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c0274f38 ER |
1 | ;;; compare-w.el --- compare text between windows for Emacs. |
2 | ||
5ff083af | 3 | ;; Copyright (C) 1986, 1989, 1993, 1997 Free Software Foundation, Inc. |
745bc783 | 4 | |
9750e079 ER |
5 | ;; Maintainer: FSF |
6 | ||
745bc783 JB |
7 | ;; This file is part of GNU Emacs. |
8 | ||
9 | ;; GNU Emacs is free software; you can redistribute it and/or modify | |
10 | ;; it under the terms of the GNU General Public License as published by | |
e5167999 | 11 | ;; the Free Software Foundation; either version 2, or (at your option) |
745bc783 JB |
12 | ;; any later version. |
13 | ||
14 | ;; GNU Emacs is distributed in the hope that it will be useful, | |
15 | ;; but WITHOUT ANY WARRANTY; without even the implied warranty of | |
16 | ;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
17 | ;; GNU General Public License for more details. | |
18 | ||
19 | ;; You should have received a copy of the GNU General Public License | |
b578f267 EN |
20 | ;; along with GNU Emacs; see the file COPYING. If not, write to the |
21 | ;; Free Software Foundation, Inc., 59 Temple Place - Suite 330, | |
22 | ;; Boston, MA 02111-1307, USA. | |
745bc783 | 23 | |
e41b2db1 ER |
24 | ;;; Commentary: |
25 | ||
26 | ;; This package provides one entry point, compare-windows. It compares | |
27 | ;; text starting from point in two adjacent windows, advancing point | |
28 | ;; until it finds a difference. Option variables permit you to ignore | |
29 | ;; whitespace differences, or case differences, or both. | |
30 | ||
e5167999 ER |
31 | ;;; Code: |
32 | ||
4bef9110 SE |
33 | (defgroup compare-w nil |
34 | "Compare text between windows." | |
35 | :prefix "compare-" | |
36 | :group 'tools) | |
37 | ||
38 | (defcustom compare-windows-whitespace "[ \t\n]+" | |
048ab7d3 | 39 | "*Regexp that defines whitespace sequences for \\[compare-windows]. |
745bc783 JB |
40 | Changes in whitespace are optionally ignored. |
41 | ||
42 | The value of `compare-windows-whitespace' may instead be a function; this | |
43 | function is called in each buffer, with point at the current scanning point. | |
44 | The function's job is to categorize any whitespace around (including before) | |
45 | point; it should also advance past any whitespace. | |
46 | ||
47 | The function is passed one argument, the point where `compare-windows' | |
48 | was originally called; it should not consider any text before that point. | |
49 | If the function returns the same value for both buffers, then the | |
4bef9110 SE |
50 | whitespace is considered to match, and is skipped." |
51 | :type '(choice regexp function) | |
52 | :group 'compare-w) | |
745bc783 | 53 | |
4bef9110 SE |
54 | (defcustom compare-ignore-case nil |
55 | "*Non-nil means \\[compare-windows] ignores case differences." | |
56 | :type 'boolean | |
57 | :group 'compare-w) | |
745bc783 JB |
58 | |
59 | ;;;###autoload | |
60 | (defun compare-windows (ignore-whitespace) | |
61 | "Compare text in current window with text in next window. | |
62 | Compares the text starting at point in each window, | |
63 | moving over text in each one as far as they match. | |
64 | ||
82734236 RS |
65 | This command pushes the mark in each window |
66 | at the prior location of point in that window. | |
67 | If both windows display the same buffer, | |
68 | the mark is pushed twice in that buffer: | |
69 | first in the other window, then in the selected window. | |
70 | ||
745bc783 JB |
71 | A prefix arg means ignore changes in whitespace. |
72 | The variable `compare-windows-whitespace' controls how whitespace is skipped. | |
73 | If `compare-ignore-case' is non-nil, changes in case are also ignored." | |
74 | (interactive "P") | |
75 | (let* (p1 p2 maxp1 maxp2 b1 b2 w2 | |
8c9dbabe | 76 | (progress 1) |
745bc783 JB |
77 | (opoint1 (point)) |
78 | opoint2 | |
8c9dbabe KH |
79 | (skip-func (if ignore-whitespace |
80 | (if (stringp compare-windows-whitespace) | |
81 | 'compare-windows-skip-whitespace | |
82 | compare-windows-whitespace)))) | |
745bc783 | 83 | (setq p1 (point) b1 (current-buffer)) |
45d642df | 84 | (setq w2 (next-window (selected-window) nil 'visible)) |
745bc783 JB |
85 | (if (eq w2 (selected-window)) |
86 | (error "No other window")) | |
87 | (setq p2 (window-point w2) | |
88 | b2 (window-buffer w2)) | |
89 | (setq opoint2 p2) | |
90 | (setq maxp1 (point-max)) | |
91 | (save-excursion | |
92 | (set-buffer b2) | |
82734236 | 93 | (push-mark p2 t) |
745bc783 | 94 | (setq maxp2 (point-max))) |
82734236 | 95 | (push-mark) |
745bc783 | 96 | |
8c9dbabe | 97 | (while (> progress 0) |
745bc783 JB |
98 | ;; If both buffers have whitespace next to point, |
99 | ;; optionally skip over it. | |
100 | ||
8c9dbabe | 101 | (and skip-func |
745bc783 JB |
102 | (save-excursion |
103 | (let (p1a p2a w1 w2 result1 result2) | |
8c9dbabe | 104 | (setq result1 (funcall skip-func opoint1)) |
048ab7d3 | 105 | (setq p1a (point)) |
745bc783 JB |
106 | (set-buffer b2) |
107 | (goto-char p2) | |
8c9dbabe | 108 | (setq result2 (funcall skip-func opoint2)) |
048ab7d3 | 109 | (setq p2a (point)) |
5ff083af | 110 | (if (or (stringp compare-windows-whitespace) |
5a534851 RS |
111 | (and result1 result2 (eq result1 result2))) |
112 | (setq p1 p1a | |
113 | p2 p2a))))) | |
745bc783 | 114 | |
8c9dbabe | 115 | (let ((size (min (- maxp1 p1) (- maxp2 p2))) |
d76bfaa2 | 116 | (case-fold-search compare-ignore-case)) |
8c9dbabe KH |
117 | (setq progress (compare-buffer-substrings b2 p2 (+ size p2) |
118 | b1 p1 (+ size p1))) | |
119 | (setq progress (if (zerop progress) size (1- (abs progress)))) | |
120 | (setq p1 (+ p1 progress) p2 (+ p2 progress))) | |
121 | ;; Advance point now rather than later, in case we're interrupted. | |
122 | (goto-char p1) | |
123 | (set-window-point w2 p2)) | |
124 | ||
745bc783 JB |
125 | (if (= (point) opoint1) |
126 | (ding)))) | |
49116ac0 | 127 | |
048ab7d3 RS |
128 | ;; Move forward over whatever might be called whitespace. |
129 | ;; compare-windows-whitespace is a regexp that matches whitespace. | |
130 | ;; Match it at various starting points before the original point | |
131 | ;; and find the latest point at which a match ends. | |
132 | ;; Don't try starting points before START, though. | |
133 | ;; Value is non-nil if whitespace is found. | |
7f5d3541 RS |
134 | |
135 | ;; If there is whitespace before point, but none after, | |
136 | ;; then return t, but don't advance point. | |
048ab7d3 RS |
137 | (defun compare-windows-skip-whitespace (start) |
138 | (let ((end (point)) | |
7f5d3541 | 139 | (beg (point)) |
048ab7d3 | 140 | (opoint (point))) |
5dd1ad8e | 141 | (while (or (and (looking-at compare-windows-whitespace) |
7f5d3541 RS |
142 | (<= end (match-end 0)) |
143 | ;; This match goes past END, so advance END. | |
144 | (progn (setq end (match-end 0)) | |
5dd1ad8e RS |
145 | (> (point) start))) |
146 | (and (/= (point) start) | |
147 | ;; Consider at least the char before point, | |
148 | ;; unless it is also before START. | |
149 | (= (point) opoint))) | |
048ab7d3 RS |
150 | ;; keep going back until whitespace |
151 | ;; doesn't extend to or past end | |
152 | (forward-char -1)) | |
7f5d3541 | 153 | (setq beg (point)) |
048ab7d3 | 154 | (goto-char end) |
7f5d3541 RS |
155 | (or (/= beg opoint) |
156 | (/= end opoint)))) | |
048ab7d3 | 157 | |
49116ac0 JB |
158 | (provide 'compare-w) |
159 | ||
c0274f38 | 160 | ;;; compare-w.el ends here |