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522f9216 | 1 | ;;; tpu-extras.el --- Scroll margins and free cursor mode for TPU-edt |
b4196a99 | 2 | |
158a958d | 3 | ;; Copyright (C) 1993, 1994, 1995 Free Software Foundation, Inc. |
522f9216 RS |
4 | |
5 | ;; Author: Rob Riepel <riepel@networking.stanford.edu> | |
6 | ;; Maintainer: Rob Riepel <riepel@networking.stanford.edu> | |
b7f66977 | 7 | ;; Keywords: emulations |
522f9216 | 8 | |
75993094 RS |
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 | |
13 | ;; the Free Software Foundation; either version 2, or (at your option) | |
14 | ;; any later version. | |
15 | ||
522f9216 | 16 | ;; GNU Emacs is distributed in the hope that it will be useful, |
75993094 RS |
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. | |
522f9216 | 24 | |
522f9216 RS |
25 | ;;; Commentary: |
26 | ||
84299083 RS |
27 | ;; Use the functions defined here to customize TPU-edt to your tastes by |
28 | ;; setting scroll margins and/or turning on free cursor mode. Here's an | |
29 | ;; example for your .emacs file. | |
30 | ||
31 | ;; (tpu-set-cursor-free) ; Set cursor free. | |
32 | ;; (tpu-set-scroll-margins "10%" "15%") ; Set scroll margins. | |
33 | ||
34 | ;; Scroll margins and cursor binding can be changed from within emacs using | |
35 | ;; the following commands: | |
36 | ||
37 | ;; tpu-set-scroll-margins or set scroll margins | |
38 | ;; tpu-set-cursor-bound or set cursor bound | |
39 | ;; tpu-set-cursor-free or set cursor free | |
40 | ||
41 | ;; Additionally, Gold-F toggles between bound and free cursor modes. | |
42 | ||
43 | ;; Note that switching out of free cursor mode or exiting TPU-edt while in | |
44 | ;; free cursor mode strips trailing whitespace from every line in the file. | |
45 | ||
46 | ||
47 | ;;; Details: | |
48 | ||
522f9216 RS |
49 | ;; The functions contained in this file implement scroll margins and free |
50 | ;; cursor mode. The following keys and commands are affected. | |
51 | ||
52 | ;; key/command function scroll cursor | |
53 | ||
54 | ;; Up-Arrow previous line x x | |
55 | ;; Down-Arrow next line x x | |
56 | ;; Right-Arrow next character x | |
57 | ;; Left-Arrow previous character x | |
58 | ;; KP0 next or previous line x | |
59 | ;; KP7 next or previous page x | |
60 | ;; KP8 next or previous screen x | |
61 | ;; KP2 next or previous end-of-line x x | |
62 | ;; Control-e current end-of-line x | |
63 | ;; Control-h previous beginning-of-line x | |
64 | ;; Next Scr next screen x | |
65 | ;; Prev Scr previous screen x | |
66 | ;; Search find a string x | |
67 | ;; Replace find and replace a string x | |
68 | ;; Newline insert a newline x | |
69 | ;; Paragraph next or previous paragraph x | |
70 | ;; Auto-Fill break lines on spaces x | |
71 | ||
72 | ;; These functions are not part of the base TPU-edt for the following | |
73 | ;; reasons: | |
74 | ||
75 | ;; Free cursor mode is implemented with the emacs picture-mode functions. | |
76 | ;; These functions support moving the cursor all over the screen, however, | |
77 | ;; when the cursor is moved past the end of a line, spaces or tabs are | |
78 | ;; appended to the line - even if no text is entered in that area. In | |
79 | ;; order for a free cursor mode to work exactly like TPU/edt, this trailing | |
80 | ;; whitespace needs to be dealt with in every function that might encounter | |
81 | ;; it. Such global changes are impractical, however, free cursor mode is | |
82 | ;; too valuable to abandon completely, so it has been implemented in those | |
83 | ;; functions where it serves best. | |
84 | ||
85 | ;; The implementation of scroll margins adds overhead to previously | |
86 | ;; simple and often used commands. These commands are now responsible | |
87 | ;; for their normal operation and part of the display function. There | |
88 | ;; is a possibility that this display overhead could adversely affect the | |
89 | ;; performance of TPU-edt on slower computers. In order to support the | |
90 | ;; widest range of computers, scroll margin support is optional. | |
91 | ||
84299083 RS |
92 | ;; It's actually not known whether the overhead associated with scroll |
93 | ;; margin support is significant. If you find that it is, please send | |
522f9216 RS |
94 | ;; a note describing the extent of the performance degradation. Be sure |
95 | ;; to include a description of the platform where you're running TPU-edt. | |
96 | ;; Send your note to the address provided by Gold-V. | |
97 | ||
98 | ;; Even with these differences and limitations, these functions implement | |
99 | ;; important aspects of the real TPU/edt. Those who miss free cursor mode | |
100 | ;; and/or scroll margins will appreciate these implementations. | |
101 | ||
522f9216 RS |
102 | ;;; Code: |
103 | ||
104 | ||
2582e468 | 105 | ;;; Gotta have tpu-edt |
522f9216 | 106 | |
2582e468 | 107 | (require 'tpu-edt) |
522f9216 RS |
108 | |
109 | ||
110 | ;;; Customization variables | |
111 | ||
112 | (defconst tpu-top-scroll-margin 0 | |
113 | "*Scroll margin at the top of the screen. | |
114 | Interpreted as a percent of the current window size.") | |
115 | (defconst tpu-bottom-scroll-margin 0 | |
116 | "*Scroll margin at the bottom of the screen. | |
117 | Interpreted as a percent of the current window size.") | |
118 | ||
119 | (defvar tpu-backward-char-like-tpu t | |
120 | "*If non-nil, in free cursor mode backward-char (left-arrow) works | |
121 | just like TPU/edt. Otherwise, backward-char will move to the end of | |
122 | the previous line when starting from a line beginning.") | |
123 | ||
124 | ||
125 | ;;; Global variables | |
126 | ||
127 | (defvar tpu-cursor-free nil | |
128 | "If non-nil, let the cursor roam free.") | |
129 | ||
130 | ||
131 | ;;; Hooks -- Set cursor free in picture mode. | |
132 | ;;; Clean up when writing a file from cursor free mode. | |
133 | ||
158a958d | 134 | (add-hook 'picture-mode-hook 'tpu-set-cursor-free) |
522f9216 RS |
135 | |
136 | (defun tpu-write-file-hook nil | |
137 | "Eliminate whitespace at ends of lines, if the cursor is free." | |
138 | (if (and (buffer-modified-p) tpu-cursor-free) (picture-clean))) | |
139 | ||
140 | (or (memq 'tpu-write-file-hook write-file-hooks) | |
141 | (setq write-file-hooks | |
142 | (cons 'tpu-write-file-hook write-file-hooks))) | |
143 | ||
144 | ||
145 | ;;; Utility routines for implementing scroll margins | |
146 | ||
147 | (defun tpu-top-check (beg lines) | |
148 | "Enforce scroll margin at the top of screen." | |
149 | (let ((margin (/ (* (window-height) tpu-top-scroll-margin) 100))) | |
150 | (cond ((< beg margin) (recenter beg)) | |
151 | ((< (- beg lines) margin) (recenter margin))))) | |
152 | ||
153 | (defun tpu-bottom-check (beg lines) | |
154 | "Enforce scroll margin at the bottom of screen." | |
155 | (let* ((height (window-height)) | |
156 | (margin (+ 1 (/ (* height tpu-bottom-scroll-margin) 100))) | |
157 | ;; subtract 1 from height because it includes mode line | |
158 | (difference (- height margin 1))) | |
159 | (cond ((> beg difference) (recenter beg)) | |
160 | ((> (+ beg lines) difference) (recenter (- margin)))))) | |
161 | ||
162 | ||
163 | ;;; Movement by character | |
164 | ||
165 | (defun tpu-forward-char (num) | |
166 | "Move right ARG characters (left if ARG is negative)." | |
167 | (interactive "p") | |
168 | (if tpu-cursor-free (picture-forward-column num) (forward-char num))) | |
169 | ||
170 | (defun tpu-backward-char (num) | |
171 | "Move left ARG characters (right if ARG is negative)." | |
172 | (interactive "p") | |
173 | (cond ((not tpu-cursor-free) | |
174 | (backward-char num)) | |
175 | (tpu-backward-char-like-tpu | |
176 | (picture-backward-column num)) | |
177 | ((bolp) | |
178 | (backward-char 1) | |
179 | (picture-end-of-line) | |
180 | (picture-backward-column (1- num))) | |
181 | (t | |
182 | (picture-backward-column num)))) | |
183 | ||
184 | ||
185 | ;;; Movement by line | |
186 | ||
187 | (defun tpu-next-line (num) | |
188 | "Move to next line. | |
189 | Prefix argument serves as a repeat count." | |
190 | (interactive "p") | |
191 | (let ((beg (tpu-current-line))) | |
192 | (if tpu-cursor-free (or (eobp) (picture-move-down num)) | |
193 | (next-line-internal num)) | |
194 | (tpu-bottom-check beg num) | |
195 | (setq this-command 'next-line))) | |
196 | ||
197 | (defun tpu-previous-line (num) | |
198 | "Move to previous line. | |
199 | Prefix argument serves as a repeat count." | |
200 | (interactive "p") | |
201 | (let ((beg (tpu-current-line))) | |
202 | (if tpu-cursor-free (picture-move-up num) (next-line-internal (- num))) | |
203 | (tpu-top-check beg num) | |
204 | (setq this-command 'previous-line))) | |
205 | ||
206 | (defun tpu-next-beginning-of-line (num) | |
207 | "Move to beginning of line; if at beginning, move to beginning of next line. | |
208 | Accepts a prefix argument for the number of lines to move." | |
209 | (interactive "p") | |
210 | (let ((beg (tpu-current-line))) | |
211 | (backward-char 1) | |
212 | (forward-line (- 1 num)) | |
213 | (tpu-top-check beg num))) | |
214 | ||
215 | (defun tpu-next-end-of-line (num) | |
216 | "Move to end of line; if at end, move to end of next line. | |
217 | Accepts a prefix argument for the number of lines to move." | |
218 | (interactive "p") | |
219 | (let ((beg (tpu-current-line))) | |
220 | (cond (tpu-cursor-free | |
221 | (let ((beg (point))) | |
222 | (if (< 1 num) (forward-line num)) | |
223 | (picture-end-of-line) | |
224 | (if (<= (point) beg) (progn (forward-line) (picture-end-of-line))))) | |
225 | (t | |
226 | (forward-char) | |
227 | (end-of-line num))) | |
228 | (tpu-bottom-check beg num))) | |
229 | ||
230 | (defun tpu-previous-end-of-line (num) | |
231 | "Move EOL upward. | |
232 | Accepts a prefix argument for the number of lines to move." | |
233 | (interactive "p") | |
234 | (let ((beg (tpu-current-line))) | |
235 | (cond (tpu-cursor-free | |
236 | (picture-end-of-line (- 1 num))) | |
237 | (t | |
238 | (end-of-line (- 1 num)))) | |
239 | (tpu-top-check beg num))) | |
240 | ||
241 | (defun tpu-current-end-of-line nil | |
242 | "Move point to end of current line." | |
243 | (interactive) | |
244 | (let ((beg (point))) | |
245 | (if tpu-cursor-free (picture-end-of-line) (end-of-line)) | |
246 | (if (= beg (point)) (message "You are already at the end of a line.")))) | |
247 | ||
248 | (defun tpu-forward-line (num) | |
249 | "Move to beginning of next line. | |
250 | Prefix argument serves as a repeat count." | |
251 | (interactive "p") | |
252 | (let ((beg (tpu-current-line))) | |
253 | (next-line-internal num) | |
254 | (tpu-bottom-check beg num) | |
255 | (beginning-of-line))) | |
256 | ||
257 | (defun tpu-backward-line (num) | |
258 | "Move to beginning of previous line. | |
259 | Prefix argument serves as repeat count." | |
260 | (interactive "p") | |
261 | (let ((beg (tpu-current-line))) | |
84299083 | 262 | (or (bolp) (>= 0 num) (setq num (- num 1))) |
522f9216 RS |
263 | (next-line-internal (- num)) |
264 | (tpu-top-check beg num) | |
265 | (beginning-of-line))) | |
266 | ||
267 | ||
268 | ;;; Movement by paragraph | |
269 | ||
270 | (defun tpu-paragraph (num) | |
271 | "Move to the next paragraph in the current direction. | |
272 | A repeat count means move that many paragraphs." | |
273 | (interactive "p") | |
274 | (let* ((left nil) | |
275 | (beg (tpu-current-line)) | |
276 | (height (window-height)) | |
277 | (top-percent | |
278 | (if (= 0 tpu-top-scroll-margin) 10 tpu-top-scroll-margin)) | |
279 | (bottom-percent | |
280 | (if (= 0 tpu-bottom-scroll-margin) 15 tpu-bottom-scroll-margin)) | |
281 | (top-margin (/ (* height top-percent) 100)) | |
282 | (bottom-up-margin (+ 1 (/ (* height bottom-percent) 100))) | |
283 | (bottom-margin (max beg (- height bottom-up-margin 1))) | |
284 | (top (save-excursion (move-to-window-line top-margin) (point))) | |
285 | (bottom (save-excursion (move-to-window-line bottom-margin) (point))) | |
286 | (far (save-excursion | |
287 | (goto-char bottom) (forward-line (- height 2)) (point)))) | |
288 | (cond (tpu-advance | |
289 | (tpu-next-paragraph num) | |
290 | (cond((> (point) far) | |
291 | (setq left (save-excursion (forward-line height))) | |
292 | (if (= 0 left) (recenter top-margin) | |
293 | (recenter (- left bottom-up-margin)))) | |
294 | (t | |
295 | (and (> (point) bottom) (recenter bottom-margin))))) | |
296 | (t | |
297 | (tpu-previous-paragraph num) | |
298 | (and (< (point) top) (recenter (min beg top-margin))))))) | |
299 | ||
300 | ||
301 | ;;; Movement by page | |
302 | ||
303 | (defun tpu-page (num) | |
304 | "Move to the next page in the current direction. | |
305 | A repeat count means move that many pages." | |
306 | (interactive "p") | |
307 | (let* ((left nil) | |
308 | (beg (tpu-current-line)) | |
309 | (height (window-height)) | |
310 | (top-percent | |
311 | (if (= 0 tpu-top-scroll-margin) 10 tpu-top-scroll-margin)) | |
312 | (bottom-percent | |
313 | (if (= 0 tpu-bottom-scroll-margin) 15 tpu-bottom-scroll-margin)) | |
314 | (top-margin (/ (* height top-percent) 100)) | |
315 | (bottom-up-margin (+ 1 (/ (* height bottom-percent) 100))) | |
316 | (bottom-margin (max beg (- height bottom-up-margin 1))) | |
317 | (top (save-excursion (move-to-window-line top-margin) (point))) | |
318 | (bottom (save-excursion (move-to-window-line bottom-margin) (point))) | |
319 | (far (save-excursion | |
320 | (goto-char bottom) (forward-line (- height 2)) (point)))) | |
321 | (cond (tpu-advance | |
322 | (forward-page num) | |
323 | (cond((> (point) far) | |
324 | (setq left (save-excursion (forward-line height))) | |
325 | (if (= 0 left) (recenter top-margin) | |
326 | (recenter (- left bottom-up-margin)))) | |
327 | (t | |
328 | (and (> (point) bottom) (recenter bottom-margin))))) | |
329 | (t | |
330 | (backward-page num) | |
331 | (and (< (point) top) (recenter (min beg top-margin))))))) | |
332 | ||
333 | ||
334 | ;;; Scrolling | |
335 | ||
336 | (defun tpu-scroll-window-down (num) | |
337 | "Scroll the display down to the next section. | |
338 | A repeat count means scroll that many sections." | |
339 | (interactive "p") | |
340 | (let* ((beg (tpu-current-line)) | |
341 | (height (1- (window-height))) | |
342 | (lines (* num (/ (* height tpu-percent-scroll) 100)))) | |
343 | (next-line-internal (- lines)) | |
344 | (tpu-top-check beg lines))) | |
345 | ||
346 | (defun tpu-scroll-window-up (num) | |
347 | "Scroll the display up to the next section. | |
348 | A repeat count means scroll that many sections." | |
349 | (interactive "p") | |
350 | (let* ((beg (tpu-current-line)) | |
351 | (height (1- (window-height))) | |
352 | (lines (* num (/ (* height tpu-percent-scroll) 100)))) | |
353 | (next-line-internal lines) | |
354 | (tpu-bottom-check beg lines))) | |
355 | ||
356 | ||
357 | ;;; Replace the TPU-edt internal search function | |
358 | ||
359 | (defun tpu-search-internal (pat &optional quiet) | |
360 | "Search for a string or regular expression." | |
361 | (let* ((left nil) | |
362 | (beg (tpu-current-line)) | |
363 | (height (window-height)) | |
364 | (top-percent | |
365 | (if (= 0 tpu-top-scroll-margin) 10 tpu-top-scroll-margin)) | |
366 | (bottom-percent | |
367 | (if (= 0 tpu-bottom-scroll-margin) 15 tpu-bottom-scroll-margin)) | |
368 | (top-margin (/ (* height top-percent) 100)) | |
369 | (bottom-up-margin (+ 1 (/ (* height bottom-percent) 100))) | |
370 | (bottom-margin (max beg (- height bottom-up-margin 1))) | |
371 | (top (save-excursion (move-to-window-line top-margin) (point))) | |
372 | (bottom (save-excursion (move-to-window-line bottom-margin) (point))) | |
373 | (far (save-excursion | |
374 | (goto-char bottom) (forward-line (- height 2)) (point)))) | |
375 | (tpu-search-internal-core pat quiet) | |
b4196a99 | 376 | (if tpu-searching-forward |
522f9216 RS |
377 | (cond((> (point) far) |
378 | (setq left (save-excursion (forward-line height))) | |
379 | (if (= 0 left) (recenter top-margin) | |
380 | (recenter (- left bottom-up-margin)))) | |
381 | (t | |
382 | (and (> (point) bottom) (recenter bottom-margin)))) | |
383 | (and (< (point) top) (recenter (min beg top-margin)))))) | |
384 | ||
385 | ||
386 | ||
387 | ;;; Replace the newline, newline-and-indent, and do-auto-fill functions | |
388 | ||
389 | (or (fboundp 'tpu-old-newline) | |
390 | (fset 'tpu-old-newline (symbol-function 'newline))) | |
391 | (or (fboundp 'tpu-old-do-auto-fill) | |
392 | (fset 'tpu-old-do-auto-fill (symbol-function 'do-auto-fill))) | |
393 | (or (fboundp 'tpu-old-newline-and-indent) | |
394 | (fset 'tpu-old-newline-and-indent (symbol-function 'newline-and-indent))) | |
395 | ||
396 | (defun newline (&optional num) | |
397 | "Insert a newline. With arg, insert that many newlines. | |
398 | In Auto Fill mode, can break the preceding line if no numeric arg. | |
399 | This is the TPU-edt version that respects the bottom scroll margin." | |
400 | (interactive "p") | |
401 | (let ((beg (tpu-current-line))) | |
402 | (or num (setq num 1)) | |
403 | (tpu-old-newline num) | |
404 | (tpu-bottom-check beg num))) | |
405 | ||
406 | (defun newline-and-indent nil | |
407 | "Insert a newline, then indent according to major mode. | |
408 | Indentation is done using the current indent-line-function. | |
409 | In programming language modes, this is the same as TAB. | |
410 | In some text modes, where TAB inserts a tab, this indents | |
411 | to the specified left-margin column. This is the TPU-edt | |
412 | version that respects the bottom scroll margin." | |
413 | (interactive) | |
414 | (let ((beg (tpu-current-line))) | |
415 | (tpu-old-newline-and-indent) | |
416 | (tpu-bottom-check beg 1))) | |
417 | ||
418 | (defun do-auto-fill nil | |
419 | "TPU-edt version that respects the bottom scroll margin." | |
420 | (let ((beg (tpu-current-line))) | |
421 | (tpu-old-do-auto-fill) | |
422 | (tpu-bottom-check beg 1))) | |
423 | ||
424 | ||
425 | ;;; Function to set scroll margins | |
426 | ||
83ba7a93 | 427 | ;;;###autoload |
522f9216 RS |
428 | (defun tpu-set-scroll-margins (top bottom) |
429 | "Set scroll margins." | |
430 | (interactive | |
431 | "sEnter top scroll margin (N lines or N%% or RETURN for current value): \ | |
432 | \nsEnter bottom scroll margin (N lines or N%% or RETURN for current value): ") | |
433 | ;; set top scroll margin | |
434 | (or (string= top "") | |
435 | (if (string= "%" (substring top -1)) | |
436 | (setq tpu-top-scroll-margin (string-to-int top)) | |
437 | (setq tpu-top-scroll-margin | |
438 | (/ (1- (+ (* (string-to-int top) 100) (window-height))) | |
439 | (window-height))))) | |
440 | ;; set bottom scroll margin | |
441 | (or (string= bottom "") | |
442 | (if (string= "%" (substring bottom -1)) | |
443 | (setq tpu-bottom-scroll-margin (string-to-int bottom)) | |
444 | (setq tpu-bottom-scroll-margin | |
445 | (/ (1- (+ (* (string-to-int bottom) 100) (window-height))) | |
446 | (window-height))))) | |
447 | ;; report scroll margin settings if running interactively | |
448 | (and (interactive-p) | |
449 | (message "Scroll margins set. Top = %s%%, Bottom = %s%%" | |
450 | tpu-top-scroll-margin tpu-bottom-scroll-margin))) | |
451 | ||
522f9216 RS |
452 | |
453 | ;;; Functions to set cursor bound or free | |
454 | ||
83ba7a93 | 455 | ;;;###autoload |
522f9216 RS |
456 | (defun tpu-set-cursor-free nil |
457 | "Allow the cursor to move freely about the screen." | |
458 | (interactive) | |
459 | (setq tpu-cursor-free t) | |
460 | (substitute-key-definition 'tpu-set-cursor-free | |
461 | 'tpu-set-cursor-bound | |
462 | GOLD-map) | |
463 | (message "The cursor will now move freely about the screen.")) | |
464 | ||
83ba7a93 | 465 | ;;;###autoload |
522f9216 RS |
466 | (defun tpu-set-cursor-bound nil |
467 | "Constrain the cursor to the flow of the text." | |
468 | (interactive) | |
469 | (picture-clean) | |
470 | (setq tpu-cursor-free nil) | |
471 | (substitute-key-definition 'tpu-set-cursor-bound | |
472 | 'tpu-set-cursor-free | |
473 | GOLD-map) | |
474 | (message "The cursor is now bound to the flow of your text.")) | |
475 | ||
522f9216 | 476 | ;;; tpu-extras.el ends here |