parser.y

%{
	#include "quad_generation.c"
	#include <stdio.h>
	#include <stdlib.h>
	#include <string.h>

	#define YYSTYPE char*

	void yyerror(char* s); 											// error handling function
	int yylex(); 													// declare the function performing lexical analysis
	extern int yylineno; 											// track the line number

	FILE* icg_quad_file;
	int temp_no = 1;
%}


%token T_ID T_NUM

/* specify start symbol */
%start START


%%
START : ASSGN	{ 
					printf("Valid syntax\n");
	 				YYACCEPT;										// If program fits the grammar, syntax is valid
	 			}

/* Grammar for assignment */
ASSGN : T_ID '=' E	{	
						$$ = strdup($1);
						char* op = strdup("=");
						char* op1 = strdup(" ");
						quad_code_gen($$,$3,op,op1);
					}
	;

/* Expression Grammar */
E : E '+' T 	{	
					$$ = new_temp();
					char* op = strdup("+");
					quad_code_gen($$,$1,op,$3);
				}
	| E '-' T 	{	
					$$ = new_temp();
					char* op = strdup("-");
					quad_code_gen($$,$1,op,$3);
				}
	| T
	;
	
	
T : T '*' F 	{	
					$$ = new_temp();
					char* op = strdup("*");
					quad_code_gen($$,$1,op,$3);
				}
	| T '/' F 	{	
					$$ = new_temp();
					char* op = strdup("*");
					quad_code_gen($$,$1,op,$3);
				}
	| F
	;

F : '(' E ')' 	{$$ = $2;}
	| T_ID 		{$$ = strdup($1);}
	| T_NUM 	{$$ = strdup($1);}
	;

%%


/* error handling function */
void yyerror(char* s)
{
	printf("Error :%s at %d \n",s,yylineno);
}


/* main function - calls the yyparse() function which will in turn drive yylex() as well */
int main(int argc, char* argv[])
{
	icg_quad_file = fopen("icg_quad.txt","w");
	yyparse();
	fclose(icg_quad_file);
	return 0;
}