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diff --git a/ClojureCLR/Clojure/Clojure/Lib/StreamSeq.cs b/ClojureCLR/Clojure/Clojure/Lib/StreamSeq.cs
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+/**
+ *   Copyright (c) David Miller. All rights reserved.
+ *   The use and distribution terms for this software are covered by the
+ *   Eclipse Public License 1.0 (http://opensource.org/licenses/eclipse-1.0.php)
+ *   which can be found in the file epl-v10.html 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.Generic;
+using System.Linq;
+using System.Text;
+
+namespace clojure.lang
+{
+
+    /// <summary>
+    /// Implements a persistent sequence over a stream.
+    /// </summary>
+    /// <remarks>Caches the stream values as retrieved.</remarks>
+    public class StreamSeq : ASeq
+    {
+        #region Data
+
+        /// <summary>
+        /// The stream whose values are being sequenced.
+        /// </summary>
+        IStream _stream;
+
+        /// <summary>
+        /// The first item in the stream.
+        /// </summary>
+        readonly object _first;
+
+        /// <summary>
+        /// The rest of the stream.
+        /// </summary>
+        ISeq _rest;
+
+        #endregion
+
+        #region Ctors and factory methods
+
+        /// <summary>
+        /// Create a sequence from a stream.
+        /// </summary>
+        /// <param name="stream">The stream to sequence.</param>
+        /// <returns>The persistent sequence.</returns>
+        /// <remarks>Requires looking at the first element of the stream.  
+        /// This is so that we know if the stream has any elements.  
+        /// This is so because the sequence must have at least element or be null.</remarks>
+        public static StreamSeq create(IStream stream)
+        {
+            object x = stream.next();
+            return (RT.isEOS(x))
+                ? null
+                : new StreamSeq(x, stream);
+        }
+
+        /// <summary>
+        /// Construct a <see cref="StreamSeq">StreamSeq</see> from metadata and first/rest.
+        /// </summary>
+        /// <param name="meta">The metadata to attach</param>
+        /// <param name="first">The first item.</param>
+        /// <param name="rest">The rest of the sequence.</param>
+        StreamSeq(IPersistentMap meta, Object first, ISeq rest)
+            : base(meta)
+        {
+            _first = first;
+            _rest = rest;
+            _stream = null;
+        }
+        
+        /// <summary>
+        /// Construct a <see cref="StreamSeq">StreamSeq</see> from a first item and a stream.
+        /// </summary>
+        /// <param name="first">The first item.</param>
+        /// <param name="stream">The stream of remaining items.</param>
+        StreamSeq(object first, IStream stream)
+        {
+            _first = first;
+            _stream = stream;
+        }
+
+        #endregion
+
+        #region IObj members
+
+
+        /// <summary>
+        /// Create a copy with new metadata.
+        /// </summary>
+        /// <param name="meta">The new metadata.</param>
+        /// <returns>A copy of the object with new metadata attached.</returns>
+        public override IObj withMeta(IPersistentMap meta)
+        {
+            if (meta != _meta)
+            {
+                rest();
+                return new StreamSeq(meta, _first, _rest);
+            }
+            return this;
+        }
+
+        #endregion
+
+        #region ISeq members
+
+        /// <summary>
+        /// Gets the first item.
+        /// </summary>
+        /// <returns>The first item.</returns>
+        public override object first()
+        {
+            return _first;
+        }
+
+        /// <summary>
+        /// Gets the rest of the sequence.
+        /// </summary>
+        /// <returns>The rest of the sequence, or <c>null</c> if no more elements.</returns>
+        public override ISeq rest()
+        {
+            if (_stream != null)
+            {
+                _rest = create(_stream);
+                _stream = null;
+            }
+            return _rest;
+        }
+
+        #endregion
+    }
+}