%{
#include <stdio.h>
#include <string.h>
#define YYSTYPE char * 

void yyerror(const char *str) {
	fprintf(stderr,"error: %s\n",str);
	return;
}

int yywrap() {
	return 1;
}

main() {
	yyparse();
}

%}

%token NUMBER WORD OPEN_BRACKET CLOSE_BRACKET OPEN_PAREN CLOSE_PAREN COMMA ASSIGNED_TO SEMI_COLON PLUS MINUS DIVIDE MULTIPLY
	
%%
statement	: /* nothing here */
			| statement WORD ASSIGNED_TO exp SEMI_COLON { printf("%s", $5); }
			;

exp	: expression OPEN_BRACKET expression CLOSE_BRACKET
	| OPEN_BRACKET expression CLOSE_BRACKET expression
	| OPEN_BRACKET expression CLOSE_BRACKET
	| expression
	;			
			
expression	: low_lvl_exp
			| low_lvl_exp PLUS expression
			| low_lvl_exp MINUS expression
			| low_lvl_exp MULTIPLY expression
			| low_lvl_exp DIVIDE expression
			;
			
			
low_lvl_exp	: NUMBER operator NUMBER 
			| WORD operator WORD
			| WORD operator NUMBER
			| NUMBER operator WORD
			| WORD
			| NUMBER
			;

operator	: PLUS
			| MINUS
			| MULTIPLY
			| DIVIDE
			;
				
%%