TransformFunc.java

package fmlist;

import fj.F;
import fj.F2;
import fj.Monoid;

abstract class TransformFunc<A, B> {

    abstract <M> M f(Monoid<M> monoid, F<A, M> func, B val);

    <M> F<B, M> f(Monoid<M> monoid, F<A, M> func) {
        final Monoid<M> qm = monoid;
        final F<A, M> fn = func;
        final TransformFunc<A, B> self = this;
        return new F<B, M>() {

            @Override
            public M f(B a) {
                return self.f(qm, fn, a);
            }
        };
    }

    <M> F<F<A, M>, F<B, M>> f(Monoid<M> monoid) {
        final Monoid<M> qm = monoid;
        final TransformFunc<A, B> self = this;
        return new F<F<A, M>, F<B, M>>() {

            @Override
            public F<B, M> f(F<A, M> a) {
                final F<A, M> fn = a;
                return new F<B, M>() {

                    @Override
                    public M f(B a) {
                        return self.f(qm, fn, a);
                    }
                };
            }
        };
    }

    <M> F2<Monoid<M>, F<A, M>, F<B, M>> f() {
        final TransformFunc<A, B> self = this;
        return new F2<Monoid<M>, F<A, M>, F<B, M>>() {

            @Override
            public F<B, M> f(Monoid<M> a, F<A, M> b) {
                final Monoid<M> qm = a;
                final F<A, M> fn = b;
                return new F<B, M>() {

                    @Override
                    public M f(B a) {
                        return self.f(qm, fn, a);
                    }
                };
            }
        };
    }
}