lisp/indent.el

   1 ;;; indent.el --- indentation commands for Emacs
   2
   3 ;; Copyright (C) 1985 Free Software Foundation, Inc.
   4
   5 ;; Maintainer: FSF
   6
   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
  11 ;; the Free Software Foundation; either version 2, or (at your option)
  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
  20 ;; along with GNU Emacs; see the file COPYING.  If not, write to
  21 ;; the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA.
  22
  23 ;;; Commentary:
  24
  25 ;; Commands for making and changing indentation in text.  These are
  26 ;; described in the Emacs manual.
  27
  28 ;;; Code:
  29
  30 (defvar indent-line-function 'indent-to-left-margin "\
  31 Function to indent current line.")
  32
  33 (defun indent-according-to-mode ()
  34   "Indent line in proper way for current major mode."
  35   (interactive)
  36   (funcall indent-line-function))
  37
  38 (defun indent-for-tab-command ()
  39   "Indent line in proper way for current major mode."
  40   (interactive)
  41   (if (eq indent-line-function 'indent-to-left-margin)
  42       (insert-tab)
  43     (funcall indent-line-function)))
  44
  45 (defun insert-tab ()
  46   (if abbrev-mode
  47       (expand-abbrev))
  48   (if indent-tabs-mode
  49       (insert ?\t)
  50     (indent-to (* tab-width (1+ (/ (current-column) tab-width))))))
  51
  52 (defun indent-rigidly (start end arg)
  53   "Indent all lines starting in the region sideways by ARG columns.
  54 Called from a program, takes three arguments, START, END and ARG."
  55   (interactive "r\np")
  56   (save-excursion
  57     (goto-char end)
  58     (setq end (point-marker))
  59     (goto-char start)
  60     (or (bolp) (forward-line 1))
  61     (while (< (point) end)
  62       (let ((indent (current-indentation)))
  63         (delete-region (point) (progn (skip-chars-forward " \t") (point)))
  64         (or (eolp)
  65             (indent-to (max 0 (+ indent arg)) 0)))
  66       (forward-line 1))
  67     (move-marker end nil)))
  68
  69 ;; This is the default indent-line-function,
  70 ;; used in Fundamental Mode, Text Mode, etc.
  71 (defun indent-to-left-margin ()
  72   (or (= (current-indentation) left-margin)
  73       (let (epos)
  74         (save-excursion
  75          (beginning-of-line)
  76          (delete-region (point)
  77                         (progn (skip-chars-forward " \t")
  78                                (point)))
  79          (indent-to left-margin)
  80          (setq epos (point)))
  81         (if (< (point) epos)
  82             (goto-char epos)))))
  83
  84 (defvar indent-region-function nil
  85   "Function which is short cut to indent region using indent-according-to-mode.
  86 A value of nil means really run indent-according-to-mode on each line.")
  87
  88 (defun indent-region (start end column)
  89   "Indent each nonblank line in the region.
  90 With no argument, indent each line using `indent-according-to-mode',
  91 or use `indent-region-function' to do the whole region if that's non-nil.
  92 If there is a fill prefix, make each line start with the fill prefix.
  93 With argument COLUMN, indent each line to that column.
  94 Called from a program, takes three args: START, END and COLUMN."
  95   (interactive "r\nP")
  96   (if (null column)
  97       (if fill-prefix
  98           (save-excursion
  99             (goto-char end)
 100             (setq end (point-marker))
 101             (goto-char start)
 102             (let ((regexp (regexp-quote fill-prefix)))
 103               (while (< (point) end)
 104                 (or (looking-at regexp)
 105                     (and (bolp) (eolp))
 106                     (insert fill-prefix))
 107                 (forward-line 1))))
 108         (if indent-region-function
 109             (funcall indent-region-function start end)
 110           (save-excursion
 111             (goto-char end)
 112             (setq end (point-marker))
 113             (goto-char start)
 114             (or (bolp) (forward-line 1))
 115             (while (< (point) end)
 116               (or (and (bolp) (eolp))
 117                   (funcall indent-line-function))
 118               (forward-line 1))
 119             (move-marker end nil))))
 120     (setq column (prefix-numeric-value column))
 121     (save-excursion
 122       (goto-char end)
 123       (setq end (point-marker))
 124       (goto-char start)
 125       (or (bolp) (forward-line 1))
 126       (while (< (point) end)
 127         (delete-region (point) (progn (skip-chars-forward " \t") (point)))
 128         (or (eolp)
 129         (indent-to column 0))
 130         (forward-line 1))
 131       (move-marker end nil))))
 132
 133 (defun indent-relative-maybe ()
 134   "Indent a new line like previous nonblank line."
 135   (interactive)
 136   (indent-relative t))
 137
 138 (defun indent-relative (&optional unindented-ok)
 139   "Space out to under next indent point in previous nonblank line.
 140 An indent point is a non-whitespace character following whitespace.
 141 If the previous nonblank line has no indent points beyond the
 142 column point starts at, `tab-to-tab-stop' is done instead."
 143   (interactive "P")
 144   (if abbrev-mode (expand-abbrev))
 145   (let ((start-column (current-column))
 146         indent)
 147     (save-excursion
 148       (beginning-of-line)
 149       (if (re-search-backward "^[^\n]" nil t)
 150           (let ((end (save-excursion (forward-line 1) (point))))
 151             (move-to-column start-column)
 152             ;; Is start-column inside a tab on this line?
 153             (if (> (current-column) start-column)
 154                 (backward-char 1))
 155             (or (looking-at "[ \t]")
 156                 unindented-ok
 157                 (skip-chars-forward "^ \t" end))
 158             (skip-chars-forward " \t" end)
 159             (or (= (point) end) (setq indent (current-column))))))
 160     (if indent
 161         (let ((opoint (point-marker)))
 162           (delete-region (point) (progn (skip-chars-backward " \t") (point)))
 163           (indent-to indent 0)
 164           (if (> opoint (point))
 165               (goto-char opoint))
 166           (move-marker opoint nil))
 167       (tab-to-tab-stop))))
 168
 169 (defvar tab-stop-list
 170   '(8 16 24 32 40 48 56 64 72 80 88 96 104 112 120)
 171   "*List of tab stop positions used by `tab-to-tab-stops'.")
 172
 173 (defvar edit-tab-stops-map nil "Keymap used in `edit-tab-stops'.")
 174 (if edit-tab-stops-map
 175     nil
 176   (setq edit-tab-stops-map (make-sparse-keymap))
 177   (define-key edit-tab-stops-map "\C-x\C-s" 'edit-tab-stops-note-changes)
 178   (define-key edit-tab-stops-map "\C-c\C-c" 'edit-tab-stops-note-changes))
 179
 180 (defvar edit-tab-stops-buffer nil
 181   "Buffer whose tab stops are being edited--in case
 182 the variable `tab-stop-list' is local in that buffer.")
 183
 184 (defun edit-tab-stops ()
 185   "Edit the tab stops used by `tab-to-tab-stop'.
 186 Creates a buffer *Tab Stops* containing text describing the tab stops.
 187 A colon indicates a column where there is a tab stop.
 188 You can add or remove colons and then do \\<edit-tab-stops-map>\\[edit-tab-stops-note-changes] to make changes take effect."
 189   (interactive)
 190   (setq edit-tab-stops-buffer (current-buffer))
 191   (switch-to-buffer (get-buffer-create "*Tab Stops*"))
 192   (use-local-map edit-tab-stops-map)
 193   (make-local-variable 'indent-tabs-mode)
 194   (setq indent-tabs-mode nil)
 195   (overwrite-mode 1)
 196   (setq truncate-lines t)
 197   (erase-buffer)
 198   (let ((tabs tab-stop-list))
 199     (while tabs
 200       (indent-to (car tabs) 0)
 201       (insert ?:)
 202       (setq tabs (cdr tabs))))
 203   (let ((count 0))
 204     (insert ?\n)
 205     (while (< count 8)
 206       (insert (+ count ?0))
 207     (insert "         ")
 208       (setq count (1+ count)))
 209     (insert ?\n)
 210     (while (> count 0)
 211       (insert "0123456789")
 212       (setq count (1- count))))
 213   (insert "\nTo install changes, type C-c C-c")
 214   (goto-char (point-min)))
 215
 216 (defun edit-tab-stops-note-changes ()
 217   "Put edited tab stops into effect."
 218   (interactive)
 219     (let (tabs)
 220       (save-excursion
 221         (goto-char 1)
 222         (end-of-line)
 223         (while (search-backward ":" nil t)
 224           (setq tabs (cons (current-column) tabs))))
 225       (bury-buffer (prog1 (current-buffer)
 226                           (switch-to-buffer edit-tab-stops-buffer)))
 227       (setq tab-stop-list tabs))
 228   (message "Tab stops installed"))
 229
 230 (defun tab-to-tab-stop ()
 231   "Insert spaces or tabs to next defined tab-stop column.
 232 The variable `tab-stop-list' is a list of columns at which there are tab stops.
 233 Use \\[edit-tab-stops] to edit them interactively."
 234   (interactive)
 235   (if abbrev-mode (expand-abbrev))
 236   (let ((tabs tab-stop-list))
 237     (while (and tabs (>= (current-column) (car tabs)))
 238       (setq tabs (cdr tabs)))
 239     (if tabs
 240         (indent-to (car tabs))
 241       (insert ?\ ))))
 242
 243 (defun move-to-tab-stop ()
 244   "Move point to next defined tab-stop column.
 245 The variable `tab-stop-list' is a list of columns at which there are tab stops.
 246 Use \\[edit-tab-stops] to edit them interactively."
 247   (interactive)
 248   (let ((tabs tab-stop-list))
 249     (while (and tabs (>= (current-column) (car tabs)))
 250       (setq tabs (cdr tabs)))
 251     (if tabs
 252         (move-to-column (car tabs) t))))
 253
 254 (define-key global-map "\t" 'indent-for-tab-command)
 255 (define-key esc-map "\034" 'indent-region)
 256 (define-key ctl-x-map "\t" 'indent-rigidly)
 257 (define-key esc-map "i" 'tab-to-tab-stop)
 258
 259 ;;; indent.el ends here