emacs-lisp/rx.el (rx): Doc fix. (Bug#6537)
[emacs.git] / lisp / master.el
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1 ;;; master.el --- make a buffer the master over another buffer
3 ;; Copyright (C) 1999, 2000, 2001, 2002, 2003, 2004, 2005, 2006, 2007, 2008, 2009, 2010
4 ;; Free Software Foundation, Inc.
6 ;; Author: Alex Schroeder <alex@gnu.org>
7 ;; Maintainer: Alex Schroeder <alex@gnu.org>
8 ;; Version: 1.0.2
9 ;; Keywords: comm
11 ;; This file is part of GNU Emacs.
13 ;; GNU Emacs is free software: you can redistribute it and/or modify
14 ;; it under the terms of the GNU General Public License as published by
15 ;; the Free Software Foundation, either version 3 of the License, or
16 ;; (at your option) any later version.
18 ;; GNU Emacs is distributed in the hope that it will be useful,
19 ;; but WITHOUT ANY WARRANTY; without even the implied warranty of
20 ;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
21 ;; GNU General Public License for more details.
23 ;; You should have received a copy of the GNU General Public License
24 ;; along with GNU Emacs. If not, see <http://www.gnu.org/licenses/>.
26 ;;; Commentary:
28 ;; master-mode is a minor mode which enables you to scroll another
29 ;; buffer (the slave) without leaving your current buffer (the master).
31 ;; It can be used by sql.el, for example: The SQL buffer is the master
32 ;; and its SQLi buffer is the slave. This allows you to scroll the SQLi
33 ;; buffer containing the output from the SQL buffer containing the
34 ;; commands.
36 ;; This is how to use sql.el and master.el together: The variable
37 ;; sql-buffer contains the slave buffer. It is a local variable in the
38 ;; SQL buffer.
40 ;; (add-hook 'sql-mode-hook
41 ;; (function (lambda ()
42 ;; (master-mode t)
43 ;; (master-set-slave sql-buffer))))
44 ;; (add-hook 'sql-set-sqli-hook
45 ;; (function (lambda ()
46 ;; (master-set-slave sql-buffer))))
48 ;;; Thanks to all the people who helped me out:
50 ;; Rob Riepel <networking.stanford.edu>
52 ;;; History:
55 ;;; Code:
57 (defgroup master nil
58 "Support for master/slave relationships between buffers."
59 :version "22.1"
60 :group 'convenience)
62 ;; Variables that don't need initialization.
64 (defvar master-of nil
65 "Slave buffer of the current buffer. See `master-mode'.
66 You can set this variable using `master-set-slave'.")
68 (defvar master-set-slave-hook nil
69 "Hook run after the slave is changed using \\[master-set-slave].")
71 ;;; Define master mode.
73 ;;;###autoload
74 (define-minor-mode master-mode
75 "Toggle Master mode.
76 With no argument, this command toggles the mode.
77 Non-null prefix argument turns on the mode.
78 Null prefix argument turns off the mode.
80 When Master mode is enabled, you can scroll the slave buffer using the
81 following commands:
83 \\{master-mode-map}
85 The slave buffer is stored in the buffer-local variable `master-of'.
86 You can set this variable using `master-set-slave'. You can show
87 yourself the value of `master-of' by calling `master-show-slave'."
88 :group 'master
89 :keymap
90 '(("\C-c\C-n" . master-says-scroll-up)
91 ("\C-c\C-p" . master-says-scroll-down)
92 ("\C-c<" . master-says-beginning-of-buffer)
93 ("\C-c>" . master-says-end-of-buffer)
94 ("\C-c\C-l" . master-says-recenter)))
96 ;; Initialize Master mode by setting a slave buffer.
98 (defun master-set-slave (buffer)
99 "Makes BUFFER the slave of the current buffer.
100 Use \\[master-mode] to toggle control of the slave buffer."
101 (interactive "bSlave: ")
102 (make-local-variable 'master-of)
103 (setq master-of buffer)
104 (run-hooks 'master-set-slave-hook))
106 (defun master-show-slave ()
107 "Displays a message with the name of the slave buffer."
108 (interactive)
109 (message "This buffer is the master of %s. Master-mode is %S."
110 (or master-of "none")
111 master-mode))
115 ;;; Functions that the master buffer can call for the slave buffer.
117 (defun master-says-scroll-up (&optional arg)
118 "Display and scroll the slave buffer up.
119 See `scroll-up'."
120 (interactive)
121 (master-says 'scroll-up arg))
123 (defun master-says-scroll-down (&optional arg)
124 "Display and scroll the slave buffer down.
125 See `scroll-down'."
126 (interactive)
127 (master-says 'scroll-down arg))
129 (defun master-says-beginning-of-buffer (&optional arg)
130 "Display and move to the beginning of the slave buffer.
131 See `beginning-of-buffer'."
132 (interactive)
133 (master-says 'beginning-of-buffer arg))
135 (defun master-says-end-of-buffer (&optional arg)
136 "Display and move to the end of the slave buffer.
137 See `end-of-buffer'."
138 (interactive)
139 (master-says 'end-of-buffer arg))
141 (defun master-says-recenter (&optional arg)
142 "Recenter the slave buffer.
143 See `recenter'."
144 (interactive)
145 (master-says 'recenter arg))
147 ;; The master function doing the stuff.
149 (defun master-says (&optional command arg)
150 "Display slave buffer and execute COMMAND with ARG in its window."
151 (interactive)
152 (if (null (buffer-live-p (get-buffer master-of)))
153 (error "Slave buffer has disappeared")
154 (let ((window (selected-window)))
155 (if (not (eq (window-buffer window) (get-buffer master-of)))
156 (switch-to-buffer-other-window master-of))
157 (if command (condition-case nil (apply command arg) (error nil)))
158 (select-window window))))
160 (provide 'master)
162 ;; arch-tag: dca08daa-8127-45ae-b77e-b135160dce98
163 ;;; master.el ends here