lisp/textmodes/text-mode.el

   1 ;;; text-mode.el --- text mode, and its idiosyncratic commands
   2
   3 ;; Copyright (C) 1985, 1992, 1994, 2001-2014 Free Software Foundation,
   4 ;; Inc.
   5
   6 ;; Maintainer: emacs-devel@gnu.org
   7 ;; Keywords: wp
   8 ;; Package: emacs
   9
  10 ;; This file is part of GNU Emacs.
  11
  12 ;; GNU Emacs is free software: you can redistribute it and/or modify
  13 ;; it under the terms of the GNU General Public License as published by
  14 ;; the Free Software Foundation, either version 3 of the License, or
  15 ;; (at your option) any later version.
  16
  17 ;; GNU Emacs is distributed in the hope that it will be useful,
  18 ;; but WITHOUT ANY WARRANTY; without even the implied warranty of
  19 ;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  20 ;; GNU General Public License for more details.
  21
  22 ;; You should have received a copy of the GNU General Public License
  23 ;; along with GNU Emacs.  If not, see <http://www.gnu.org/licenses/>.
  24
  25 ;;; Commentary:
  26
  27 ;; This package provides the fundamental text mode documented in the
  28 ;; Emacs user's manual.
  29
  30 ;;; Code:
  31
  32 (defcustom text-mode-hook nil
  33   "Normal hook run when entering Text mode and many related modes."
  34   :type 'hook
  35   :options '(turn-on-auto-fill turn-on-flyspell)
  36   :group 'wp)
  37
  38 (defvar text-mode-variant nil
  39   "Non-nil if this buffer's major mode is a variant of Text mode.
  40 Use (derived-mode-p 'text-mode) instead.")
  41
  42 (defvar text-mode-syntax-table
  43   (let ((st (make-syntax-table)))
  44     (modify-syntax-entry ?\" ".   " st)
  45     (modify-syntax-entry ?\\ ".   " st)
  46     ;; We add `p' so that M-c on 'hello' leads to 'Hello' rather than 'hello'.
  47     (modify-syntax-entry ?' "w p" st)
  48     st)
  49   "Syntax table used while in `text-mode'.")
  50
  51 (defvar text-mode-map
  52   (let ((map (make-sparse-keymap)))
  53     (define-key map "\e\t" 'ispell-complete-word)
  54     (define-key map [menu-bar text]
  55       (cons "Text" (make-sparse-keymap "Text")))
  56     (bindings--define-key map [menu-bar text toggle-text-mode-auto-fill]
  57       '(menu-item "Auto Fill" toggle-text-mode-auto-fill
  58                   :button (:toggle . (memq 'turn-on-auto-fill text-mode-hook))
  59                   :help "Automatically fill text while typing in text modes (Auto Fill mode)"))
  60     (bindings--define-key map [menu-bar text paragraph-indent-minor-mode]
  61       '(menu-item "Paragraph Indent" paragraph-indent-minor-mode
  62                   :button (:toggle . (bound-and-true-p paragraph-indent-minor-mode))
  63                   :help "Toggle paragraph indent minor mode"))
  64     (bindings--define-key map [menu-bar text sep] menu-bar-separator)
  65     (bindings--define-key map [menu-bar text center-region]
  66       '(menu-item "Center Region" center-region
  67                   :help "Center the marked region"
  68                   :enable (region-active-p)))
  69     (bindings--define-key map [menu-bar text center-paragraph]
  70       '(menu-item "Center Paragraph" center-paragraph
  71                   :help "Center the current paragraph"))
  72     (bindings--define-key map [menu-bar text center-line]
  73       '(menu-item "Center Line" center-line
  74                   :help "Center the current line"))
  75     map)
  76   "Keymap for `text-mode'.
  77 Many other modes, such as `mail-mode', `outline-mode' and `indented-text-mode',
  78 inherit all the commands defined in this map.")
  79
  80 \f
  81 (define-derived-mode text-mode nil "Text"
  82   "Major mode for editing text written for humans to read.
  83 In this mode, paragraphs are delimited only by blank or white lines.
  84 You can thus get the full benefit of adaptive filling
  85  (see the variable `adaptive-fill-mode').
  86 \\{text-mode-map}
  87 Turning on Text mode runs the normal hook `text-mode-hook'."
  88   (set (make-local-variable 'text-mode-variant) t)
  89   (set (make-local-variable 'require-final-newline)
  90        mode-require-final-newline)
  91   (set (make-local-variable 'indent-line-function) 'indent-relative))
  92
  93 (define-derived-mode paragraph-indent-text-mode text-mode "Parindent"
  94   "Major mode for editing text, with leading spaces starting a paragraph.
  95 In this mode, you do not need blank lines between paragraphs
  96 when the first line of the following paragraph starts with whitespace.
  97 `paragraph-indent-minor-mode' provides a similar facility as a minor mode.
  98 Special commands:
  99 \\{text-mode-map}
 100 Turning on Paragraph-Indent Text mode runs the normal hooks
 101 `text-mode-hook' and `paragraph-indent-text-mode-hook'."
 102   :abbrev-table nil :syntax-table nil
 103   (paragraph-indent-minor-mode))
 104
 105 (define-minor-mode paragraph-indent-minor-mode
 106   "Minor mode for editing text, with leading spaces starting a paragraph.
 107 In this mode, you do not need blank lines between paragraphs when the
 108 first line of the following paragraph starts with whitespace, as with
 109 `paragraph-indent-text-mode'.
 110 Turning on Paragraph-Indent minor mode runs the normal hook
 111 `paragraph-indent-text-mode-hook'."
 112   :initial-value nil
 113   ;; Change the definition of a paragraph start.
 114   (let ((ps-re "[ \t\n\f]\\|"))
 115     (if (eq t (compare-strings ps-re nil nil
 116                                paragraph-start nil (length ps-re)))
 117         (if (not paragraph-indent-minor-mode)
 118             (set (make-local-variable 'paragraph-start)
 119                  (substring paragraph-start (length ps-re))))
 120       (if paragraph-indent-minor-mode
 121           (set (make-local-variable 'paragraph-start)
 122                (concat ps-re paragraph-start)))))
 123   ;; Change the indentation function.
 124   (if paragraph-indent-minor-mode
 125       (add-function :override (local 'indent-line-function)
 126                     #'indent-to-left-margin)
 127     (remove-function (local 'indent-line-function)
 128                      #'indent-to-left-margin)))
 129
 130 (defalias 'indented-text-mode 'text-mode)
 131
 132 ;; This can be made a no-op once all modes that use text-mode-hook
 133 ;; are "derived" from text-mode.
 134 (defun text-mode-hook-identify ()
 135   "Mark that this mode has run `text-mode-hook'.
 136 This is how `toggle-text-mode-auto-fill' knows which buffers to operate on."
 137   (set (make-local-variable 'text-mode-variant) t))
 138
 139 (add-hook 'text-mode-hook 'text-mode-hook-identify)
 140
 141 (defun toggle-text-mode-auto-fill ()
 142   "Toggle whether to use Auto Fill in Text mode and related modes.
 143 This command affects all buffers that use modes related to Text mode,
 144 both existing buffers and buffers that you subsequently create."
 145   (interactive)
 146   (let ((enable-mode (not (memq 'turn-on-auto-fill text-mode-hook))))
 147     (if enable-mode
 148         (add-hook 'text-mode-hook 'turn-on-auto-fill)
 149       (remove-hook 'text-mode-hook 'turn-on-auto-fill))
 150     (dolist (buffer (buffer-list))
 151       (with-current-buffer buffer
 152         (if (or (derived-mode-p 'text-mode) text-mode-variant)
 153             (auto-fill-mode (if enable-mode 1 0)))))
 154     (message "Auto Fill %s in Text modes"
 155              (if enable-mode "enabled" "disabled"))))
 156 \f
 157
 158 (define-key facemenu-keymap "\eS" 'center-paragraph)
 159
 160 (defun center-paragraph ()
 161   "Center each nonblank line in the paragraph at or after point.
 162 See `center-line' for more info."
 163   (interactive)
 164   (save-excursion
 165     (forward-paragraph)
 166     (or (bolp) (newline 1))
 167     (let ((end (point)))
 168       (backward-paragraph)
 169       (center-region (point) end))))
 170
 171 (defun center-region (from to)
 172   "Center each nonblank line starting in the region.
 173 See `center-line' for more info."
 174   (interactive "r")
 175   (if (> from to)
 176       (let ((tem to))
 177         (setq to from from tem)))
 178   (save-excursion
 179     (save-restriction
 180       (narrow-to-region from to)
 181       (goto-char from)
 182       (while (not (eobp))
 183         (or (save-excursion (skip-chars-forward " \t") (eolp))
 184             (center-line))
 185         (forward-line 1)))))
 186
 187 (define-key facemenu-keymap "\es" 'center-line)
 188
 189 (defun center-line (&optional nlines)
 190   "Center the line point is on, within the width specified by `fill-column'.
 191 This means adjusting the indentation so that it equals
 192 the distance between the end of the text and `fill-column'.
 193 The argument NLINES says how many lines to center."
 194   (interactive "P")
 195   (if nlines (setq nlines (prefix-numeric-value nlines)))
 196   (while (not (eq nlines 0))
 197     (save-excursion
 198       (let ((lm (current-left-margin))
 199             line-length)
 200         (beginning-of-line)
 201         (delete-horizontal-space)
 202         (end-of-line)
 203         (delete-horizontal-space)
 204         (setq line-length (current-column))
 205         (if (> (- fill-column lm line-length) 0)
 206             (indent-line-to
 207              (+ lm (/ (- fill-column lm line-length) 2))))))
 208     (cond ((null nlines)
 209            (setq nlines 0))
 210           ((> nlines 0)
 211            (setq nlines (1- nlines))
 212            (forward-line 1))
 213           ((< nlines 0)
 214            (setq nlines (1+ nlines))
 215            (forward-line -1)))))
 216
 217 ;;; text-mode.el ends here