152 lines
4.7 KiB
EmacsLisp
152 lines
4.7 KiB
EmacsLisp
;;; master.el --- make a buffer the master over another buffer -*- lexical-binding: t -*-
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;; Copyright (C) 1999-2024 Free Software Foundation, Inc.
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;; Author: Alex Schroeder <alex@gnu.org>
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;; Old-Version: 1.0.2
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;; Keywords: comm
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;; This file is part of GNU Emacs.
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;; GNU Emacs is free software: you can redistribute it and/or modify
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;; it under the terms of the GNU General Public License as published by
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;; the Free Software Foundation, either version 3 of the License, or
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;; (at your option) any later version.
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;; GNU Emacs is distributed in the hope that it will be useful,
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;; but WITHOUT ANY WARRANTY; without even the implied warranty of
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;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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;; GNU General Public License for more details.
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;; You should have received a copy of the GNU General Public License
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;; along with GNU Emacs. If not, see <https://www.gnu.org/licenses/>.
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;;; Commentary:
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;; `master-mode' is a minor mode which enables you to scroll another
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;; buffer (the slave) without leaving your current buffer (the master).
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;; It can be used by sql.el, for example: The SQL buffer is the master
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;; and its SQLi buffer is the slave. This allows you to scroll the SQLi
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;; buffer containing the output from the SQL buffer containing the
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;; commands.
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;;
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;; This is how to use sql.el and master.el together: The variable
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;; sql-buffer contains the slave buffer. It is a local variable in the
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;; SQL buffer.
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;;
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;; (add-hook 'sql-mode-hook
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;; (lambda ()
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;; (master-mode t)
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;; (master-set-slave sql-buffer)))
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;; (add-hook 'sql-set-sqli-hook
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;; (lambda ()
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;; (master-set-slave sql-buffer)))
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;;; Thanks to all the people who helped me out:
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;;
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;; Rob Riepel <networking.stanford.edu>
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;;; Code:
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;; Variables that don't need initialization.
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(defvar master-of nil
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"Slave buffer of the current buffer. See `master-mode'.
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You can set this variable using `master-set-slave'.")
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(defvar master-set-slave-hook nil
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"Hook run after the slave is changed using \\[master-set-slave].")
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;;; Define master mode.
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;;;###autoload
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(define-minor-mode master-mode
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"Toggle Master mode.
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When Master mode is enabled, you can scroll the slave buffer
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using the following commands:
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\\{master-mode-map}
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The slave buffer is stored in the buffer-local variable `master-of'.
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You can set this variable using `master-set-slave'. You can show
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yourself the value of `master-of' by calling `master-show-slave'."
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;; Not global, so no effect.
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;;; :group 'master
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:keymap
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'(("\C-c\C-n" . master-says-scroll-up)
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("\C-c\C-p" . master-says-scroll-down)
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("\C-c<" . master-says-beginning-of-buffer)
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("\C-c>" . master-says-end-of-buffer)
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("\C-c\C-l" . master-says-recenter)))
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;; Initialize Master mode by setting a slave buffer.
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(defun master-set-slave (buffer)
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"Make BUFFER the slave of the current buffer.
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Use \\[master-mode] to toggle control of the slave buffer."
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(interactive "bSlave: ")
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(setq-local master-of buffer)
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(run-hooks 'master-set-slave-hook))
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(defun master-show-slave ()
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"Displays a message with the name of the slave buffer."
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(interactive)
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(message "This buffer is the master of %s. Master-mode is %S."
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(or master-of "none")
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master-mode))
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;;; Functions that the master buffer can call for the slave buffer.
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(defun master-says-scroll-up (&optional arg)
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"Display and scroll the slave buffer up.
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See `scroll-up'."
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(interactive)
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(master-says 'scroll-up arg))
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(defun master-says-scroll-down (&optional arg)
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"Display and scroll the slave buffer down.
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See `scroll-down'."
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(interactive)
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(master-says 'scroll-down arg))
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(defun master-says-beginning-of-buffer (&optional arg)
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"Display and move to the beginning of the slave buffer.
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See `beginning-of-buffer'."
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(interactive)
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(master-says 'beginning-of-buffer arg))
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(defun master-says-end-of-buffer (&optional arg)
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"Display and move to the end of the slave buffer.
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See `end-of-buffer'."
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(interactive)
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(master-says 'end-of-buffer arg))
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(defun master-says-recenter (&optional arg)
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"Recenter the slave buffer.
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See `recenter'."
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(interactive)
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(master-says 'recenter arg))
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;; The master function doing the stuff.
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(defun master-says (&optional command arg)
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"Display slave buffer and execute COMMAND with ARG in its window."
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(interactive)
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(unless master-of
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(error "Current buffer is not a master of any other buffer"))
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(if (null (buffer-live-p (get-buffer master-of)))
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(error "Slave buffer has disappeared")
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(let ((window (selected-window)))
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(if (not (eq (window-buffer window) (get-buffer master-of)))
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(switch-to-buffer-other-window master-of))
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(if command (condition-case nil (apply command arg) (error nil)))
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(select-window window))))
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(provide 'master)
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;;; master.el ends here
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