the
22 ;; Free Software Foundation, 59 Temple Place - Suite 330,
23 ;; Boston, MA 02111-1307, USA.
24
25 ;;; Synched up with: Not in FSF.
26
27 ;;; Commentary:
28
29 ;; This file is dumped with XEmacs (when window system support is compiled in).
30
31 ;;; Code:
32
33 (defvar mode-motion-hook nil
34 "Function or functions which are called whenever the mouse moves.
35 Each function must take a single argument of the motion event.
36 You should normally use this rather than `mouse-motion-handler', which
37 does some additional window-system-dependent things. This hook is local
38 to every buffer, and should normally be set up by major-modes which want
39 to use special highlighting. Every time the mouse moves over a window,
40 the mode-motion-hook of the buffer of that window is run.")
41
42 (make-variable-buffer-local 'mode-motion-hook)
43
44 (defvar mode-motion-extent nil)
45 (make-variable-buffer-local 'mode-motion-extent)
46
47 (defvar mode-motion-help-echo-string nil
48 "String to be added as the 'help-echo property of the mode-motion extent.
49 In order for this to work, you need to add the hook function
50 `mode-motion-add-help-echo' to the mode-motion hook. If this is a function,
51 it will be called with one argument (the event) and should return a string
52 to be added. This variable is local to every buffer.")
53 (make-variable-buffer-local 'mode-motion-help-echo-string)
54
55 (defun mode-motion-ensure-extent-ok (event)
56 (let ((buffer (event-buffer event)))
57 (if (and (extent-live-p mode-motion-extent)
58 (eq buffer (extent-object mode-motion-extent)))
59 nil
60 (setq mode-motion-extent (make-extent nil nil buffer))
61 (set-extent-property mode-motion-extent 'mouse-face 'highlight))))
62
63 (defun mode-motion-highlight-internal (event backward forward)
64 (let* ((buffer (event-buffer event))
65 (point (and buffer (event-point event))))
66 (if (and buffer
67 (not (eq buffer mouse-grabbed-buffer)))
68 ;; #### ack!! Too many calls to save-window-excursion /
69 ;; save-excursion (x-track-pointer calls, so does
70 ;; minibuf-mouse-tracker ...) This needs to be looked
71 ;; into. It's complicated by the fact that sometimes
72 ;; a mode-motion-hook might really want to change
73 ;; the point.
74 ;;
75 ;; #### The save-excursion must come before the
76 ;; save-window-excursion in order to function properly. I
77 ;; haven't given this much thought. Is it a bug that this
78 ;; ordering is necessary or is it correct behavior?
79 (save-excursion
80 (save-window-excursion
81 (set-buffer buffer)
82 (mode-motion-ensure-extent-ok event)
83 (if point
84 ;; Use save-excursion here to avoid
85 ;; save-window-excursion seeing a change in
86 ;; window point's value which would make the
87 ;; display code do a whole lot of useless work
88 ;; and making the display flicker horribly.
89 (save-excursion
90 (goto-char point)
91 (condition-case nil (funcall backward) (error nil))
92 (setq point (point))
93 (condition-case nil (funcall forward) (error nil))
94 (if (eq point (point))
95 (detach-extent mode-motion-extent)
96 (set-extent-endpoints mode-motion-extent point (point))))
97 ;; not over text; zero the extent.
98 (detach-extent mode-motion-extent)))))))
99
100 (defun mode-motion-highlight-line (event)
101 "For use as the value of `mode-motion-hook' -- highlight line under mouse."
102 (mode-motion-highlight-internal event 'beginning-of-line 'end-of-line))
103
104 (defun mode-motion-highlight-word (event)
105 "For use as the value of `mode-motion-hook' -- highlight word under mouse."
106 (mode-motion-highlight-internal
107 event
108 #'(lambda () (default-mouse-track-beginning-of-word nil))
109 #'(lambda () (default-mouse-track-end-of-word nil))))
110
111 (defun mode-motion-highlight-symbol (event)
112 "For use as the value of `mode-motion-hook' -- highlight symbol under mouse."
113 (mode-motion-highlight-internal
114 event
115 #'(lambda () (default-mouse-track-beginning-of-word t))
116 #'(lambda () (default-mouse-track-end-of-word t))))
117
118 (defun mode-motion-highlight-sexp (event)
119 "For use as the value of `mode-motion-hook' -- highlight form under mouse."
120 (mode-motion-highlight-internal
121 event
122 #'(lambda ()
123 (if (= (char-syntax (following-char)) ?\()
124 nil
125 (goto-char (scan-sexps (point) -1))))
126 #'(lambda ()
127 (if (= (char-syntax (following-char)) ?\))
128 (forward-char 1))
129 (goto-char (scan-sexps (point) 1)))))
130
131 (defun mode-motion-add-help-echo (event)
132 "For use as the value of `mode-motion-hook' -- add a 'help-echo property.
133 This causes the string in the 'help-echo property to be displayed when the
134 mouse moves over the extent. See `mode-motion-help-echo-string' for
135 documentation on how to control the string that is added."
136 (mode-motion-ensure-extent-ok event)
137 (let ((string (cond ((null mode-motion-help-echo-string) nil)
138 ((stringp mode-motion-help-echo-string)
139 mode-motion-help-echo-string)
140 (t (funcall mode-motion-help-echo-string event)))))
141 (if (stringp string)
142 (set-extent-property mode-motion-extent 'help-echo string))))
143
144
145 (provide 'mode-motion)
146
147 ;;; mode-motion.el ends here