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c88ab9ce ER |
1 | ;;; tabify.el --- tab conversion commands for Emacs |
2 | ||
c90f2757 | 3 | ;; Copyright (C) 1985, 1994, 2001, 2002, 2003, 2004, |
114f9c96 | 4 | ;; 2005, 2006, 2007, 2008, 2009, 2010 Free Software Foundation, Inc. |
a2535589 | 5 | |
58142744 | 6 | ;; Maintainer: FSF |
bd78fa1d | 7 | ;; Package: emacs |
58142744 | 8 | |
a2535589 JA |
9 | ;; This file is part of GNU Emacs. |
10 | ||
eb3fa2cf | 11 | ;; GNU Emacs is free software: you can redistribute it and/or modify |
a2535589 | 12 | ;; it under the terms of the GNU General Public License as published by |
eb3fa2cf GM |
13 | ;; the Free Software Foundation, either version 3 of the License, or |
14 | ;; (at your option) any later version. | |
a2535589 JA |
15 | |
16 | ;; GNU Emacs is distributed in the hope that it will be useful, | |
17 | ;; but WITHOUT ANY WARRANTY; without even the implied warranty of | |
18 | ;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
19 | ;; GNU General Public License for more details. | |
20 | ||
21 | ;; You should have received a copy of the GNU General Public License | |
eb3fa2cf | 22 | ;; along with GNU Emacs. If not, see <http://www.gnu.org/licenses/>. |
a2535589 | 23 | |
d9ecc911 ER |
24 | ;;; Commentary: |
25 | ||
26 | ;; Commands to optimize spaces to tabs or expand tabs to spaces in a region | |
27 | ;; (`tabify' and `untabify'). The variable tab-width does the obvious. | |
28 | ||
22a89ee8 | 29 | ;;; Code: |
a2535589 | 30 | |
f9f9507e | 31 | ;;;###autoload |
a2535589 JA |
32 | (defun untabify (start end) |
33 | "Convert all tabs in region to multiple spaces, preserving columns. | |
e47b2570 RS |
34 | Called non-interactively, the region is specified by arguments |
35 | START and END, rather than by the position of point and mark. | |
36 | The variable `tab-width' controls the spacing of tab stops." | |
a2535589 JA |
37 | (interactive "r") |
38 | (save-excursion | |
39 | (save-restriction | |
5119b412 | 40 | (narrow-to-region (point-min) end) |
a2535589 JA |
41 | (goto-char start) |
42 | (while (search-forward "\t" nil t) ; faster than re-search | |
bb8143d9 | 43 | (forward-char -1) |
2d8e81a5 | 44 | (let ((tab-beg (point)) |
bb8143d9 KH |
45 | (indent-tabs-mode nil) |
46 | column) | |
47 | (skip-chars-forward "\t") | |
48 | (setq column (current-column)) | |
2d8e81a5 | 49 | (delete-region tab-beg (point)) |
a2535589 JA |
50 | (indent-to column)))))) |
51 | ||
49c7d1ac | 52 | (defvar tabify-regexp " [ \t]+" |
bb8143d9 | 53 | "Regexp matching whitespace that tabify should consider. |
e5b1b45c | 54 | Usually this will be \" [ \\t]+\" to match a space followed by whitespace. |
49c7d1ac | 55 | \"^\\t* [ \\t]+\" is also useful, for tabifying only initial whitespace.") |
bb8143d9 | 56 | |
f9f9507e | 57 | ;;;###autoload |
a2535589 JA |
58 | (defun tabify (start end) |
59 | "Convert multiple spaces in region to tabs when possible. | |
60 | A group of spaces is partially replaced by tabs | |
61 | when this can be done without changing the column they end at. | |
e47b2570 RS |
62 | Called non-interactively, the region is specified by arguments |
63 | START and END, rather than by the position of point and mark. | |
64 | The variable `tab-width' controls the spacing of tab stops." | |
a2535589 JA |
65 | (interactive "r") |
66 | (save-excursion | |
67 | (save-restriction | |
7be313ea RS |
68 | ;; Include the beginning of the line in the narrowing |
69 | ;; since otherwise it will throw off current-column. | |
70 | (goto-char start) | |
71 | (beginning-of-line) | |
72 | (narrow-to-region (point) end) | |
a2535589 | 73 | (goto-char start) |
49c7d1ac SM |
74 | (let ((indent-tabs-mode t)) |
75 | (while (re-search-forward tabify-regexp nil t) | |
76 | ;; The region between (match-beginning 0) and (match-end 0) is just | |
77 | ;; spacing which we want to adjust to use TABs where possible. | |
78 | (let ((end-col (current-column)) | |
79 | (beg-col (save-excursion (goto-char (match-beginning 0)) | |
80 | (skip-chars-forward "\t") | |
81 | (current-column)))) | |
82 | (if (= (/ end-col tab-width) (/ beg-col tab-width)) | |
83 | ;; The spacing (after some leading TABs which we wouldn't | |
84 | ;; want to touch anyway) does not straddle a TAB boundary, | |
85 | ;; so it neither contains a TAB, nor will we be able to use | |
86 | ;; a TAB here anyway: there's nothing to do. | |
87 | nil | |
88 | (delete-region (match-beginning 0) (point)) | |
89 | (indent-to end-col)))))))) | |
c88ab9ce | 90 | |
85588571 RS |
91 | (provide 'tabify) |
92 | ||
49c7d1ac | 93 | ;; arch-tag: c83893b1-e0cc-4e57-8a09-73fd03466416 |
c88ab9ce | 94 | ;;; tabify.el ends here |