//
// Author:
//   Jb Evain (jbevain@gmail.com)
//
// Copyright (c) 2008 - 2015 Jb Evain
// Copyright (c) 2008 - 2011 Novell, Inc.
//
// Licensed under the MIT/X11 license.
//

using System;
using System.Collections.Generic;

namespace MonoFN.Cecil.Rocks
{
    internal static class Functional
    {
        public static Func<A, R> Y<A, R>(Func<Func<A, R>, Func<A, R>> f)
        {
            Func<A, R> g = null;
            g = f(a => g(a));
            return g;
        }

        public static IEnumerable<TSource> Prepend<TSource>(this IEnumerable<TSource> source, TSource element)
        {
            if (source == null)
                throw new ArgumentNullException("source");

            return PrependIterator(source, element);
        }

        private static IEnumerable<TSource> PrependIterator<TSource>(IEnumerable<TSource> source, TSource element)
        {
            yield return element;

            foreach (TSource item in source)
                yield return item;
        }
    }
}