source: liacs/coco/assignment2/comp.y@ 26

Last change on this file since 26 was 2, checked in by Rick van der Zwet, 15 years ago

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[2]1/* C declarations */
2%{
3
4#include <stdio.h>
5#include <stdlib.h>
6#include <unistd.h>
7#include <math.h>
8#include <assert.h>
9#include <sysexits.h>
10#include "debug.h"
11#include "SyntaxTree.h"
12#include "SymbolTable.h"
13#include "Node.h"
14#include "messages.h"
15#include "coercion.h"
16#include "lookup.h"
17
18/* Prototypes */
19static void yyerror(const char *);
20
21/* Import from comp.l */
22extern int yylex(void); /* Lexer function */
23extern int lineno; /* Current line number */
24extern string lastID; /* The most recently read ID */
25extern string lastNUM; /* The most recently read value expression */
26extern string lastOP; /* The most recently read MULOP or RELOP */
27
28/* Other declarations */
29SyntaxTree * tree; /* The syntax tree */
30SymbolTable * symtab; /* The symbol table */
31string mainScopeName; /* The name of the main scope */
32Messages messages; /* Keeps track of warning/error messages */
33
34#ifdef DEBUG
35int msglevel = 90; /* higher = more debugging messages */
36#else
37int msglevel = 0; /* don't bother sensitive souls */
38#endif
39
40/* Macro to allow pretty display of parser tree calling stack debug print calls */
41#define pdebug(x) pmesg(100, "Parser: '"); pmesg(100, x); pmesg(100, "'\n")
42
43%}
44
45/* Start symbol */
46%start program
47
48/* Tokens */
49%token PROGRAM ID VAR NUM INTEGER REAL FUNCTION PROCEDURE
50%token PASCALBEGIN /* BEGIN is used internally by flex :-( */
51%token END ADDOP ASSIGNOP IF THEN ELSE WHILE DO RELOP
52%token MULOP NOT PROG_PARAMETER IRRELEVANT
53%token UMINUS /* unary minus */
54
55/* We wish to pass Node, Symbols and ReturnType pointers between the rules and
56 * actions
57 */
58%union {
59 Node *node;
60 ReturnType returntype;
61 Symbol *symbol;
62}
63
64%expect 1 /* shift/reduce conflict: dangling ELSE */
65%%
66
67/* GRAMMAR RULES AND ACTIONS */
68
69program: PROGRAM ID {
70 pdebug("program: PROGRAM ID");
71 /* The program name has just been read; save it */
72 mainScopeName = lastID;
73
74 /* Put the program name into the syntax tree */
75 tree->SetProgramName (mainScopeName);
76
77 /* Create a new scope in the symbol table */
78 symtab->AddScope (mainScopeName);
79
80 /* Add builtin functions and procedures */
81
82 /* function readinteger() : integer; */
83 Symbol * freshFunction = new Symbol_Subprogram();
84 freshFunction->SetName("readinteger");
85 freshFunction->SetReturnType(RT_INT);
86 freshFunction->SetSymbolType(ST_FUNCTION);
87 freshFunction->SetLine(0);
88 symtab->AddSymbol(freshFunction);
89
90 /* procedure writeinteger(i: integer); */
91 freshFunction = new Symbol_Subprogram();
92 freshFunction->SetName("writeinteger");
93 freshFunction->SetReturnType(RT_VOID);
94 freshFunction->SetSymbolType(ST_PROCEDURE);
95 freshFunction->SetLine(0);
96
97 Symbol * freshParam = new Symbol();
98 freshParam->SetReturnType(RT_INT);
99 freshParam->SetName("i");
100 freshFunction->AddParameter(freshParam);
101
102 symtab->AddSymbol(freshFunction);
103
104 /* function readreal() : real; */
105 freshFunction = new Symbol_Subprogram();
106 freshFunction->SetName("readreal");
107 freshFunction->SetReturnType(RT_REAL);
108 freshFunction->SetSymbolType(ST_FUNCTION);
109 freshFunction->SetLine(0);
110 symtab->AddSymbol(freshFunction);
111
112 /* procedure writereal(r: real); */
113 freshFunction = new Symbol_Subprogram();
114 freshFunction->SetName("writereal");
115 freshFunction->SetReturnType(RT_VOID);
116 freshFunction->SetSymbolType(ST_PROCEDURE);
117 freshFunction->SetLine(0);
118
119 freshParam = new Symbol();
120 freshParam->SetReturnType(RT_REAL);
121 freshParam->SetName("r");
122 freshFunction->AddParameter(freshParam);
123
124 symtab->AddSymbol(freshFunction);
125
126 }
127 ';' declarations subprogram_declarations compound_statement '.' {
128 tree->SetProgramBody($<node>7);
129 }
130 ;
131
132
133type_identifier_list:
134 ',' ID {
135 /* Create new symbol */
136 check_id(lastID);
137 Symbol * freshVar = new Symbol();
138 symtab->AddSymbol(freshVar);
139 /* Fill with yet known values */
140 freshVar->SetSymbolType(ST_UNKNOWN);
141 freshVar->SetName(lastID);
142 freshVar->SetLine(lineno);
143 $<node>$ = tree->CreateLeaf(freshVar);
144
145 } type_identifier_list {
146 pdebug("type_identifier_list: ',' ID type_identifier_list");
147 $<node>3->GetSymbol()->SetReturnType($<node>4->GetReturnType());
148
149 /* Create list out of it */
150 $<node>$ = tree->CreateParentNode(NODE_ID, $<node>4->GetReturnType(),
151 $<node>3, $<node>4); //XXX: Check: NODE_ID that's not a leaf?
152 }
153 | ':' type {
154 pdebug("type_identifier_list: ':' type");
155 /* Closing of list is a Node of type NODE_EMPTY */
156 Node * freshNode = tree->CreateLeaf();
157 freshNode->SetReturnType($<returntype>2);
158 $<node>$ = freshNode;
159 }
160 ;
161
162
163declarations: /* In declarations the VAR-variables are listed for the
164 program as well as for the procedures and functions. */
165
166 declarations VAR ID {
167 pdebug("declarations: declarations VAR ID");
168 /* Create new symbol */
169 check_id(lastID);
170 Symbol * freshVar = new Symbol();
171 symtab->AddSymbol(freshVar);
172
173 /* Fill with yet known values */
174 freshVar->SetSymbolType(ST_UNKNOWN);
175 freshVar->SetName(lastID);
176 freshVar->SetLine(lineno);
177 /* Temporary fill first Node with leaf value, as official value is not yet known */
178 $<node>$ = tree->CreateParentNode(NODE_ID, RT_UNKNOWN, tree->CreateLeaf(freshVar), tree->CreateLeaf());
179 }
180 type_identifier_list ';' {
181 pdebug("declarations: type_identifier_list ';'");
182 /* Fix temporary node */
183 Node * ptrNode = $<node>4;
184 ptrNode->SetReturnType($<node>5->GetReturnType());
185 ptrNode->GetLeftChild()->GetSymbol()->SetReturnType($<node>5->GetReturnType());
186 ptrNode->SetRightChild($<node>5);
187
188 /* Set all symbols to be parameters */
189 while ( ptrNode->GetNodeType() != NODE_EMPTY ) {
190 ptrNode->GetLeftChild()->GetSymbol()->SetSymbolType(ST_VARIABLE);
191 ptrNode = ptrNode->GetRightChild();
192 }
193 $<node>$ = $<node>4;
194 }
195 | /* lambda */ {
196 pdebug("declarations: <lambda>");
197 $<node>$ = tree->CreateLeaf() ;
198 }
199 ;
200
201
202type: standard_type {
203 pdebug("type: standard_type");
204 $<returntype>$ = $<returntype>1;
205 }
206 ;
207
208
209standard_type: INTEGER {
210 pdebug("standard_type: INTEGER");
211 $<returntype>$ = RT_INT;
212 }
213
214
215 | REAL {
216 pdebug("standard_type: REAL");
217 $<returntype>$ = RT_REAL;
218 }
219 ;
220
221
222subprogram_declarations:
223 subprogram_declarations subprogram_declaration ';' {
224 pdebug("subprogram_declaration: subprogram_declarations subprogram_declarations ';'");
225 /* Empty, no actions required */
226 }
227 | /* lambda */ {
228 pdebug("subprogram_declarations: <lambda>");
229 /* Empty, no actions required */
230 }
231 ;
232
233
234subprogram_declaration:
235 subprogram_head declarations compound_statement {
236 pdebug("subprogram_declaration: subprogram_head declarations compound_statement");
237 tree->AddSubprogram($<symbol>1->GetName(), $<node>3);
238 // leave subprogram scope
239 symtab->SetCurrentScope(symtab->GetRootScope()->GetName());
240 }
241 ;
242
243
244subprogram_head:
245 FUNCTION ID {
246 pdebug("subprogram_head: FUNCTION ID");
247 check_id(lastID);
248 /* Create New subprogram */
249 Symbol * freshProgram = new Symbol_Subprogram();
250 freshProgram->SetLine(lineno);
251 freshProgram->SetName(lastID);
252 freshProgram->SetSymbolType(ST_FUNCTION);
253 symtab->AddSymbol(freshProgram);
254
255 /* Subprogram means new scope */
256 symtab->AddScope(lastID);
257 symtab->SetCurrentScope(lastID);
258 Node * freshNode = tree->CreateLeaf(freshProgram);
259 /* Push fresh function into passing variable */
260 $<node>$ = freshNode;
261 }
262 arguments ':' standard_type ';' {
263 pdebug("subprogram_head: arguments ':' standard_type ';'");
264 /* Set returntype of new function */
265 Node * ptrNode = $<node>3;
266 Symbol * ptrSymbol = ptrNode->GetSymbol();
267 ptrNode->SetReturnType($<returntype>6);
268 ptrSymbol->SetReturnType($<returntype>6);
269
270 /* Add parameters to new function */
271 Node * ptrNodeParam;
272 ptrNode = $<node>4;
273 while (ptrNode->GetNodeType() != NODE_EMPTY) {
274 ptrNodeParam = ptrNode->GetLeftChild();
275 while (ptrNodeParam->GetNodeType() != NODE_EMPTY) {
276 ptrSymbol->AddParameter(ptrNodeParam->GetLeftChild()->GetSymbol());
277 ptrNodeParam = ptrNodeParam->GetRightChild();
278 }
279 ptrNode = ptrNode->GetRightChild();
280 }
281
282 $<symbol>$ = $<node>3->GetSymbol();
283 }
284 | PROCEDURE ID {
285 pdebug("subprogram_head: PROCEDURE ID");
286 /* Looks a bit like a FUNCTION ID clone, but got subtle
287 * differences in arguments and return values
288 */
289 check_id(lastID);
290
291 /* Procedure mean new subprogram */
292 Symbol * freshProgram = new Symbol_Subprogram();
293 freshProgram->SetLine(lineno);
294 freshProgram->SetName(lastID);
295 freshProgram->SetSymbolType(ST_PROCEDURE);
296 freshProgram->SetReturnType(RT_VOID);
297 symtab->AddSymbol(freshProgram);
298
299 /* Procedure mean new scope */
300 symtab->AddScope(lastID);
301 symtab->SetCurrentScope(lastID);
302 Node * freshNode = tree->CreateLeaf(freshProgram);
303 freshNode->SetReturnType(RT_VOID);
304 $<node>$ = freshNode;
305
306 }
307 arguments ';' {
308 pdebug("subprogram_head: arguments ';'");
309 /* Add parameters to procedure */
310 Node * ptrNode = $<node>4;
311 Node * ptrNodeParam;
312 Symbol * ptrSymbol = $<node>3->GetSymbol();
313 while (ptrNode->GetNodeType() != NODE_EMPTY) {
314 ptrNodeParam = ptrNode->GetLeftChild();
315 while (ptrNodeParam->GetNodeType() != NODE_EMPTY) {
316 ptrSymbol->AddParameter(ptrNodeParam->GetLeftChild()->GetSymbol());
317 ptrNodeParam = ptrNodeParam->GetRightChild();
318 }
319 ptrNode = ptrNode->GetRightChild();
320 }
321 $<symbol>$ = $<node>3->GetSymbol();
322 }
323 ;
324
325
326arguments: '(' parameter_lists ')' {
327 pdebug("arguments: '(' parameter_lists ')'");
328 $<node>$ = $<node>2;
329 }
330 | /* lambda */ {
331 pdebug("arguments: <lambda>");
332 $<node>$ = tree->CreateLeaf();
333 }
334 ;
335
336
337parameter_lists: parameter_list ';' parameter_lists {
338 pdebug("parameter_lists: parameter_lists ';' parameter_lists");
339 $<node>$ = tree->CreateParentNode(NODE_UNKNOWN, RT_VOID, $<node>1, $<node>3);
340 }
341 | parameter_list {
342 pdebug("parameter_lists: parameter_list");
343 $<node>$ = tree->CreateParentNode(NODE_UNKNOWN, RT_VOID, $<node>1, tree->CreateLeaf());
344 }
345 ;
346
347
348parameter_list: ID {
349 pdebug("parameter_list: ID");
350 /* Create new symbol */
351 check_id(lastID);
352 Symbol * freshVar = new Symbol();
353 symtab->AddSymbol(freshVar);
354
355 /* Fill with yet known values */
356 freshVar->SetSymbolType(ST_UNKNOWN);
357 freshVar->SetName(lastID);
358 freshVar->SetLine(lineno);
359
360 /* Temporary add leaf as end node, not yet fully fillable */
361 $<node>$ = tree->CreateParentNode(NODE_ID, RT_UNKNOWN, tree->CreateLeaf(freshVar), tree->CreateLeaf());
362 }
363 type_identifier_list {
364 pdebug("parameter_list: type_identifier_list");
365 /* Fill missing (returnType) information */
366 Node * ptrNode = $<node>2;
367 ptrNode->SetReturnType($<node>3->GetReturnType());
368 ptrNode->GetLeftChild()->GetSymbol()->SetReturnType($<node>3->GetReturnType());
369 ptrNode->SetRightChild($<node>3);
370
371 /* Set all symbols to be parameters */
372 while ( ptrNode->GetNodeType() != NODE_EMPTY ) {
373 ptrNode->GetLeftChild()->GetSymbol()->SetSymbolType(ST_PARAMETER);
374 ptrNode = ptrNode->GetRightChild();
375 }
376 $<node>$ = $<node>2;
377 }
378 ;
379
380
381compound_statement:
382 PASCALBEGIN optional_statements END {
383 pdebug("compound_statement: PASCALBEGIN optional_statements END");
384 $<node>$ = $<node>2;
385 }
386 ;
387
388
389optional_statements:
390 statement_list {
391 pdebug("optional_statements: statement_list");
392 $<node>$ = $<node>1;
393 }
394 | /* lambda */ {
395 pdebug("optional_statements: <lambda>");
396 $<node>$ = tree->CreateLeaf();
397 }
398 ;
399
400
401statement_list: statement {
402 pdebug("statement_list: statement");
403 $<node>$ = tree->CreateParentNode(NODE_STATEMENT_LIST, RT_VOID,
404 $<node>1, tree->CreateLeaf());
405 }
406 | statement_list ';' statement {
407 pdebug("statement_list: statement_list ';' statement");
408 /* Make sure statements, get appended the right way e.g.
409 * always rightmost of the list
410 */
411
412 /* Find the last statement list */
413 Node *statement_list = $<node>1;
414 while (statement_list->GetRightChild()->GetNodeType() != NODE_EMPTY) {
415 statement_list = statement_list->GetRightChild();
416 }
417 /* Replace empty node with new statement list */
418 Node *new_statement_list = tree->CreateParentNode(NODE_STATEMENT_LIST, RT_VOID,
419 $<node>3, statement_list->GetRightChild());
420 statement_list->SetRightChild(new_statement_list);
421 $<node>$ = $<node>1;
422 }
423 ;
424
425
426statement: variable ASSIGNOP expression {
427 pdebug("statement: variable ASSIGNOP expression");
428 ReturnType returntype = $<node>1->GetReturnType();
429 $<node>$ = tree->CreateParentNode(NODE_ASSIGNMENT, returntype, $<node>1, coerce(returntype, $<node>3));
430 }
431 | procedure_statement {
432 pdebug("statement: procedure_statement");
433 $<node>$ = $<node>1;
434 }
435 | compound_statement {
436 pdebug("statement: compound_statement");
437 $<node>$ = $<node>1;
438 }
439 | IF boollikeexp THEN statement optional_else_statement {
440 pdebug("statement: IF boollikeexp THEN statement optional_else_statement");
441 if ($<node>5->GetNodeType() == NODE_EMPTY) {
442 /* No ELSE part */
443 $<node>$ = tree->CreateParentNode(NODE_IF, RT_VOID, $<node>2, $<node>4);
444 } else {
445 $<node>$ = tree->CreateParentNode(NODE_IF, RT_VOID, $<node>2,
446 tree->CreateParentNode(NODE_IF_TARGETS, RT_VOID, $<node>4, $<node>5));
447 }
448 }
449 | WHILE boollikeexp DO statement {
450 pdebug("statement: WHILE boollikeexp DO statement");
451 $<node>$ = tree->CreateParentNode(NODE_WHILE, RT_VOID, $<node>2, $<node>4);
452 }
453 ;
454
455
456optional_else_statement:
457 ELSE statement {
458 pdebug("optional_else_statement: ELSE statement");
459 $<node>$ = $<node>2;
460 }
461
462 | /* lambda */ {
463 pdebug("optional_else_statement: <lambda>");
464 $<node>$ = tree->CreateLeaf();
465 }
466 ;
467
468
469variable:
470 ID {
471 pdebug("variable: ID");
472 /* Find ID in symbol table */
473 Symbol *symbol = lookup(lastID, ST_VARIABLE);
474
475 /* symbol found: make sure it is a variable or a function return value */
476 SymbolType symboltype = symbol->GetSymbolType();
477 bool isvariable = (symboltype == ST_VARIABLE || symboltype == ST_PARAMETER);
478 bool isfuncretval = (symboltype == ST_FUNCTION && symtab->GetCurrentScopeName() == lastID);
479 if ( !isvariable && !isfuncretval ) {
480 messages.LValueError(lineno, lastID);
481 }
482 $<node>$ = tree->CreateLeaf(symbol);
483 }
484 ;
485
486
487procedure_statement:
488 ID {
489 pdebug("procedure_statement: ID");
490 /* Lookup ID */
491 Symbol *symbol = lookup(lastID, ST_PROCEDURE);
492
493 /* check the type of the symbol */
494 Node *node = NULL;
495 switch (symbol->GetSymbolType()) {
496 case ST_FUNCTION:
497 node = tree->CreateParentNode(NODE_FUNCTIONCALL, symbol->GetReturnType(),
498 tree->CreateLeaf(symbol), tree->CreateLeaf());
499 messages.ReturnValueError(lineno, lastID, symbol->GetReturnType());
500 check_parameters(node);
501 break;
502 case ST_PROCEDURE:
503 node = tree->CreateParentNode(NODE_PROCCALL, RT_VOID,
504 tree->CreateLeaf(symbol), tree->CreateLeaf());
505 check_parameters(node);
506 break;
507 case ST_VARIABLE: /* fall through */
508 case ST_PARAMETER:
509 case ST_UNKNOWN:
510 case ST_ERROR:
511 case ST_PROGRAM:
512 case ST_TEMPVAR:
513 case ST_LABEL:
514 default:
515 messages.CallError(lineno, lastID, symbol->GetSymbolType());
516 /* return dummy NODE_EMPTY, to avoid freeze/crashing tree */
517 node = tree->CreateLeaf();
518 }
519 assert(node != NULL);
520 $<node>$ = node;
521 }
522 | ID {
523 /* Lookup ID */
524 $<symbol>$ = lookup(lastID, ST_PROCEDURE);
525 }
526 '(' expression_list ')' {
527 pdebug("procedure_statement: ID '(' expression_list ')'");
528 /* check the type of the symbol */
529 Symbol *symbol = $<symbol>2;
530 Node *node = NULL;
531 switch (symbol->GetSymbolType()) {
532 case ST_FUNCTION:
533 node = tree->CreateParentNode(NODE_FUNCTIONCALL, symbol->GetReturnType(),
534 tree->CreateLeaf(symbol), $<node>4);
535 messages.ReturnValueError(lineno, lastID, symbol->GetReturnType());
536 check_parameters(node);
537 break;
538 case ST_PROCEDURE:
539 node = tree->CreateParentNode(NODE_PROCCALL, symbol->GetReturnType(),
540 tree->CreateLeaf(symbol), $<node>4);
541 check_parameters(node);
542 break;
543 case ST_VARIABLE: /* fall through */
544 case ST_PARAMETER:
545 case ST_UNKNOWN:
546 case ST_ERROR:
547 case ST_PROGRAM:
548 case ST_TEMPVAR:
549 case ST_LABEL:
550 default:
551 messages.CallError(lineno, symbol->GetName(), symbol->GetSymbolType());
552 /* return dummy NODE_EMPTY, to avoid freeze/crashing tree */
553 node = tree->CreateLeaf();
554 }
555 assert(node != NULL);
556 $<node>$ = node;
557 }
558 ;
559
560expression_list:
561 expression {
562 pdebug("expression_list: expression");
563 $<node>$ = tree->CreateParentNode(NODE_EXPRLIST, RT_VOID, $<node>1, tree->CreateLeaf());
564 }
565 | expression ',' expression_list {
566 pdebug("expression_list: expression ',' expression_list");
567 $<node>$ = tree->CreateParentNode(NODE_EXPRLIST, RT_VOID, $<node>1, $<node>3);
568 }
569 ;
570
571boollikeexp: expression RELOP expression {
572 pdebug("boollikeexp: expression RELOP expression");
573 ReturnType returnType = minimumtype($<node>1->GetReturnType(), $<node>3->GetReturnType());
574 Node *node_relop = NULL;
575 /* Find proper nodeType = mapping lastOP 1:1 NODE_* */
576 NodeType nodeType = NODE_UNKNOWN;
577 if (lastOP == "=") {
578 nodeType = NODE_REL_EQUAL;
579 } else if (lastOP == "<") {
580 nodeType = NODE_REL_LT;
581 } else if (lastOP == ">") {
582 nodeType = NODE_REL_GT;
583 } else if (lastOP == "<=") {
584 nodeType = NODE_REL_LTE;
585 } else if (lastOP == ">=") {
586 nodeType = NODE_REL_GTE;
587 } else if (lastOP == "<>") {
588 nodeType = NODE_REL_NOTEQUAL;
589 }
590 node_relop = tree->CreateParentNode(nodeType, RT_BOOL, coerce(returnType, $<node>1),
591 coerce(returnType, $<node>3));
592 $<node>$ = tree->CreateParentNode(NODE_BOOLEXPR, RT_BOOL, node_relop);
593 }
594 | '(' boollikeexp ')' {
595 pdebug("boollikeexp: '(' boollikeexp ')'");
596 /* to allow stuff like "if (a > 3) then" */
597 $<node>$ = $<node>2;
598 }
599 ;
600
601
602expression: simple_expression {
603 pdebug("expression: simple_expression");
604 $<node>$ = $<node>1;
605 }
606 ;
607
608
609simple_expression:
610 term {
611 pdebug("simple_expression: term");
612 $<node>$ = $<node>1;
613 }
614 | signplus term {
615 pdebug("simple_expression: signplus term");
616 $<node>$ = tree->CreateParentNode(NODE_SIGNMINUS, $<node>2->GetReturnType(), $<node>2);
617 }
618 | signminus term {
619 pdebug("simple_expression: signminus term");
620 $<node>$ = tree->CreateParentNode(NODE_SIGNPLUS, $<node>2->GetReturnType(), $<node>2);
621 }
622 | simple_expression '+' term {
623 pdebug("simple_expression: simple_expression '+' term");
624 ReturnType returnType = minimumtype($<node>1->GetReturnType(), $<node>3->GetReturnType());
625 $<node>$ = tree->CreateParentNode(NODE_ADD, returnType, coerce(returnType, $<node>1),
626 coerce(returnType, $<node>3));
627 }
628
629 | simple_expression '-' term {
630 pdebug("simple_expression: simple_expression '-' term");
631 ReturnType returnType = minimumtype($<node>1->GetReturnType(), $<node>3->GetReturnType());
632 $<node>$ = tree->CreateParentNode(NODE_SUB, returnType, coerce(returnType, $<node>1),
633 coerce(returnType, $<node>3));
634 }
635 | simple_expression ADDOP term {
636 pdebug("simple_expression: simple_expression ADDOP term");
637 /* According to ../tests/varia/no_real_in_boolean_expr.p1 no
638 * reals allowed in boolean expressions, so set returnType and coerce will TypeError
639 */
640 ReturnType returnType = RT_INT;
641 $<node>$ = tree->CreateParentNode(NODE_OR, returnType, coerce(returnType, $<node>1),
642 coerce(returnType, $<node>3));
643 }
644 ;
645
646
647term: factor {
648 pdebug("term: factor");
649 $<node>$ = $<node>1;
650 }
651 | term MULOP factor {
652 pdebug("term: term MULOP factor");
653 ReturnType returnType = minimumtype($<node>1->GetReturnType(), $<node>3->GetReturnType());
654 if (lastOP == "*") {
655 $<node>$ = tree->CreateParentNode(NODE_MUL, returnType, coerce(returnType, $<node>1),
656 coerce(returnType, $<node>3));
657 } else if (lastOP == "/") {
658 // real division operator always returns real
659 $<node>$ = tree->CreateParentNode(NODE_DIV, RT_REAL, coerce(RT_REAL, $<node>1),
660 coerce(RT_REAL, $<node>3));
661 } else if (lastOP == "div") {
662 // integer division operator always returns integer
663 $<node>$ = tree->CreateParentNode(NODE_IDIV, RT_INT, coerce(RT_INT, $<node>1),
664 coerce(RT_INT, $<node>3));
665 } else if (lastOP == "mod") {
666 // only works on integers
667 $<node>$ = tree->CreateParentNode(NODE_MOD, RT_INT, coerce(RT_INT, $<node>1),
668 coerce(RT_INT, $<node>3));
669 } else if (lastOP == "and") {
670 /* Bitwise operator, not allowed on reals, coerce will TypeError */
671 returnType = RT_INT;
672 $<node>$ = tree->CreateParentNode(NODE_AND, returnType, coerce(returnType, $<node>1),
673 coerce(returnType, $<node>3));
674 }
675 }
676 ;
677
678
679factor: ID {
680 pdebug("factor: ID");
681 /* Lookup ID */
682 Symbol *symbol = lookup(lastID, ST_VARIABLE);
683
684 /* check the type of the symbol */
685 Node *node = NULL;
686 switch (symbol->GetSymbolType()) {
687 case ST_VARIABLE: /* fall through */
688 case ST_PARAMETER:
689 node = tree->CreateLeaf(symbol);
690 break;
691 case ST_FUNCTION:
692 node = tree->CreateParentNode(NODE_FUNCTIONCALL, symbol->GetReturnType(),
693 tree->CreateLeaf(symbol), tree->CreateLeaf());
694 check_parameters(node);
695 break;
696 case ST_PROCEDURE: /* fall through */
697 case ST_UNKNOWN:
698 case ST_ERROR:
699 case ST_PROGRAM:
700 case ST_TEMPVAR:
701 case ST_LABEL:
702 default:
703 messages.RValueError(lineno, lastID, symbol->GetSymbolType());
704 /* return dummy NODE_EMPTY, to avoid crashing/freezing tree */
705 node = tree->CreateLeaf();
706 }
707 assert(node != NULL);
708 $<node>$ = node;
709 }
710 | ID {
711 /* Lookup ID */
712 $<symbol>$ = lookup(lastID, ST_FUNCTION);
713 }
714 '(' expression_list ')' {
715 pdebug("factor: ID '(' expression_list ')'");
716 /* check the type of the symbol */
717 Node *node = NULL;
718 Symbol *symbol = $<symbol>2;
719 switch (symbol->GetSymbolType()) {
720 case ST_FUNCTION:
721 node = tree->CreateParentNode(NODE_FUNCTIONCALL, symbol->GetReturnType(),
722 tree->CreateLeaf(symbol), $<node>4);
723 check_parameters(node);
724 break;
725 case ST_PROCEDURE:
726 node = tree->CreateParentNode(NODE_PROCCALL, symbol->GetReturnType(),
727 tree->CreateLeaf(symbol), $<node>4);
728 check_parameters(node);
729 break;
730 case ST_VARIABLE: /* fall through */
731 case ST_PARAMETER:
732 case ST_UNKNOWN:
733 case ST_ERROR:
734 case ST_PROGRAM:
735 case ST_TEMPVAR:
736 case ST_LABEL:
737 default:
738 messages.CallError(lineno, symbol->GetName(), symbol->GetSymbolType());
739 /* return dummy NODE_EMPTY, to avoid crashing/freezing tree */
740 node = tree->CreateLeaf();
741 }
742 assert(node != NULL);
743 $<node>$ = node;
744 }
745 | NUM {
746 pdebug("factor: NUM");
747 /* XXX: Hack to find out whether value is set to be real or
748 * integer, should really be something which needs to be done
749 * by the lexer, but we are not allowed to alter the language
750 * during this assignment
751 */
752 if (lastNUM.find_first_of(".E") != string::npos) {
753 /* found real */
754 float value = atof(lastNUM.c_str());
755 $<node>$ = tree->CreateLeaf(value);
756 } else {
757 /* found integer */
758 int value = atoi(lastNUM.c_str());
759 $<node>$ = tree->CreateLeaf(value);
760 }
761 }
762 | '(' expression ')' {
763 pdebug("factor: '(' expression ')'");
764 $<node>$ = $<node>2;
765 }
766 | NOT factor {
767 pdebug("factor: NOT factor");
768 /* Bitwise operator, no real allowed, coerce will TypeError */
769 ReturnType returnType = RT_INT;
770 $<node>$ = tree->CreateParentNode(NODE_NOT, returnType, coerce(returnType, $<node>2));
771 }
772 ;
773
774
775signplus: '+' {
776 pdebug("signplus: '+'");
777 }
778 ;
779
780signminus: '-' %prec UMINUS {
781 pdebug("signminus: '-' \%prec UMINUS");
782 }
783 ;
784
785%%
786
787/* End of rules, more C code will follow now */
788
789void initialize()
790{
791 /* Create & initialize the abstract data structures */
792 tree = new SyntaxTree;
793 symtab = new SymbolTable;
794}
795
796void cleanup()
797{
798 /* Free objects */
799 delete tree;
800 delete symtab;
801}
802
803/* Nice usage warning, for the ones in need */
804void usage()
805{
806 fprintf(stderr, "Arguments:\n");
807 fprintf(stderr, "-v[vv] = more verbose output\n");
808 fprintf(stderr, "-q[qq] = less verbose output\n");
809 fprintf(stderr, "-w = turn on warning messages\n");
810 fprintf(stderr, "-n = turn off warning messages\n");
811 fprintf(stderr, "-h = usage\n");
812 exit(EX_USAGE);
813}
814
815int main(int argc, char * argv[])
816{
817 int parseResult;
818 int ch;
819
820 /* Set trace settings */
821 while ((ch = getopt(argc, argv, "hnqvw")) != -1) {
822 switch (ch) {
823 case 'v':
824 msglevel += 30;
825 break;
826 case 'q':
827 msglevel -= 30;
828 break;
829 case 'w':
830 messages.EnableWarnings();
831 break;
832 case 'n':
833 messages.DisableWarnings();
834 break;
835 case 'h':
836 default:
837 usage();
838 }
839 }
840
841 initialize();
842
843 /* Start the parsing procedure */
844 parseResult = yyparse();
845 messages.ShowNumbers();
846
847 /* Dump the syntax tree & symbol table */
848 tree->Dump (stdout);
849 printf("\n");
850 symtab->Dump (stdout);
851
852 cleanup();
853
854 /* Return the exit code. Note that the exit code does not depend on
855 * parseResult only, but also on the result of your semantic checks
856 */
857 return (parseResult == 0 && messages.GetErrors() == 0) ? 0 : 1;
858}
859
860
861static void yyerror(const char *s)
862{
863 fprintf(stderr, "line %d: %s\n", lineno, s);
864}
865
866int yywrap()
867{
868 return(1);
869}
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