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// 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
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expr_part;
expr_part ::= expr:e
{: System.out.println("= " + e); :}
SEMI
;
expr ::= expr:e1 PLUS expr:e2
{: RESULT = new Integer(e1.intValue() + e2.intValue()); :}
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expr:e1 MINUS expr:e2
{: RESULT = new Integer(e1.intValue() - e2.intValue()); :}
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expr:e1 TIMES expr:e2
{: RESULT = new Integer(e1.intValue() * e2.intValue()); :}
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expr:e1 DIVIDE expr:e2
{: RESULT = new Integer(e1.intValue() / e2.intValue()); :}
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expr:e1 MOD expr:e2
{: RESULT = new Integer(e1.intValue() % e2.intValue()); :}
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NUMBER:n
{: RESULT = n; :}
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MINUS expr:e
{: RESULT = new Integer(0 - e.intValue()); :}
%prec UMINUS
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LPAREN expr:e RPAREN
{: RESULT = e; :}
;
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