1;;; tpu-extras.el --- scroll margins and free cursor mode for TPU-edt 2 3;; Copyright (C) 1993, 1994, 1995, 2000, 2001, 2002, 2003, 2004, 4;; 2005, 2006, 2007 Free Software Foundation, Inc. 5 6;; Author: Rob Riepel <riepel@networking.stanford.edu> 7;; Maintainer: Rob Riepel <riepel@networking.stanford.edu> 8;; Keywords: emulations 9 10;; This file is part of GNU Emacs. 11 12;; GNU Emacs is free software; you can redistribute it and/or modify 13;; it under the terms of the GNU General Public License as published by 14;; the Free Software Foundation; either version 2, or (at your option) 15;; any later version. 16 17;; GNU Emacs is distributed in the hope that it will be useful, 18;; but WITHOUT ANY WARRANTY; without even the implied warranty of 19;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 20;; GNU General Public License for more details. 21 22;; You should have received a copy of the GNU General Public License 23;; along with GNU Emacs; see the file COPYING. If not, write to the 24;; Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, 25;; Boston, MA 02110-1301, USA. 26 27;;; Commentary: 28 29;; Use the functions defined here to customize TPU-edt to your tastes by 30;; setting scroll margins and/or turning on free cursor mode. Here's an 31;; example for your .emacs file. 32 33;; (tpu-set-cursor-free) ; Set cursor free. 34;; (tpu-set-scroll-margins "10%" "15%") ; Set scroll margins. 35 36;; Scroll margins and cursor binding can be changed from within emacs using 37;; the following commands: 38 39;; tpu-set-scroll-margins or set scroll margins 40;; tpu-set-cursor-bound or set cursor bound 41;; tpu-set-cursor-free or set cursor free 42 43;; Additionally, Gold-F toggles between bound and free cursor modes. 44 45;; Note that switching out of free cursor mode or exiting TPU-edt while in 46;; free cursor mode strips trailing whitespace from every line in the file. 47 48 49;;; Details: 50 51;; The functions contained in this file implement scroll margins and free 52;; cursor mode. The following keys and commands are affected. 53 54;; key/command function scroll cursor 55 56;; Up-Arrow previous line x x 57;; Down-Arrow next line x x 58;; Right-Arrow next character x 59;; Left-Arrow previous character x 60;; KP0 next or previous line x 61;; KP7 next or previous page x 62;; KP8 next or previous screen x 63;; KP2 next or previous end-of-line x x 64;; Control-e current end-of-line x 65;; Control-h previous beginning-of-line x 66;; Next Scr next screen x 67;; Prev Scr previous screen x 68;; Search find a string x 69;; Replace find and replace a string x 70;; Newline insert a newline x 71;; Paragraph next or previous paragraph x 72;; Auto-Fill break lines on spaces x 73 74;; These functions are not part of the base TPU-edt for the following 75;; reasons: 76 77;; Free cursor mode is implemented with the emacs picture-mode functions. 78;; These functions support moving the cursor all over the screen, however, 79;; when the cursor is moved past the end of a line, spaces or tabs are 80;; appended to the line - even if no text is entered in that area. In 81;; order for a free cursor mode to work exactly like TPU/edt, this trailing 82;; whitespace needs to be dealt with in every function that might encounter 83;; it. Such global changes are impractical, however, free cursor mode is 84;; too valuable to abandon completely, so it has been implemented in those 85;; functions where it serves best. 86 87;; The implementation of scroll margins adds overhead to previously 88;; simple and often used commands. These commands are now responsible 89;; for their normal operation and part of the display function. There 90;; is a possibility that this display overhead could adversely affect the 91;; performance of TPU-edt on slower computers. In order to support the 92;; widest range of computers, scroll margin support is optional. 93 94;; It's actually not known whether the overhead associated with scroll 95;; margin support is significant. If you find that it is, please send 96;; a note describing the extent of the performance degradation. Be sure 97;; to include a description of the platform where you're running TPU-edt. 98;; Send your note to the address provided by Gold-V. 99 100;; Even with these differences and limitations, these functions implement 101;; important aspects of the real TPU/edt. Those who miss free cursor mode 102;; and/or scroll margins will appreciate these implementations. 103 104;;; Code: 105 106 107;;; Gotta have tpu-edt 108 109(require 'tpu-edt) 110 111 112;;; Customization variables 113 114(defcustom tpu-top-scroll-margin 0 115 "*Scroll margin at the top of the screen. 116Interpreted as a percent of the current window size." 117 :type 'integer 118 :group 'tpu) 119(defcustom tpu-bottom-scroll-margin 0 120 "*Scroll margin at the bottom of the screen. 121Interpreted as a percent of the current window size." 122 :type 'integer 123 :group 'tpu) 124 125(defcustom tpu-backward-char-like-tpu t 126 "*If non-nil, in free cursor mode backward-char (left-arrow) works 127just like TPU/edt. Otherwise, backward-char will move to the end of 128the previous line when starting from a line beginning." 129 :type 'boolean 130 :group 'tpu) 131 132 133;;; Global variables 134 135(defvar tpu-cursor-free nil 136 "If non-nil, let the cursor roam free.") 137 138 139;;; Hooks -- Set cursor free in picture mode. 140;;; Clean up when writing a file from cursor free mode. 141 142(add-hook 'picture-mode-hook 'tpu-set-cursor-free) 143 144(defun tpu-write-file-hook nil 145 "Eliminate whitespace at ends of lines, if the cursor is free." 146 (if (and (buffer-modified-p) tpu-cursor-free) (tpu-trim-line-ends))) 147 148(or (memq 'tpu-write-file-hook write-file-functions) 149 (setq write-file-functions 150 (cons 'tpu-write-file-hook write-file-functions))) 151 152 153;;; Utility routines for implementing scroll margins 154 155(defun tpu-top-check (beg lines) 156 "Enforce scroll margin at the top of screen." 157 (let ((margin (/ (* (window-height) tpu-top-scroll-margin) 100))) 158 (cond ((< beg margin) (recenter beg)) 159 ((< (- beg lines) margin) (recenter margin))))) 160 161(defun tpu-bottom-check (beg lines) 162 "Enforce scroll margin at the bottom of screen." 163 (let* ((height (window-height)) 164 (margin (+ 1 (/ (* height tpu-bottom-scroll-margin) 100))) 165 ;; subtract 1 from height because it includes mode line 166 (difference (- height margin 1))) 167 (cond ((> beg difference) (recenter beg)) 168 ((> (+ beg lines) difference) (recenter (- margin)))))) 169 170 171;;; Movement by character 172 173(defun tpu-forward-char (num) 174 "Move right ARG characters (left if ARG is negative)." 175 (interactive "p") 176 (if tpu-cursor-free (picture-forward-column num) (forward-char num))) 177 178(defun tpu-backward-char (num) 179 "Move left ARG characters (right if ARG is negative)." 180 (interactive "p") 181 (cond ((not tpu-cursor-free) 182 (backward-char num)) 183 (tpu-backward-char-like-tpu 184 (picture-backward-column num)) 185 ((bolp) 186 (backward-char 1) 187 (picture-end-of-line) 188 (picture-backward-column (1- num))) 189 (t 190 (picture-backward-column num)))) 191 192 193;;; Movement by line 194 195(defun tpu-next-line (num) 196 "Move to next line. 197Prefix argument serves as a repeat count." 198 (interactive "p") 199 (let ((beg (tpu-current-line))) 200 (if tpu-cursor-free (or (eobp) (picture-move-down num)) 201 (next-line-internal num)) 202 (tpu-bottom-check beg num) 203 (setq this-command 'next-line))) 204 205(defun tpu-previous-line (num) 206 "Move to previous line. 207Prefix argument serves as a repeat count." 208 (interactive "p") 209 (let ((beg (tpu-current-line))) 210 (if tpu-cursor-free (picture-move-up num) (next-line-internal (- num))) 211 (tpu-top-check beg num) 212 (setq this-command 'previous-line))) 213 214(defun tpu-next-beginning-of-line (num) 215 "Move to beginning of line; if at beginning, move to beginning of next line. 216Accepts a prefix argument for the number of lines to move." 217 (interactive "p") 218 (let ((beg (tpu-current-line))) 219 (backward-char 1) 220 (forward-visible-line (- 1 num)) 221 (tpu-top-check beg num))) 222 223(defun tpu-next-end-of-line (num) 224 "Move to end of line; if at end, move to end of next line. 225Accepts a prefix argument for the number of lines to move." 226 (interactive "p") 227 (let ((beg (tpu-current-line))) 228 (cond (tpu-cursor-free 229 (let ((beg (point))) 230 (if (< 1 num) (forward-line num)) 231 (picture-end-of-line) 232 (if (<= (point) beg) (progn (forward-line) (picture-end-of-line))))) 233 (t 234 (forward-char) 235 (end-of-line num))) 236 (tpu-bottom-check beg num))) 237 238(defun tpu-previous-end-of-line (num) 239 "Move EOL upward. 240Accepts a prefix argument for the number of lines to move." 241 (interactive "p") 242 (let ((beg (tpu-current-line))) 243 (cond (tpu-cursor-free 244 (picture-end-of-line (- 1 num))) 245 (t 246 (end-of-line (- 1 num)))) 247 (tpu-top-check beg num))) 248 249(defun tpu-current-end-of-line nil 250 "Move point to end of current line." 251 (interactive) 252 (let ((beg (point))) 253 (if tpu-cursor-free (picture-end-of-line) (end-of-line)) 254 (if (= beg (point)) (message "You are already at the end of a line.")))) 255 256(defun tpu-forward-line (num) 257 "Move to beginning of next line. 258Prefix argument serves as a repeat count." 259 (interactive "p") 260 (let ((beg (tpu-current-line))) 261 (next-line-internal num) 262 (tpu-bottom-check beg num) 263 (beginning-of-line))) 264 265(defun tpu-backward-line (num) 266 "Move to beginning of previous line. 267Prefix argument serves as repeat count." 268 (interactive "p") 269 (let ((beg (tpu-current-line))) 270 (or (bolp) (>= 0 num) (setq num (- num 1))) 271 (next-line-internal (- num)) 272 (tpu-top-check beg num) 273 (beginning-of-line))) 274 275 276;;; Movement by paragraph 277 278(defun tpu-paragraph (num) 279 "Move to the next paragraph in the current direction. 280A repeat count means move that many paragraphs." 281 (interactive "p") 282 (let* ((left nil) 283 (beg (tpu-current-line)) 284 (height (window-height)) 285 (top-percent 286 (if (= 0 tpu-top-scroll-margin) 10 tpu-top-scroll-margin)) 287 (bottom-percent 288 (if (= 0 tpu-bottom-scroll-margin) 15 tpu-bottom-scroll-margin)) 289 (top-margin (/ (* height top-percent) 100)) 290 (bottom-up-margin (+ 1 (/ (* height bottom-percent) 100))) 291 (bottom-margin (max beg (- height bottom-up-margin 1))) 292 (top (save-excursion (move-to-window-line top-margin) (point))) 293 (bottom (save-excursion (move-to-window-line bottom-margin) (point))) 294 (far (save-excursion 295 (goto-char bottom) (forward-line (- height 2)) (point)))) 296 (cond (tpu-advance 297 (tpu-next-paragraph num) 298 (cond((> (point) far) 299 (setq left (save-excursion (forward-line height))) 300 (if (= 0 left) (recenter top-margin) 301 (recenter (- left bottom-up-margin)))) 302 (t 303 (and (> (point) bottom) (recenter bottom-margin))))) 304 (t 305 (tpu-previous-paragraph num) 306 (and (< (point) top) (recenter (min beg top-margin))))))) 307 308 309;;; Movement by page 310 311(defun tpu-page (num) 312 "Move to the next page in the current direction. 313A repeat count means move that many pages." 314 (interactive "p") 315 (let* ((left nil) 316 (beg (tpu-current-line)) 317 (height (window-height)) 318 (top-percent 319 (if (= 0 tpu-top-scroll-margin) 10 tpu-top-scroll-margin)) 320 (bottom-percent 321 (if (= 0 tpu-bottom-scroll-margin) 15 tpu-bottom-scroll-margin)) 322 (top-margin (/ (* height top-percent) 100)) 323 (bottom-up-margin (+ 1 (/ (* height bottom-percent) 100))) 324 (bottom-margin (max beg (- height bottom-up-margin 1))) 325 (top (save-excursion (move-to-window-line top-margin) (point))) 326 (bottom (save-excursion (move-to-window-line bottom-margin) (point))) 327 (far (save-excursion 328 (goto-char bottom) (forward-line (- height 2)) (point)))) 329 (cond (tpu-advance 330 (forward-page num) 331 (cond((> (point) far) 332 (setq left (save-excursion (forward-line height))) 333 (if (= 0 left) (recenter top-margin) 334 (recenter (- left bottom-up-margin)))) 335 (t 336 (and (> (point) bottom) (recenter bottom-margin))))) 337 (t 338 (backward-page num) 339 (and (< (point) top) (recenter (min beg top-margin))))))) 340 341 342;;; Scrolling 343 344(defun tpu-scroll-window-down (num) 345 "Scroll the display down to the next section. 346A repeat count means scroll that many sections." 347 (interactive "p") 348 (let* ((beg (tpu-current-line)) 349 (height (1- (window-height))) 350 (lines (* num (/ (* height tpu-percent-scroll) 100)))) 351 (next-line-internal (- lines)) 352 (tpu-top-check beg lines))) 353 354(defun tpu-scroll-window-up (num) 355 "Scroll the display up to the next section. 356A repeat count means scroll that many sections." 357 (interactive "p") 358 (let* ((beg (tpu-current-line)) 359 (height (1- (window-height))) 360 (lines (* num (/ (* height tpu-percent-scroll) 100)))) 361 (next-line-internal lines) 362 (tpu-bottom-check beg lines))) 363 364 365;;; Replace the TPU-edt internal search function 366 367(defun tpu-search-internal (pat &optional quiet) 368 "Search for a string or regular expression." 369 (let* ((left nil) 370 (beg (tpu-current-line)) 371 (height (window-height)) 372 (top-percent 373 (if (= 0 tpu-top-scroll-margin) 10 tpu-top-scroll-margin)) 374 (bottom-percent 375 (if (= 0 tpu-bottom-scroll-margin) 15 tpu-bottom-scroll-margin)) 376 (top-margin (/ (* height top-percent) 100)) 377 (bottom-up-margin (+ 1 (/ (* height bottom-percent) 100))) 378 (bottom-margin (max beg (- height bottom-up-margin 1))) 379 (top (save-excursion (move-to-window-line top-margin) (point))) 380 (bottom (save-excursion (move-to-window-line bottom-margin) (point))) 381 (far (save-excursion 382 (goto-char bottom) (forward-line (- height 2)) (point)))) 383 (tpu-search-internal-core pat quiet) 384 (if tpu-searching-forward 385 (cond((> (point) far) 386 (setq left (save-excursion (forward-line height))) 387 (if (= 0 left) (recenter top-margin) 388 (recenter (- left bottom-up-margin)))) 389 (t 390 (and (> (point) bottom) (recenter bottom-margin)))) 391 (and (< (point) top) (recenter (min beg top-margin)))))) 392 393 394 395;;; Replace the newline, newline-and-indent, and do-auto-fill functions 396 397(or (fboundp 'tpu-old-newline) 398 (fset 'tpu-old-newline (symbol-function 'newline))) 399(or (fboundp 'tpu-old-do-auto-fill) 400 (fset 'tpu-old-do-auto-fill (symbol-function 'do-auto-fill))) 401(or (fboundp 'tpu-old-newline-and-indent) 402 (fset 'tpu-old-newline-and-indent (symbol-function 'newline-and-indent))) 403 404(defun newline (&optional num) 405 "Insert a newline. With arg, insert that many newlines. 406In Auto Fill mode, can break the preceding line if no numeric arg. 407This is the TPU-edt version that respects the bottom scroll margin." 408 (interactive "p") 409 (let ((beg (tpu-current-line))) 410 (or num (setq num 1)) 411 (tpu-old-newline num) 412 (tpu-bottom-check beg num))) 413 414(defun newline-and-indent nil 415 "Insert a newline, then indent according to major mode. 416Indentation is done using the current indent-line-function. 417In programming language modes, this is the same as TAB. 418In some text modes, where TAB inserts a tab, this indents 419to the specified left-margin column. This is the TPU-edt 420version that respects the bottom scroll margin." 421 (interactive) 422 (let ((beg (tpu-current-line))) 423 (tpu-old-newline-and-indent) 424 (tpu-bottom-check beg 1))) 425 426(defun do-auto-fill nil 427 "TPU-edt version that respects the bottom scroll margin." 428 (let ((beg (tpu-current-line))) 429 (tpu-old-do-auto-fill) 430 (tpu-bottom-check beg 1))) 431 432 433;;; Function to set scroll margins 434 435;;;###autoload 436(defun tpu-set-scroll-margins (top bottom) 437 "Set scroll margins." 438 (interactive 439 "sEnter top scroll margin (N lines or N%% or RETURN for current value): \ 440\nsEnter bottom scroll margin (N lines or N%% or RETURN for current value): ") 441 ;; set top scroll margin 442 (or (string= top "") 443 (if (string= "%" (substring top -1)) 444 (setq tpu-top-scroll-margin (string-to-number top)) 445 (setq tpu-top-scroll-margin 446 (/ (1- (+ (* (string-to-number top) 100) (window-height))) 447 (window-height))))) 448 ;; set bottom scroll margin 449 (or (string= bottom "") 450 (if (string= "%" (substring bottom -1)) 451 (setq tpu-bottom-scroll-margin (string-to-number bottom)) 452 (setq tpu-bottom-scroll-margin 453 (/ (1- (+ (* (string-to-number bottom) 100) (window-height))) 454 (window-height))))) 455 ;; report scroll margin settings if running interactively 456 (and (interactive-p) 457 (message "Scroll margins set. Top = %s%%, Bottom = %s%%" 458 tpu-top-scroll-margin tpu-bottom-scroll-margin))) 459 460 461;;; Functions to set cursor bound or free 462 463;;;###autoload 464(defun tpu-set-cursor-free nil 465 "Allow the cursor to move freely about the screen." 466 (interactive) 467 (setq tpu-cursor-free t) 468 (substitute-key-definition 'tpu-set-cursor-free 469 'tpu-set-cursor-bound 470 GOLD-map) 471 (message "The cursor will now move freely about the screen.")) 472 473;;;###autoload 474(defun tpu-set-cursor-bound nil 475 "Constrain the cursor to the flow of the text." 476 (interactive) 477 (tpu-trim-line-ends) 478 (setq tpu-cursor-free nil) 479 (substitute-key-definition 'tpu-set-cursor-bound 480 'tpu-set-cursor-free 481 GOLD-map) 482 (message "The cursor is now bound to the flow of your text.")) 483 484;;; arch-tag: 89676fa4-33ec-48cb-9135-6f3bf230ab1a 485;;; tpu-extras.el ends here 486