/**
 *   Copyright (c) Rich Hickey. All rights reserved.
 *   The use and distribution terms for this software are covered by the
 *   Common Public License 1.0 (http://opensource.org/licenses/cpl.php)
 *   which can be found in the file CPL.TXT at the root of this distribution.
 *   By using this software in any fashion, you are agreeing to be bound by
 * 	 the terms of this license.
 *   You must not remove this notice, or any other, from this software.
 **/

using System;
using System.Collections;

namespace clojure.lang
{
	public class EnumeratorSeq : ASeq
	{
		IEnumerator e;
		ISeq _rest;

		public static EnumeratorSeq create(IEnumerator e) {
			if (e.MoveNext())
				return new EnumeratorSeq(e);
			return null;
		}

		EnumeratorSeq(IEnumerator e) {
			this.e = e;
			this._rest = this;
		}

		override public Object first() {
			return e.Current;
		}

		override public ISeq rest() {
			lock (this)
			{
				if (_rest == this)
				{
					_rest = create(e);
				}
				return _rest;
			}
		}
	}
}