remove redundant NULL

SQLPGrammar_new.tab.c

@@ -1702,7 +1702,7 @@ yyreduce:
 		printf("BasicPred 1\n");
 		cons_cell* first_term = create_term((yyvsp[-2]));
 		cons_cell* second_term = create_term((yyvsp[0]));
-		(yyval) = create_comp_operator((yyvsp[-1]), first_term, second_term, NULL);
+		(yyval) = create_comp_operator((yyvsp[-1]), first_term, second_term);
 	}
 #line 1708 "SQLPGrammar_new.tab.c" /* yacc.c:1646  */
     break;

SQLPGrammar_new.y

@@ -261,7 +261,7 @@ BasicPred
 		printf("BasicPred 1\n");
 		cons_cell* first_term = create_term($1);
 		cons_cell* second_term = create_term($3);
-		$$ = create_comp_operator($2, first_term, second_term, NULL);
+		$$ = create_comp_operator($2, first_term, second_term);
 	}
 	| EXIST '(' Body ')'
 	{

util_new.c

@@ -84,10 +84,9 @@ cons_cell* create_op(char *op) {
 }
 
 // todo: why need ra
-cons_cell* create_comp_operator(cons_cell* op, cons_cell* term1, cons_cell* term2, cons_cell* ra) {
+cons_cell* create_comp_operator(cons_cell* op, cons_cell* term1, cons_cell* term2) {
 
-	cons_cell* ra_cons = create_cons_cell(ra, NULL);
-	cons_cell* term2_cons = create_cons_cell(term2, ra_cons);
+	cons_cell* term2_cons = create_cons_cell(term2, NULL);
 	cons_cell* term1_cons = create_cons_cell(term1, term2_cons);
 	cons_cell* op_cons = create_cons_cell(op, term1_cons);
 	char operator[5] = "COMP\0";

util_new.h

@@ -69,7 +69,7 @@ cons_cell* create_col(char *col);
 cons_cell* create_attr(char *attr);
 cons_cell* create_var(char *var);
 cons_cell* create_op(char *op);
-cons_cell* create_comp_operator(cons_cell* op, cons_cell* term1, cons_cell* term2, cons_cell* ra);
+cons_cell* create_comp_operator(cons_cell* op, cons_cell* term1, cons_cell* term2);
 cons_cell* create_atom_operator(cons_cell* table, cons_cell* var);
 cons_cell* create_union_all_operator(cons_cell* ra1, cons_cell* ra2);
 cons_cell* create_union_operator(cons_cell* ra1, cons_cell* ra2);