lisp/erc/erc-ring.el

   1 ;; erc-ring.el -- Command history handling for erc using ring.el
   2
   3 ;; Copyright (C) 2001-2004, 2006-2013 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 ;;;###autoload (autoload 'erc-ring-mode "erc-ring" nil t)
  42 (define-erc-module ring nil
  43   "Stores input in a ring so that previous commands and messages can
  44 be recalled using M-p and M-n."
  45   ((add-hook 'erc-send-pre-hook 'erc-add-to-input-ring)
  46    (define-key erc-mode-map "\M-p" 'erc-previous-command)
  47    (define-key erc-mode-map "\M-n" 'erc-next-command))
  48   ((remove-hook 'erc-send-pre-hook 'erc-add-to-input-ring)
  49    (define-key erc-mode-map "\M-p" 'undefined)
  50    (define-key erc-mode-map "\M-n" 'undefined)))
  51
  52 (defvar erc-input-ring nil "Input ring for erc.")
  53 (make-variable-buffer-local 'erc-input-ring)
  54
  55 (defvar erc-input-ring-index nil
  56   "Position in the input ring for erc.
  57 If nil, the input line is blank and the user is conceptually 'after'
  58 the most recently added item in the ring. If an integer, the input
  59 line is non-blank and displays the item from the ring indexed by this
  60 variable.")
  61 (make-variable-buffer-local 'erc-input-ring-index)
  62
  63 (defun erc-input-ring-setup ()
  64   "Do the setup required so that we can use comint style input rings.
  65 Call this function when setting up the mode."
  66   (setq erc-input-ring (make-ring comint-input-ring-size))
  67   (setq erc-input-ring-index nil))
  68
  69 (defun erc-add-to-input-ring (s)
  70   "Add string S to the input ring and reset history position."
  71   (unless erc-input-ring (erc-input-ring-setup))
  72   (ring-insert erc-input-ring s)
  73   (setq erc-input-ring-index nil))
  74
  75 (defun erc-clear-input-ring ()
  76   "Remove all entries from the input ring, then call garbage-collect.
  77 You might use this for security purposes if you have typed a command
  78 containing a password."
  79   (interactive)
  80   (setq erc-input-ring (make-ring comint-input-ring-size)
  81         erc-input-ring-index nil)
  82   (garbage-collect)
  83   (message "ERC input ring cleared."))
  84
  85 (defun erc-previous-command ()
  86   "Replace current command with the previous one from the history."
  87   (interactive)
  88   (unless erc-input-ring (erc-input-ring-setup))
  89   ;; if the ring isn't empty
  90   (when (> (ring-length erc-input-ring) 0)
  91     (if (and erc-input-ring-index
  92              (= (ring-length erc-input-ring) (1+ erc-input-ring-index)))
  93         (progn
  94           (erc-replace-current-command "")
  95           (setq erc-input-ring-index nil))
  96
  97       ;; If we are not viewing old input and there's text in the input
  98       ;; area, push it on the history ring before moving back through
  99       ;; the input history, so it will be there when we return to the
 100       ;; front.
 101       (if (null erc-input-ring-index)
 102           (when (> (point-max) erc-input-marker)
 103             (erc-add-to-input-ring (buffer-substring erc-input-marker
 104                                                      (point-max)))
 105             (setq erc-input-ring-index 0)))
 106
 107       (setq erc-input-ring-index (if erc-input-ring-index
 108                                      (ring-plus1 erc-input-ring-index
 109                                                  (ring-length erc-input-ring))
 110                                    0))
 111       (erc-replace-current-command (ring-ref erc-input-ring
 112                                              erc-input-ring-index)))))
 113
 114 (defun erc-next-command ()
 115   "Replace current command with the next one from the history."
 116   (interactive)
 117   (unless erc-input-ring (erc-input-ring-setup))
 118   ;; if the ring isn't empty
 119   (when (> (ring-length erc-input-ring) 0)
 120     (if (and erc-input-ring-index
 121              (= 0 erc-input-ring-index))
 122         (progn
 123           (erc-replace-current-command "")
 124           (setq erc-input-ring-index nil))
 125       (setq erc-input-ring-index (ring-minus1 (or erc-input-ring-index 0)
 126                                               (ring-length erc-input-ring)))
 127       (erc-replace-current-command (ring-ref erc-input-ring
 128       erc-input-ring-index)))))
 129
 130
 131 (defun erc-replace-current-command (s)
 132   "Replace current command with string S."
 133   ;; delete line
 134   (let ((inhibit-read-only t))
 135     (delete-region
 136      (progn (goto-char erc-insert-marker) (erc-bol))
 137      (goto-char (point-max)))
 138     (insert s)))
 139
 140 (provide 'erc-ring)
 141
 142 ;;; erc-ring.el ends here
 143 ;; Local Variables:
 144 ;; indent-tabs-mode: nil
 145 ;; End:
 146