The YACC Parser Generator/Exercise 4 - Revision history

Root: /* The Syntactic Analyzer (YACC) Specification */

2021-04-21T14:38:38Z

The Syntactic Analyzer (YACC) Specification

← Older revision		Revision as of 14:38, 21 April 2021
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	#include <iostream>		#include <iostream>
	#include <string>		#include <string>
			extern int yylex();
	namespace { int vars[10]; }		namespace { int vars[10]; }
	%}		%}
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	%%		%%
	~~extern int yylex();~~
	extern int yyparse();		extern int yyparse();
	void yyerror(const char *s) { std::cout << s << std::endl; }		void yyerror(const char *s) { std::cout << s << std::endl; }

Root: /* The Lexical Analyzer (Flex) Specification */

2020-04-01T17:08:13Z

The Lexical Analyzer (Flex) Specification

← Older revision		Revision as of 17:08, 1 April 2020
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	%%		%%
	[[:digit:]] yylval.i = std::stoi(yytext); return tVAR;		[[:digit:]] yylval.i = std::stoi(yytext); return tVAR;
	"VERD" yylval.i = !0; return tVAL;		"VERD" yylval.i = !0; return tVAL;
	"FALS" yylval.i = 0; return tVAL;		"FALS" yylval.i = 0; return tVAL;
	[!&\|~;,()=] return *yytext;		[!&\|~;,()=] return *yytext;
	"==" return tEQ;		"==" return tEQ;
	"!=" return tNE;		"!=" return tNE;
	.\|\n ; /* ignore all the rest */		.\|\n ; /* ignore all the rest */
	%%		%%

Root: /* The Lexical Analyzer (Flex) Specification */

2020-04-01T17:07:35Z

The Lexical Analyzer (Flex) Specification

← Older revision		Revision as of 17:07, 1 April 2020
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	%option noyywrap		%option noyywrap
	%{		%{
	#include <~~cstdlib~~>		#include <string>
	#include "y.tab.h"		#include "y.tab.h"
	%}		%}
	%%		%%
	[[:digit:]] yylval.i = ~~strtol~~(yytext~~, NULL, 10~~); return tVAR;		[[:digit:]] yylval.i = std::stoi(yytext); return tVAR;
	"VERD" yylval.i = !0; return tVAL;		"VERD" yylval.i = !0; return tVAL;
	"FALS" yylval.i = 0; return tVAL;		"FALS" yylval.i = 0; return tVAL;

Root: /* The Syntactic Analyzer (YACC) Specification */

2020-04-01T17:07:00Z

The Syntactic Analyzer (YACC) Specification

← Older revision		Revision as of 17:07, 1 April 2020
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	#include <iostream>		#include <iostream>
	#include <string>		#include <string>
	~~#include <map>~~
	namespace { int vars[10]; }		namespace { int vars[10]; }
	%}		%}

Root: /* The Syntactic Analyzer (YACC) Specification */

2020-04-01T17:05:33Z

The Syntactic Analyzer (YACC) Specification

← Older revision		Revision as of 17:05, 1 April 2020
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	extern int yylex();		extern int yylex();
	extern int yyparse();		extern int yyparse();
	void yyerror(char *s) { std::cout << s << std::endl; }		void yyerror(const char *s) { std::cout << s << std::endl; }
	int main() { yyparse(); }		int main() { yyparse(); }
	</source>		</source>

Root: /* The Lexical Analyzer (Flex) Specification */

2020-04-01T17:05:00Z

The Lexical Analyzer (Flex) Specification

← Older revision		Revision as of 17:05, 1 April 2020
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	"VERD" yylval.i = !0; return tVAL;		"VERD" yylval.i = !0; return tVAL;
	"FALS" yylval.i = 0; return tVAL;		"FALS" yylval.i = 0; return tVAL;
	[!&\|~<>()=] return *yytext;		[!&\|~;,()=] return *yytext;
	"==" return tEQ;		"==" return tEQ;
	"!=" return tNE;		"!=" return tNE;

Root at 11:19, 12 February 2019

2019-02-12T11:19:39Z

← Older revision		Revision as of 11:19, 12 February 2019
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	The lexical analyzer (<tt>vars.l</tt>) is very simple and limited to recognizing variable names (token '''tVAR'''), integers numbers (token '''tVAL'''), and the operators themselves.		The lexical analyzer (<tt>vars.l</tt>) is very simple and limited to recognizing variable names (token '''tVAR'''), integers numbers (token '''tVAL'''), and the operators themselves.
	<text>		<source lang="text">
	%option noyywrap		%option noyywrap
	%{		%{
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	.\|\n ; /* ignore all the rest */		.\|\n ; /* ignore all the rest */
	%%		%%
	</~~text~~>		</source>

	== The Syntactic Analyzer (YACC) Specification ==		== The Syntactic Analyzer (YACC) Specification ==

	The syntactic analyzer will be built to immediately compute the expressions in a syntax-directed fashion as they occur. It is, thus, important to use trees that build nodes as the expressions occur (left-recursive grammars). If the grammar were right-recursive, the last node would be the first to be built and the (syntax-directed) evaluation would be from the last expression to the first.		The syntactic analyzer will be built to immediately compute the expressions in a syntax-directed fashion as they occur. It is, thus, important to use trees that build nodes as the expressions occur (left-recursive grammars). If the grammar were right-recursive, the last node would be the first to be built and the (syntax-directed) evaluation would be from the last expression to the first.
	<text>		<source lang="text">
	%{		%{
	#include <iostream>		#include <iostream>
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	void yyerror(char *s) { std::cout << s << std::endl; }		void yyerror(char *s) { std::cout << s << std::endl; }
	int main() { yyparse(); }		int main() { yyparse(); }
	</~~text~~>		</source>

	== How to Compile? ==		== How to Compile? ==

Root: /* The Syntactic Analyzer (YACC) Specification */

2016-04-11T08:51:46Z

The Syntactic Analyzer (YACC) Specification

← Older revision		Revision as of 08:51, 11 April 2016
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	int main() { yyparse(); }		int main() { yyparse(); }
	</text>		</text>

	Token '''BATATA''' is not recognized by the lexical analyzer and is only used to specify the precedence of the unary operators (+ and -) by specifying that the corresponding rules should be reduced with the precedence associated with the token '''BATATA''' (the highest in the grammar).

	== How to Compile? ==		== How to Compile? ==

Root: /* Solução */

2016-04-11T08:51:23Z

Solução

@@ Line 12: / Line 12: @@
 Todas as rotinas auxiliares devem ser codificadas.
-== Solução ==
+== The Lexical Analyzer (Flex) Specification ==
 [[category:Compiladores]]
 [[category:Ensino]]

Root: /* Problema */

2016-04-11T08:40:50Z

Problema

← Older revision		Revision as of 08:40, 11 April 2016
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	* '''OU inclusivo lógico:''' operador binário, associativo à esquerda, designado por '\|'.		* '''OU inclusivo lógico:''' operador binário, associativo à esquerda, designado por '\|'.
	* '''OU exclusivo lógico:''' operador binário, associativo à direita, designado por ' ~ '.		* '''OU exclusivo lógico:''' operador binário, associativo à direita, designado por ' ~ '.
	* '''comparação:''' operadores binários, associativos à esquerda, designados por EQ e NE.		* '''comparação:''' operadores binários, '==', e '!=', associativos à esquerda, designados por '''EQ''' e '''NE'''.

	A prioridade dos operadores pode ser alterada utilizando parenteses curvos '(' e ')'. No início todos os registos têm o valor lógico falso.		A prioridade dos operadores pode ser alterada utilizando parenteses curvos '(' e ')'. No início todos os registos têm o valor lógico falso.