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1# Java skeleton for Bison -*- autoconf -*-
2
3# Copyright (C) 2007-2012 Free Software Foundation, Inc.
4
5# This program is free software: you can redistribute it and/or modify
6# it under the terms of the GNU General Public License as published by
7# the Free Software Foundation, either version 3 of the License, or
8# (at your option) any later version.
9#
10# This program is distributed in the hope that it will be useful,
11# but WITHOUT ANY WARRANTY; without even the implied warranty of
12# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
13# GNU General Public License for more details.
14#
15# You should have received a copy of the GNU General Public License
16# along with this program. If not, see <http://www.gnu.org/licenses/>.
17
18m4_include(b4_pkgdatadir/[java.m4])
19
20b4_defines_if([b4_fatal([%s: %%defines does not make sense in Java],
21 [b4_skeleton])])
22
23# We don't depend on %debug in Java, but pacify warnings about non-used flags.
24b4_parse_trace_if([0], [0])
25
26m4_define([b4_symbol_no_destructor_assert],
27[b4_symbol_if([$1], [has_destructor],
28 [b4_fatal([%s: %s: %%destructor does not make sense in Java],
29 [b4_skeleton],
30 [b4_symbol_action_location([$1], [destructor])])])])
31b4_symbol_foreach([b4_symbol_no_destructor_assert])
32
33m4_divert_push(0)dnl
34@output(b4_parser_file_name@)@
35b4_copyright([Skeleton implementation for Bison LALR(1) parsers in Java],
36 [2007-2012])
37
38b4_percent_define_ifdef([package], [package b4_percent_define_get([package]);
39])[/* First part of user declarations. */
40]b4_user_pre_prologue
41b4_user_post_prologue
42b4_percent_code_get([[imports]])
43[/**
44 * A Bison parser, automatically generated from <tt>]m4_bpatsubst(b4_file_name, [^"\(.*\)"$], [\1])[</tt>.
45 *
46 * @@author LALR (1) parser skeleton written by Paolo Bonzini.
47 */
48]b4_percent_define_get3([annotations], [], [ ])dnl
49b4_public_if([public ])dnl
50b4_abstract_if([abstract ])dnl
51b4_final_if([final ])dnl
52b4_strictfp_if([strictfp ])dnl
53[class ]b4_parser_class_name[]dnl
54b4_percent_define_get3([extends], [ extends ])dnl
55b4_percent_define_get3([implements], [ implements ])[
56{
57 ]b4_identification[
58]b4_error_verbose_if([[
59 /** True if verbose error messages are enabled. */
60 private boolean yyErrorVerbose = true;
61
62 /**
63 * Return whether verbose error messages are enabled.
64 */
65 public final boolean getErrorVerbose() { return yyErrorVerbose; }
66
67 /**
68 * Set the verbosity of error messages.
69 * @@param verbose True to request verbose error messages.
70 */
71 public final void setErrorVerbose(boolean verbose)
72 { yyErrorVerbose = verbose; }
73]])
74
75b4_locations_if([[
76 /**
77 * A class defining a pair of positions. Positions, defined by the
78 * <code>]b4_position_type[</code> class, denote a point in the input.
79 * Locations represent a part of the input through the beginning
80 * and ending positions. */
81 public class ]b4_location_type[ {
82 /** The first, inclusive, position in the range. */
83 public ]b4_position_type[ begin;
84
85 /** The first position beyond the range. */
86 public ]b4_position_type[ end;
87
88 /**
89 * Create a <code>]b4_location_type[</code> denoting an empty range located at
90 * a given point.
91 * @@param loc The position at which the range is anchored. */
92 public ]b4_location_type[ (]b4_position_type[ loc) {
93 this.begin = this.end = loc;
94 }
95
96 /**
97 * Create a <code>]b4_location_type[</code> from the endpoints of the range.
98 * @@param begin The first position included in the range.
99 * @@param end The first position beyond the range. */
100 public ]b4_location_type[ (]b4_position_type[ begin, ]b4_position_type[ end) {
101 this.begin = begin;
102 this.end = end;
103 }
104
105 /**
106 * Print a representation of the location. For this to be correct,
107 * <code>]b4_position_type[</code> should override the <code>equals</code>
108 * method. */
109 public String toString () {
110 if (begin.equals (end))
111 return begin.toString ();
112 else
113 return begin.toString () + "-" + end.toString ();
114 }
115 }
116
117]])
118
119 b4_locations_if([[
120 private ]b4_location_type[ yylloc (YYStack rhs, int n)
121 {
122 if (n > 0)
123 return new ]b4_location_type[ (rhs.locationAt (n-1).begin, rhs.locationAt (0).end);
124 else
125 return new ]b4_location_type[ (rhs.locationAt (0).end);
126 }]])[
127
128 /**
129 * Communication interface between the scanner and the Bison-generated
130 * parser <tt>]b4_parser_class_name[</tt>.
131 */
132 public interface Lexer {
133 /** Token returned by the scanner to signal the end of its input. */
134 public static final int EOF = 0;
135
136]b4_token_enums(b4_tokens)[
137
138 ]b4_locations_if([[/**
139 * Method to retrieve the beginning position of the last scanned token.
140 * @@return the position at which the last scanned token starts. */
141 ]b4_position_type[ getStartPos ();
142
143 /**
144 * Method to retrieve the ending position of the last scanned token.
145 * @@return the first position beyond the last scanned token. */
146 ]b4_position_type[ getEndPos ();]])[
147
148 /**
149 * Method to retrieve the semantic value of the last scanned token.
150 * @@return the semantic value of the last scanned token. */
151 ]b4_yystype[ getLVal ();
152
153 /**
154 * Entry point for the scanner. Returns the token identifier corresponding
155 * to the next token and prepares to return the semantic value
156 * ]b4_locations_if([and beginning/ending positions ])[of the token.
157 * @@return the token identifier corresponding to the next token. */
158 int yylex () ]b4_maybe_throws([b4_lex_throws])[;
159
160 /**
161 * Entry point for error reporting. Emits an error
162 * ]b4_locations_if([referring to the given location ])[in a user-defined way.
163 *
164 * ]b4_locations_if([[@@param loc The location of the element to which the
165 * error message is related]])[
166 * @@param msg The string for the error message. */
167 void yyerror (]b4_locations_if([b4_location_type[ loc, ]])[String msg);]
168 }
169
170 b4_lexer_if([[private class YYLexer implements Lexer {
171]b4_percent_code_get([[lexer]])[
172 }
173
174 ]])[/** The object doing lexical analysis for us. */
175 private Lexer yylexer;
176 ]
177 b4_parse_param_vars
178
179b4_lexer_if([[
180 /**
181 * Instantiates the Bison-generated parser.
182 */
183 public ]b4_parser_class_name (b4_parse_param_decl([b4_lex_param_decl])[) ]b4_maybe_throws([b4_init_throws])[
184 {
185 ]b4_percent_code_get([[init]])[
186 this.yylexer = new YYLexer(]b4_lex_param_call[);
187 ]b4_parse_param_cons[
188 }
189]])
190
191 /**
192 * Instantiates the Bison-generated parser.
193 * @@param yylexer The scanner that will supply tokens to the parser.
194 */
195 b4_lexer_if([[protected]], [[public]]) b4_parser_class_name[ (]b4_parse_param_decl([[Lexer yylexer]])[) ]b4_maybe_throws([b4_init_throws])[
196 {
197 ]b4_percent_code_get([[init]])[
198 this.yylexer = yylexer;
199 ]b4_parse_param_cons[
200 }
201
202 private java.io.PrintStream yyDebugStream = System.err;
203
204 /**
205 * Return the <tt>PrintStream</tt> on which the debugging output is
206 * printed.
207 */
208 public final java.io.PrintStream getDebugStream () { return yyDebugStream; }
209
210 /**
211 * Set the <tt>PrintStream</tt> on which the debug output is printed.
212 * @@param s The stream that is used for debugging output.
213 */
214 public final void setDebugStream(java.io.PrintStream s) { yyDebugStream = s; }
215
216 private int yydebug = 0;
217
218 /**
219 * Answer the verbosity of the debugging output; 0 means that all kinds of
220 * output from the parser are suppressed.
221 */
222 public final int getDebugLevel() { return yydebug; }
223
224 /**
225 * Set the verbosity of the debugging output; 0 means that all kinds of
226 * output from the parser are suppressed.
227 * @@param level The verbosity level for debugging output.
228 */
229 public final void setDebugLevel(int level) { yydebug = level; }
230
231 /**
232 * Print an error message via the lexer.
233 *]b4_locations_if([[ Use a <code>null</code> location.]])[
234 * @@param msg The error message.
235 */
236 public final void yyerror (String msg)
237 {
238 yylexer.yyerror (]b4_locations_if([[(]b4_location_type[)null, ]])[msg);
239 }
240]b4_locations_if([[
241 /**
242 * Print an error message via the lexer.
243 * @@param loc The location associated with the message.
244 * @@param msg The error message.
245 */
246 public final void yyerror (]b4_location_type[ loc, String msg)
247 {
248 yylexer.yyerror (loc, msg);
249 }
250
251 /**
252 * Print an error message via the lexer.
253 * @@param pos The position associated with the message.
254 * @@param msg The error message.
255 */
256 public final void yyerror (]b4_position_type[ pos, String msg)
257 {
258 yylexer.yyerror (new ]b4_location_type[ (pos), msg);
259 }]])
260
261 [protected final void yycdebug (String s) {
262 if (yydebug > 0)
263 yyDebugStream.println (s);
264 }
265
266 private final class YYStack {
267 private int[] stateStack = new int[16];
268 ]b4_locations_if([[private ]b4_location_type[[] locStack = new ]b4_location_type[[16];]])[
269 private ]b4_yystype[[] valueStack = new ]b4_yystype[[16];
270
271 public int size = 16;
272 public int height = -1;
273
274 public final void push (int state, ]b4_yystype[ value]dnl
275 b4_locations_if([, ]b4_location_type[ loc])[) {
276 height++;
277 if (size == height)
278 {
279 int[] newStateStack = new int[size * 2];
280 System.arraycopy (stateStack, 0, newStateStack, 0, height);
281 stateStack = newStateStack;
282 ]b4_locations_if([[
283 ]b4_location_type[[] newLocStack = new ]b4_location_type[[size * 2];
284 System.arraycopy (locStack, 0, newLocStack, 0, height);
285 locStack = newLocStack;]])
286
287 b4_yystype[[] newValueStack = new ]b4_yystype[[size * 2];
288 System.arraycopy (valueStack, 0, newValueStack, 0, height);
289 valueStack = newValueStack;
290
291 size *= 2;
292 }
293
294 stateStack[height] = state;
295 ]b4_locations_if([[locStack[height] = loc;]])[
296 valueStack[height] = value;
297 }
298
299 public final void pop () {
300 pop (1);
301 }
302
303 public final void pop (int num) {
304 // Avoid memory leaks... garbage collection is a white lie!
305 if (num > 0) {
306 java.util.Arrays.fill (valueStack, height - num + 1, height + 1, null);
307 ]b4_locations_if([[java.util.Arrays.fill (locStack, height - num + 1, height + 1, null);]])[
308 }
309 height -= num;
310 }
311
312 public final int stateAt (int i) {
313 return stateStack[height - i];
314 }
315
316 ]b4_locations_if([[public final ]b4_location_type[ locationAt (int i) {
317 return locStack[height - i];
318 }
319
320 ]])[public final ]b4_yystype[ valueAt (int i) {
321 return valueStack[height - i];
322 }
323
324 // Print the state stack on the debug stream.
325 public void print (java.io.PrintStream out)
326 {
327 out.print ("Stack now");
328
329 for (int i = 0; i <= height; i++)
330 {
331 out.print (' ');
332 out.print (stateStack[i]);
333 }
334 out.println ();
335 }
336 }
337
338 /**
339 * Returned by a Bison action in order to stop the parsing process and
340 * return success (<tt>true</tt>). */
341 public static final int YYACCEPT = 0;
342
343 /**
344 * Returned by a Bison action in order to stop the parsing process and
345 * return failure (<tt>false</tt>). */
346 public static final int YYABORT = 1;
347
348 /**
349 * Returned by a Bison action in order to start error recovery without
350 * printing an error message. */
351 public static final int YYERROR = 2;
352
353 // Internal return codes that are not supported for user semantic
354 // actions.
355 private static final int YYERRLAB = 3;
356 private static final int YYNEWSTATE = 4;
357 private static final int YYDEFAULT = 5;
358 private static final int YYREDUCE = 6;
359 private static final int YYERRLAB1 = 7;
360 private static final int YYRETURN = 8;
361
362 private int yyerrstatus_ = 0;
363
364 /**
365 * Return whether error recovery is being done. In this state, the parser
366 * reads token until it reaches a known state, and then restarts normal
367 * operation. */
368 public final boolean recovering ()
369 {
370 return yyerrstatus_ == 0;
371 }
372
373 private int yyaction (int yyn, YYStack yystack, int yylen) ]b4_maybe_throws([b4_throws])[
374 {
375 ]b4_yystype[ yyval;
376 ]b4_locations_if([b4_location_type[ yyloc = yylloc (yystack, yylen);]])[
377
378 /* If YYLEN is nonzero, implement the default value of the action:
379 `$$ = $1'. Otherwise, use the top of the stack.
380
381 Otherwise, the following line sets YYVAL to garbage.
382 This behavior is undocumented and Bison
383 users should not rely upon it. */
384 if (yylen > 0)
385 yyval = yystack.valueAt (yylen - 1);
386 else
387 yyval = yystack.valueAt (0);
388
389 yy_reduce_print (yyn, yystack);
390
391 switch (yyn)
392 {
393 ]b4_user_actions[
394 default: break;
395 }
396
397 yy_symbol_print ("-> $$ =", yyr1_[yyn], yyval]b4_locations_if([, yyloc])[);
398
399 yystack.pop (yylen);
400 yylen = 0;
401
402 /* Shift the result of the reduction. */
403 yyn = yyr1_[yyn];
404 int yystate = yypgoto_[yyn - yyntokens_] + yystack.stateAt (0);
405 if (0 <= yystate && yystate <= yylast_
406 && yycheck_[yystate] == yystack.stateAt (0))
407 yystate = yytable_[yystate];
408 else
409 yystate = yydefgoto_[yyn - yyntokens_];
410
411 yystack.push (yystate, yyval]b4_locations_if([, yyloc])[);
412 return YYNEWSTATE;
413 }
414
415]b4_error_verbose_if([[
416 /* Return YYSTR after stripping away unnecessary quotes and
417 backslashes, so that it's suitable for yyerror. The heuristic is
418 that double-quoting is unnecessary unless the string contains an
419 apostrophe, a comma, or backslash (other than backslash-backslash).
420 YYSTR is taken from yytname. */
421 private final String yytnamerr_ (String yystr)
422 {
423 if (yystr.charAt (0) == '"')
424 {
425 StringBuffer yyr = new StringBuffer ();
426 strip_quotes: for (int i = 1; i < yystr.length (); i++)
427 switch (yystr.charAt (i))
428 {
429 case '\'':
430 case ',':
431 break strip_quotes;
432
433 case '\\':
434 if (yystr.charAt(++i) != '\\')
435 break strip_quotes;
436 /* Fall through. */
437 default:
438 yyr.append (yystr.charAt (i));
439 break;
440
441 case '"':
442 return yyr.toString ();
443 }
444 }
445 else if (yystr.equals ("$end"))
446 return "end of input";
447
448 return yystr;
449 }
450]])[
451
452 /*--------------------------------.
453 | Print this symbol on YYOUTPUT. |
454 `--------------------------------*/
455
456 private void yy_symbol_print (String s, int yytype,
457 ]b4_yystype[ yyvaluep]dnl
458 b4_locations_if([, Object yylocationp])[)
459 {
460 if (yydebug > 0)
461 yycdebug (s + (yytype < yyntokens_ ? " token " : " nterm ")
462 + yytname_[yytype] + " ("]b4_locations_if([
463 + yylocationp + ": "])[
464 + (yyvaluep == null ? "(null)" : yyvaluep.toString ()) + ")");
465 }
466
467 /**
468 * Parse input from the scanner that was specified at object construction
469 * time. Return whether the end of the input was reached successfully.
470 *
471 * @@return <tt>true</tt> if the parsing succeeds. Note that this does not
472 * imply that there were no syntax errors.
473 */
474 public boolean parse () ]b4_maybe_throws([b4_list2([b4_lex_throws], [b4_throws])])[
475 {
476 /// Lookahead and lookahead in internal form.
477 int yychar = yyempty_;
478 int yytoken = 0;
479
480 /* State. */
481 int yyn = 0;
482 int yylen = 0;
483 int yystate = 0;
484
485 YYStack yystack = new YYStack ();
486
487 /* Error handling. */
488 int yynerrs_ = 0;
489 ]b4_locations_if([/// The location where the error started.
490 ]b4_location_type[ yyerrloc = null;
491
492 /// ]b4_location_type[ of the lookahead.
493 ]b4_location_type[ yylloc = new ]b4_location_type[ (null, null);
494
495 /// @@$.
496 ]b4_location_type[ yyloc;])
497
498 /// Semantic value of the lookahead.
499 b4_yystype[ yylval = null;
500
501 yycdebug ("Starting parse\n");
502 yyerrstatus_ = 0;
503
504]m4_ifdef([b4_initial_action], [
505m4_pushdef([b4_at_dollar], [yylloc])dnl
506m4_pushdef([b4_dollar_dollar], [yylval])dnl
507 /* User initialization code. */
508 b4_user_initial_action
509m4_popdef([b4_dollar_dollar])dnl
510m4_popdef([b4_at_dollar])])dnl
511
512 [ /* Initialize the stack. */
513 yystack.push (yystate, yylval]b4_locations_if([, yylloc])[);
514
515 int label = YYNEWSTATE;
516 for (;;)
517 switch (label)
518 {
519 /* New state. Unlike in the C/C++ skeletons, the state is already
520 pushed when we come here. */
521 case YYNEWSTATE:
522 yycdebug ("Entering state " + yystate + "\n");
523 if (yydebug > 0)
524 yystack.print (yyDebugStream);
525
526 /* Accept? */
527 if (yystate == yyfinal_)
528 return true;
529
530 /* Take a decision. First try without lookahead. */
531 yyn = yypact_[yystate];
532 if (yy_pact_value_is_default_ (yyn))
533 {
534 label = YYDEFAULT;
535 break;
536 }
537
538 /* Read a lookahead token. */
539 if (yychar == yyempty_)
540 {
541 yycdebug ("Reading a token: ");
542 yychar = yylexer.yylex ();]
543 b4_locations_if([[
544 yylloc = new ]b4_location_type[(yylexer.getStartPos (),
545 yylexer.getEndPos ());]])
546 yylval = yylexer.getLVal ();[
547 }
548
549 /* Convert token to internal form. */
550 if (yychar <= Lexer.EOF)
551 {
552 yychar = yytoken = Lexer.EOF;
553 yycdebug ("Now at end of input.\n");
554 }
555 else
556 {
557 yytoken = yytranslate_ (yychar);
558 yy_symbol_print ("Next token is", yytoken,
559 yylval]b4_locations_if([, yylloc])[);
560 }
561
562 /* If the proper action on seeing token YYTOKEN is to reduce or to
563 detect an error, take that action. */
564 yyn += yytoken;
565 if (yyn < 0 || yylast_ < yyn || yycheck_[yyn] != yytoken)
566 label = YYDEFAULT;
567
568 /* <= 0 means reduce or error. */
569 else if ((yyn = yytable_[yyn]) <= 0)
570 {
571 if (yy_table_value_is_error_ (yyn))
572 label = YYERRLAB;
573 else
574 {
575 yyn = -yyn;
576 label = YYREDUCE;
577 }
578 }
579
580 else
581 {
582 /* Shift the lookahead token. */
583 yy_symbol_print ("Shifting", yytoken,
584 yylval]b4_locations_if([, yylloc])[);
585
586 /* Discard the token being shifted. */
587 yychar = yyempty_;
588
589 /* Count tokens shifted since error; after three, turn off error
590 status. */
591 if (yyerrstatus_ > 0)
592 --yyerrstatus_;
593
594 yystate = yyn;
595 yystack.push (yystate, yylval]b4_locations_if([, yylloc])[);
596 label = YYNEWSTATE;
597 }
598 break;
599
600 /*-----------------------------------------------------------.
601 | yydefault -- do the default action for the current state. |
602 `-----------------------------------------------------------*/
603 case YYDEFAULT:
604 yyn = yydefact_[yystate];
605 if (yyn == 0)
606 label = YYERRLAB;
607 else
608 label = YYREDUCE;
609 break;
610
611 /*-----------------------------.
612 | yyreduce -- Do a reduction. |
613 `-----------------------------*/
614 case YYREDUCE:
615 yylen = yyr2_[yyn];
616 label = yyaction (yyn, yystack, yylen);
617 yystate = yystack.stateAt (0);
618 break;
619
620 /*------------------------------------.
621 | yyerrlab -- here on detecting error |
622 `------------------------------------*/
623 case YYERRLAB:
624 /* If not already recovering from an error, report this error. */
625 if (yyerrstatus_ == 0)
626 {
627 ++yynerrs_;
628 if (yychar == yyempty_)
629 yytoken = yyempty_;
630 yyerror (]b4_locations_if([yylloc, ])[yysyntax_error (yystate, yytoken));
631 }
632
633 ]b4_locations_if([yyerrloc = yylloc;])[
634 if (yyerrstatus_ == 3)
635 {
636 /* If just tried and failed to reuse lookahead token after an
637 error, discard it. */
638
639 if (yychar <= Lexer.EOF)
640 {
641 /* Return failure if at end of input. */
642 if (yychar == Lexer.EOF)
643 return false;
644 }
645 else
646 yychar = yyempty_;
647 }
648
649 /* Else will try to reuse lookahead token after shifting the error
650 token. */
651 label = YYERRLAB1;
652 break;
653
654 /*---------------------------------------------------.
655 | errorlab -- error raised explicitly by YYERROR. |
656 `---------------------------------------------------*/
657 case YYERROR:
658
659 ]b4_locations_if([yyerrloc = yystack.locationAt (yylen - 1);])[
660 /* Do not reclaim the symbols of the rule which action triggered
661 this YYERROR. */
662 yystack.pop (yylen);
663 yylen = 0;
664 yystate = yystack.stateAt (0);
665 label = YYERRLAB1;
666 break;
667
668 /*-------------------------------------------------------------.
669 | yyerrlab1 -- common code for both syntax error and YYERROR. |
670 `-------------------------------------------------------------*/
671 case YYERRLAB1:
672 yyerrstatus_ = 3; /* Each real token shifted decrements this. */
673
674 for (;;)
675 {
676 yyn = yypact_[yystate];
677 if (!yy_pact_value_is_default_ (yyn))
678 {
679 yyn += yyterror_;
680 if (0 <= yyn && yyn <= yylast_ && yycheck_[yyn] == yyterror_)
681 {
682 yyn = yytable_[yyn];
683 if (0 < yyn)
684 break;
685 }
686 }
687
688 /* Pop the current state because it cannot handle the error token. */
689 if (yystack.height == 0)
690 return false;
691
692 ]b4_locations_if([yyerrloc = yystack.locationAt (0);])[
693 yystack.pop ();
694 yystate = yystack.stateAt (0);
695 if (yydebug > 0)
696 yystack.print (yyDebugStream);
697 }
698
699 ]b4_locations_if([
700 /* Muck with the stack to setup for yylloc. */
701 yystack.push (0, null, yylloc);
702 yystack.push (0, null, yyerrloc);
703 yyloc = yylloc (yystack, 2);
704 yystack.pop (2);])[
705
706 /* Shift the error token. */
707 yy_symbol_print ("Shifting", yystos_[yyn],
708 yylval]b4_locations_if([, yyloc])[);
709
710 yystate = yyn;
711 yystack.push (yyn, yylval]b4_locations_if([, yyloc])[);
712 label = YYNEWSTATE;
713 break;
714
715 /* Accept. */
716 case YYACCEPT:
717 return true;
718
719 /* Abort. */
720 case YYABORT:
721 return false;
722 }
723 }
724
725 // Generate an error message.
726 private String yysyntax_error (int yystate, int tok)
727 {]b4_error_verbose_if([[
728 if (yyErrorVerbose)
729 {
730 /* There are many possibilities here to consider:
731 - Assume YYFAIL is not used. It's too flawed to consider.
732 See
733 <http://lists.gnu.org/archive/html/bison-patches/2009-12/msg00024.html>
734 for details. YYERROR is fine as it does not invoke this
735 function.
736 - If this state is a consistent state with a default action,
737 then the only way this function was invoked is if the
738 default action is an error action. In that case, don't
739 check for expected tokens because there are none.
740 - The only way there can be no lookahead present (in tok) is
741 if this state is a consistent state with a default action.
742 Thus, detecting the absence of a lookahead is sufficient to
743 determine that there is no unexpected or expected token to
744 report. In that case, just report a simple "syntax error".
745 - Don't assume there isn't a lookahead just because this
746 state is a consistent state with a default action. There
747 might have been a previous inconsistent state, consistent
748 state with a non-default action, or user semantic action
749 that manipulated yychar. (However, yychar is currently out
750 of scope during semantic actions.)
751 - Of course, the expected token list depends on states to
752 have correct lookahead information, and it depends on the
753 parser not to perform extra reductions after fetching a
754 lookahead from the scanner and before detecting a syntax
755 error. Thus, state merging (from LALR or IELR) and default
756 reductions corrupt the expected token list. However, the
757 list is correct for canonical LR with one exception: it
758 will still contain any token that will not be accepted due
759 to an error action in a later state.
760 */
761 if (tok != yyempty_)
762 {
763 // FIXME: This method of building the message is not compatible
764 // with internationalization.
765 StringBuffer res =
766 new StringBuffer ("syntax error, unexpected ");
767 res.append (yytnamerr_ (yytname_[tok]));
768 int yyn = yypact_[yystate];
769 if (!yy_pact_value_is_default_ (yyn))
770 {
771 /* Start YYX at -YYN if negative to avoid negative
772 indexes in YYCHECK. In other words, skip the first
773 -YYN actions for this state because they are default
774 actions. */
775 int yyxbegin = yyn < 0 ? -yyn : 0;
776 /* Stay within bounds of both yycheck and yytname. */
777 int yychecklim = yylast_ - yyn + 1;
778 int yyxend = yychecklim < yyntokens_ ? yychecklim : yyntokens_;
779 int count = 0;
780 for (int x = yyxbegin; x < yyxend; ++x)
781 if (yycheck_[x + yyn] == x && x != yyterror_
782 && !yy_table_value_is_error_ (yytable_[x + yyn]))
783 ++count;
784 if (count < 5)
785 {
786 count = 0;
787 for (int x = yyxbegin; x < yyxend; ++x)
788 if (yycheck_[x + yyn] == x && x != yyterror_
789 && !yy_table_value_is_error_ (yytable_[x + yyn]))
790 {
791 res.append (count++ == 0 ? ", expecting " : " or ");
792 res.append (yytnamerr_ (yytname_[x]));
793 }
794 }
795 }
796 return res.toString ();
797 }
798 }
799]])[
800 return "syntax error";
801 }
802
803 /**
804 * Whether the given <code>yypact_</code> value indicates a defaulted state.
805 * @@param yyvalue the value to check
806 */
807 private static boolean yy_pact_value_is_default_ (int yyvalue)
808 {
809 return yyvalue == yypact_ninf_;
810 }
811
812 /**
813 * Whether the given <code>yytable_</code> value indicates a syntax error.
814 * @@param yyvalue the value to check
815 */
816 private static boolean yy_table_value_is_error_ (int yyvalue)
817 {
818 return yyvalue == yytable_ninf_;
819 }
820
821 private static final ]b4_int_type_for([b4_pact])[ yypact_ninf_ = ]b4_pact_ninf[;
822 private static final ]b4_int_type_for([b4_table])[ yytable_ninf_ = ]b4_table_ninf[;
823
824 ]b4_parser_tables_define[
825 ]b4_integral_parser_table_define([token_number], [b4_toknum],
826 [TOKEN_NUMBER_[YYLEX-NUM] -- Internal symbol number corresponding
827 to YYLEX-NUM.])[
828
829 /* YYTNAME[SYMBOL-NUM] -- String name of the symbol SYMBOL-NUM.
830 First, the terminals, then, starting at \a yyntokens_, nonterminals. */
831 ]b4_typed_parser_table_define([String], [tname], [b4_tname])[
832
833 ]b4_integral_parser_table_define([rline], [b4_rline],
834 [YYRLINE[YYN] -- Source line where rule number YYN was defined.])[
835
836 // Report on the debug stream that the rule yyrule is going to be reduced.
837 private void yy_reduce_print (int yyrule, YYStack yystack)
838 {
839 if (yydebug == 0)
840 return;
841
842 int yylno = yyrline_[yyrule];
843 int yynrhs = yyr2_[yyrule];
844 /* Print the symbols being reduced, and their result. */
845 yycdebug ("Reducing stack by rule " + (yyrule - 1)
846 + " (line " + yylno + "), ");
847
848 /* The symbols being reduced. */
849 for (int yyi = 0; yyi < yynrhs; yyi++)
850 yy_symbol_print (" $" + (yyi + 1) + " =",
851 yystos_[yystack.stateAt(yynrhs - (yyi + 1))],
852 ]b4_rhs_value(yynrhs, yyi + 1)b4_locations_if([,
853 b4_rhs_location(yynrhs, yyi + 1)])[);
854 }
855
856 /* YYTRANSLATE(YYLEX) -- Bison symbol number corresponding to YYLEX. */
857 ]b4_integral_parser_table_define([translate_table], [b4_translate])[
858
859 private static final ]b4_int_type_for([b4_translate])[ yytranslate_ (int t)
860 {
861 if (t >= 0 && t <= yyuser_token_number_max_)
862 return yytranslate_table_[t];
863 else
864 return yyundef_token_;
865 }
866
867 private static final int yylast_ = ]b4_last[;
868 private static final int yynnts_ = ]b4_nterms_number[;
869 private static final int yyempty_ = -2;
870 private static final int yyfinal_ = ]b4_final_state_number[;
871 private static final int yyterror_ = 1;
872 private static final int yyerrcode_ = 256;
873 private static final int yyntokens_ = ]b4_tokens_number[;
874
875 private static final int yyuser_token_number_max_ = ]b4_user_token_number_max[;
876 private static final int yyundef_token_ = ]b4_undef_token_number[;
877
878]/* User implementation code. */
879b4_percent_code_get[]dnl
880
881}
882
883b4_epilogue[]dnl
884m4_divert_pop(0)dnl