TestGrammar.java

package com.github.parboiled1.grappa.samples;

import org.parboiled.BaseParser;
import org.parboiled.Rule;

import java.util.ArrayList;
import java.util.List;

@SuppressWarnings("AutoBoxing")
public class TestGrammar
    extends BaseParser<List<Integer>>
{
    Rule whitespace()
    {
        return zeroOrMore(wsp());
    }

    boolean pushInt()
    {
        try {
            peek().add(Integer.parseInt(match()));
            return true;
        } catch (NumberFormatException ignored) {
            return false;
        }
    }

    Rule integer()
    {
        return sequence(optional('-'), oneOrMore(digit()));
    }

    Rule addInteger()
    {
        return sequence(integer(), pushInt());
    }

    Rule separator()
    {
        return sequence(whitespace(), ',', whitespace());
    }

    Rule intList()
    {
        return join(addInteger()).using(separator()).min(0);
    }

    Rule integerArray()
    {
        return sequence('[', whitespace(), intList(), whitespace(), ']');
    }
    
    Rule a()
    {
        return sequence('A', whitespace(), '=', whitespace());
    }

    Rule mainRule()
    {
        return sequence(a(), push(new ArrayList<Integer>()), integerArray());
    }
}