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1 | ;;; electric.el --- window maker and Command loop for `electric' modes. |
2 | ||
9750e079 ER |
3 | ;; Copyright (C) 1985, 1986 Free Software Foundation, Inc. |
4 | ||
e5167999 ER |
5 | ;; Author: K. Shane Hartman |
6 | ;; Maintainer: FSF | |
fd7fa35a | 7 | ;; Keywords: extensions |
e5167999 | 8 | |
0d20f9a0 JB |
9 | ;; This file is part of GNU Emacs. |
10 | ||
11 | ;; GNU Emacs is free software; you can redistribute it and/or modify | |
12 | ;; it under the terms of the GNU General Public License as published by | |
e5167999 | 13 | ;; the Free Software Foundation; either version 2, or (at your option) |
0d20f9a0 JB |
14 | ;; any later version. |
15 | ||
16 | ;; GNU Emacs is distributed in the hope that it will be useful, | |
17 | ;; but WITHOUT ANY WARRANTY; without even the implied warranty of | |
18 | ;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
19 | ;; GNU General Public License for more details. | |
20 | ||
21 | ;; You should have received a copy of the GNU General Public License | |
22 | ;; along with GNU Emacs; see the file COPYING. If not, write to | |
23 | ;; the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA. | |
24 | ||
c8472948 | 25 | ;;; Commentary: |
0d20f9a0 | 26 | |
49116ac0 | 27 | ; zaaaaaaap |
0d20f9a0 | 28 | |
c8472948 ER |
29 | ;;; Code: |
30 | ||
0d20f9a0 JB |
31 | ;; This loop is the guts for non-standard modes which retain control |
32 | ;; until some event occurs. It is a `do-forever', the only way out is to | |
33 | ;; throw. It assumes that you have set up the keymap, window, and | |
34 | ;; everything else: all it does is read commands and execute them - | |
35 | ;; providing error messages should one occur (if there is no loop | |
36 | ;; function - which see). The required argument is a tag which should | |
37 | ;; expect a value of nil if the user decides to punt. The | |
38 | ;; second argument is a prompt string (defaults to "->"). Given third | |
39 | ;; argument non-nil, it INHIBITS quitting unless the user types C-g at | |
40 | ;; toplevel. This is so user can do things like C-u C-g and not get | |
41 | ;; thrown out. Fourth argument, if non-nil, should be a function of two | |
42 | ;; arguments which is called after every command is executed. The fifth | |
43 | ;; argument, if provided, is the state variable for the function. If the | |
44 | ;; loop-function gets an error, the loop will abort WITHOUT throwing | |
45 | ;; (moral: use unwind-protect around call to this function for any | |
46 | ;; critical stuff). The second argument for the loop function is the | |
47 | ;; conditions for any error that occurred or nil if none. | |
48 | ||
49 | (defun Electric-command-loop (return-tag | |
50 | &optional prompt inhibit-quit | |
51 | loop-function loop-state) | |
52 | (if (not prompt) (setq prompt "->")) | |
53 | (let (cmd (err nil)) | |
54 | (while t | |
55 | (setq cmd (read-key-sequence (if (stringp prompt) | |
56 | prompt (funcall prompt)))) | |
57 | (setq last-command-char (aref cmd (1- (length cmd))) | |
58 | this-command (key-binding cmd) | |
59 | cmd this-command) | |
60 | (if (or (prog1 quit-flag (setq quit-flag nil)) | |
61 | (= last-input-char ?\C-g)) | |
dbc4e1c1 | 62 | (progn (setq unread-command-events nil |
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63 | prefix-arg nil) |
64 | ;; If it wasn't cancelling a prefix character, then quit. | |
65 | (if (or (= (length (this-command-keys)) 1) | |
66 | (not inhibit-quit)) ; safety | |
67 | (progn (ding) | |
68 | (message "Quit") | |
69 | (throw return-tag nil)) | |
70 | (setq cmd nil)))) | |
71 | (setq current-prefix-arg prefix-arg) | |
72 | (if cmd | |
73 | (condition-case conditions | |
74 | (progn (command-execute cmd) | |
17c17ec9 | 75 | (setq last-command this-command) |
0d20f9a0 JB |
76 | (if (or (prog1 quit-flag (setq quit-flag nil)) |
77 | (= last-input-char ?\C-g)) | |
dbc4e1c1 | 78 | (progn (setq unread-command-events nil) |
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79 | (if (not inhibit-quit) |
80 | (progn (ding) | |
81 | (message "Quit") | |
82 | (throw return-tag nil)) | |
83 | (ding))))) | |
84 | (buffer-read-only (if loop-function | |
85 | (setq err conditions) | |
86 | (ding) | |
87 | (message "Buffer is read-only") | |
88 | (sit-for 2))) | |
89 | (beginning-of-buffer (if loop-function | |
90 | (setq err conditions) | |
91 | (ding) | |
92 | (message "Beginning of Buffer") | |
93 | (sit-for 2))) | |
94 | (end-of-buffer (if loop-function | |
95 | (setq err conditions) | |
96 | (ding) | |
97 | (message "End of Buffer") | |
98 | (sit-for 2))) | |
99 | (error (if loop-function | |
100 | (setq err conditions) | |
101 | (ding) | |
102 | (message "Error: %s" | |
103 | (if (eq (car conditions) 'error) | |
104 | (car (cdr conditions)) | |
105 | (prin1-to-string conditions))) | |
106 | (sit-for 2)))) | |
107 | (ding)) | |
108 | (if loop-function (funcall loop-function loop-state err)))) | |
109 | (ding) | |
110 | (throw return-tag nil)) | |
111 | ||
112 | ;; This function is like pop-to-buffer, sort of. | |
113 | ;; The algorithm is | |
114 | ;; If there is a window displaying buffer | |
115 | ;; Select it | |
116 | ;; Else if there is only one window | |
117 | ;; Split it, selecting the window on the bottom with height being | |
118 | ;; the lesser of max-height (if non-nil) and the number of lines in | |
119 | ;; the buffer to be displayed subject to window-min-height constraint. | |
120 | ;; Else | |
121 | ;; Switch to buffer in the current window. | |
122 | ;; | |
123 | ;; Then if max-height is nil, and not all of the lines in the buffer | |
f98955ea | 124 | ;; are displayed, grab the whole frame. |
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125 | ;; |
126 | ;; Returns selected window on buffer positioned at point-min. | |
127 | ||
128 | (defun Electric-pop-up-window (buffer &optional max-height) | |
129 | (let* ((win (or (get-buffer-window buffer) (selected-window))) | |
130 | (buf (get-buffer buffer)) | |
131 | (one-window (one-window-p t)) | |
132 | (pop-up-windows t) | |
133 | (target-height) | |
134 | (lines)) | |
135 | (if (not buf) | |
136 | (error "Buffer %s does not exist" buffer) | |
137 | (save-excursion | |
138 | (set-buffer buf) | |
139 | (setq lines (count-lines (point-min) (point-max))) | |
140 | (setq target-height | |
141 | (min (max (if max-height (min max-height (1+ lines)) (1+ lines)) | |
142 | window-min-height) | |
143 | (save-window-excursion | |
144 | (delete-other-windows) | |
145 | (1- (window-height (selected-window))))))) | |
146 | (cond ((and (eq (window-buffer win) buf)) | |
147 | (select-window win)) | |
148 | (one-window | |
149 | (goto-char (window-start win)) | |
150 | (pop-to-buffer buffer) | |
151 | (setq win (selected-window)) | |
152 | (enlarge-window (- target-height (window-height win)))) | |
153 | (t | |
154 | (switch-to-buffer buf))) | |
155 | (if (and (not max-height) | |
156 | (> target-height (window-height (selected-window)))) | |
157 | (progn (goto-char (window-start win)) | |
158 | (enlarge-window (- target-height (window-height win))))) | |
159 | (goto-char (point-min)) | |
160 | win))) | |
49116ac0 | 161 | |
c0274f38 ER |
162 | (provide 'electric) |
163 | ||
c8472948 | 164 | ;;; electric.el ends here |