diff --git a/paket-files/gsscoder/CSharpx/src/CSharpx/Either.cs b/paket-files/gsscoder/CSharpx/src/CSharpx/Either.cs
index 5bf424b2..b79f4c27 100644
--- a/paket-files/gsscoder/CSharpx/src/CSharpx/Either.cs
+++ b/paket-files/gsscoder/CSharpx/src/CSharpx/Either.cs
@@ -1,9 +1,9 @@
-//#define CSHARPX_PUBLIC // Comment this to set visibility to internal.
-//#define CSHARPX_EITHER_3 // Comment this to remove Either<T1, T2, T3> and realted functions.
-//#define CSHARPX_EITHER_4 // Comment this to remove Either<T1, T2, T3, T4> and realted functions.
-//#define CSHARPX_EITHER_5 // Comment this to remove Either<T1, T2, T3, T4, T5> and realted functions.
-//#define CSHARPX_EITHER_6 // Comment this to remove Either<T1, T2, T3, T6, T5. T6> and realted functions.
-//#define CSHARPX_EITHER_7 // Comment this to remove Either<T1, T2, T3, T6, T5. T6, T7> and realted functions.
+#define CSHARPX_PUBLIC // Comment this to set visibility to internal.
+#define CSHARPX_EITHER_3 // Comment this to remove Either<T1, T2, T3> and realted functions.
+#define CSHARPX_EITHER_4 // Comment this to remove Either<T1, T2, T3, T4> and realted functions.
+#define CSHARPX_EITHER_5 // Comment this to remove Either<T1, T2, T3, T4, T5> and realted functions.
+#define CSHARPX_EITHER_6 // Comment this to remove Either<T1, T2, T3, T6, T5. T6> and realted functions.
+#define CSHARPX_EITHER_7 // Comment this to remove Either<T1, T2, T3, T6, T5. T6, T7> and realted functions.
 #define CSHARPX_MAYBE_FUNC // Comment this to remove dependency from Maybe.cs.
 
 using System;
diff --git a/paket-files/gsscoder/CSharpx/src/CSharpx/EnumerableExtensions.cs b/paket-files/gsscoder/CSharpx/src/CSharpx/EnumerableExtensions.cs
new file mode 100644
index 00000000..876e428d
--- /dev/null
+++ b/paket-files/gsscoder/CSharpx/src/CSharpx/EnumerableExtensions.cs
@@ -0,0 +1,332 @@
+// Most methods taken from code.google.com/p/morelinq/.
+
+#define CSHARPX_PUBLIC // Comment this to set visibility to internal.
+#define CSHARPX_CARTESIAN // Comment this to remove Cartesian method.
+#define CSHARPX_PREPEND // Comment this to remove Prepend method.
+#define CSHARPX_CONCAT // Comment this to remove Concat methods (depend on Prepend).
+#define CSHARPX_EXCLUDE // Comment this to remove Prepend method.
+#define CSHARPX_INDEX // Comment this to remove Index methods.
+#define CSHARPX_FOLD // Comment this to remove Fold methods (depend on Index).
+#define CSHARPX_FOREACH // Comment this to remove ForEach method.
+#define CSHARPX_PAIRWISE // Comment this to remove Index method.
+#define CSHARPX_TODELIMITEDSTRING // Comment this to remove ToDelimitedString methods.
+
+using System;
+using System.Collections.Generic;
+using System.Diagnostics;
+using System.Globalization;
+using System.Linq;
+using System.Text;
+using LinqEnumerable = System.Linq.Enumerable;
+
+namespace CSharpx
+{
+#if CSHARPX_PUBLIC
+    public
+#endif
+    static partial class EnumerableExtensions
+    {
+        private static IEnumerable<TSource> AssertCountImpl<TSource>(IEnumerable<TSource> source,
+            int count, Func<int, int, Exception> errorSelector)
+        {
+            var collection = source as ICollection<TSource>; // Optimization for collections
+            if (collection != null)
+            {
+                if (collection.Count != count)
+                    throw errorSelector(collection.Count.CompareTo(count), count);
+                return source;
+            }
+
+            return ExpectingCountYieldingImpl(source, count, errorSelector);
+        }
+
+        private static IEnumerable<TSource> ExpectingCountYieldingImpl<TSource>(IEnumerable<TSource> source,
+            int count, Func<int, int, Exception> errorSelector)
+        {
+            var iterations = 0;
+            foreach (var element in source)
+            {
+                iterations++;
+                if (iterations > count)
+                {
+                    throw errorSelector(1, count);
+                }
+                yield return element;
+            }
+            if (iterations != count)
+            {
+                throw errorSelector(-1, count);
+            }
+        }
+
+#if CSHARPX_CARTESIAN
+        /// <summary>
+        /// Returns the Cartesian product of two sequences by combining each element of the first set with each in the second
+        /// and applying the user=define projection to the pair.
+        /// </summary>
+        public static IEnumerable<TResult> Cartesian<TFirst, TSecond, TResult>(this IEnumerable<TFirst> first, IEnumerable<TSecond> second, Func<TFirst, TSecond, TResult> resultSelector)
+        {
+            if (first == null) throw new ArgumentNullException("first");
+            if (second == null) throw new ArgumentNullException("second");
+            if (resultSelector == null) throw new ArgumentNullException("resultSelector");
+
+            return from item1 in first
+                   from item2 in second // TODO buffer to avoid multiple enumerations
+                   select resultSelector(item1, item2);
+        }
+#endif
+
+#if CSHARPX_PREPEND
+        /// <summary>
+        /// Prepends a single value to a sequence.
+        /// </summary>
+        public static IEnumerable<TSource> Prepend<TSource>(this IEnumerable<TSource> source, TSource value)
+        {
+            if (source == null) throw new ArgumentNullException("source");
+            return LinqEnumerable.Concat(LinqEnumerable.Repeat(value, 1), source);
+        }
+#endif
+
+#if CSHARPX_CONCAT
+        /// <summary>
+        /// Returns a sequence consisting of the head element and the given tail elements.
+        /// </summary>
+        public static IEnumerable<T> Concat<T>(this T head, IEnumerable<T> tail)
+        {
+            if (tail == null) throw new ArgumentNullException("tail");
+            return tail.Prepend(head);
+        }
+
+        /// <summary>
+        /// Returns a sequence consisting of the head elements and the given tail element.
+        /// </summary>
+        public static IEnumerable<T> Concat<T>(this IEnumerable<T> head, T tail)
+        {
+            if (head == null) throw new ArgumentNullException("head");
+            return LinqEnumerable.Concat(head, LinqEnumerable.Repeat(tail, 1));
+        }
+#endif
+
+#if CSHARPX_EXCLUDE
+        /// <summary>
+        /// Excludes <paramref name="count"/> elements from a sequence starting at a given index
+        /// </summary>
+        /// <typeparam name="T">The type of the elements of the sequence</typeparam>
+        public static IEnumerable<T> Exclude<T>(this IEnumerable<T> sequence, int startIndex, int count)
+        {
+            if (sequence == null) throw new ArgumentNullException("sequence");
+            if (startIndex < 0) throw new ArgumentOutOfRangeException("startIndex");
+            if (count < 0) throw new ArgumentOutOfRangeException("count");
+
+            return ExcludeImpl(sequence, startIndex, count);
+        }
+
+        private static IEnumerable<T> ExcludeImpl<T>(IEnumerable<T> sequence, int startIndex, int count)
+        {
+            var index = -1;
+            var endIndex = startIndex + count;
+            using (var iter = sequence.GetEnumerator())
+            {
+                // yield the first part of the sequence
+                while (iter.MoveNext() && ++index < startIndex)
+                    yield return iter.Current;
+                // skip the next part (up to count items)
+                while (++index < endIndex && iter.MoveNext())
+                    continue;
+                // yield the remainder of the sequence
+                while (iter.MoveNext())
+                    yield return iter.Current;
+            }
+        }
+#endif
+
+#if CSHARPX_INDEX
+        /// <summary>
+        /// Returns a sequence of <see cref="KeyValuePair{TKey,TValue}"/> 
+        /// where the key is the zero-based index of the value in the source 
+        /// sequence.
+        /// </summary>
+        public static IEnumerable<KeyValuePair<int, TSource>> Index<TSource>(this IEnumerable<TSource> source)
+        {
+            return source.Index(0);
+        }
+
+        /// <summary>
+        /// Returns a sequence of <see cref="KeyValuePair{TKey,TValue}"/> 
+        /// where the key is the index of the value in the source sequence.
+        /// An additional parameter specifies the starting index.
+        /// </summary>
+        public static IEnumerable<KeyValuePair<int, TSource>> Index<TSource>(this IEnumerable<TSource> source, int startIndex)
+        {
+            return source.Select((item, index) => new KeyValuePair<int, TSource>(startIndex + index, item));
+        }
+#endif
+
+#if CSHARPX_FOLD
+        /// <summary>
+        /// Returns the result of applying a function to a sequence of 
+        /// 1 element.
+        /// </summary>
+        public static TResult Fold<T, TResult>(this IEnumerable<T> source, Func<T, TResult> folder)
+        {
+            return FoldImpl(source, 1, folder, null, null, null);
+        }
+
+        /// <summary>
+        /// Returns the result of applying a function to a sequence of 
+        /// 2 elements.
+        /// </summary>
+        public static TResult Fold<T, TResult>(this IEnumerable<T> source, Func<T, T, TResult> folder)
+        {
+            return FoldImpl(source, 2, null, folder, null, null);
+        }
+
+        /// <summary>
+        /// Returns the result of applying a function to a sequence of 
+        /// 3 elements.
+        /// </summary>
+        public static TResult Fold<T, TResult>(this IEnumerable<T> source, Func<T, T, T, TResult> folder)
+        {
+            return FoldImpl(source, 3, null, null, folder, null);
+        }
+
+        /// <summary>
+        /// Returns the result of applying a function to a sequence of 
+        /// 4 elements.
+        /// </summary>
+        public static TResult Fold<T, TResult>(this IEnumerable<T> source, Func<T, T, T, T, TResult> folder)
+        {
+            return FoldImpl(source, 4, null, null, null, folder);
+        }
+
+        static TResult FoldImpl<T, TResult>(IEnumerable<T> source, int count,
+            Func<T, TResult> folder1,
+            Func<T, T, TResult> folder2,
+            Func<T, T, T, TResult> folder3,
+            Func<T, T, T, T, TResult> folder4)
+        {
+            if (source == null) throw new ArgumentNullException("source");
+            if (count == 1 && folder1 == null
+                || count == 2 && folder2 == null
+                || count == 3 && folder3 == null
+                || count == 4 && folder4 == null)
+            {                                                // ReSharper disable NotResolvedInText
+                throw new ArgumentNullException("folder");   // ReSharper restore NotResolvedInText
+            }
+
+            var elements = new T[count];
+            foreach (var e in AssertCountImpl(source.Index(), count, OnFolderSourceSizeErrorSelector))
+                elements[e.Key] = e.Value;
+
+            switch (count)
+            {
+                case 1: return folder1(elements[0]);
+                case 2: return folder2(elements[0], elements[1]);
+                case 3: return folder3(elements[0], elements[1], elements[2]);
+                case 4: return folder4(elements[0], elements[1], elements[2], elements[3]);
+                default: throw new NotSupportedException();
+            }
+        }
+
+        static readonly Func<int, int, Exception> OnFolderSourceSizeErrorSelector = OnFolderSourceSizeError;
+
+        static Exception OnFolderSourceSizeError(int cmp, int count)
+        {
+            var message = cmp < 0
+                        ? "Sequence contains too few elements when exactly {0} {1} expected."
+                        : "Sequence contains too many elements when exactly {0} {1} expected.";
+            return new Exception(string.Format(message, count.ToString("N0"), count == 1 ? "was" : "were"));
+        }
+#endif
+
+#if CSHARPX_FOREACH
+        /// <summary>
+        /// Immediately executes the given action on each element in the source sequence.
+        /// </summary>
+        /// <typeparam name="T">The type of the elements in the sequence</typeparam>
+        public static void ForEach<T>(this IEnumerable<T> source, Action<T> action)
+        {
+            if (source == null) throw new ArgumentNullException("source");
+            if (action == null) throw new ArgumentNullException("action");
+
+            foreach (var element in source)
+            {
+                action(element);
+            }
+        }
+#endif
+
+#if CSHARPX_PAIRWISE
+        /// <summary>
+        /// Returns a sequence resulting from applying a function to each 
+        /// element in the source sequence and its 
+        /// predecessor, with the exception of the first element which is 
+        /// only returned as the predecessor of the second element.
+        /// </summary>
+        public static IEnumerable<TResult> Pairwise<TSource, TResult>(this IEnumerable<TSource> source, Func<TSource, TSource, TResult> resultSelector)
+        {
+            if (source == null) throw new ArgumentNullException("source");
+            if (resultSelector == null) throw new ArgumentNullException("resultSelector");
+            return PairwiseImpl(source, resultSelector);
+        }
+
+        private static IEnumerable<TResult> PairwiseImpl<TSource, TResult>(this IEnumerable<TSource> source, Func<TSource, TSource, TResult> resultSelector)
+        {
+            Debug.Assert(source != null);
+            Debug.Assert(resultSelector != null);
+
+            using (var e = source.GetEnumerator())
+            {
+                if (!e.MoveNext())
+                    yield break;
+
+                var previous = e.Current;
+                while (e.MoveNext())
+                {
+                    yield return resultSelector(previous, e.Current);
+                    previous = e.Current;
+                }
+            }
+        }
+#endif
+
+#if CSHARPX_TODELIMITEDSTRING
+        /// <summary>
+        /// Creates a delimited string from a sequence of values. The 
+        /// delimiter used depends on the current culture of the executing thread.
+        /// </summary>
+        public static string ToDelimitedString<TSource>(this IEnumerable<TSource> source)
+        {
+            return ToDelimitedString(source, null);
+        }
+
+        /// <summary>
+        /// Creates a delimited string from a sequence of values and
+        /// a given delimiter.
+        /// </summary>
+        public static string ToDelimitedString<TSource>(this IEnumerable<TSource> source, string delimiter)
+        {
+            if (source == null) throw new ArgumentNullException("source");
+            return ToDelimitedStringImpl(source, delimiter, (sb, e) => sb.Append(e));
+        }
+
+        static string ToDelimitedStringImpl<T>(IEnumerable<T> source, string delimiter, Func<StringBuilder, T, StringBuilder> append)
+        {
+            Debug.Assert(source != null);
+            Debug.Assert(append != null);
+
+            delimiter = delimiter ?? CultureInfo.CurrentCulture.TextInfo.ListSeparator;
+            var sb = new StringBuilder();
+            var i = 0;
+
+            foreach (var value in source)
+            {
+                if (i++ > 0) sb.Append(delimiter);
+                append(sb, value);
+            }
+
+            return sb.ToString();
+        }
+#endif
+    }
+}
diff --git a/paket-files/gsscoder/CSharpx/src/CSharpx/Maybe.cs b/paket-files/gsscoder/CSharpx/src/CSharpx/Maybe.cs
index 46f74b5e..f19e2da7 100644
--- a/paket-files/gsscoder/CSharpx/src/CSharpx/Maybe.cs
+++ b/paket-files/gsscoder/CSharpx/src/CSharpx/Maybe.cs
@@ -1,4 +1,4 @@
-//#define CSHARPX_PUBLIC // Comment this to set visibility to internal.
+#define CSHARPX_PUBLIC // Comment this to set visibility to internal.
 #define CSHARPX_EITHER_FUNC // Comment this to remove dependency from Either.cs.
 
 using System;
diff --git a/paket-files/gsscoder/CSharpx/src/CSharpx/paket.version b/paket-files/gsscoder/CSharpx/src/CSharpx/paket.version
index b0cca172..cc16163f 100644
--- a/paket-files/gsscoder/CSharpx/src/CSharpx/paket.version
+++ b/paket-files/gsscoder/CSharpx/src/CSharpx/paket.version
@@ -1 +1 @@
-d2ecc2810fe4e29b62934e51242f98f1e47f3a79
+5c88658b2553e59b3aa989660dc1e36c48673af5
diff --git a/paket.dependencies b/paket.dependencies
index f6479c2f..ed9a1996 100644
--- a/paket.dependencies
+++ b/paket.dependencies
@@ -7,3 +7,4 @@ nuget xunit.runner.visualstudio
 
 github gsscoder/CSharpx src/CSharpx/Maybe.cs
 github gsscoder/CSharpx src/CSharpx/Either.cs
+github gsscoder/CSharpx src/CSharpx/EnumerableExtensions.cs
diff --git a/paket.lock b/paket.lock
index b69383df..4138ce3b 100644
--- a/paket.lock
+++ b/paket.lock
@@ -16,5 +16,6 @@ NUGET
 GITHUB
   remote: gsscoder/CSharpx
   specs:
-    src/CSharpx/Either.cs (d2ecc2810fe4e29b62934e51242f98f1e47f3a79)
-    src/CSharpx/Maybe.cs (d2ecc2810fe4e29b62934e51242f98f1e47f3a79)
\ No newline at end of file
+    src/CSharpx/Either.cs (5c88658b2553e59b3aa989660dc1e36c48673af5)
+    src/CSharpx/EnumerableExtensions.cs (5c88658b2553e59b3aa989660dc1e36c48673af5)
+    src/CSharpx/Maybe.cs (5c88658b2553e59b3aa989660dc1e36c48673af5)
\ No newline at end of file
diff --git a/src/CommandLine/CommandLine.csproj b/src/CommandLine/CommandLine.csproj
index 6f6df341..3aedeceb 100644
--- a/src/CommandLine/CommandLine.csproj
+++ b/src/CommandLine/CommandLine.csproj
@@ -42,6 +42,10 @@
     <AssemblyOriginatorKeyFile>..\..\CommandLine.snk</AssemblyOriginatorKeyFile>
   </PropertyGroup>
   <ItemGroup>
+    <Compile Include="..\..\paket-files\gsscoder\CSharpx\src\CSharpx\EnumerableExtensions.cs">
+      <Paket>True</Paket>
+      <Link>Infrastructure/EnumerableExtensions.cs</Link>
+    </Compile>
     <Compile Include="..\..\paket-files\gsscoder\CSharpx\src\CSharpx\Either.cs">
       <Paket>True</Paket>
       <Link>Infrastructure/Either.cs</Link>
@@ -76,7 +80,7 @@
     <Compile Include="Core\StatePair.cs" />
     <Compile Include="Core\Switch.cs" />
     <Compile Include="Core\TokenPartitions.cs" />
-    <Compile Include="Infrastructure\EnumerableExtensions.cs" />
+    <Compile Include="Infrastructure\EnumerableExtensionsExtra.cs" />
     <Compile Include="Core\InstanceChooser.cs" />
     <Compile Include="Core\Tokenizer.cs">
       <SubType>Code</SubType>
diff --git a/src/CommandLine/paket.references b/src/CommandLine/paket.references
index 3f2e183a..0b555821 100644
--- a/src/CommandLine/paket.references
+++ b/src/CommandLine/paket.references
@@ -1,3 +1,4 @@
 File:Maybe.cs Infrastructure
 File:Either.cs Infrastructure
+File:EnumerableExtensions.cs Infrastructure
 FSharp.Core