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18ac0782 | 1 | ;;; ebnf-otz.el --- syntactic chart OpTimiZer |
984ae001 | 2 | |
ae16d111 | 3 | ;; Copyright (C) 1999, 2000, 2001 Free Software Foundation, Inc. |
984ae001 | 4 | |
ae16d111 | 5 | ;; Author: Vinicius Jose Latorre <vinicius@cpqd.com.br> |
984ae001 | 6 | ;; Maintainer: Vinicius Jose Latorre <vinicius@cpqd.com.br> |
ae16d111 | 7 | ;; Keywords: wp, ebnf, PostScript |
18ac0782 | 8 | ;; Time-stamp: <2003-02-10 10:46:51 jbarranquero> |
ae16d111 | 9 | ;; Version: 1.0 |
984ae001 | 10 | |
8d9ea7b1 | 11 | ;; This file is part of GNU Emacs. |
984ae001 | 12 | |
8d9ea7b1 | 13 | ;; GNU Emacs is free software; you can redistribute it and/or modify |
984ae001 GM |
14 | ;; it under the terms of the GNU General Public License as published by |
15 | ;; the Free Software Foundation; either version 2, or (at your option) | |
16 | ;; any later version. | |
17 | ||
8d9ea7b1 | 18 | ;; GNU Emacs is distributed in the hope that it will be useful, |
984ae001 GM |
19 | ;; but WITHOUT ANY WARRANTY; without even the implied warranty of |
20 | ;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
21 | ;; GNU General Public License for more details. | |
22 | ||
23 | ;; You should have received a copy of the GNU General Public License | |
24 | ;; along with GNU Emacs; see the file COPYING. If not, write to the | |
25 | ;; Free Software Foundation, Inc., 59 Temple Place - Suite 330, | |
26 | ;; Boston, MA 02111-1307, USA. | |
27 | ||
28 | ;;; Commentary: | |
29 | ||
30 | ;; ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;; | |
31 | ;; | |
32 | ;; | |
33 | ;; This is part of ebnf2ps package. | |
34 | ;; | |
35 | ;; This package defines an optimizer for ebnf2ps. | |
36 | ;; | |
37 | ;; See ebnf2ps.el for documentation. | |
38 | ;; | |
39 | ;; | |
40 | ;; ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;; | |
41 | ||
e8af40ee | 42 | ;;; Code: |
984ae001 GM |
43 | |
44 | ||
45 | (require 'ebnf2ps) | |
46 | ||
47 | \f | |
48 | ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;; | |
49 | ||
50 | ||
51 | (defvar ebnf-empty-rule-list nil | |
52 | "List of empty rule name.") | |
53 | ||
54 | ||
55 | (defun ebnf-add-empty-rule-list (rule) | |
56 | "Add empty RULE in `ebnf-empty-rule-list'." | |
57 | (and ebnf-ignore-empty-rule | |
58 | (eq (ebnf-node-kind (ebnf-node-production rule)) | |
59 | 'ebnf-generate-empty) | |
60 | (setq ebnf-empty-rule-list (cons (ebnf-node-name rule) | |
61 | ebnf-empty-rule-list)))) | |
62 | ||
63 | ||
64 | (defun ebnf-otz-initialize () | |
65 | "Initialize optimizer." | |
66 | (setq ebnf-empty-rule-list nil)) | |
67 | ||
68 | \f | |
69 | ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;; | |
70 | ;; Eliminate empty rules | |
71 | ||
72 | ||
73 | (defun ebnf-eliminate-empty-rules (syntax-list) | |
74 | "Eliminate empty rules." | |
75 | (while ebnf-empty-rule-list | |
76 | (let ((ebnf-total (length syntax-list)) | |
77 | (ebnf-nprod 0) | |
78 | (prod-list syntax-list) | |
79 | new-list before) | |
80 | (while prod-list | |
81 | (ebnf-message-info "Eliminating empty rules") | |
82 | (let ((rule (car prod-list))) | |
83 | ;; if any non-terminal pertains to ebnf-empty-rule-list | |
84 | ;; then eliminate non-terminal from rule | |
85 | (if (ebnf-eliminate-empty rule) | |
86 | (setq before prod-list) | |
87 | ;; eliminate empty rule from syntax-list | |
88 | (setq new-list (cons (ebnf-node-name rule) new-list)) | |
89 | (if before | |
90 | (setcdr before (cdr prod-list)) | |
91 | (setq syntax-list (cdr syntax-list))))) | |
92 | (setq prod-list (cdr prod-list))) | |
93 | (setq ebnf-empty-rule-list new-list))) | |
94 | syntax-list) | |
95 | ||
96 | ||
97 | ;; [production width-func entry height width name production action] | |
98 | ;; [sequence width-func entry height width list] | |
99 | ;; [alternative width-func entry height width list] | |
100 | ;; [non-terminal width-func entry height width name default] | |
101 | ;; [empty width-func entry height width] | |
102 | ;; [terminal width-func entry height width name default] | |
103 | ;; [special width-func entry height width name default] | |
104 | ||
105 | (defun ebnf-eliminate-empty (rule) | |
106 | (let ((kind (ebnf-node-kind rule))) | |
107 | (cond | |
108 | ;; non-terminal | |
109 | ((eq kind 'ebnf-generate-non-terminal) | |
110 | (if (member (ebnf-node-name rule) ebnf-empty-rule-list) | |
111 | nil | |
112 | rule)) | |
113 | ;; sequence | |
114 | ((eq kind 'ebnf-generate-sequence) | |
115 | (let ((seq (ebnf-node-list rule)) | |
116 | (header (ebnf-node-list rule)) | |
117 | before elt) | |
118 | (while seq | |
119 | (setq elt (car seq)) | |
120 | (if (ebnf-eliminate-empty elt) | |
121 | (setq before seq) | |
122 | (if before | |
123 | (setcdr before (cdr seq)) | |
124 | (setq header (cdr header)))) | |
125 | (setq seq (cdr seq))) | |
126 | (when header | |
127 | (ebnf-node-list rule header) | |
128 | rule))) | |
129 | ;; alternative | |
130 | ((eq kind 'ebnf-generate-alternative) | |
131 | (let ((seq (ebnf-node-list rule)) | |
132 | (header (ebnf-node-list rule)) | |
133 | before elt) | |
134 | (while seq | |
135 | (setq elt (car seq)) | |
136 | (if (ebnf-eliminate-empty elt) | |
137 | (setq before seq) | |
138 | (if before | |
139 | (setcdr before (cdr seq)) | |
140 | (setq header (cdr header)))) | |
141 | (setq seq (cdr seq))) | |
142 | (when header | |
143 | (if (= (length header) 1) | |
144 | (car header) | |
145 | (ebnf-node-list rule header) | |
146 | rule)))) | |
147 | ;; production | |
148 | ((eq kind 'ebnf-generate-production) | |
149 | (let ((prod (ebnf-eliminate-empty (ebnf-node-production rule)))) | |
150 | (when prod | |
151 | (ebnf-node-production rule prod) | |
152 | rule))) | |
153 | ;; terminal, special and empty | |
154 | (t | |
155 | rule) | |
156 | ))) | |
157 | ||
158 | \f | |
159 | ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;; | |
160 | ;; Optimizations | |
161 | ||
162 | ||
163 | ;; *To be implemented*: | |
164 | ;; left recursion: | |
165 | ;; A = B | A C B | A C D. ==> A = B {C (B | D)}*. | |
166 | ||
167 | ;; right recursion: | |
168 | ;; A = B | C A. ==> A = {C}* B. | |
169 | ;; A = B | D | C A | E A. ==> A = { C | E }* ( B | D ). | |
170 | ||
171 | ;; optional: | |
172 | ;; A = B | C B. ==> A = [C] B. | |
173 | ;; A = B | B C. ==> A = B [C]. | |
174 | ;; A = D | B D | B C D. ==> A = [B [C]] D. | |
175 | ||
176 | ||
177 | ;; *Already implemented*: | |
178 | ;; left recursion: | |
179 | ;; A = B | A C. ==> A = B {C}*. | |
180 | ;; A = B | A B. ==> A = {B}+. | |
181 | ;; A = | A B. ==> A = {B}*. | |
182 | ;; A = B | A C B. ==> A = {B || C}+. | |
183 | ;; A = B | D | A C | A E. ==> A = ( B | D ) { C | E }*. | |
184 | ||
185 | ;; optional: | |
186 | ;; A = B | . ==> A = [B]. | |
187 | ;; A = | B . ==> A = [B]. | |
188 | ||
189 | ;; factoration: | |
190 | ;; A = B C | B D. ==> A = B (C | D). | |
191 | ;; A = C B | D B. ==> A = (C | D) B. | |
192 | ;; A = B C E | B D E. ==> A = B (C | D) E. | |
193 | ||
194 | ;; none: | |
195 | ;; A = B | C | . ==> A = B | C | . | |
196 | ;; A = B | C A D. ==> A = B | C A D. | |
197 | ||
198 | (defun ebnf-optimize (syntax-list) | |
18ac0782 | 199 | "Syntactic chart optimizer." |
984ae001 GM |
200 | (if (not ebnf-optimize) |
201 | syntax-list | |
202 | (let ((ebnf-total (length syntax-list)) | |
203 | (ebnf-nprod 0) | |
204 | new) | |
205 | (while syntax-list | |
206 | (setq new (cons (ebnf-optimize1 (car syntax-list)) new) | |
207 | syntax-list (cdr syntax-list))) | |
208 | (nreverse new)))) | |
209 | ||
210 | ||
211 | ;; left recursion: | |
212 | ;; 1. A = B | A C. ==> A = B {C}*. | |
213 | ;; 2. A = B | A B. ==> A = {B}+. | |
214 | ;; 3. A = | A B. ==> A = {B}*. | |
215 | ;; 4. A = B | A C B. ==> A = {B || C}+. | |
216 | ;; 5. A = B | D | A C | A E. ==> A = ( B | D ) { C | E }*. | |
217 | ||
218 | ;; optional: | |
219 | ;; 6. A = B | . ==> A = [B]. | |
220 | ;; 7. A = | B . ==> A = [B]. | |
221 | ||
222 | ;; factoration: | |
223 | ;; 8. A = B C | B D. ==> A = B (C | D). | |
224 | ;; 9. A = C B | D B. ==> A = (C | D) B. | |
225 | ;; 10. A = B C E | B D E. ==> A = B (C | D) E. | |
226 | ||
227 | (defun ebnf-optimize1 (prod) | |
18ac0782 | 228 | (ebnf-message-info "Optimizing syntactic chart") |
984ae001 GM |
229 | (let ((production (ebnf-node-production prod))) |
230 | (and (eq (ebnf-node-kind production) 'ebnf-generate-alternative) | |
231 | (let* ((hlist (ebnf-split-header-prefix | |
232 | (ebnf-node-list production) | |
233 | (ebnf-node-name prod))) | |
234 | (nlist (car hlist)) | |
235 | (zlist (cdr hlist)) | |
236 | (elist (ebnf-split-header-suffix nlist zlist))) | |
237 | (ebnf-node-production | |
238 | prod | |
239 | (cond | |
240 | ;; cases 2., 4. | |
241 | (elist | |
242 | (and (eq elist t) | |
243 | (setq elist nil)) | |
244 | (setq elist (or (ebnf-prefix-suffix elist) | |
245 | elist)) | |
246 | (let* ((nl (ebnf-extract-empty nlist)) | |
247 | (el (or (ebnf-prefix-suffix (cdr nl)) | |
248 | (ebnf-create-alternative (cdr nl))))) | |
249 | (if (car nl) | |
250 | (ebnf-make-zero-or-more el elist) | |
251 | (ebnf-make-one-or-more el elist)))) | |
252 | ;; cases 1., 3., 5. | |
253 | (zlist | |
254 | (let* ((xlist (cdr (ebnf-extract-empty zlist))) | |
255 | (znode (ebnf-make-zero-or-more | |
256 | (or (ebnf-prefix-suffix xlist) | |
257 | (ebnf-create-alternative xlist)))) | |
258 | (nnode (ebnf-map-list-to-optional nlist))) | |
259 | (and nnode | |
260 | (setq nlist (list nnode))) | |
261 | (if (or (null nlist) | |
262 | (and (= (length nlist) 1) | |
263 | (eq (ebnf-node-kind (car nlist)) | |
264 | 'ebnf-generate-empty))) | |
265 | znode | |
266 | (ebnf-make-sequence | |
267 | (list (or (ebnf-prefix-suffix nlist) | |
268 | (ebnf-create-alternative nlist)) | |
269 | znode))))) | |
270 | ;; cases 6., 7. | |
271 | ((ebnf-map-node-to-optional production) | |
272 | ) | |
273 | ;; cases 8., 9., 10. | |
274 | ((ebnf-prefix-suffix nlist) | |
275 | ) | |
276 | ;; none | |
277 | (t | |
278 | production) | |
279 | )))) | |
280 | prod)) | |
281 | ||
282 | ||
283 | (defun ebnf-split-header-prefix (node-list header) | |
284 | (let* ((hlist (ebnf-split-header-prefix1 node-list header)) | |
285 | (nlist (car hlist)) | |
286 | zlist empty-p) | |
287 | (while (setq hlist (cdr hlist)) | |
288 | (let ((elt (car hlist))) | |
289 | (if (eq (ebnf-node-kind elt) 'ebnf-generate-sequence) | |
290 | (setq zlist (cons | |
291 | (let ((seq (cdr (ebnf-node-list elt)))) | |
292 | (if (= (length seq) 1) | |
293 | (car seq) | |
294 | (ebnf-node-list elt seq) | |
295 | elt)) | |
296 | zlist)) | |
297 | (setq empty-p t)))) | |
298 | (and empty-p | |
299 | (setq zlist (cons (ebnf-make-empty) | |
300 | zlist))) | |
301 | (cons nlist (nreverse zlist)))) | |
302 | ||
303 | ||
304 | (defun ebnf-split-header-prefix1 (node-list header) | |
305 | (let (hlist nlist) | |
306 | (while node-list | |
307 | (if (ebnf-node-equal-header (car node-list) header) | |
308 | (setq hlist (cons (car node-list) hlist)) | |
309 | (setq nlist (cons (car node-list) nlist))) | |
310 | (setq node-list (cdr node-list))) | |
311 | (cons (nreverse nlist) (nreverse hlist)))) | |
312 | ||
313 | ||
314 | (defun ebnf-node-equal-header (node header) | |
315 | (let ((kind (ebnf-node-kind node))) | |
316 | (cond | |
317 | ((eq kind 'ebnf-generate-sequence) | |
318 | (ebnf-node-equal-header (car (ebnf-node-list node)) header)) | |
319 | ((eq kind 'ebnf-generate-non-terminal) | |
320 | (string= (ebnf-node-name node) header)) | |
321 | (t | |
322 | nil) | |
323 | ))) | |
324 | ||
325 | ||
326 | (defun ebnf-map-node-to-optional (node) | |
327 | (and (eq (ebnf-node-kind node) 'ebnf-generate-alternative) | |
328 | (ebnf-map-list-to-optional (ebnf-node-list node)))) | |
329 | ||
330 | ||
331 | (defun ebnf-map-list-to-optional (nlist) | |
332 | (and (= (length nlist) 2) | |
333 | (let ((first (nth 0 nlist)) | |
334 | (second (nth 1 nlist))) | |
335 | (cond | |
336 | ;; empty second | |
337 | ((eq (ebnf-node-kind first) 'ebnf-generate-empty) | |
338 | (ebnf-make-optional second)) | |
339 | ;; first empty | |
340 | ((eq (ebnf-node-kind second) 'ebnf-generate-empty) | |
341 | (ebnf-make-optional first)) | |
342 | ;; first second | |
343 | (t | |
344 | nil) | |
345 | )))) | |
346 | ||
347 | ||
348 | (defun ebnf-extract-empty (elist) | |
349 | (let ((now elist) | |
350 | before empty-p) | |
351 | (while now | |
352 | (if (not (eq (ebnf-node-kind (car now)) 'ebnf-generate-empty)) | |
353 | (setq before now) | |
354 | (setq empty-p t) | |
355 | (if before | |
356 | (setcdr before (cdr now)) | |
357 | (setq elist (cdr elist)))) | |
358 | (setq now (cdr now))) | |
359 | (cons empty-p elist))) | |
360 | ||
361 | ||
362 | (defun ebnf-split-header-suffix (nlist zlist) | |
363 | (let (new empty-p) | |
364 | (and (cond | |
365 | ((= (length nlist) 1) | |
366 | (let ((ok t) | |
367 | (elt (car nlist))) | |
368 | (while (and ok zlist) | |
369 | (setq ok (ebnf-split-header-suffix1 elt (car zlist)) | |
370 | zlist (cdr zlist)) | |
371 | (if (eq ok t) | |
372 | (setq empty-p t) | |
373 | (setq new (cons ok new)))) | |
374 | ok)) | |
375 | ((= (length nlist) (length zlist)) | |
376 | (let ((ok t)) | |
377 | (while (and ok zlist) | |
378 | (setq ok (ebnf-split-header-suffix1 (car nlist) (car zlist)) | |
379 | nlist (cdr nlist) | |
380 | zlist (cdr zlist)) | |
381 | (if (eq ok t) | |
382 | (setq empty-p t) | |
383 | (setq new (cons ok new)))) | |
384 | ok)) | |
385 | (t | |
386 | nil) | |
387 | ) | |
388 | (let* ((lis (ebnf-unique-list new)) | |
389 | (len (length lis))) | |
390 | (cond | |
391 | ((zerop len) | |
392 | t) | |
393 | ((= len 1) | |
394 | (setq lis (car lis)) | |
395 | (if empty-p | |
396 | (ebnf-make-optional lis) | |
397 | lis)) | |
398 | (t | |
399 | (and empty-p | |
400 | (setq lis (cons (ebnf-make-empty) lis))) | |
401 | (ebnf-create-alternative (nreverse lis))) | |
402 | ))))) | |
403 | ||
404 | ||
405 | (defun ebnf-split-header-suffix1 (ne ze) | |
406 | (cond | |
407 | ((eq (ebnf-node-kind ne) 'ebnf-generate-sequence) | |
408 | (and (eq (ebnf-node-kind ze) 'ebnf-generate-sequence) | |
409 | (let ((nl (ebnf-node-list ne)) | |
410 | (zl (ebnf-node-list ze)) | |
411 | len z) | |
412 | (and (>= (length zl) (length nl)) | |
413 | (let ((ok t)) | |
414 | (setq len (- (length zl) (length nl)) | |
415 | z (nthcdr len zl)) | |
416 | (while (and ok z) | |
417 | (setq ok (ebnf-node-equal (car z) (car nl)) | |
418 | z (cdr z) | |
419 | nl (cdr nl))) | |
420 | ok) | |
421 | (if (zerop len) | |
422 | t | |
423 | (setcdr (nthcdr (1- len) zl) nil) | |
424 | ze))))) | |
425 | ((eq (ebnf-node-kind ze) 'ebnf-generate-sequence) | |
426 | (let* ((zl (ebnf-node-list ze)) | |
427 | (len (length zl))) | |
428 | (and (ebnf-node-equal ne (car (nthcdr (1- len) zl))) | |
429 | (cond | |
430 | ((= len 1) | |
431 | t) | |
432 | ((= len 2) | |
433 | (car zl)) | |
434 | (t | |
435 | (setcdr (nthcdr (- len 2) zl) nil) | |
436 | ze) | |
437 | )))) | |
438 | (t | |
439 | (ebnf-node-equal ne ze)) | |
440 | )) | |
441 | ||
442 | ||
443 | (defun ebnf-prefix-suffix (lis) | |
444 | (and lis (listp lis) | |
445 | (let* ((prefix (ebnf-split-prefix lis)) | |
446 | (suffix (ebnf-split-suffix (cdr prefix))) | |
447 | (middle (cdr suffix))) | |
448 | (setq prefix (car prefix) | |
449 | suffix (car suffix)) | |
450 | (and (or prefix suffix) | |
451 | (ebnf-make-sequence | |
452 | (nconc prefix | |
453 | (and middle | |
454 | (list (or (ebnf-map-list-to-optional middle) | |
455 | (ebnf-create-alternative middle)))) | |
456 | suffix)))))) | |
457 | ||
458 | ||
459 | (defun ebnf-split-prefix (lis) | |
460 | (let* ((len (length lis)) | |
461 | (tail lis) | |
462 | (head (if (eq (ebnf-node-kind (car lis)) 'ebnf-generate-sequence) | |
463 | (ebnf-node-list (car lis)) | |
464 | (list (car lis)))) | |
465 | (ipre (1+ len))) | |
466 | ;; determine prefix length | |
467 | (while (and (> ipre 0) (setq tail (cdr tail))) | |
468 | (let ((cur head) | |
469 | (this (if (eq (ebnf-node-kind (car tail)) 'ebnf-generate-sequence) | |
470 | (ebnf-node-list (car tail)) | |
471 | (list (car tail)))) | |
472 | (i 0)) | |
473 | (while (and cur this | |
474 | (ebnf-node-equal (car cur) (car this))) | |
475 | (setq cur (cdr cur) | |
476 | this (cdr this) | |
477 | i (1+ i))) | |
478 | (setq ipre (min ipre i)))) | |
479 | (if (or (zerop ipre) (> ipre len)) | |
480 | ;; no prefix at all | |
481 | (cons nil lis) | |
482 | (let* ((tail (nthcdr ipre head)) | |
483 | ;; get prefix | |
484 | (prefix (progn | |
485 | (and tail | |
486 | (setcdr (nthcdr (1- ipre) head) nil)) | |
487 | head)) | |
488 | empty-p before) | |
489 | ;; adjust first element | |
490 | (if (or (not (eq (ebnf-node-kind (car lis)) 'ebnf-generate-sequence)) | |
491 | (null tail)) | |
492 | (setq lis (cdr lis) | |
493 | tail lis | |
494 | empty-p t) | |
495 | (if (= (length tail) 1) | |
496 | (setcar lis (car tail)) | |
497 | (ebnf-node-list (car lis) tail)) | |
498 | (setq tail (cdr lis))) | |
499 | ;; eliminate prefix from lis based on ipre | |
500 | (while tail | |
501 | (let ((elt (car tail)) | |
502 | rest) | |
503 | (if (and (eq (ebnf-node-kind elt) 'ebnf-generate-sequence) | |
504 | (setq rest (nthcdr ipre (ebnf-node-list elt)))) | |
505 | (progn | |
506 | (if (= (length rest) 1) | |
507 | (setcar tail (car rest)) | |
508 | (ebnf-node-list elt rest)) | |
509 | (setq before tail)) | |
510 | (setq empty-p t) | |
511 | (if before | |
512 | (setcdr before (cdr tail)) | |
513 | (setq lis (cdr lis)))) | |
514 | (setq tail (cdr tail)))) | |
515 | (cons prefix (ebnf-unique-list | |
516 | (if empty-p | |
517 | (nconc lis (list (ebnf-make-empty))) | |
518 | lis))))))) | |
519 | ||
520 | ||
521 | (defun ebnf-split-suffix (lis) | |
522 | (let* ((len (length lis)) | |
523 | (tail lis) | |
524 | (head (nreverse | |
525 | (if (eq (ebnf-node-kind (car lis)) 'ebnf-generate-sequence) | |
526 | (ebnf-node-list (car lis)) | |
527 | (list (car lis))))) | |
528 | (isuf (1+ len))) | |
529 | ;; determine suffix length | |
530 | (while (and (> isuf 0) (setq tail (cdr tail))) | |
531 | (let* ((cur head) | |
532 | (tlis (nreverse | |
533 | (if (eq (ebnf-node-kind (car tail)) 'ebnf-generate-sequence) | |
534 | (ebnf-node-list (car tail)) | |
535 | (list (car tail))))) | |
536 | (this tlis) | |
537 | (i 0)) | |
538 | (while (and cur this | |
539 | (ebnf-node-equal (car cur) (car this))) | |
540 | (setq cur (cdr cur) | |
541 | this (cdr this) | |
542 | i (1+ i))) | |
543 | (nreverse tlis) | |
544 | (setq isuf (min isuf i)))) | |
545 | (setq head (nreverse head)) | |
546 | (if (or (zerop isuf) (> isuf len)) | |
547 | ;; no suffix at all | |
548 | (cons nil lis) | |
549 | (let* ((n (- (length head) isuf)) | |
550 | ;; get suffix | |
551 | (suffix (nthcdr n head)) | |
552 | (tail (and (> n 0) | |
553 | (progn | |
554 | (setcdr (nthcdr (1- n) head) nil) | |
555 | head))) | |
556 | before empty-p) | |
557 | ;; adjust first element | |
558 | (if (or (not (eq (ebnf-node-kind (car lis)) 'ebnf-generate-sequence)) | |
559 | (null tail)) | |
560 | (setq lis (cdr lis) | |
561 | tail lis | |
562 | empty-p t) | |
563 | (if (= (length tail) 1) | |
564 | (setcar lis (car tail)) | |
565 | (ebnf-node-list (car lis) tail)) | |
566 | (setq tail (cdr lis))) | |
567 | ;; eliminate suffix from lis based on isuf | |
568 | (while tail | |
569 | (let ((elt (car tail)) | |
570 | rest) | |
571 | (if (and (eq (ebnf-node-kind elt) 'ebnf-generate-sequence) | |
572 | (setq rest (ebnf-node-list elt) | |
573 | n (- (length rest) isuf)) | |
574 | (> n 0)) | |
575 | (progn | |
576 | (if (= n 1) | |
577 | (setcar tail (car rest)) | |
578 | (setcdr (nthcdr (1- n) rest) nil) | |
579 | (ebnf-node-list elt rest)) | |
580 | (setq before tail)) | |
581 | (setq empty-p t) | |
582 | (if before | |
583 | (setcdr before (cdr tail)) | |
584 | (setq lis (cdr lis)))) | |
585 | (setq tail (cdr tail)))) | |
586 | (cons suffix (ebnf-unique-list | |
587 | (if empty-p | |
588 | (nconc lis (list (ebnf-make-empty))) | |
589 | lis))))))) | |
590 | ||
591 | ||
592 | (defun ebnf-unique-list (nlist) | |
593 | (let ((current nlist) | |
594 | before) | |
595 | (while current | |
596 | (let ((tail (cdr current)) | |
597 | (head (car current)) | |
598 | remove-p) | |
599 | (while tail | |
600 | (if (not (ebnf-node-equal head (car tail))) | |
601 | (setq tail (cdr tail)) | |
602 | (setq remove-p t | |
603 | tail nil) | |
604 | (if before | |
605 | (setcdr before (cdr current)) | |
606 | (setq nlist (cdr nlist))))) | |
607 | (or remove-p | |
608 | (setq before current)) | |
609 | (setq current (cdr current)))) | |
610 | nlist)) | |
611 | ||
612 | ||
613 | (defun ebnf-node-equal (A B) | |
614 | (let ((kindA (ebnf-node-kind A)) | |
615 | (kindB (ebnf-node-kind B))) | |
616 | (and (eq kindA kindB) | |
617 | (cond | |
618 | ;; empty | |
619 | ((eq kindA 'ebnf-generate-empty) | |
620 | t) | |
621 | ;; non-terminal, terminal, special | |
622 | ((memq kindA '(ebnf-generate-non-terminal | |
623 | ebnf-generate-terminal | |
624 | ebnf-generate-special)) | |
625 | (string= (ebnf-node-name A) (ebnf-node-name B))) | |
626 | ;; alternative, sequence | |
627 | ((memq kindA '(ebnf-generate-alternative ; any order | |
628 | ebnf-generate-sequence)) ; order is important | |
629 | (let ((listA (ebnf-node-list A)) | |
630 | (listB (ebnf-node-list B))) | |
631 | (and (= (length listA) (length listB)) | |
632 | (let ((ok t)) | |
633 | (while (and ok listA) | |
634 | (setq ok (ebnf-node-equal (car listA) (car listB)) | |
635 | listA (cdr listA) | |
636 | listB (cdr listB))) | |
637 | ok)))) | |
638 | ;; production | |
639 | ((eq kindA 'ebnf-generate-production) | |
640 | (and (string= (ebnf-node-name A) (ebnf-node-name B)) | |
641 | (ebnf-node-equal (ebnf-node-production A) | |
642 | (ebnf-node-production B)))) | |
643 | ;; otherwise | |
644 | (t | |
645 | nil) | |
646 | )))) | |
647 | ||
648 | ||
649 | (defun ebnf-create-alternative (alt) | |
650 | (if (> (length alt) 1) | |
651 | (ebnf-make-alternative alt) | |
652 | (car alt))) | |
653 | ||
654 | \f | |
655 | ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;; | |
656 | ||
657 | ||
658 | (provide 'ebnf-otz) | |
659 | ||
660 | ||
ab5796a9 | 661 | ;;; arch-tag: 7ef2249d-9e8b-4bc1-999f-95d784690636 |
984ae001 | 662 | ;;; ebnf-otz.el ends here |