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Functional patterns for Java

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package com.jnape.palatable.lambda.functions.builtin.fn2;

import com.jnape.palatable.lambda.functions.Fn1;
import com.jnape.palatable.lambda.functions.Fn2;
import com.jnape.palatable.lambda.iterators.SnocIterator;

/**
 * Opposite of {@link Cons}: lazily append an element to the end of the given {@link Iterable}.
 * 
 * Note that obtaining both laziness and stack-safety is particularly tricky here, and requires an initial eager
 * deforestation of O(k) traversals where k is the number of contiguously nested
 * {@link Snoc}s.
 *
 * @param  the Iterable element type
 */
public final class Snoc implements Fn2, Iterable> {

    private static final Snoc INSTANCE = new Snoc();

    private Snoc() {
    }

    @Override
    public Iterable apply(A a, Iterable as) {
        return () -> new SnocIterator<>(a, as);
    }

    @SuppressWarnings("unchecked")
    public static  Snoc snoc() {
        return INSTANCE;
    }

    public static  Fn1, Iterable> snoc(A a) {
        return Snoc.snoc().apply(a);
    }

    public static  Iterable snoc(A a, Iterable as) {
        return snoc(a).apply(as);
    }
}