1 /* Driver template for the LEMON parser generator.
2 ** The author disclaims copyright to this source code.
3 */
4 /* First off, code is include which follows the "include" declaration
5 ** in the input file. */
6 #include <stdio.h>
7 %%
8 /* Next is all token values, in a form suitable for use by makeheaders.
9 ** This section will be null unless lemon is run with the -m switch.
10 */
11 /*
12 ** These constants (all generated automatically by the parser generator)
13 ** specify the various kinds of tokens (terminals) that the parser
14 ** understands.
15 **
16 ** Each symbol here is a terminal symbol in the grammar.
17 */
18 %%
19 /* Make sure the INTERFACE macro is defined.
20 */
21 #ifndef INTERFACE
22 # define INTERFACE 1
23 #endif
24 /* The next thing included is series of defines which control
25 ** various aspects of the generated parser.
26 **    YYCODETYPE         is the data type used for storing terminal
27 **                       and nonterminal numbers.  "unsigned char" is
28 **                       used if there are fewer than 250 terminals
29 **                       and nonterminals.  "int" is used otherwise.
30 **    YYNOCODE           is a number of type YYCODETYPE which corresponds
31 **                       to no legal terminal or nonterminal number.  This
32 **                       number is used to fill in empty slots of the hash
33 **                       table.
34 **    YYFALLBACK         If defined, this indicates that one or more tokens
35 **                       have fall-back values which should be used if the
36 **                       original value of the token will not parse.
37 **    YYACTIONTYPE       is the data type used for storing terminal
38 **                       and nonterminal numbers.  "unsigned char" is
39 **                       used if there are fewer than 250 rules and
40 **                       states combined.  "int" is used otherwise.
41 **    ParseTOKENTYPE     is the data type used for minor tokens given
42 **                       directly to the parser from the tokenizer.
43 **    YYMINORTYPE        is the data type used for all minor tokens.
44 **                       This is typically a union of many types, one of
45 **                       which is ParseTOKENTYPE.  The entry in the union
46 **                       for base tokens is called "yy0".
47 **    YYSTACKDEPTH       is the maximum depth of the parser's stack.
48 **    ParseARG_SDECL     A static variable declaration for the %extra_argument
49 **    ParseARG_PDECL     A parameter declaration for the %extra_argument
50 **    ParseARG_STORE     Code to store %extra_argument into yypParser
51 **    ParseARG_FETCH     Code to extract %extra_argument from yypParser
52 **    YYNSTATE           the combined number of states.
53 **    YYNRULE            the number of rules in the grammar
54 **    YYERRORSYMBOL      is the code number of the error symbol.  If not
55 **                       defined, then do no error processing.
56 */
57 %%
58 #define YY_NO_ACTION      (YYNSTATE+YYNRULE+2)
59 #define YY_ACCEPT_ACTION  (YYNSTATE+YYNRULE+1)
60 #define YY_ERROR_ACTION   (YYNSTATE+YYNRULE)
61 
62 /* Next are that tables used to determine what action to take based on the
63 ** current state and lookahead token.  These tables are used to implement
64 ** functions that take a state number and lookahead value and return an
65 ** action integer.
66 **
67 ** Suppose the action integer is N.  Then the action is determined as
68 ** follows
69 **
70 **   0 <= N < YYNSTATE                  Shift N.  That is, push the lookahead
71 **                                      token onto the stack and goto state N.
72 **
73 **   YYNSTATE <= N < YYNSTATE+YYNRULE   Reduce by rule N-YYNSTATE.
74 **
75 **   N == YYNSTATE+YYNRULE              A syntax error has occurred.
76 **
77 **   N == YYNSTATE+YYNRULE+1            The parser accepts its input.
78 **
79 **   N == YYNSTATE+YYNRULE+2            No such action.  Denotes unused
80 **                                      slots in the yy_action[] table.
81 **
82 ** The action table is constructed as a single large table named yy_action[].
83 ** Given state S and lookahead X, the action is computed as
84 **
85 **      yy_action[ yy_shift_ofst[S] + X ]
86 **
87 ** If the index value yy_shift_ofst[S]+X is out of range or if the value
88 ** yy_lookahead[yy_shift_ofst[S]+X] is not equal to X or if yy_shift_ofst[S]
89 ** is equal to YY_SHIFT_USE_DFLT, it means that the action is not in the table
90 ** and that yy_default[S] should be used instead.
91 **
92 ** The formula above is for computing the action when the lookahead is
93 ** a terminal symbol.  If the lookahead is a non-terminal (as occurs after
94 ** a reduce action) then the yy_reduce_ofst[] array is used in place of
95 ** the yy_shift_ofst[] array and YY_REDUCE_USE_DFLT is used in place of
96 ** YY_SHIFT_USE_DFLT.
97 **
98 ** The following are the tables generated in this section:
99 **
100 **  yy_action[]        A single table containing all actions.
101 **  yy_lookahead[]     A table containing the lookahead for each entry in
102 **                     yy_action.  Used to detect hash collisions.
103 **  yy_shift_ofst[]    For each state, the offset into yy_action for
104 **                     shifting terminals.
105 **  yy_reduce_ofst[]   For each state, the offset into yy_action for
106 **                     shifting non-terminals after a reduce.
107 **  yy_default[]       Default action for each state.
108 */
109 %%
110 #define YY_SZ_ACTTAB (sizeof(yy_action)/sizeof(yy_action[0]))
111 
112 /* The next table maps tokens into fallback tokens.  If a construct
113 ** like the following:
114 **
115 **      %fallback ID X Y Z.
116 **
117 ** appears in the grammer, then ID becomes a fallback token for X, Y,
118 ** and Z.  Whenever one of the tokens X, Y, or Z is input to the parser
119 ** but it does not parse, the type of the token is changed to ID and
120 ** the parse is retried before an error is thrown.
121 */
122 #ifdef YYFALLBACK
123 static const YYCODETYPE yyFallback[] = {
124 %%
125 };
126 #endif /* YYFALLBACK */
127 
128 /* The following structure represents a single element of the
129 ** parser's stack.  Information stored includes:
130 **
131 **   +  The state number for the parser at this level of the stack.
132 **
133 **   +  The value of the token stored at this level of the stack.
134 **      (In other words, the "major" token.)
135 **
136 **   +  The semantic value stored at this level of the stack.  This is
137 **      the information used by the action routines in the grammar.
138 **      It is sometimes called the "minor" token.
139 */
140 struct yyStackEntry {
141   int stateno;       /* The state-number */
142   int major;         /* The major token value.  This is the code
143                      ** number for the token at this stack level */
144   YYMINORTYPE minor; /* The user-supplied minor token value.  This
145                      ** is the value of the token  */
146 };
147 typedef struct yyStackEntry yyStackEntry;
148 
149 /* The state of the parser is completely contained in an instance of
150 ** the following structure */
151 struct yyParser {
152   int yyidx;                    /* Index of top element in stack */
153   int yyerrcnt;                 /* Shifts left before out of the error */
154   ParseARG_SDECL                /* A place to hold %extra_argument */
155   yyStackEntry yystack[YYSTACKDEPTH];  /* The parser's stack */
156 };
157 typedef struct yyParser yyParser;
158 
159 #ifndef NDEBUG
160 #include <stdio.h>
161 static FILE *yyTraceFILE = NULL;
162 static char *yyTracePrompt = NULL;
163 #endif /* NDEBUG */
164 
165 #ifndef NDEBUG
166 /*
167 ** Turn parser tracing on by giving a stream to which to write the trace
168 ** and a prompt to preface each trace message.  Tracing is turned off
169 ** by making either argument NULL
170 **
171 ** Inputs:
172 ** <ul>
173 ** <li> A FILE* to which trace output should be written.
174 **      If NULL, then tracing is turned off.
175 ** <li> A prefix string written at the beginning of every
176 **      line of trace output.  If NULL, then tracing is
177 **      turned off.
178 ** </ul>
179 **
180 ** Outputs:
181 ** None.
182 */
183 #if 0
184 void ParseTrace(FILE *TraceFILE, char *zTracePrompt){
185   yyTraceFILE = TraceFILE;
186   yyTracePrompt = zTracePrompt;
187   if( yyTraceFILE==0 ) yyTracePrompt = 0;
188   else if( yyTracePrompt==0 ) yyTraceFILE = 0;
189 }
190 #endif
191 #endif /* NDEBUG */
192 
193 #ifndef NDEBUG
194 /* For tracing shifts, the names of all terminals and nonterminals
195 ** are required.  The following table supplies these names */
196 static const char *yyTokenName[] = {
197 %%
198 };
199 #endif /* NDEBUG */
200 
201 #ifndef NDEBUG
202 /* For tracing reduce actions, the names of all rules are required.
203 */
204 static const char *yyRuleName[] = {
205 %%
206 };
207 #endif /* NDEBUG */
208 
209 /*
210 ** This function returns the symbolic name associated with a token
211 ** value.
212 */
213 #if 0
214 const char *ParseTokenName(int tokenType){
215 #ifndef NDEBUG
216   if( tokenType>0 && (size_t)tokenType<(sizeof(yyTokenName)/sizeof(yyTokenName[0])) ){
217     return yyTokenName[tokenType];
218   }else{
219     return "Unknown";
220   }
221 #else
222   return "";
223 #endif
224 }
225 #endif
226 
227 /*
228 ** This function allocates a new parser.
229 ** The only argument is a pointer to a function which works like
230 ** malloc.
231 **
232 ** Inputs:
233 ** A pointer to the function used to allocate memory.
234 **
235 ** Outputs:
236 ** A pointer to a parser.  This pointer is used in subsequent calls
237 ** to Parse and ParseFree.
238 */
ParseAlloc(void * (* mallocProc)(size_t))239 void *ParseAlloc(void *(*mallocProc)(size_t)){
240   yyParser *pParser;
241   pParser = (yyParser*)(*mallocProc)( (size_t)sizeof(yyParser) );
242   if( pParser ){
243     pParser->yyidx = -1;
244   }
245   return pParser;
246 }
247 
248 /* The following function deletes the value associated with a
249 ** symbol.  The symbol can be either a terminal or nonterminal.
250 ** "yymajor" is the symbol code, and "yypminor" is a pointer to
251 ** the value.
252 */
yy_destructor(YYCODETYPE yymajor,YYMINORTYPE * yypminor)253 static void yy_destructor(YYCODETYPE yymajor, YYMINORTYPE *yypminor){
254   switch( yymajor ){
255     /* Here is inserted the actions which take place when a
256     ** terminal or non-terminal is destroyed.  This can happen
257     ** when the symbol is popped from the stack during a
258     ** reduce or during error processing or when a parser is
259     ** being destroyed before it is finished parsing.
260     **
261     ** Note: during a reduce, the only symbols destroyed are those
262     ** which appear on the RHS of the rule, but which are not used
263     ** inside the C code.
264     */
265 %%
266     default:  break;   /* If no destructor action specified: do nothing */
267   }
268 }
269 
270 /*
271 ** Pop the parser's stack once.
272 **
273 ** If there is a destructor routine associated with the token which
274 ** is popped from the stack, then call it.
275 **
276 ** Return the major token number for the symbol popped.
277 */
yy_pop_parser_stack(yyParser * pParser)278 static int yy_pop_parser_stack(yyParser *pParser){
279   YYCODETYPE yymajor;
280   yyStackEntry *yytos = &pParser->yystack[pParser->yyidx];
281 
282   if( pParser->yyidx<0 ) return 0;
283 #ifndef NDEBUG
284   if( yyTraceFILE && pParser->yyidx>=0 ){
285     fprintf(yyTraceFILE,"%sPopping %s\n",
286       yyTracePrompt,
287       yyTokenName[yytos->major]);
288   }
289 #endif
290   yymajor = yytos->major;
291   yy_destructor( yymajor, &yytos->minor);
292   pParser->yyidx--;
293   return yymajor;
294 }
295 
296 /*
297 ** Deallocate and destroy a parser.  Destructors are all called for
298 ** all stack elements before shutting the parser down.
299 **
300 ** Inputs:
301 ** <ul>
302 ** <li>  A pointer to the parser.  This should be a pointer
303 **       obtained from ParseAlloc.
304 ** <li>  A pointer to a function used to reclaim memory obtained
305 **       from malloc.
306 ** </ul>
307 */
ParseFree(void * p,void (* freeProc)(void *))308 void ParseFree(
309   void *p,                    /* The parser to be deleted */
310   void (*freeProc)(void*)     /* Function used to reclaim memory */
311 ){
312   yyParser *pParser = (yyParser*)p;
313   if( pParser==NULL ) return;
314   while( pParser->yyidx>=0 ) yy_pop_parser_stack(pParser);
315   (*freeProc)((void*)pParser);
316 }
317 
318 /*
319 ** Find the appropriate action for a parser given the terminal
320 ** look-ahead token iLookAhead.
321 **
322 ** If the look-ahead token is YYNOCODE, then check to see if the action is
323 ** independent of the look-ahead.  If it is, return the action, otherwise
324 ** return YY_NO_ACTION.
325 */
yy_find_shift_action(yyParser * pParser,int iLookAhead)326 static int yy_find_shift_action(
327   yyParser *pParser,        /* The parser */
328   int iLookAhead            /* The look-ahead token */
329 ){
330   int i;
331   int stateno = pParser->yystack[pParser->yyidx].stateno;
332 
333   /* if( pParser->yyidx<0 ) return YY_NO_ACTION;  */
334   i = yy_shift_ofst[stateno];
335   if( i==YY_SHIFT_USE_DFLT ){
336     return yy_default[stateno];
337   }
338   if( iLookAhead==YYNOCODE ){
339     return YY_NO_ACTION;
340   }
341   i += iLookAhead;
342   if( i<0 || (size_t)i>=YY_SZ_ACTTAB || yy_lookahead[i]!=iLookAhead ){
343 #ifdef YYFALLBACK
344     int iFallback;            /* Fallback token */
345     if( iLookAhead<sizeof(yyFallback)/sizeof(yyFallback[0])
346            && (iFallback = yyFallback[iLookAhead])!=0 ){
347 #ifndef NDEBUG
348       if( yyTraceFILE ){
349         fprintf(yyTraceFILE, "%sFALLBACK %s => %s\n",
350            yyTracePrompt, yyTokenName[iLookAhead], yyTokenName[iFallback]);
351       }
352 #endif
353       return yy_find_shift_action(pParser, iFallback);
354     }
355 #endif
356     return yy_default[stateno];
357   }else{
358     return yy_action[i];
359   }
360 }
361 
362 /*
363 ** Find the appropriate action for a parser given the non-terminal
364 ** look-ahead token iLookAhead.
365 **
366 ** If the look-ahead token is YYNOCODE, then check to see if the action is
367 ** independent of the look-ahead.  If it is, return the action, otherwise
368 ** return YY_NO_ACTION.
369 */
yy_find_reduce_action(yyParser * pParser,int iLookAhead)370 static int yy_find_reduce_action(
371   yyParser *pParser,        /* The parser */
372   int iLookAhead            /* The look-ahead token */
373 ){
374   int i;
375   int stateno = pParser->yystack[pParser->yyidx].stateno;
376 
377   i = yy_reduce_ofst[stateno];
378   if( i==YY_REDUCE_USE_DFLT ){
379     return yy_default[stateno];
380   }
381   if( iLookAhead==YYNOCODE ){
382     return YY_NO_ACTION;
383   }
384   i += iLookAhead;
385   if( i<0 || (size_t)i>=YY_SZ_ACTTAB || yy_lookahead[i]!=iLookAhead ){
386     return yy_default[stateno];
387   }else{
388     return yy_action[i];
389   }
390 }
391 
392 /*
393 ** Perform a shift action.
394 */
yy_shift(yyParser * yypParser,int yyNewState,int yyMajor,YYMINORTYPE * yypMinor)395 static void yy_shift(
396   yyParser *yypParser,          /* The parser to be shifted */
397   int yyNewState,               /* The new state to shift in */
398   int yyMajor,                  /* The major token to shift in */
399   YYMINORTYPE *yypMinor         /* Pointer ot the minor token to shift in */
400 ){
401   yyStackEntry *yytos;
402   yypParser->yyidx++;
403   if( yypParser->yyidx>=YYSTACKDEPTH ){
404      ParseARG_FETCH;
405      yypParser->yyidx--;
406 #ifndef NDEBUG
407      if( yyTraceFILE ){
408        fprintf(yyTraceFILE,"%sStack Overflow!\n",yyTracePrompt);
409      }
410 #endif
411      while( yypParser->yyidx>=0 ) yy_pop_parser_stack(yypParser);
412      /* Here code is inserted which will execute if the parser
413      ** stack every overflows */
414 %%
415      ParseARG_STORE; /* Suppress warning about unused %extra_argument var */
416      return;
417   }
418   yytos = &yypParser->yystack[yypParser->yyidx];
419   yytos->stateno = yyNewState;
420   yytos->major = yyMajor;
421   yytos->minor = *yypMinor;
422 #ifndef NDEBUG
423   if( yyTraceFILE && yypParser->yyidx>0 ){
424     int i;
425     fprintf(yyTraceFILE,"%sShift %d\n",yyTracePrompt,yyNewState);
426     fprintf(yyTraceFILE,"%sStack:",yyTracePrompt);
427     for(i=1; i<=yypParser->yyidx; i++)
428       fprintf(yyTraceFILE," %s",yyTokenName[yypParser->yystack[i].major]);
429     fprintf(yyTraceFILE,"\n");
430   }
431 #endif
432 }
433 
434 /* The following table contains information about every rule that
435 ** is used during the reduce.
436 */
437 static struct {
438   YYCODETYPE lhs;         /* Symbol on the left-hand side of the rule */
439   unsigned char nrhs;     /* Number of right-hand side symbols in the rule */
440 } yyRuleInfo[] = {
441 %%
442 };
443 
444 static void yy_accept(yyParser*);  /* Forward Declaration */
445 
446 /*
447 ** Perform a reduce action and the shift that must immediately
448 ** follow the reduce.
449 */
yy_reduce(yyParser * yypParser,int yyruleno)450 static void yy_reduce(
451   yyParser *yypParser,         /* The parser */
452   int yyruleno                 /* Number of the rule by which to reduce */
453 ){
454   int yygoto;                     /* The next state */
455   int yyact;                      /* The next action */
456   YYMINORTYPE yygotominor;        /* The LHS of the rule reduced */
457   yyStackEntry *yymsp;            /* The top of the parser's stack */
458   int yysize;                     /* Amount to pop the stack */
459   ParseARG_FETCH;
460   yymsp = &yypParser->yystack[yypParser->yyidx];
461 #ifndef NDEBUG
462   if( yyTraceFILE && yyruleno>=0
463         && (size_t)yyruleno<sizeof(yyRuleName)/sizeof(yyRuleName[0]) ){
464     fprintf(yyTraceFILE, "%sReduce [%s].\n", yyTracePrompt,
465       yyRuleName[yyruleno]);
466   }
467 #endif /* NDEBUG */
468 
469   switch( yyruleno ){
470   /* Beginning here are the reduction cases.  A typical example
471   ** follows:
472   **   case 0:
473   **  #line <lineno> <grammarfile>
474   **     { ... }           // User supplied code
475   **  #line <lineno> <thisfile>
476   **     break;
477   */
478 %%
479   };
480   yygoto = yyRuleInfo[yyruleno].lhs;
481   yysize = yyRuleInfo[yyruleno].nrhs;
482   yypParser->yyidx -= yysize;
483   yyact = yy_find_reduce_action(yypParser,yygoto);
484   if( yyact < YYNSTATE ){
485     yy_shift(yypParser,yyact,yygoto,&yygotominor);
486   }else if( yyact == YYNSTATE + YYNRULE + 1 ){
487     yy_accept(yypParser);
488   }
489 }
490 
491 /*
492 ** The following code executes when the parse fails
493 */
yy_parse_failed(yyParser * yypParser)494 static void yy_parse_failed(
495   yyParser *yypParser           /* The parser */
496 ){
497   ParseARG_FETCH;
498 #ifndef NDEBUG
499   if( yyTraceFILE ){
500     fprintf(yyTraceFILE,"%sFail!\n",yyTracePrompt);
501   }
502 #endif
503   while( yypParser->yyidx>=0 ) yy_pop_parser_stack(yypParser);
504   /* Here code is inserted which will be executed whenever the
505   ** parser fails */
506 %%
507   ParseARG_STORE; /* Suppress warning about unused %extra_argument variable */
508 }
509 
510 /*
511 ** The following code executes when a syntax error first occurs.
512 */
yy_syntax_error(yyParser * yypParser,int yymajor,YYMINORTYPE yyminor)513 static void yy_syntax_error(
514   yyParser *yypParser,           /* The parser */
515   int yymajor,                   /* The major type of the error token */
516   YYMINORTYPE yyminor            /* The minor type of the error token */
517 ){
518   ParseARG_FETCH;
519   UNUSED(yymajor);
520   UNUSED(yyminor);
521 #define TOKEN (yyminor.yy0)
522 %%
523   ParseARG_STORE; /* Suppress warning about unused %extra_argument variable */
524 }
525 
526 /*
527 ** The following is executed when the parser accepts
528 */
yy_accept(yyParser * yypParser)529 static void yy_accept(
530   yyParser *yypParser           /* The parser */
531 ){
532   ParseARG_FETCH;
533 #ifndef NDEBUG
534   if( yyTraceFILE ){
535     fprintf(yyTraceFILE,"%sAccept!\n",yyTracePrompt);
536   }
537 #endif
538   while( yypParser->yyidx>=0 ) yy_pop_parser_stack(yypParser);
539   /* Here code is inserted which will be executed whenever the
540   ** parser accepts */
541 %%
542   ParseARG_STORE; /* Suppress warning about unused %extra_argument variable */
543 }
544 
545 /* The main parser program.
546 ** The first argument is a pointer to a structure obtained from
547 ** "ParseAlloc" which describes the current state of the parser.
548 ** The second argument is the major token number.  The third is
549 ** the minor token.  The fourth optional argument is whatever the
550 ** user wants (and specified in the grammar) and is available for
551 ** use by the action routines.
552 **
553 ** Inputs:
554 ** <ul>
555 ** <li> A pointer to the parser (an opaque structure.)
556 ** <li> The major token number.
557 ** <li> The minor token number.
558 ** <li> An option argument of a grammar-specified type.
559 ** </ul>
560 **
561 ** Outputs:
562 ** None.
563 */
Parse(void * yyp,int yymajor,ParseTOKENTYPE yyminor ParseARG_PDECL)564 void Parse(
565   void *yyp,                   /* The parser */
566   int yymajor,                 /* The major token code number */
567   ParseTOKENTYPE yyminor       /* The value for the token */
568   ParseARG_PDECL               /* Optional %extra_argument parameter */
569 ){
570   YYMINORTYPE yyminorunion;
571   int yyact;            /* The parser action. */
572   int yyendofinput;     /* True if we are at the end of input */
573   int yyerrorhit = 0;   /* True if yymajor has invoked an error */
574   yyParser *yypParser;  /* The parser */
575 
576   /* (re)initialize the parser, if necessary */
577   yypParser = (yyParser*)yyp;
578   if( yypParser->yyidx<0 ){
579     if( yymajor==0 ) return;
580     yypParser->yyidx = 0;
581     yypParser->yyerrcnt = -1;
582     yypParser->yystack[0].stateno = 0;
583     yypParser->yystack[0].major = 0;
584   }
585   yyminorunion.yy0 = yyminor;
586   yyendofinput = (yymajor==0);
587   ParseARG_STORE;
588 
589 #ifndef NDEBUG
590   if( yyTraceFILE ){
591     fprintf(yyTraceFILE,"%sInput %s\n",yyTracePrompt,yyTokenName[yymajor]);
592   }
593 #endif
594 
595   do{
596     yyact = yy_find_shift_action(yypParser,yymajor);
597     if( yyact<YYNSTATE ){
598       yy_shift(yypParser,yyact,yymajor,&yyminorunion);
599       yypParser->yyerrcnt--;
600       if( yyendofinput && yypParser->yyidx>=0 ){
601         yymajor = 0;
602       }else{
603         yymajor = YYNOCODE;
604       }
605     }else if( yyact < YYNSTATE + YYNRULE ){
606       yy_reduce(yypParser,yyact-YYNSTATE);
607     }else if( yyact == YY_ERROR_ACTION ){
608       int yymx;
609 #ifndef NDEBUG
610       if( yyTraceFILE ){
611         fprintf(yyTraceFILE,"%sSyntax Error!\n",yyTracePrompt);
612       }
613 #endif
614 #ifdef YYERRORSYMBOL
615       /* A syntax error has occurred.
616       ** The response to an error depends upon whether or not the
617       ** grammar defines an error token "ERROR".
618       **
619       ** This is what we do if the grammar does define ERROR:
620       **
621       **  * Call the %syntax_error function.
622       **
623       **  * Begin popping the stack until we enter a state where
624       **    it is legal to shift the error symbol, then shift
625       **    the error symbol.
626       **
627       **  * Set the error count to three.
628       **
629       **  * Begin accepting and shifting new tokens.  No new error
630       **    processing will occur until three tokens have been
631       **    shifted successfully.
632       **
633       */
634       if( yypParser->yyerrcnt<0 ){
635         yy_syntax_error(yypParser,yymajor,yyminorunion);
636       }
637       yymx = yypParser->yystack[yypParser->yyidx].major;
638       if( yymx==YYERRORSYMBOL || yyerrorhit ){
639 #ifndef NDEBUG
640         if( yyTraceFILE ){
641           fprintf(yyTraceFILE,"%sDiscard input token %s\n",
642              yyTracePrompt,yyTokenName[yymajor]);
643         }
644 #endif
645         yy_destructor(yymajor,&yyminorunion);
646         yymajor = YYNOCODE;
647       }else{
648          while(
649           yypParser->yyidx >= 0 &&
650           yymx != YYERRORSYMBOL &&
651           (yyact = yy_find_shift_action(yypParser,YYERRORSYMBOL)) >= YYNSTATE
652         ){
653           yy_pop_parser_stack(yypParser);
654         }
655         if( yypParser->yyidx < 0 || yymajor==0 ){
656           yy_destructor(yymajor,&yyminorunion);
657           yy_parse_failed(yypParser);
658           yymajor = YYNOCODE;
659         }else if( yymx!=YYERRORSYMBOL ){
660           YYMINORTYPE u2;
661           u2.YYERRSYMDT = 0;
662           yy_shift(yypParser,yyact,YYERRORSYMBOL,&u2);
663         }
664       }
665       yypParser->yyerrcnt = 3;
666       yyerrorhit = 1;
667 #else  /* YYERRORSYMBOL is not defined */
668       /* This is what we do if the grammar does not define ERROR:
669       **
670       **  * Report an error message, and throw away the input token.
671       **
672       **  * If the input token is $, then fail the parse.
673       **
674       ** As before, subsequent error messages are suppressed until
675       ** three input tokens have been successfully shifted.
676       */
677       if( yypParser->yyerrcnt<=0 ){
678         yy_syntax_error(yypParser,yymajor,yyminorunion);
679       }
680       yypParser->yyerrcnt = 3;
681       yy_destructor(yymajor,&yyminorunion);
682       if( yyendofinput ){
683         yy_parse_failed(yypParser);
684       }
685       yymajor = YYNOCODE;
686 #endif
687     }else{
688       yy_accept(yypParser);
689       yymajor = YYNOCODE;
690     }
691   }while( yymajor!=YYNOCODE && yypParser->yyidx>=0 );
692   return;
693 }
694