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4a5717d19f
no longer disconcertingly move point in the original buffer.
179 lines
6.4 KiB
EmacsLisp
179 lines
6.4 KiB
EmacsLisp
;;; electric.el --- window maker and Command loop for `electric' modes
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;; Copyright (C) 1985, 1986, 1995 Free Software Foundation, Inc.
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;; Author: K. Shane Hartman
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;; Maintainer: FSF
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;; Keywords: extensions
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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 2, or (at your option)
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;; 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; see the file COPYING. If not, write to the
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;; Free Software Foundation, Inc., 59 Temple Place - Suite 330,
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;; Boston, MA 02111-1307, USA.
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;;; Commentary:
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; zaaaaaaap
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;;; Code:
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;; This loop is the guts for non-standard modes which retain control
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;; until some event occurs. It is a `do-forever', the only way out is
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;; to throw. It assumes that you have set up the keymap, window, and
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;; everything else: all it does is read commands and execute them -
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;; providing error messages should one occur (if there is no loop
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;; function - which see). The required argument is a tag which should
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;; expect a value of nil if the user decides to punt. The second
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;; argument is the prompt to be used: if nil, use "->", if 'noprompt,
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;; don't use a prompt, if a string, use that string as prompt, and if
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;; a function of no variable, it will be evaluated in every iteration
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;; of the loop and its return value, which can be nil, 'noprompt or a
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;; string, will be used as prompt. Given third argument non-nil, it
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;; INHIBITS quitting unless the user types C-g at toplevel. This is
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;; so user can do things like C-u C-g and not get thrown out. Fourth
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;; argument, if non-nil, should be a function of two arguments which
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;; is called after every command is executed. The fifth argument, if
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;; provided, is the state variable for the function. If the
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;; loop-function gets an error, the loop will abort WITHOUT throwing
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;; (moral: use unwind-protect around call to this function for any
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;; critical stuff). The second argument for the loop function is the
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;; conditions for any error that occurred or nil if none.
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(defun Electric-command-loop (return-tag
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&optional prompt inhibit-quit
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loop-function loop-state)
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(let (cmd
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(err nil)
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(prompt-string prompt))
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(while t
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(if (not (or (stringp prompt) (eq prompt nil) (eq prompt 'noprompt)))
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(setq prompt-string (funcall prompt)))
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(if (not (stringp prompt-string))
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(if (eq prompt-string 'noprompt)
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(setq prompt-string nil)
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(setq prompt-string "->")))
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(setq cmd (read-key-sequence prompt-string))
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(setq last-command-char (aref cmd (1- (length cmd)))
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this-command (key-binding cmd t)
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cmd this-command)
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;; This makes universal-argument-other-key work.
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(setq universal-argument-num-events 0)
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(if (or (prog1 quit-flag (setq quit-flag nil))
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(eq last-input-char ?\C-g))
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(progn (setq unread-command-events nil
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prefix-arg nil)
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;; If it wasn't cancelling a prefix character, then quit.
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(if (or (= (length (this-command-keys)) 1)
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(not inhibit-quit)) ; safety
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(progn (ding)
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(message "Quit")
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(throw return-tag nil))
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(setq cmd nil))))
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(setq current-prefix-arg prefix-arg)
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(if cmd
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(condition-case conditions
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(progn (command-execute cmd)
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(setq last-command this-command)
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(if (or (prog1 quit-flag (setq quit-flag nil))
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(eq last-input-char ?\C-g))
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(progn (setq unread-command-events nil)
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(if (not inhibit-quit)
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(progn (ding)
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(message "Quit")
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(throw return-tag nil))
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(ding)))))
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(buffer-read-only (if loop-function
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(setq err conditions)
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(ding)
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(message "Buffer is read-only")
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(sit-for 2)))
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(beginning-of-buffer (if loop-function
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(setq err conditions)
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(ding)
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(message "Beginning of Buffer")
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(sit-for 2)))
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(end-of-buffer (if loop-function
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(setq err conditions)
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(ding)
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(message "End of Buffer")
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(sit-for 2)))
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(error (if loop-function
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(setq err conditions)
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(ding)
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(message "Error: %s"
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(if (eq (car conditions) 'error)
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(car (cdr conditions))
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(prin1-to-string conditions)))
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(sit-for 2))))
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(ding))
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(if loop-function (funcall loop-function loop-state err))))
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(ding)
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(throw return-tag nil))
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;; This function is like pop-to-buffer, sort of.
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;; The algorithm is
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;; If there is a window displaying buffer
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;; Select it
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;; Else if there is only one window
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;; Split it, selecting the window on the bottom with height being
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;; the lesser of max-height (if non-nil) and the number of lines in
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;; the buffer to be displayed subject to window-min-height constraint.
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;; Else
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;; Switch to buffer in the current window.
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;;
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;; Then if max-height is nil, and not all of the lines in the buffer
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;; are displayed, grab the whole frame.
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;;
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;; Returns selected window on buffer positioned at point-min.
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(defun Electric-pop-up-window (buffer &optional max-height)
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(let* ((win (or (get-buffer-window buffer) (selected-window)))
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(buf (get-buffer buffer))
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(one-window (one-window-p t))
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(pop-up-windows t)
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(target-height)
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(lines))
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(if (not buf)
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(error "Buffer %s does not exist" buffer)
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(save-excursion
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(set-buffer buf)
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(setq lines (count-lines (point-min) (point-max)))
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(setq target-height
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(min (max (if max-height (min max-height (1+ lines)) (1+ lines))
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window-min-height)
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(save-window-excursion
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(delete-other-windows)
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(1- (window-height (selected-window)))))))
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(cond ((and (eq (window-buffer win) buf))
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(select-window win))
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(one-window
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(pop-to-buffer buffer)
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(setq win (selected-window))
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(enlarge-window (- target-height (window-height win))))
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(t
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(switch-to-buffer buf)))
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(if (and (not max-height)
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(> target-height (window-height (selected-window))))
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(progn (goto-char (window-start win))
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(enlarge-window (- target-height (window-height win)))))
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(goto-char (point-min))
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win)))
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(provide 'electric)
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;;; arch-tag: dae045eb-dc2d-4fb7-9f27-9cc2ce277be8
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;;; electric.el ends here
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