Implement Syntax analyzer to validate type and syntax of variable declaration using YACC

Problem Statement:-

Write a program using YACC specifications to implement the syntax analysis phase of the compiler to validate type and syntax of variable declaration in Java

Input:-

int a,b,c,d=10;

view raw input.txt hosted with ❤ by GitHub

Source Code:-

	%{
	#include <stdio.h>
	#include "y.tab.h"
	%}
	DIGIT [0-9]
	REAL {DIGIT}+[.]{DIGIT}*
	LETTER [A-Za-z]
	ASSIGN =
	%%
	[\t ] ;
	int {printf("%s\t==> DataType\n",yytext);return (INT);}
	float {printf("%s\t==> DataType\n",yytext);return (FLOAT);}
	char {printf("%s\t==> DataType\n",yytext);return (CHAR);}
	boolean {printf("%s\t==> DataType\n",yytext);return (BL);}
	true|false { printf("%s\t==> BOOLEAN VAL\n",yytext);return BLVAL;}
	['][^\t\n]['] { printf("%s\t==> CHAR VALUE\n",yytext);return CHVAL;}
	[a-zA-z]+[a-zA-z0-9_]* {printf("%s\t==> ID\n",yytext);return ID;}
	{REAL} { printf("%s\t==> REAL NUMBER\n",yytext);return REAL;}
	{DIGIT}+ { printf("%s\t==> INT NUMBER\n",yytext);return NUM;}
	"," {printf("%s\t==> COMMA\n",yytext);return COMMA;}
	";" {printf("%s\t==> SC\n",yytext);;return SC;}
	{ASSIGN} {printf("%s\t==> ASSIGN\n",yytext);return AS;}
	\n return NL;
	. ;
	%%
	int yywrap()
	{
	return 1;
	}

view raw declaration.l hosted with ❤ by GitHub

	%{
	#include<stdio.h>
	void yyerror(char*);
	int yylex();
	//FILE* yyin;
	%}
	%token ID SC INT CHAR FLOAT BL BLVAL CHVAL REAL AS NUM COMMA NL
	%%
	s: type1|type2|type3|type4
	;
	type1:INT varlist SC NL { printf("valid INT Variable declaration"); return 0;}
	/// for "int a" Test case(without SC ;) NL is added at end otherwise it waits for input
	;
	type2:FLOAT varlist2 SC NL{ printf("valid FLOAT Variable declaration");return 0;}
	;
	type3:CHAR varlist3 SC NL{ printf("valid CHAR Variable declaration");return 0;}
	;
	type4:BL varlist4 SC NL{ printf("valid BOOLEAN Variable declaration");return 0;}
	;
	varlist: ID | ID COMMA varlist | ID AS NUM |ID AS NUM COMMA varlist | //THIS IS FOR EPSILON CASE (EMPTY)
	;
	varlist2: ID | ID COMMA varlist2 | ID AS REAL |ID AS REAL COMMA varlist2 |
	;
	varlist3: ID | ID COMMA varlist3 | ID AS CHVAL | ID AS CHVAL COMMA varlist3 |
	;
	varlist4: ID | ID COMMA varlist4 | ID AS BLVAL | AS BLVAL COMMA varlist4 |
	;
	%%
	void yyerror(char *s )
	{
	fprintf(stderr, "ERROR: %s\n",s);
	}
	int main()
	{
	//yyin=fopen("input.txt","r");
	yyparse();
	//fclose(yyin);
	return 0;
	}

view raw declaration.y hosted with ❤ by GitHub

Output:-

Link For Source Code:-  B4_SPOS