CalculatorParser.java

public class CalculatorParser extends BaseParser<Integer> {

    public Rule Expression() {
        return Sequence(
                Term(), 
                ZeroOrMore(
                        FirstOf(
                                Sequence('+', Term(), push(pop() + pop())),
                                Sequence('-', Term(), push(pop(1) - pop()))
                        )
                ),
                EOI
        );
    }
    
    
    
    
    
    
    
    
    public Rule Term() {
        return Sequence(
                Number(),
                ZeroOrMore(
                        FirstOf(
                                Sequence('*', Number(), push(pop() * pop())),
                                Sequence('/', Number(), push(pop(1) / pop()))
                        )
                )
        );
    }
    
    
    
    
    
    
    
    
    public Rule Number() {
        return Sequence(
                OneOrMore(Digit()),
                push(Integer.parseInt(  match()  ))
        );
    }
    
    
    
    
    
    
    
    
    public Rule Digit() {
        return CharRange('0', '9');
    }
    
    
    
    
    
    
    
    
    //**************** MAIN ****************
    public static void main(String[] args) {
        CalculatorParser<V> parser = Parboiled.createParser(CalculatorParser.class);

        ParsingResult<?> result = new RecoveringParseRunner(parser.Expression()).run(args[0]);
    
        System.out.println(result.parseTreeRoot.getValue().toString());
    }

}