lisp/rect.el

   1 ;;; rect.el --- rectangle functions for GNU Emacs.
   2
   3 ;; Copyright (C) 1985 Free Software Foundation, Inc.
   4
   5 ;; Maintainer: FSF
   6 ;; Keywords: internal
   7
   8 ;; This file is part of GNU Emacs.
   9
  10 ;; GNU Emacs is free software; you can redistribute it and/or modify
  11 ;; it 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 ;; GNU Emacs is distributed in the hope that it will be useful,
  16 ;; but WITHOUT ANY WARRANTY; without even the implied warranty of
  17 ;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  18 ;; GNU General Public License for more details.
  19
  20 ;; You should have received a copy of the GNU General Public License
  21 ;; along with GNU Emacs; see the file COPYING.  If not, write to
  22 ;; the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA.
  23
  24 ;;; Commentary:
  25
  26 ;; This package provides the operations on rectangles that are ocumented
  27 ;; in the Emacs manual.
  28
  29 ;;; Code:
  30
  31 (defun operate-on-rectangle (function start end coerce-tabs)
  32   "Call FUNCTION for each line of rectangle with corners at START, END.
  33 If COERCE-TABS is non-nil, convert multi-column characters
  34 that span the starting or ending columns on any line
  35 to multiple spaces before calling FUNCTION.
  36 FUNCTION is called with three arguments:
  37  position of start of segment of this line within the rectangle,
  38  number of columns that belong to rectangle but are before that position,
  39  number of columns that belong to rectangle but are after point.
  40 Point is at the end of the segment of this line within the rectangle."
  41   (let (startcol startlinepos endcol endlinepos)
  42     (save-excursion
  43      (goto-char start)
  44      (setq startcol (current-column))
  45      (beginning-of-line)
  46      (setq startlinepos (point)))
  47     (save-excursion
  48      (goto-char end)
  49      (setq endcol (current-column))
  50      (forward-line 1)
  51      (setq endlinepos (point-marker)))
  52     (if (< endcol startcol)
  53         (setq startcol (prog1 endcol (setq endcol startcol))))
  54     (if (/= endcol startcol)
  55         (save-excursion
  56          (goto-char startlinepos)
  57          (while (< (point) endlinepos)
  58            (let (startpos begextra endextra)
  59              (move-to-column startcol coerce-tabs)
  60              (setq begextra (- (current-column) startcol))
  61              (setq startpos (point))
  62              (move-to-column endcol coerce-tabs)
  63              (setq endextra (- endcol (current-column)))
  64              (if (< begextra 0)
  65                  (setq endextra (+ endextra begextra)
  66                        begextra 0))
  67              (funcall function startpos begextra endextra))
  68            (forward-line 1))))
  69     (- endcol startcol)))
  70
  71 (defun delete-rectangle-line (startdelpos ignore ignore)
  72   (delete-region startdelpos (point)))
  73
  74 (defun delete-extract-rectangle-line (startdelpos begextra endextra)
  75   (save-excursion
  76    (extract-rectangle-line startdelpos begextra endextra))
  77   (delete-region startdelpos (point)))
  78
  79 (defun extract-rectangle-line (startdelpos begextra endextra)
  80   (let ((line (buffer-substring startdelpos (point)))
  81         (end (point)))
  82     (goto-char startdelpos)
  83     (while (search-forward "\t" end t)
  84       (let ((width (- (current-column)
  85                       (save-excursion (forward-char -1)
  86                                       (current-column)))))
  87         (setq line (concat (substring line 0 (- (point) end 1))
  88                            (spaces-string width)
  89                            (substring line (+ (length line) (- (point) end)))))))
  90     (if (or (> begextra 0) (> endextra 0))
  91         (setq line (concat (spaces-string begextra)
  92                            line
  93                            (spaces-string endextra))))
  94     (setq lines (cons line lines))))
  95
  96 (defconst spaces-strings
  97   '["" " " "  " "   " "    " "     " "      " "       " "        "])
  98
  99 (defun spaces-string (n)
 100   (if (<= n 8) (aref spaces-strings n)
 101     (let ((val ""))
 102       (while (> n 8)
 103         (setq val (concat "        " val)
 104               n (- n 8)))
 105       (concat val (aref spaces-strings n)))))
 106
 107 ;;;###autoload
 108 (defun delete-rectangle (start end)
 109   "Delete (don't save) text in rectangle with point and mark as corners.
 110 The same range of columns is deleted in each line starting with the line
 111 where the region begins and ending with the line where the region ends."
 112   (interactive "r")
 113   (operate-on-rectangle 'delete-rectangle-line start end t))
 114
 115 ;;;###autoload
 116 (defun delete-extract-rectangle (start end)
 117   "Delete contents of rectangle and return it as a list of strings.
 118 Arguments START and END are the corners of the rectangle.
 119 The value is list of strings, one for each line of the rectangle."
 120   (let (lines)
 121     (operate-on-rectangle 'delete-extract-rectangle-line
 122                           start end t)
 123     (nreverse lines)))
 124
 125 ;;;###autoload
 126 (defun extract-rectangle (start end)
 127   "Return contents of rectangle with corners at START and END.
 128 Value is list of strings, one for each line of the rectangle."
 129   (let (lines)
 130     (operate-on-rectangle 'extract-rectangle-line start end nil)
 131     (nreverse lines)))
 132
 133 (defvar killed-rectangle nil
 134   "Rectangle for yank-rectangle to insert.")
 135
 136 ;;;###autoload
 137 (defun kill-rectangle (start end)
 138   "Delete rectangle with corners at point and mark; save as last killed one.
 139 Calling from program, supply two args START and END, buffer positions.
 140 But in programs you might prefer to use `delete-extract-rectangle'."
 141   (interactive "r")
 142   (setq killed-rectangle (delete-extract-rectangle start end)))
 143
 144 ;;;###autoload
 145 (defun yank-rectangle ()
 146   "Yank the last killed rectangle with upper left corner at point."
 147   (interactive)
 148   (insert-rectangle killed-rectangle))
 149
 150 ;;;###autoload
 151 (defun insert-rectangle (rectangle)
 152   "Insert text of RECTANGLE with upper left corner at point.
 153 RECTANGLE's first line is inserted at point, its second
 154 line is inserted at a point vertically under point, etc.
 155 RECTANGLE should be a list of strings.
 156 After this command, the mark is at the upper left corner
 157 and point is at the lower right corner."
 158   (let ((lines rectangle)
 159         (insertcolumn (current-column))
 160         (first t))
 161     (push-mark)
 162     (while lines
 163       (or first
 164           (progn
 165            (forward-line 1)
 166            (or (bolp) (insert ?\n))
 167            (move-to-column insertcolumn t)))
 168       (setq first nil)
 169       (insert (car lines))
 170       (setq lines (cdr lines)))))
 171
 172 ;;;###autoload
 173 (defun open-rectangle (start end)
 174   "Blank out rectangle with corners at point and mark, shifting text right.
 175 The text previously in the region is not overwritten by the blanks,
 176 but instead winds up to the right of the rectangle."
 177   (interactive "r")
 178   (operate-on-rectangle 'open-rectangle-line start end nil)
 179   (goto-char start))
 180
 181 (defun open-rectangle-line (startpos begextra endextra)
 182   (let ((column (+ (current-column) begextra endextra)))
 183     (goto-char startpos)
 184     (let ((ocol (current-column)))
 185       (skip-chars-forward " \t")
 186       (setq column (+ column (- (current-column) ocol))))
 187     (delete-region (point)
 188                    ;; Use skip-chars-backward's LIM argument to leave
 189                    ;; characters before STARTPOS undisturbed.
 190                    (progn (skip-chars-backward " \t" startpos)
 191                           (point)))
 192     (indent-to column)))
 193
 194 ;;;###autoload
 195 (defun string-rectangle (start end string)
 196   "Insert STRING on each line of the region-rectangle, shifting text right.
 197 The left edge of the rectangle specifies the column for insertion.
 198 This command does not delete or overwrite any existing text.
 199
 200 Called from a program, takes three args; START, END and STRING."
 201   (interactive "r\nsString rectangle: ")
 202   (operate-on-rectangle 'string-rectangle-line start end nil)
 203   (goto-char start))
 204
 205 (defun string-rectangle-line (startpos begextra endextra)
 206   (let ((column (+ (current-column) begextra endextra)))
 207     (goto-char startpos)
 208     (let ((ocol (current-column)))
 209       (skip-chars-forward " \t")
 210       (setq column (+ column (- (current-column) ocol))))
 211     (delete-region (point)
 212                    ;; Use skip-chars-backward's LIM argument to leave
 213                    ;; characters before STARTPOS undisturbed.
 214                    (progn (skip-chars-backward " \t" startpos)
 215                           (point)))
 216     (insert string)))
 217
 218 ;;;###autoload
 219 (defun clear-rectangle (start end)
 220   "Blank out rectangle with corners at point and mark.
 221 The text previously in the region is overwritten by the blanks.
 222 When called from a program, requires two args which specify the corners."
 223   (interactive "r")
 224   (operate-on-rectangle 'clear-rectangle-line start end t))
 225
 226 (defun clear-rectangle-line (startpos begextra endextra)
 227   (skip-chars-forward " \t")
 228   (let ((column (+ (current-column) endextra)))
 229     (delete-region (point)
 230                    (progn (goto-char startpos)
 231                           (skip-chars-backward " \t")
 232                           (point)))
 233     (indent-to column)))
 234
 235 (provide 'rect)
 236
 237 ;;; rect.el ends here