less.el

   1 ;;; less.el --- less style view mode
   2
   3 ;; Copyright (C) 2005, 2007 William Xu
   4
   5 ;; Author: William Xu <william.xwl@gmail.com>
   6 ;; Version: 0.2
   7
   8 ;; This program is free software; you can redistribute it and/or modify
   9 ;; it under the terms of the GNU General Public License as published by
  10 ;; the Free Software Foundation; either version 2, or (at your option)
  11 ;; any later version.
  12 ;;
  13 ;; This program is distributed in the hope that it will be useful,
  14 ;; but WITHOUT ANY WARRANTY; without even the implied warranty of
  15 ;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  16 ;; GNU General Public License for more details.
  17 ;;
  18 ;; You should have received a copy of the GNU General Public License
  19 ;; along with this program; if not, write to the Free Software
  20 ;; Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
  21 ;; 02110-1301 USA
  22
  23 ;;; Commentary:
  24
  25 ;; View file like a simple `less'. Provide limited less keys, mainly j,
  26 ;; k, f, b, g, G, etc.
  27
  28 ;; Put this file into your load-path and the following into your ~/.emacs:
  29 ;;   (require 'less)
  30 ;;
  31 ;; Then use `M-x less-minor-mode' to toggle `less-minor-mode'.
  32
  33 ;; There's also a `view-less.el' in XEmacs. But it does too much for me,
  34 ;; i just wanna less keys like j, k, f, b, g, G, not to mess with other
  35 ;; keys in major mode.
  36
  37 ;;; Code:
  38
  39 ;;;###autoload
  40 (define-minor-mode less-minor-mode
  41   "Toggle less-minor-mode.
  42
  43 With less-minor-mode enabled, you could use `less' like keys to view files.
  44 \\{less-minor-mode-map}."
  45   nil " Less"
  46   '(("j" . less-scroll-up-one-line)
  47     ("k" . less-scroll-down-one-line)
  48     ("f" . scroll-up)
  49     ("b" . scroll-down)
  50     ("g" . beginning-of-buffer)
  51     ("G" . end-of-buffer)
  52     (" " . scroll-up)
  53     ("\x7f" . scroll-down)
  54     ("e" . less-quit))
  55     (set (make-local-variable 'buffer-read-only) less-minor-mode))
  56
  57 (defun less-scroll-up-one-line ()
  58   "Scroll up one line."
  59   (interactive)
  60   (scroll-up 1))
  61
  62 (defun less-scroll-down-one-line ()
  63   "Scroll down one line."
  64   (interactive)
  65   (scroll-down 1))
  66
  67 (defun less-quit ()
  68   "Quit `less-minor-mode'."
  69   (interactive)
  70   (less-minor-mode -1))
  71
  72 ;;;###autoload
  73 (defun auto-less-minor-mode ()
  74   "Auto enter `less-minor-mode' when visiting read-only files. You can
  75 add this to `find-file-hooks'."
  76   (unless (file-writable-p buffer-file-name)
  77     (less-minor-mode 1)))
  78
  79 ;;;###autoload
  80 (defun less-minor-mode-on ()
  81   "Turn on `less-minor-mode'."
  82   (less-minor-mode 1))
  83
  84 ;;;###autoload
  85 (defun less-minor-mode-off ()
  86   "Turn off `less-minor-mode'."
  87   (less-minor-mode -1))
  88
  89 (provide 'less)
  90
  91 ;;; less.el ends here