diff --git a/PorygonSharp/EvalValues/EvalValue.cs b/PorygonSharp/EvalValues/EvalValue.cs
index 1ddeb63..c1ee037 100644
--- a/PorygonSharp/EvalValues/EvalValue.cs
+++ b/PorygonSharp/EvalValues/EvalValue.cs
@@ -64,6 +64,12 @@ namespace PorygonSharp.EvalValues
             var ptr = EvaluateUserDataObj(Handle);
             return GCHandle.FromIntPtr(ptr).Target;
         }
+        
+        private object EvaluateUserdataCollection()
+        {
+            var listHelper = ListEvalValue.Fetch(Handle);
+            return listHelper.List;
+        }
 
         public object GetObjectValue()
         {
@@ -74,7 +80,7 @@ namespace PorygonSharp.EvalValues
                 case TypeClass.Nil:
                     return null;
                 case TypeClass.Number:
-                    if (IsNumericValueFloat(Handle) == 1)
+                    if (IsNumericValueFloat())
                         return EvaluateFloat();
                     else
                         return EvaluateInteger();
@@ -84,6 +90,8 @@ namespace PorygonSharp.EvalValues
                     return EvaluateString();
                 case TypeClass.UserData:
                     return EvaluateGenericObject();
+                case TypeClass.UserdataCollection:
+                    return EvaluateUserdataCollection();
                 case TypeClass.Table:
                     var val = new TableEvalValue(Handle);
                     return val.EvaluateNumericalTable();
@@ -97,6 +105,11 @@ namespace PorygonSharp.EvalValues
             return Handle;
         }
 
+        public bool IsNumericValueFloat()
+        {
+            return IsNumericValueFloat(Handle) == 1;
+        }
+        
         [DllImport("PorygonLang", EntryPoint = "GetEvalValueTypeClass", CallingConvention = CallingConvention.Cdecl)]
         private static extern int GetTypeClass(IntPtr ptr);
         [DllImport("PorygonLang", EntryPoint = "GetEvalValueType", CallingConvention = CallingConvention.Cdecl)]
diff --git a/PorygonSharp/EvalValues/EvalValueCreator.cs b/PorygonSharp/EvalValues/EvalValueCreator.cs
index 488f000..becdfc6 100644
--- a/PorygonSharp/EvalValues/EvalValueCreator.cs
+++ b/PorygonSharp/EvalValues/EvalValueCreator.cs
@@ -64,9 +64,7 @@ namespace PorygonSharp.EvalValues
 
         private static EvalValue CreateListEvalValue(IList collection, Type type)
         {
-            var helper = new ListEvalValue(collection, type);
-            var ptr = CreateCollectionValue(IntPtr.Zero, helper.ParentCollectionPtr, helper.GetterPtr, helper.SetterPtr,
-                helper.GetIteratorPtr, helper.GetLengthPtr);
+            var ptr = ListEvalValue.Create(collection, type);
             return new EvalValue(ptr);
         }
 
@@ -100,7 +98,7 @@ namespace PorygonSharp.EvalValues
         internal static extern IntPtr CreateFunctionEvalValue(IntPtr func, IntPtr parent);
 
         [DllImport("PorygonLang", EntryPoint = "CreateCollectionValue", CallingConvention = CallingConvention.Cdecl)]
-        private static extern IntPtr CreateCollectionValue(IntPtr type, IntPtr parent, IntPtr getter, IntPtr setter,
+        internal static extern IntPtr CreateCollectionValue(IntPtr type, IntPtr parent, IntPtr getter, IntPtr setter,
             IntPtr iterator, IntPtr size);
     }
 }
\ No newline at end of file
diff --git a/PorygonSharp/EvalValues/ListEvalValue.cs b/PorygonSharp/EvalValues/ListEvalValue.cs
index 267d3a8..46414b2 100644
--- a/PorygonSharp/EvalValues/ListEvalValue.cs
+++ b/PorygonSharp/EvalValues/ListEvalValue.cs
@@ -1,12 +1,17 @@
 using System;
 using System.Collections;
+using System.Collections.Concurrent;
 using System.Runtime.InteropServices;
+using PorygonSharp.Utilities;
 
 namespace PorygonSharp.EvalValues
 {
     internal class ListEvalValue
     {
-        private readonly IList _list;
+        private static readonly ConcurrentDictionary<IntPtr, WeakReference<ListEvalValue>> _cache 
+            = new ConcurrentDictionary<IntPtr, WeakReference<ListEvalValue>>();
+        
+        public IList List { get; }
         private readonly Type _valueType;
         
         private delegate IntPtr GetterDelegate(IntPtr parent, IntPtr index);
@@ -28,9 +33,9 @@ namespace PorygonSharp.EvalValues
         public readonly IntPtr GetLengthPtr;
         
         
-        public ListEvalValue(IList list, Type type)
+        private ListEvalValue(IList list, Type type)
         {
-            _list = list;
+            List = list;
             _valueType = type.IsArray ? type.GetElementType() : type.GetGenericArguments()[0];
             if (_valueType == null)
                 throw new ArgumentNullException();
@@ -46,29 +51,51 @@ namespace PorygonSharp.EvalValues
             SetterPtr = Marshal.GetFunctionPointerForDelegate(_setter);
             GetIteratorPtr = Marshal.GetFunctionPointerForDelegate(_getIterator);
             GetLengthPtr = Marshal.GetFunctionPointerForDelegate(_getLength);
+            
+        }
+
+        public static IntPtr Create(IList list, Type type)
+        {
+            var v = new ListEvalValue(list, type);
+            var ptr = EvalValueCreator.CreateCollectionValue(IntPtr.Zero, v.ParentCollectionPtr, v.GetterPtr,
+                v.SetterPtr, v.GetIteratorPtr, v.GetLengthPtr);
+            _cache.TryAdd(ptr, new WeakReference<ListEvalValue>(v));
+            return ptr;
+        }
+
+        internal static ListEvalValue Fetch(IntPtr ptr)
+        {
+            if (_cache.TryGetValue(ptr, out var r))
+            {
+                if (r.TryGetTarget(out var v))
+                {
+                    return v;
+                }
+            }
+            throw new Exception("Can't get list eval value.");
         }
 
         private IntPtr Getter(IntPtr parent, IntPtr index)
         {
             var val = new EvalValue(index).EvaluateInteger();
-            return EvalValueCreator.CreateValue(_list[(int) val - 1]).GetPointer();
+            return EvalValueCreator.CreateValue(List[(int) val - 1]).GetPointer();
         }
         
         private void Setter(IntPtr parent, IntPtr index, IntPtr value)
         {
             var key = new EvalValue(index).EvaluateInteger();
-            var val = new EvalValue(value).GetObjectValue();
-            _list[(int) key - 1] = Convert.ChangeType(val, _valueType);
+            var val = new EvalValue(value);
+            List[(int) key - 1] = Caster.Cast(val, _valueType);
         }
         
         private IntPtr GetIterator(IntPtr parent)
         {
-            return ListIterator.CreateListIterator(_list);
+            return ListIterator.CreateListIterator(List);
         }
 
         private int GetLength(IntPtr parent)
         {
-            return _list.Count;
+            return List.Count;
         }
     }
 }
\ No newline at end of file
diff --git a/PorygonSharp/TypeClass.cs b/PorygonSharp/TypeClass.cs
index c4da3df..4254e14 100644
--- a/PorygonSharp/TypeClass.cs
+++ b/PorygonSharp/TypeClass.cs
@@ -9,6 +9,7 @@ namespace PorygonSharp
         String,
         Function,
         UserData,
+        UserdataCollection,
         Table,
         Any
     }
diff --git a/PorygonSharp/libPorygonLang.so b/PorygonSharp/libPorygonLang.so
index d53d841..028ab9a 100755
Binary files a/PorygonSharp/libPorygonLang.so and b/PorygonSharp/libPorygonLang.so differ