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comparison lisp/modes/lazy-shot.el @ 193:f53b5ca2e663 r20-3b23

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Import from CVS: tag r20-3b23
author cvs
date Mon, 13 Aug 2007 09:58:30 +0200
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192:9d35321dd38c 193:f53b5ca2e663
1 ;;; lazy-shot.el --- Lazy font locking for XEmacs
2
3 ;; Copyright (C) 1997 Jan Vroonhof
4
5 ;; Author: Jan Vroonhof <vroonhof@math.ethz.ch>
6 ;; Keywords: languages, faces
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, Inc., 59 Temple Place - Suite 330,
23 ;; Boston, MA 02111-1307, USA.
24
25 ;;; Synched up with: Not synched.
26
27 ;;; Commentary:
28
29 ;; This versions has basic demand lock functionality. Somebody please
30 ;; sync further with lazy-lock v2 from FSF, customize etc.
31 ;;
32 ;;
33 ;; Idea for the stealth lock function:
34 ;;
35 ;;
36 ;; On an Idle itimer
37 ;; Loop over all buffers with lazy-lock set
38 ;; mapcar-extent in the region (point) point-max for
39 ;; one-shot-function property
40 ;; If not found do the same for [point-min,point]
41 ;; font-lock the found region and delete the extent
42
43 ;;; Code:
44
45 (require 'font-lock)
46
47 (defvar lazy-shot-mode nil)
48
49
50 (defvar lazy-shot-step-size (* 1 124)) ;; Please test diffent sizes
51
52 ;;;###autoload
53 (defun lazy-shot-mode (&optional arg)
54 "Toggle Lazy Lock mode.
55 With arg, turn Lazy Lock mode on if and only if arg is positive."
56 (interactive "P")
57 (set (make-local-variable 'lazy-shot-mode)
58 (and (if arg (> (prefix-numeric-value arg) 0) (not lazy-shot-mode))))
59 (cond ((and lazy-shot-mode (not font-lock-mode))
60 ;; Turned on `lazy-shot-mode' rather than `font-lock-mode'.
61 (let ((font-lock-support-mode 'lazy-shot-mode))
62 (font-lock-mode t)))
63 (lazy-shot-mode
64 ;; Turn ourselves on.
65 (lazy-shot-install))
66 (t
67 ;; Turn ourselves off.
68 (lazy-shot-unstall))))
69
70 ;;;###autoload
71 (defun turn-on-lazy-shot ()
72 "Unconditionally turn on Lazy Lock mode."
73 (lazy-shot-mode t))
74
75
76 (defun lazy-shot-shot-function (extent)
77 "Lazy lock the extent when it has become visisble"
78 (let ((start (extent-start-position extent))
79 (end (extent-end-position extent))
80 (buffer (extent-buffer extent)))
81 (delete-extent extent)
82 (save-excursion
83 ;; This magic should really go into font-lock-fonity-region
84 (goto-char start)
85 (unless (bolp)
86 (beginning-of-line)
87 (setq start (point)))
88 (goto-char end)
89 (unless (bolp)
90 (forward-line)
91 (setq end (point)))
92 (message "Lazy-shot fontifying from %s to %s in %s" start end buffer)
93 (save-match-data
94 (font-lock-fontify-region start end)))))
95
96 (defun lazy-shot-install-extent (spos epos &optional buffer)
97 "Make an extent that will lazy-shot if it is displayed"
98 (let ((extent (make-extent spos epos buffer)))
99 (when extent
100 (set-extent-one-shot-function extent
101 'lazy-shot-shot-function))
102 extent))
103
104 (defun lazy-shot-install-extents (fontifying)
105 ;;
106 ;; Add hook if lazy-shot.el is deferring or is fontifying on scrolling.
107 (when fontifying
108 (let ((start (point-min)))
109 (while (< start (point-max))
110 (lazy-shot-install-extent start
111 (min (point-max) (+ start lazy-shot-step-size)))
112 (setq start (+ start lazy-shot-step-size))))))
113
114 (defun lazy-shot-install ()
115 (make-local-variable 'font-lock-fontified)
116 (setq font-lock-fontified t)
117 (lazy-shot-install-extents font-lock-fontified))
118
119 (defun lazy-shot-unstall ()
120 ;;
121 ;; Remove the extents.
122 (map-extents
123 (lambda (e arg) (delete-extent e) nil)
124 nil nil nil nil nil 'one-shot-function 'lazy-shot-shot-function)
125 ;;
126 ;; Remove the fontification hooks.
127 (remove-hook 'after-change-functions 'lazy-shot-defer-after-change t)
128 ;;
129 ;; If Font Lock mode is still enabled, reinstall its hook.
130 (when font-lock-mode
131 (add-hook 'after-change-functions 'font-lock-after-change-function nil t)))
132
133
134 (provide 'lazy-shot)
135
136 ;;; lazy-shot.el ends here