// JavaCup specification for a simple expression evaluator (w/ actions)package java_cup.simple_calc;import java_cup.runtime.*;/* Terminals (tokens returned by the scanner). */terminal           SEMI, PLUS, MINUS, TIMES, DIVIDE, MOD;terminal           UMINUS, LPAREN, RPAREN;terminal Integer   NUMBER;/* Non terminals */non terminal Object     expr_list, expr_part;non terminal Integer    expr;/* Precedences */precedence left PLUS, MINUS;precedence left TIMES, DIVIDE, MOD;precedence left UMINUS, LPAREN;/* The grammar */expr_list ::= expr_list expr_part 	      |               expr_part;expr_part ::= expr:e 	      {: System.out.println("= " + e); :}               SEMI              	      ;expr      ::= expr:e1 PLUS expr:e2    	      {: RESULT = new Integer(e1.intValue() + e2.intValue()); :} 	      |               expr:e1 MINUS expr:e2                  {: RESULT = new Integer(e1.intValue() - e2.intValue()); :} 	      |               expr:e1 TIMES expr:e2 	      {: RESULT = new Integer(e1.intValue() * e2.intValue()); :} 	      |               expr:e1 DIVIDE expr:e2 	      {: RESULT = new Integer(e1.intValue() / e2.intValue()); :} 	      |               expr:e1 MOD expr:e2 	      {: RESULT = new Integer(e1.intValue() % e2.intValue()); :} 	      |               NUMBER:n                 	      {: RESULT = n; :} 	      |               MINUS expr:e             	      {: RESULT = new Integer(0 - e.intValue()); :} 	      %prec UMINUS	      |               LPAREN expr:e RPAREN     	      {: RESULT = e; :} 	      ;