lisp/erc/erc-ring.el

   1 ;; erc-ring.el -- Command history handling for erc using ring.el
   2
   3 ;; Copyright (C) 2001-2004, 2006-2014 Free Software Foundation, Inc.
   4
   5 ;; Author: Alex Schroeder <alex@gnu.org>
   6 ;; Maintainer: FSF
   7 ;; Keywords: comm
   8 ;; URL: http://www.emacswiki.org/cgi-bin/wiki.pl?ErcHistory
   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 file implements an input ring -- a history of the stuff you
  28 ;; wrote.  To activate:
  29 ;;
  30 ;; (require 'erc-auto) or (require 'erc-ring)
  31 ;; (erc-ring-mode 1)
  32 ;;
  33 ;; Use M-n and M-p to navigate the ring
  34
  35 ;;; Code:
  36
  37 (require 'erc)
  38 (require 'comint)
  39 (require 'ring)
  40
  41 (defgroup erc-ring nil
  42   "An input ring for ERC."
  43   :group 'erc)
  44
  45 ;;;###autoload (autoload 'erc-ring-mode "erc-ring" nil t)
  46 (define-erc-module ring nil
  47   "Stores input in a ring so that previous commands and messages can
  48 be recalled using M-p and M-n."
  49   ((add-hook 'erc-send-pre-hook 'erc-add-to-input-ring)
  50    (define-key erc-mode-map "\M-p" 'erc-previous-command)
  51    (define-key erc-mode-map "\M-n" 'erc-next-command))
  52   ((remove-hook 'erc-send-pre-hook 'erc-add-to-input-ring)
  53    (define-key erc-mode-map "\M-p" 'undefined)
  54    (define-key erc-mode-map "\M-n" 'undefined)))
  55
  56 (defvar erc-input-ring nil "Input ring for erc.")
  57 (make-variable-buffer-local 'erc-input-ring)
  58
  59 (defvar erc-input-ring-index nil
  60   "Position in the input ring for erc.
  61 If nil, the input line is blank and the user is conceptually 'after'
  62 the most recently added item in the ring. If an integer, the input
  63 line is non-blank and displays the item from the ring indexed by this
  64 variable.")
  65 (make-variable-buffer-local 'erc-input-ring-index)
  66
  67 (defun erc-input-ring-setup ()
  68   "Do the setup required so that we can use comint style input rings.
  69 Call this function when setting up the mode."
  70   (setq erc-input-ring (make-ring comint-input-ring-size))
  71   (setq erc-input-ring-index nil))
  72
  73 (defun erc-add-to-input-ring (s)
  74   "Add string S to the input ring and reset history position."
  75   (unless erc-input-ring (erc-input-ring-setup))
  76   (ring-insert erc-input-ring s)
  77   (setq erc-input-ring-index nil))
  78
  79 (defun erc-clear-input-ring ()
  80   "Remove all entries from the input ring, then call garbage-collect.
  81 You might use this for security purposes if you have typed a command
  82 containing a password."
  83   (interactive)
  84   (setq erc-input-ring (make-ring comint-input-ring-size)
  85         erc-input-ring-index nil)
  86   (garbage-collect)
  87   (message "ERC input ring cleared."))
  88
  89 (defun erc-previous-command ()
  90   "Replace current command with the previous one from the history."
  91   (interactive)
  92   (unless erc-input-ring (erc-input-ring-setup))
  93   ;; if the ring isn't empty
  94   (when (> (ring-length erc-input-ring) 0)
  95     (if (and erc-input-ring-index
  96              (= (ring-length erc-input-ring) (1+ erc-input-ring-index)))
  97         (progn
  98           (erc-replace-current-command "")
  99           (setq erc-input-ring-index nil))
 100
 101       ;; If we are not viewing old input and there's text in the input
 102       ;; area, push it on the history ring before moving back through
 103       ;; the input history, so it will be there when we return to the
 104       ;; front.
 105       (if (null erc-input-ring-index)
 106           (when (> (point-max) erc-input-marker)
 107             (erc-add-to-input-ring (buffer-substring erc-input-marker
 108                                                      (point-max)))
 109             (setq erc-input-ring-index 0)))
 110
 111       (setq erc-input-ring-index (if erc-input-ring-index
 112                                      (ring-plus1 erc-input-ring-index
 113                                                  (ring-length erc-input-ring))
 114                                    0))
 115       (erc-replace-current-command (ring-ref erc-input-ring
 116                                              erc-input-ring-index)))))
 117
 118 (defun erc-next-command ()
 119   "Replace current command with the next one from the history."
 120   (interactive)
 121   (unless erc-input-ring (erc-input-ring-setup))
 122   ;; if the ring isn't empty
 123   (when (> (ring-length erc-input-ring) 0)
 124     (if (and erc-input-ring-index
 125              (= 0 erc-input-ring-index))
 126         (progn
 127           (erc-replace-current-command "")
 128           (setq erc-input-ring-index nil))
 129       (setq erc-input-ring-index (ring-minus1 (or erc-input-ring-index 0)
 130                                               (ring-length erc-input-ring)))
 131       (erc-replace-current-command (ring-ref erc-input-ring
 132       erc-input-ring-index)))))
 133
 134
 135 (defun erc-replace-current-command (s)
 136   "Replace current command with string S."
 137   ;; delete line
 138   (let ((inhibit-read-only t))
 139     (delete-region
 140      (progn (goto-char erc-insert-marker) (erc-bol))
 141      (goto-char (point-max)))
 142     (insert s)))
 143
 144 (provide 'erc-ring)
 145
 146 ;;; erc-ring.el ends here
 147 ;; Local Variables:
 148 ;; indent-tabs-mode: nil
 149 ;; End:
 150