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18ac0782 | 1 | ;;; ebnf-otz.el --- syntactic chart OpTimiZer |
984ae001 | 2 | |
ba318903 | 3 | ;; Copyright (C) 1999-2014 Free Software Foundation, Inc. |
984ae001 | 4 | |
ac4780a1 VJL |
5 | ;; Author: Vinicius Jose Latorre <viniciusjl@ig.com.br> |
6 | ;; Maintainer: Vinicius Jose Latorre <viniciusjl@ig.com.br> | |
ae16d111 | 7 | ;; Keywords: wp, ebnf, PostScript |
12059709 | 8 | ;; Old-Version: 1.0 |
bd78fa1d | 9 | ;; Package: ebnf2ps |
984ae001 | 10 | |
8d9ea7b1 | 11 | ;; This file is part of GNU Emacs. |
984ae001 | 12 | |
b1fc2b50 | 13 | ;; GNU Emacs is free software: you can redistribute it and/or modify |
984ae001 | 14 | ;; it under the terms of the GNU General Public License as published by |
b1fc2b50 GM |
15 | ;; the Free Software Foundation, either version 3 of the License, or |
16 | ;; (at your option) any later version. | |
984ae001 | 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 | |
b1fc2b50 | 24 | ;; along with GNU Emacs. If not, see <http://www.gnu.org/licenses/>. |
984ae001 GM |
25 | |
26 | ;;; Commentary: | |
27 | ||
28 | ;; ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;; | |
29 | ;; | |
30 | ;; | |
31 | ;; This is part of ebnf2ps package. | |
32 | ;; | |
33 | ;; This package defines an optimizer for ebnf2ps. | |
34 | ;; | |
35 | ;; See ebnf2ps.el for documentation. | |
36 | ;; | |
37 | ;; | |
60df7255 VJL |
38 | ;; Optimizations |
39 | ;; ------------- | |
40 | ;; | |
41 | ;; | |
42 | ;; *To be implemented*: | |
43 | ;; left recursion: | |
44 | ;; A = B | A C B | A C D. ==> A = B {C (B | D)}*. | |
45 | ;; | |
46 | ;; right recursion: | |
47 | ;; A = B | C A. ==> A = {C}* B. | |
48 | ;; A = B | D | C A | E A. ==> A = { C | E }* ( B | D ). | |
49 | ;; | |
50 | ;; optional: | |
51 | ;; A = B | C B. ==> A = [C] B. | |
52 | ;; A = B | B C. ==> A = B [C]. | |
53 | ;; A = D | B D | B C D. ==> A = [B [C]] D. | |
54 | ;; | |
55 | ;; | |
56 | ;; *Already implemented*: | |
57 | ;; left recursion: | |
58 | ;; A = B | A C. ==> A = B {C}*. | |
59 | ;; A = B | A B. ==> A = {B}+. | |
60 | ;; A = | A B. ==> A = {B}*. | |
61 | ;; A = B | A C B. ==> A = {B || C}+. | |
62 | ;; A = B | D | A C | A E. ==> A = ( B | D ) { C | E }*. | |
63 | ;; | |
64 | ;; optional: | |
65 | ;; A = B | . ==> A = [B]. | |
66 | ;; A = | B . ==> A = [B]. | |
67 | ;; | |
ad96a7ef | 68 | ;; factorization: |
60df7255 VJL |
69 | ;; A = B C | B D. ==> A = B (C | D). |
70 | ;; A = C B | D B. ==> A = (C | D) B. | |
71 | ;; A = B C E | B D E. ==> A = B (C | D) E. | |
72 | ;; | |
73 | ;; none: | |
74 | ;; A = B | C | . ==> A = B | C | . | |
75 | ;; A = B | C A D. ==> A = B | C A D. | |
76 | ;; | |
77 | ;; | |
984ae001 GM |
78 | ;; ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;; |
79 | ||
e8af40ee | 80 | ;;; Code: |
984ae001 GM |
81 | |
82 | ||
83 | (require 'ebnf2ps) | |
84 | ||
85 | \f | |
86 | ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;; | |
87 | ||
88 | ||
89 | (defvar ebnf-empty-rule-list nil | |
90 | "List of empty rule name.") | |
91 | ||
92 | ||
93 | (defun ebnf-add-empty-rule-list (rule) | |
94 | "Add empty RULE in `ebnf-empty-rule-list'." | |
95 | (and ebnf-ignore-empty-rule | |
96 | (eq (ebnf-node-kind (ebnf-node-production rule)) | |
97 | 'ebnf-generate-empty) | |
98 | (setq ebnf-empty-rule-list (cons (ebnf-node-name rule) | |
99 | ebnf-empty-rule-list)))) | |
100 | ||
101 | ||
102 | (defun ebnf-otz-initialize () | |
103 | "Initialize optimizer." | |
104 | (setq ebnf-empty-rule-list nil)) | |
105 | ||
106 | \f | |
107 | ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;; | |
108 | ;; Eliminate empty rules | |
109 | ||
110 | ||
111 | (defun ebnf-eliminate-empty-rules (syntax-list) | |
112 | "Eliminate empty rules." | |
113 | (while ebnf-empty-rule-list | |
114 | (let ((ebnf-total (length syntax-list)) | |
115 | (ebnf-nprod 0) | |
116 | (prod-list syntax-list) | |
117 | new-list before) | |
118 | (while prod-list | |
119 | (ebnf-message-info "Eliminating empty rules") | |
120 | (let ((rule (car prod-list))) | |
121 | ;; if any non-terminal pertains to ebnf-empty-rule-list | |
122 | ;; then eliminate non-terminal from rule | |
123 | (if (ebnf-eliminate-empty rule) | |
124 | (setq before prod-list) | |
125 | ;; eliminate empty rule from syntax-list | |
126 | (setq new-list (cons (ebnf-node-name rule) new-list)) | |
127 | (if before | |
128 | (setcdr before (cdr prod-list)) | |
129 | (setq syntax-list (cdr syntax-list))))) | |
130 | (setq prod-list (cdr prod-list))) | |
131 | (setq ebnf-empty-rule-list new-list))) | |
132 | syntax-list) | |
133 | ||
134 | ||
135 | ;; [production width-func entry height width name production action] | |
136 | ;; [sequence width-func entry height width list] | |
137 | ;; [alternative width-func entry height width list] | |
138 | ;; [non-terminal width-func entry height width name default] | |
139 | ;; [empty width-func entry height width] | |
140 | ;; [terminal width-func entry height width name default] | |
141 | ;; [special width-func entry height width name default] | |
142 | ||
143 | (defun ebnf-eliminate-empty (rule) | |
144 | (let ((kind (ebnf-node-kind rule))) | |
145 | (cond | |
146 | ;; non-terminal | |
147 | ((eq kind 'ebnf-generate-non-terminal) | |
148 | (if (member (ebnf-node-name rule) ebnf-empty-rule-list) | |
149 | nil | |
150 | rule)) | |
151 | ;; sequence | |
152 | ((eq kind 'ebnf-generate-sequence) | |
153 | (let ((seq (ebnf-node-list rule)) | |
154 | (header (ebnf-node-list rule)) | |
155 | before elt) | |
156 | (while seq | |
157 | (setq elt (car seq)) | |
158 | (if (ebnf-eliminate-empty elt) | |
159 | (setq before seq) | |
160 | (if before | |
161 | (setcdr before (cdr seq)) | |
162 | (setq header (cdr header)))) | |
163 | (setq seq (cdr seq))) | |
164 | (when header | |
165 | (ebnf-node-list rule header) | |
166 | rule))) | |
167 | ;; alternative | |
168 | ((eq kind 'ebnf-generate-alternative) | |
169 | (let ((seq (ebnf-node-list rule)) | |
170 | (header (ebnf-node-list rule)) | |
171 | before elt) | |
172 | (while seq | |
173 | (setq elt (car seq)) | |
174 | (if (ebnf-eliminate-empty elt) | |
175 | (setq before seq) | |
176 | (if before | |
177 | (setcdr before (cdr seq)) | |
178 | (setq header (cdr header)))) | |
179 | (setq seq (cdr seq))) | |
180 | (when header | |
181 | (if (= (length header) 1) | |
182 | (car header) | |
183 | (ebnf-node-list rule header) | |
184 | rule)))) | |
185 | ;; production | |
186 | ((eq kind 'ebnf-generate-production) | |
187 | (let ((prod (ebnf-eliminate-empty (ebnf-node-production rule)))) | |
188 | (when prod | |
189 | (ebnf-node-production rule prod) | |
190 | rule))) | |
191 | ;; terminal, special and empty | |
192 | (t | |
193 | rule) | |
194 | ))) | |
195 | ||
196 | \f | |
197 | ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;; | |
198 | ;; Optimizations | |
199 | ||
200 | ||
201 | ;; *To be implemented*: | |
202 | ;; left recursion: | |
203 | ;; A = B | A C B | A C D. ==> A = B {C (B | D)}*. | |
204 | ||
205 | ;; right recursion: | |
206 | ;; A = B | C A. ==> A = {C}* B. | |
207 | ;; A = B | D | C A | E A. ==> A = { C | E }* ( B | D ). | |
208 | ||
209 | ;; optional: | |
210 | ;; A = B | C B. ==> A = [C] B. | |
211 | ;; A = B | B C. ==> A = B [C]. | |
212 | ;; A = D | B D | B C D. ==> A = [B [C]] D. | |
213 | ||
214 | ||
215 | ;; *Already implemented*: | |
216 | ;; left recursion: | |
217 | ;; A = B | A C. ==> A = B {C}*. | |
218 | ;; A = B | A B. ==> A = {B}+. | |
219 | ;; A = | A B. ==> A = {B}*. | |
220 | ;; A = B | A C B. ==> A = {B || C}+. | |
221 | ;; A = B | D | A C | A E. ==> A = ( B | D ) { C | E }*. | |
222 | ||
223 | ;; optional: | |
224 | ;; A = B | . ==> A = [B]. | |
225 | ;; A = | B . ==> A = [B]. | |
226 | ||
ad96a7ef | 227 | ;; factorization: |
984ae001 GM |
228 | ;; A = B C | B D. ==> A = B (C | D). |
229 | ;; A = C B | D B. ==> A = (C | D) B. | |
230 | ;; A = B C E | B D E. ==> A = B (C | D) E. | |
231 | ||
232 | ;; none: | |
233 | ;; A = B | C | . ==> A = B | C | . | |
234 | ;; A = B | C A D. ==> A = B | C A D. | |
235 | ||
236 | (defun ebnf-optimize (syntax-list) | |
18ac0782 | 237 | "Syntactic chart optimizer." |
984ae001 GM |
238 | (if (not ebnf-optimize) |
239 | syntax-list | |
240 | (let ((ebnf-total (length syntax-list)) | |
241 | (ebnf-nprod 0) | |
242 | new) | |
243 | (while syntax-list | |
244 | (setq new (cons (ebnf-optimize1 (car syntax-list)) new) | |
245 | syntax-list (cdr syntax-list))) | |
246 | (nreverse new)))) | |
247 | ||
248 | ||
249 | ;; left recursion: | |
250 | ;; 1. A = B | A C. ==> A = B {C}*. | |
251 | ;; 2. A = B | A B. ==> A = {B}+. | |
252 | ;; 3. A = | A B. ==> A = {B}*. | |
253 | ;; 4. A = B | A C B. ==> A = {B || C}+. | |
254 | ;; 5. A = B | D | A C | A E. ==> A = ( B | D ) { C | E }*. | |
255 | ||
256 | ;; optional: | |
257 | ;; 6. A = B | . ==> A = [B]. | |
258 | ;; 7. A = | B . ==> A = [B]. | |
259 | ||
ad96a7ef | 260 | ;; factorization: |
984ae001 GM |
261 | ;; 8. A = B C | B D. ==> A = B (C | D). |
262 | ;; 9. A = C B | D B. ==> A = (C | D) B. | |
263 | ;; 10. A = B C E | B D E. ==> A = B (C | D) E. | |
264 | ||
265 | (defun ebnf-optimize1 (prod) | |
18ac0782 | 266 | (ebnf-message-info "Optimizing syntactic chart") |
984ae001 GM |
267 | (let ((production (ebnf-node-production prod))) |
268 | (and (eq (ebnf-node-kind production) 'ebnf-generate-alternative) | |
269 | (let* ((hlist (ebnf-split-header-prefix | |
270 | (ebnf-node-list production) | |
271 | (ebnf-node-name prod))) | |
272 | (nlist (car hlist)) | |
273 | (zlist (cdr hlist)) | |
274 | (elist (ebnf-split-header-suffix nlist zlist))) | |
275 | (ebnf-node-production | |
276 | prod | |
277 | (cond | |
278 | ;; cases 2., 4. | |
279 | (elist | |
280 | (and (eq elist t) | |
281 | (setq elist nil)) | |
282 | (setq elist (or (ebnf-prefix-suffix elist) | |
283 | elist)) | |
284 | (let* ((nl (ebnf-extract-empty nlist)) | |
285 | (el (or (ebnf-prefix-suffix (cdr nl)) | |
286 | (ebnf-create-alternative (cdr nl))))) | |
287 | (if (car nl) | |
288 | (ebnf-make-zero-or-more el elist) | |
289 | (ebnf-make-one-or-more el elist)))) | |
290 | ;; cases 1., 3., 5. | |
291 | (zlist | |
292 | (let* ((xlist (cdr (ebnf-extract-empty zlist))) | |
293 | (znode (ebnf-make-zero-or-more | |
294 | (or (ebnf-prefix-suffix xlist) | |
295 | (ebnf-create-alternative xlist)))) | |
296 | (nnode (ebnf-map-list-to-optional nlist))) | |
297 | (and nnode | |
298 | (setq nlist (list nnode))) | |
299 | (if (or (null nlist) | |
300 | (and (= (length nlist) 1) | |
301 | (eq (ebnf-node-kind (car nlist)) | |
302 | 'ebnf-generate-empty))) | |
303 | znode | |
304 | (ebnf-make-sequence | |
305 | (list (or (ebnf-prefix-suffix nlist) | |
306 | (ebnf-create-alternative nlist)) | |
307 | znode))))) | |
308 | ;; cases 6., 7. | |
309 | ((ebnf-map-node-to-optional production) | |
310 | ) | |
311 | ;; cases 8., 9., 10. | |
312 | ((ebnf-prefix-suffix nlist) | |
313 | ) | |
314 | ;; none | |
315 | (t | |
316 | production) | |
317 | )))) | |
318 | prod)) | |
319 | ||
320 | ||
321 | (defun ebnf-split-header-prefix (node-list header) | |
322 | (let* ((hlist (ebnf-split-header-prefix1 node-list header)) | |
323 | (nlist (car hlist)) | |
324 | zlist empty-p) | |
325 | (while (setq hlist (cdr hlist)) | |
326 | (let ((elt (car hlist))) | |
327 | (if (eq (ebnf-node-kind elt) 'ebnf-generate-sequence) | |
328 | (setq zlist (cons | |
329 | (let ((seq (cdr (ebnf-node-list elt)))) | |
330 | (if (= (length seq) 1) | |
331 | (car seq) | |
332 | (ebnf-node-list elt seq) | |
333 | elt)) | |
334 | zlist)) | |
335 | (setq empty-p t)))) | |
336 | (and empty-p | |
337 | (setq zlist (cons (ebnf-make-empty) | |
338 | zlist))) | |
339 | (cons nlist (nreverse zlist)))) | |
340 | ||
341 | ||
342 | (defun ebnf-split-header-prefix1 (node-list header) | |
343 | (let (hlist nlist) | |
344 | (while node-list | |
345 | (if (ebnf-node-equal-header (car node-list) header) | |
346 | (setq hlist (cons (car node-list) hlist)) | |
347 | (setq nlist (cons (car node-list) nlist))) | |
348 | (setq node-list (cdr node-list))) | |
349 | (cons (nreverse nlist) (nreverse hlist)))) | |
350 | ||
351 | ||
352 | (defun ebnf-node-equal-header (node header) | |
353 | (let ((kind (ebnf-node-kind node))) | |
354 | (cond | |
355 | ((eq kind 'ebnf-generate-sequence) | |
356 | (ebnf-node-equal-header (car (ebnf-node-list node)) header)) | |
357 | ((eq kind 'ebnf-generate-non-terminal) | |
358 | (string= (ebnf-node-name node) header)) | |
359 | (t | |
360 | nil) | |
361 | ))) | |
362 | ||
363 | ||
364 | (defun ebnf-map-node-to-optional (node) | |
365 | (and (eq (ebnf-node-kind node) 'ebnf-generate-alternative) | |
366 | (ebnf-map-list-to-optional (ebnf-node-list node)))) | |
367 | ||
368 | ||
369 | (defun ebnf-map-list-to-optional (nlist) | |
370 | (and (= (length nlist) 2) | |
371 | (let ((first (nth 0 nlist)) | |
372 | (second (nth 1 nlist))) | |
373 | (cond | |
374 | ;; empty second | |
375 | ((eq (ebnf-node-kind first) 'ebnf-generate-empty) | |
376 | (ebnf-make-optional second)) | |
377 | ;; first empty | |
378 | ((eq (ebnf-node-kind second) 'ebnf-generate-empty) | |
379 | (ebnf-make-optional first)) | |
380 | ;; first second | |
381 | (t | |
382 | nil) | |
383 | )))) | |
384 | ||
385 | ||
386 | (defun ebnf-extract-empty (elist) | |
387 | (let ((now elist) | |
388 | before empty-p) | |
389 | (while now | |
390 | (if (not (eq (ebnf-node-kind (car now)) 'ebnf-generate-empty)) | |
391 | (setq before now) | |
392 | (setq empty-p t) | |
393 | (if before | |
394 | (setcdr before (cdr now)) | |
395 | (setq elist (cdr elist)))) | |
396 | (setq now (cdr now))) | |
397 | (cons empty-p elist))) | |
398 | ||
399 | ||
400 | (defun ebnf-split-header-suffix (nlist zlist) | |
401 | (let (new empty-p) | |
402 | (and (cond | |
403 | ((= (length nlist) 1) | |
404 | (let ((ok t) | |
405 | (elt (car nlist))) | |
406 | (while (and ok zlist) | |
407 | (setq ok (ebnf-split-header-suffix1 elt (car zlist)) | |
408 | zlist (cdr zlist)) | |
409 | (if (eq ok t) | |
410 | (setq empty-p t) | |
411 | (setq new (cons ok new)))) | |
412 | ok)) | |
413 | ((= (length nlist) (length zlist)) | |
414 | (let ((ok t)) | |
415 | (while (and ok zlist) | |
416 | (setq ok (ebnf-split-header-suffix1 (car nlist) (car zlist)) | |
417 | nlist (cdr nlist) | |
418 | zlist (cdr zlist)) | |
419 | (if (eq ok t) | |
420 | (setq empty-p t) | |
421 | (setq new (cons ok new)))) | |
422 | ok)) | |
423 | (t | |
424 | nil) | |
425 | ) | |
426 | (let* ((lis (ebnf-unique-list new)) | |
427 | (len (length lis))) | |
428 | (cond | |
429 | ((zerop len) | |
430 | t) | |
431 | ((= len 1) | |
432 | (setq lis (car lis)) | |
433 | (if empty-p | |
434 | (ebnf-make-optional lis) | |
435 | lis)) | |
436 | (t | |
437 | (and empty-p | |
438 | (setq lis (cons (ebnf-make-empty) lis))) | |
439 | (ebnf-create-alternative (nreverse lis))) | |
440 | ))))) | |
441 | ||
442 | ||
443 | (defun ebnf-split-header-suffix1 (ne ze) | |
444 | (cond | |
445 | ((eq (ebnf-node-kind ne) 'ebnf-generate-sequence) | |
446 | (and (eq (ebnf-node-kind ze) 'ebnf-generate-sequence) | |
447 | (let ((nl (ebnf-node-list ne)) | |
448 | (zl (ebnf-node-list ze)) | |
449 | len z) | |
450 | (and (>= (length zl) (length nl)) | |
451 | (let ((ok t)) | |
452 | (setq len (- (length zl) (length nl)) | |
453 | z (nthcdr len zl)) | |
454 | (while (and ok z) | |
455 | (setq ok (ebnf-node-equal (car z) (car nl)) | |
456 | z (cdr z) | |
457 | nl (cdr nl))) | |
458 | ok) | |
459 | (if (zerop len) | |
460 | t | |
461 | (setcdr (nthcdr (1- len) zl) nil) | |
462 | ze))))) | |
463 | ((eq (ebnf-node-kind ze) 'ebnf-generate-sequence) | |
464 | (let* ((zl (ebnf-node-list ze)) | |
465 | (len (length zl))) | |
466 | (and (ebnf-node-equal ne (car (nthcdr (1- len) zl))) | |
467 | (cond | |
468 | ((= len 1) | |
469 | t) | |
470 | ((= len 2) | |
471 | (car zl)) | |
472 | (t | |
473 | (setcdr (nthcdr (- len 2) zl) nil) | |
474 | ze) | |
475 | )))) | |
476 | (t | |
477 | (ebnf-node-equal ne ze)) | |
478 | )) | |
479 | ||
480 | ||
481 | (defun ebnf-prefix-suffix (lis) | |
482 | (and lis (listp lis) | |
483 | (let* ((prefix (ebnf-split-prefix lis)) | |
484 | (suffix (ebnf-split-suffix (cdr prefix))) | |
485 | (middle (cdr suffix))) | |
486 | (setq prefix (car prefix) | |
487 | suffix (car suffix)) | |
488 | (and (or prefix suffix) | |
489 | (ebnf-make-sequence | |
490 | (nconc prefix | |
491 | (and middle | |
492 | (list (or (ebnf-map-list-to-optional middle) | |
493 | (ebnf-create-alternative middle)))) | |
494 | suffix)))))) | |
495 | ||
496 | ||
497 | (defun ebnf-split-prefix (lis) | |
498 | (let* ((len (length lis)) | |
499 | (tail lis) | |
500 | (head (if (eq (ebnf-node-kind (car lis)) 'ebnf-generate-sequence) | |
501 | (ebnf-node-list (car lis)) | |
502 | (list (car lis)))) | |
503 | (ipre (1+ len))) | |
504 | ;; determine prefix length | |
505 | (while (and (> ipre 0) (setq tail (cdr tail))) | |
506 | (let ((cur head) | |
507 | (this (if (eq (ebnf-node-kind (car tail)) 'ebnf-generate-sequence) | |
508 | (ebnf-node-list (car tail)) | |
509 | (list (car tail)))) | |
510 | (i 0)) | |
511 | (while (and cur this | |
512 | (ebnf-node-equal (car cur) (car this))) | |
513 | (setq cur (cdr cur) | |
514 | this (cdr this) | |
515 | i (1+ i))) | |
516 | (setq ipre (min ipre i)))) | |
517 | (if (or (zerop ipre) (> ipre len)) | |
518 | ;; no prefix at all | |
519 | (cons nil lis) | |
520 | (let* ((tail (nthcdr ipre head)) | |
521 | ;; get prefix | |
522 | (prefix (progn | |
523 | (and tail | |
524 | (setcdr (nthcdr (1- ipre) head) nil)) | |
525 | head)) | |
526 | empty-p before) | |
527 | ;; adjust first element | |
528 | (if (or (not (eq (ebnf-node-kind (car lis)) 'ebnf-generate-sequence)) | |
529 | (null tail)) | |
530 | (setq lis (cdr lis) | |
531 | tail lis | |
532 | empty-p t) | |
533 | (if (= (length tail) 1) | |
534 | (setcar lis (car tail)) | |
535 | (ebnf-node-list (car lis) tail)) | |
536 | (setq tail (cdr lis))) | |
537 | ;; eliminate prefix from lis based on ipre | |
538 | (while tail | |
539 | (let ((elt (car tail)) | |
540 | rest) | |
541 | (if (and (eq (ebnf-node-kind elt) 'ebnf-generate-sequence) | |
542 | (setq rest (nthcdr ipre (ebnf-node-list elt)))) | |
543 | (progn | |
544 | (if (= (length rest) 1) | |
545 | (setcar tail (car rest)) | |
546 | (ebnf-node-list elt rest)) | |
547 | (setq before tail)) | |
548 | (setq empty-p t) | |
549 | (if before | |
550 | (setcdr before (cdr tail)) | |
551 | (setq lis (cdr lis)))) | |
552 | (setq tail (cdr tail)))) | |
553 | (cons prefix (ebnf-unique-list | |
554 | (if empty-p | |
555 | (nconc lis (list (ebnf-make-empty))) | |
556 | lis))))))) | |
557 | ||
558 | ||
559 | (defun ebnf-split-suffix (lis) | |
560 | (let* ((len (length lis)) | |
561 | (tail lis) | |
562 | (head (nreverse | |
563 | (if (eq (ebnf-node-kind (car lis)) 'ebnf-generate-sequence) | |
564 | (ebnf-node-list (car lis)) | |
565 | (list (car lis))))) | |
566 | (isuf (1+ len))) | |
567 | ;; determine suffix length | |
568 | (while (and (> isuf 0) (setq tail (cdr tail))) | |
569 | (let* ((cur head) | |
570 | (tlis (nreverse | |
571 | (if (eq (ebnf-node-kind (car tail)) 'ebnf-generate-sequence) | |
572 | (ebnf-node-list (car tail)) | |
573 | (list (car tail))))) | |
574 | (this tlis) | |
575 | (i 0)) | |
576 | (while (and cur this | |
577 | (ebnf-node-equal (car cur) (car this))) | |
578 | (setq cur (cdr cur) | |
579 | this (cdr this) | |
580 | i (1+ i))) | |
581 | (nreverse tlis) | |
582 | (setq isuf (min isuf i)))) | |
583 | (setq head (nreverse head)) | |
584 | (if (or (zerop isuf) (> isuf len)) | |
585 | ;; no suffix at all | |
586 | (cons nil lis) | |
587 | (let* ((n (- (length head) isuf)) | |
588 | ;; get suffix | |
589 | (suffix (nthcdr n head)) | |
590 | (tail (and (> n 0) | |
591 | (progn | |
592 | (setcdr (nthcdr (1- n) head) nil) | |
593 | head))) | |
594 | before empty-p) | |
595 | ;; adjust first element | |
596 | (if (or (not (eq (ebnf-node-kind (car lis)) 'ebnf-generate-sequence)) | |
597 | (null tail)) | |
598 | (setq lis (cdr lis) | |
599 | tail lis | |
600 | empty-p t) | |
601 | (if (= (length tail) 1) | |
602 | (setcar lis (car tail)) | |
603 | (ebnf-node-list (car lis) tail)) | |
604 | (setq tail (cdr lis))) | |
605 | ;; eliminate suffix from lis based on isuf | |
606 | (while tail | |
607 | (let ((elt (car tail)) | |
608 | rest) | |
609 | (if (and (eq (ebnf-node-kind elt) 'ebnf-generate-sequence) | |
610 | (setq rest (ebnf-node-list elt) | |
611 | n (- (length rest) isuf)) | |
612 | (> n 0)) | |
613 | (progn | |
614 | (if (= n 1) | |
615 | (setcar tail (car rest)) | |
616 | (setcdr (nthcdr (1- n) rest) nil) | |
617 | (ebnf-node-list elt rest)) | |
618 | (setq before tail)) | |
619 | (setq empty-p t) | |
620 | (if before | |
621 | (setcdr before (cdr tail)) | |
622 | (setq lis (cdr lis)))) | |
623 | (setq tail (cdr tail)))) | |
624 | (cons suffix (ebnf-unique-list | |
625 | (if empty-p | |
626 | (nconc lis (list (ebnf-make-empty))) | |
627 | lis))))))) | |
628 | ||
629 | ||
630 | (defun ebnf-unique-list (nlist) | |
631 | (let ((current nlist) | |
632 | before) | |
633 | (while current | |
634 | (let ((tail (cdr current)) | |
635 | (head (car current)) | |
636 | remove-p) | |
637 | (while tail | |
638 | (if (not (ebnf-node-equal head (car tail))) | |
639 | (setq tail (cdr tail)) | |
640 | (setq remove-p t | |
641 | tail nil) | |
642 | (if before | |
643 | (setcdr before (cdr current)) | |
644 | (setq nlist (cdr nlist))))) | |
645 | (or remove-p | |
646 | (setq before current)) | |
647 | (setq current (cdr current)))) | |
648 | nlist)) | |
649 | ||
650 | ||
651 | (defun ebnf-node-equal (A B) | |
652 | (let ((kindA (ebnf-node-kind A)) | |
653 | (kindB (ebnf-node-kind B))) | |
654 | (and (eq kindA kindB) | |
655 | (cond | |
656 | ;; empty | |
657 | ((eq kindA 'ebnf-generate-empty) | |
658 | t) | |
659 | ;; non-terminal, terminal, special | |
660 | ((memq kindA '(ebnf-generate-non-terminal | |
661 | ebnf-generate-terminal | |
662 | ebnf-generate-special)) | |
663 | (string= (ebnf-node-name A) (ebnf-node-name B))) | |
664 | ;; alternative, sequence | |
665 | ((memq kindA '(ebnf-generate-alternative ; any order | |
666 | ebnf-generate-sequence)) ; order is important | |
667 | (let ((listA (ebnf-node-list A)) | |
668 | (listB (ebnf-node-list B))) | |
669 | (and (= (length listA) (length listB)) | |
670 | (let ((ok t)) | |
671 | (while (and ok listA) | |
672 | (setq ok (ebnf-node-equal (car listA) (car listB)) | |
673 | listA (cdr listA) | |
674 | listB (cdr listB))) | |
675 | ok)))) | |
676 | ;; production | |
677 | ((eq kindA 'ebnf-generate-production) | |
678 | (and (string= (ebnf-node-name A) (ebnf-node-name B)) | |
679 | (ebnf-node-equal (ebnf-node-production A) | |
680 | (ebnf-node-production B)))) | |
681 | ;; otherwise | |
682 | (t | |
683 | nil) | |
684 | )))) | |
685 | ||
686 | ||
687 | (defun ebnf-create-alternative (alt) | |
688 | (if (> (length alt) 1) | |
689 | (ebnf-make-alternative alt) | |
690 | (car alt))) | |
691 | ||
692 | \f | |
693 | ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;; | |
694 | ||
695 | ||
696 | (provide 'ebnf-otz) | |
697 | ||
698 | ||
699 | ;;; ebnf-otz.el ends here |