The YACC Parser Generator/Exercise 5 - Revision history

Root: /* How to Compile? */

2021-04-21T14:37:40Z

How to Compile?

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	The YACC specification is processed as follows (files '''y.tab.h''', needed by the Flex-generated code, and '''y.tab.c'''):		The YACC specification is processed as follows (files '''y.tab.h''', needed by the Flex-generated code, and '''y.tab.c'''):

	~~byacc~~ -dtv funcoffs.y		bison -dtv funcoffs.y

	Compiling the C/C++ code (it is C++ simply because we programmed the extra code in that language):		Compiling the C/C++ code (it is C++ simply because we programmed the extra code in that language):

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

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The Syntactic Analyzer (YACC) Specification

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	#include <string>		#include <string>
	#include <iostream>		#include <iostream>
			extern int yylex();
	inline void yyerror(const char *msg) { std::cerr << msg << std::endl; }		inline void yyerror(const char *msg) { std::cerr << msg << std::endl; }
	%}		%}
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	%%		%%
	~~extern int yylex();~~
	extern int yyparse();		extern int yyparse();
	int main() {		int main() {

Root: /* How to Compile? */

2020-04-02T14:07:29Z

How to Compile?

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	[[category:Compiladores]]		[[category:Compiladores]]
	[[category:Ensino]]		[[category:Ensino]]
	~~[[category:PRIVATE]]~~

Root at 15:23, 27 March 2020

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	[[category:Compiladores]]		[[category:Compiladores]]
	[[category:Ensino]]		[[category:Ensino]]
			[[category:PRIVATE]]

Root at 11:21, 12 February 2019

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	Por exemplo, na seguinte assinatura, os argumentos estarão (respectivamente), nas posições 8, 12, 16 e 17:		Por exemplo, na seguinte assinatura, os argumentos estarão (respectivamente), nas posições 8, 12, 16 e 17:
	<~~cpp~~>		<source lang="c++">
	void f(int a, char *b, char c, double d);		void f(int a, char *b, char c, double d);
	</~~cpp~~>		</source>
	== The Lexical Analyzer (Flex) Specification ==		== The Lexical Analyzer (Flex) Specification ==

	The lexical analyzer ('''funcoffs.l''') is very simple and limited to recognizing the indispensable tokens.		The lexical analyzer ('''funcoffs.l''') is very simple and limited to recognizing the indispensable tokens.
	<text>		<source lang="text">
	%option 8bit noyywrap yylineno		%option 8bit noyywrap yylineno
	%{		%{
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	%%		%%
	</~~text~~>		</source>

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

	The syntactic analyzer ('''funcoffs.y''') 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).		The syntactic analyzer ('''funcoffs.y''') 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).
	<text>		<source lang="text">
	%{		%{
	#include <string>		#include <string>
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	return yyparse();		return yyparse();
	}		}
	</~~text~~>		</source>

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

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

2017-04-07T10:47:03Z

The Syntactic Analyzer (YACC) Specification

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	\| tFLOAT { $$ = 4; }		\| tFLOAT { $$ = 4; }
	\| tDOUBLE { $$ = 8; }		\| tDOUBLE { $$ = 8; }
			\| tVOID '*' { $$ = 4; }
	\| atype '*' { $$ = 4; }		\| atype '*' { $$ = 4; }
	;		;

Root at 18:36, 14 April 2016

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			{{TOCright}}
	== Problema ==		== Problema ==

Root: Created page with "== Problema == O problema a resolver consiste na localização na pilha dos argumentos actuais de uma função C++. Considere que os argumentos apenas podem ser dos tipos '''..."

2016-04-14T18:36:15Z

Created page with "== Problema == O problema a resolver consiste na localização na pilha dos argumentos actuais de uma função C++. Considere que os argumentos apenas podem ser dos tipos '''..."

New page

== Problema ==

O problema a resolver consiste na localização na pilha dos argumentos actuais de uma função C++. Considere que os argumentos apenas podem ser dos tipos '''char''', '''short''', '''int''', ponteiro, '''float''' e '''double''' (ocupando, respectivamente, 1, 2, 4, 4, 4 e 8 bytes). Considere ainda que o argumento mais à esquerda está na posição 8.

Construa um ficheiro YACC (.y) que receba uma assinatura de uma função e que imprima a posição de cada argumento. Considere que a especificação Flex (não é necessário implementá-la) detecta os seguintes tokens: '''tVOID''', '''tID''', '''tCHAR''', '''tSHORT''', '''tINT''', '''tFLOAT''', '''tDOUBLE''', '''(''', ''')''', ''',''', '''*''' e ''';'''.

Por exemplo, na seguinte assinatura, os argumentos estarão (respectivamente), nas posições 8, 12, 16 e 17:
<cpp>
void f(int a, char *b, char c, double d);
</cpp>
== The Lexical Analyzer (Flex) Specification ==

The lexical analyzer ('''funcoffs.l''') is very simple and limited to recognizing the indispensable tokens.
<text>
%option 8bit noyywrap yylineno
%{
#include <string>
#include "y.tab.h"
%}
%%

"void" return tVOID;
"char" return tCHAR;
"short" return tSHORT;
"int" return tINT;
"float" return tFLOAT;
"double" return tDOUBLE;

[_A-Za-z][_A-Za-z0-9]* yylval.s = new std::string(yytext); return tID;
[,()*;] return *yytext;

.|\n ; // ignore the rest

%%
</text>

== The Syntactic Analyzer (YACC) Specification ==

The syntactic analyzer ('''funcoffs.y''') 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).
<text>
%{
#include <string>
#include <iostream>
inline void yyerror(const char *msg) { std::cerr << msg << std::endl; }
%}
%union {
int i;
std::string *s;
std::pair<int, std::string> *p;
}

%token <s> tID
%token tVOID tCHAR tSHORT tINT tFLOAT tDOUBLE

%type <i> args atype
%type <p> arg

%%

funcs: func
| funcs func
;

func : rtype tID '(' ')' ';'
| rtype tID '(' args ')' ';'
;

args : arg { std::cout << $1->second << "@" << ($$ = 8) << std::endl; $$ += $1->first; delete $1; }
| args ',' arg { std::cout << $3->second << "@" << ($$ = $1) << std::endl; $$ += $3->first; delete $3; }
;

arg : atype tID { $$ = new std::pair<int,std::string>($1,*$2); delete $2; }
;

rtype : tVOID | tCHAR | tSHORT | tINT | tFLOAT | tDOUBLE | rtype '*' ;

atype : tCHAR { $$ = 1; }
| tSHORT { $$ = 2; }
| tINT { $$ = 4; }
| tFLOAT { $$ = 4; }
| tDOUBLE { $$ = 8; }
| atype '*' { $$ = 4; }
;

%%
extern int yylex();
extern int yyparse();
int main() {
return yyparse();
}
</text>

== How to Compile? ==

The Flex specification is processed as follows (the file '''lex.yy.c''' is produced):

flex funcoffs.l

The YACC specification is processed as follows (files '''y.tab.h''', needed by the Flex-generated code, and '''y.tab.c'''):

byacc -dtv funcoffs.y

Compiling the C/C++ code (it is C++ simply because we programmed the extra code in that language):

g++ -c lex.yy.c
g++ -c y.tab.c
g++ -o funcoffs y.tab.o lex.yy.o

[[category:Compiladores]]
[[category:Ensino]]