Dummy example of dropincc.java

Test.java

package test;

import com.github.pfmiles.dropincc.Action;
import com.github.pfmiles.dropincc.CC;
import com.github.pfmiles.dropincc.Exe;
import com.github.pfmiles.dropincc.Grule;
import com.github.pfmiles.dropincc.Lang;
import com.github.pfmiles.dropincc.TokenDef;

public class Test {

    /**
     * <pre>
     * S ::= L $
     * L ::= Q*
     * Q ::= 'a'
     *     | 'bc'
     *     | '(' Q ')'
     * </pre>
     */
    public static void main(String... args) throws Throwable {
        Lang lang = new Lang("Dummy");
        TokenDef a = lang.newToken("a");
        TokenDef bc = lang.newToken("bc");
        TokenDef lp = lang.newToken("\\(");
        TokenDef rp = lang.newToken("\\)");
        Grule L = lang.newGrule();
        Grule Q = lang.newGrule();

        lang.defineGrule(L, CC.EOF).action(new Action() {
            public String act(Object matched) {
                return (String) ((Object[]) matched)[0];
            }
        }); // S ::= L $
        L.define(CC.ks(Q)).action(new Action() {
            public String act(Object matched) {
                Object[] ms = (Object[]) matched;
                StringBuilder sb = new StringBuilder();
                for (Object m : ms)
                    sb.append(m);
                return sb.toString();
            }
        });// L ::= Q*
        /*
         * Q ::= 'a' | 'bc' | '(' Q ')'
         */
        Q.define(a).alt(bc).alt(lp, Q, rp).action(new Action() {
            public String act(Object matched) {
                // returns the middle element matched, that's the returned value
                // of the enclosing 'Q' rule
                return (String) ((Object[]) matched)[1];
            }
        });

        Exe exe = lang.compile();
        System.out.println(exe.eval("a(a)((bc))"));
    }
}