diff --git a/LINQ/LINQ/Interpreter/Executable.vb b/LINQ/LINQ/Interpreter/Executable.vb
deleted file mode 100644
index b2adbb7..0000000
--- a/LINQ/LINQ/Interpreter/Executable.vb
+++ /dev/null
@@ -1,6 +0,0 @@
-Namespace Interpreter
-
-    Public Class Executable
-
-    End Class
-End Namespace
\ No newline at end of file
diff --git a/LINQ/LINQ/Interpreter/ExecutableContext.vb b/LINQ/LINQ/Interpreter/ExecutableContext.vb
new file mode 100644
index 0000000..5b6aa67
--- /dev/null
+++ b/LINQ/LINQ/Interpreter/ExecutableContext.vb
@@ -0,0 +1,11 @@
+Imports LINQ.Runtime
+
+Namespace Interpreter
+
+    Public Class ExecutableContext
+
+        Public Property env As Environment
+        Public Property throwError As Boolean = True
+
+    End Class
+End Namespace
\ No newline at end of file
diff --git a/LINQ/LINQ/Interpreter/Expressions/ArrayExpression.vb b/LINQ/LINQ/Interpreter/Expressions/ArrayExpression.vb
index 17b09e3..6b5b463 100644
--- a/LINQ/LINQ/Interpreter/Expressions/ArrayExpression.vb
+++ b/LINQ/LINQ/Interpreter/Expressions/ArrayExpression.vb
@@ -10,11 +10,11 @@ Namespace Interpreter.Expressions
             Me.seq = seq.ToArray
         End Sub
 
-        Public Overrides Function Exec(env As Environment) As Object
+        Public Overrides Function Exec(context As ExecutableContext) As Object
             Dim list As New List(Of Object)
 
             For Each item In seq
-                list.Add(item.Exec(env))
+                list.Add(item.Exec(context))
             Next
 
             Return list.ToArray
diff --git a/LINQ/LINQ/Interpreter/Expressions/BinaryExpression.vb b/LINQ/LINQ/Interpreter/Expressions/BinaryExpression.vb
index 46efb93..dcec6f3 100644
--- a/LINQ/LINQ/Interpreter/Expressions/BinaryExpression.vb
+++ b/LINQ/LINQ/Interpreter/Expressions/BinaryExpression.vb
@@ -23,9 +23,9 @@ Namespace Interpreter.Expressions
             Me.op = op
         End Sub
 
-        Public Overrides Function Exec(env As Environment) As Object
-            Dim x As Object = left.Exec(env)
-            Dim y As Object = right.Exec(env)
+        Public Overrides Function Exec(context As ExecutableContext) As Object
+            Dim x As Object = left.Exec(context)
+            Dim y As Object = right.Exec(context)
 
             Select Case op
                 Case "+" : Return x + y
diff --git a/LINQ/LINQ/Interpreter/Expressions/Expression.vb b/LINQ/LINQ/Interpreter/Expressions/Expression.vb
index c396026..d2f4148 100644
--- a/LINQ/LINQ/Interpreter/Expressions/Expression.vb
+++ b/LINQ/LINQ/Interpreter/Expressions/Expression.vb
@@ -6,11 +6,11 @@ Namespace Interpreter.Expressions
 
         Public ReadOnly Property name As String
             Get
-                Return MyClass.GetType.Name
+                Return MyClass.GetType.Name.ToLower
             End Get
         End Property
 
-        Public MustOverride Function Exec(env As Environment) As Object
+        Public MustOverride Function Exec(context As ExecutableContext) As Object
 
     End Class
 End Namespace
\ No newline at end of file
diff --git a/LINQ/LINQ/Interpreter/Expressions/FuncEval.vb b/LINQ/LINQ/Interpreter/Expressions/FuncEval.vb
index 63078ae..6c036ca 100644
--- a/LINQ/LINQ/Interpreter/Expressions/FuncEval.vb
+++ b/LINQ/LINQ/Interpreter/Expressions/FuncEval.vb
@@ -7,15 +7,20 @@ Namespace Interpreter.Expressions
         Public Property func As Expression
         Public Property parameters As Expression()
 
-        Public Overrides Function Exec(env As Environment) As Object
-            Dim invoke As Object = func.Exec(env)
+        Sub New(func As Expression, parameters As IEnumerable(Of Expression))
+            Me.func = func
+            Me.parameters = parameters.ToArray
+        End Sub
+
+        Public Overrides Function Exec(context As ExecutableContext) As Object
+            Dim invoke As Object = func.Exec(New ExecutableContext With {.env = context.env, .throwError = False})
 
             If invoke Is Nothing Then
                 Throw New NullReferenceException
             ElseIf TypeOf invoke Is String Then
-                invoke = env.FindInvoke(invoke)
+                invoke = context.env.FindInvoke(invoke)
             ElseIf TypeOf invoke Is SymbolReference Then
-                invoke = env.FindInvoke(DirectCast(invoke, SymbolReference).symbolName)
+                invoke = context.env.FindInvoke(DirectCast(invoke, SymbolReference).symbolName)
             Else
                 Throw New NotImplementedException
             End If
@@ -23,12 +28,16 @@ Namespace Interpreter.Expressions
             Dim args As New List(Of Object)
 
             For Each item In parameters
-                args.Add(item.Exec(env))
+                args.Add(item.Exec(context))
             Next
 
             Dim result As Object = invoke(args.ToArray)
 
             Return result
         End Function
+
+        Public Overrides Function ToString() As String
+            Return $"{func}({parameters.JoinBy(", ")})"
+        End Function
     End Class
 End Namespace
\ No newline at end of file
diff --git a/LINQ/LINQ/Interpreter/Expressions/Keywords/Options/OrderBy.vb b/LINQ/LINQ/Interpreter/Expressions/Keywords/Options/OrderBy.vb
index 1b222e9..620efe8 100644
--- a/LINQ/LINQ/Interpreter/Expressions/Keywords/Options/OrderBy.vb
+++ b/LINQ/LINQ/Interpreter/Expressions/Keywords/Options/OrderBy.vb
@@ -18,19 +18,21 @@ Namespace Interpreter.Expressions
             Me.key = FixLiteral(key)
         End Sub
 
-        Public Overrides Function Exec(env As Environment) As Object
-            Return key.Exec(env)
+        Public Overrides Function Exec(context As ExecutableContext) As Object
+            Return key.Exec(context)
         End Function
 
-        Private Function GetOrderKey(obj As JavaScriptObject, env As Environment) As Object
+        Private Function GetOrderKey(obj As JavaScriptObject, context As ExecutableContext) As Object
+            Dim env As Environment = context.env
+
             For Each key As String In obj
                 env.FindSymbol(key).value = obj(key)
             Next
 
-            Return Exec(env)
+            Return Exec(context)
         End Function
 
-        Public Overrides Function Exec(result As IEnumerable(Of JavaScriptObject), env As Environment) As IEnumerable(Of JavaScriptObject)
+        Public Overrides Function Exec(result As IEnumerable(Of JavaScriptObject), context As ExecutableContext) As IEnumerable(Of JavaScriptObject)
             Dim raw As JavaScriptObject() = result.ToArray
             Dim keys As Object()
             Dim i As Integer()
@@ -42,7 +44,7 @@ Namespace Interpreter.Expressions
             Else
                 keys = raw _
                     .Select(Function(obj)
-                                Return GetOrderKey(obj, env)
+                                Return GetOrderKey(obj, context)
                             End Function) _
                     .ToArray
             End If
diff --git a/LINQ/LINQ/Interpreter/Expressions/Keywords/Options/PipelineKeyword.vb b/LINQ/LINQ/Interpreter/Expressions/Keywords/Options/PipelineKeyword.vb
index eb2929e..b854cf0 100644
--- a/LINQ/LINQ/Interpreter/Expressions/Keywords/Options/PipelineKeyword.vb
+++ b/LINQ/LINQ/Interpreter/Expressions/Keywords/Options/PipelineKeyword.vb
@@ -5,7 +5,7 @@ Namespace Interpreter.Expressions
 
     Public MustInherit Class PipelineKeyword : Inherits KeywordExpression
 
-        Public MustOverride Overloads Function Exec(result As IEnumerable(Of JavaScriptObject), env As Environment) As IEnumerable(Of JavaScriptObject)
+        Public MustOverride Overloads Function Exec(result As IEnumerable(Of JavaScriptObject), context As ExecutableContext) As IEnumerable(Of JavaScriptObject)
 
         ''' <summary>
         ''' 将字符串常量表示转换为变量引用
diff --git a/LINQ/LINQ/Interpreter/Expressions/Keywords/Options/TakeItems.vb b/LINQ/LINQ/Interpreter/Expressions/Keywords/Options/TakeItems.vb
index d0c882e..c21784b 100644
--- a/LINQ/LINQ/Interpreter/Expressions/Keywords/Options/TakeItems.vb
+++ b/LINQ/LINQ/Interpreter/Expressions/Keywords/Options/TakeItems.vb
@@ -18,12 +18,12 @@ Namespace Interpreter.Expressions
             Me.n = n
         End Sub
 
-        Public Overrides Function Exec(result As IEnumerable(Of JavaScriptObject), env As Environment) As IEnumerable(Of JavaScriptObject)
-            Return result.Take(count:=CInt(Exec(env)))
+        Public Overrides Function Exec(result As IEnumerable(Of JavaScriptObject), context As ExecutableContext) As IEnumerable(Of JavaScriptObject)
+            Return result.Take(count:=CInt(Exec(context)))
         End Function
 
-        Public Overrides Function Exec(env As Environment) As Object
-            Return n.Exec(env)
+        Public Overrides Function Exec(context As ExecutableContext) As Object
+            Return n.Exec(context)
         End Function
     End Class
 End Namespace
\ No newline at end of file
diff --git a/LINQ/LINQ/Interpreter/Expressions/Keywords/OutputProjection.vb b/LINQ/LINQ/Interpreter/Expressions/Keywords/OutputProjection.vb
index 4891012..0cce916 100644
--- a/LINQ/LINQ/Interpreter/Expressions/Keywords/OutputProjection.vb
+++ b/LINQ/LINQ/Interpreter/Expressions/Keywords/OutputProjection.vb
@@ -18,11 +18,11 @@ Namespace Interpreter.Expressions
             Me.fields = fields.ToArray
         End Sub
 
-        Public Overrides Function Exec(env As Environment) As Object
+        Public Overrides Function Exec(context As ExecutableContext) As Object
             Dim obj As New JavaScriptObject
 
             For Each field In fields
-                obj(field.Name) = field.Value.Exec(env)
+                obj(field.Name) = field.Value.Exec(context)
             Next
 
             Return obj
diff --git a/LINQ/LINQ/Interpreter/Expressions/Keywords/SymbolDeclare.vb b/LINQ/LINQ/Interpreter/Expressions/Keywords/SymbolDeclare.vb
index 7c8a9d3..cb58bae 100644
--- a/LINQ/LINQ/Interpreter/Expressions/Keywords/SymbolDeclare.vb
+++ b/LINQ/LINQ/Interpreter/Expressions/Keywords/SymbolDeclare.vb
@@ -13,7 +13,7 @@ Namespace Interpreter.Expressions
             End Get
         End Property
 
-        Public Overrides Function Exec(env As Environment) As Object
+        Public Overrides Function Exec(context As ExecutableContext) As Object
             Throw New NotImplementedException()
         End Function
 
diff --git a/LINQ/LINQ/Interpreter/Expressions/Keywords/WhereFilter.vb b/LINQ/LINQ/Interpreter/Expressions/Keywords/WhereFilter.vb
index 3f895f4..f132411 100644
--- a/LINQ/LINQ/Interpreter/Expressions/Keywords/WhereFilter.vb
+++ b/LINQ/LINQ/Interpreter/Expressions/Keywords/WhereFilter.vb
@@ -16,8 +16,8 @@ Namespace Interpreter.Expressions
             Me.filter = filter
         End Sub
 
-        Public Overrides Function Exec(env As Environment) As Object
-            Return filter.Exec(env)
+        Public Overrides Function Exec(context As ExecutableContext) As Object
+            Return filter.Exec(context)
         End Function
 
         Public Overrides Function ToString() As String
diff --git a/LINQ/LINQ/Interpreter/Expressions/Literals.vb b/LINQ/LINQ/Interpreter/Expressions/Literals.vb
index 2bd8a30..55b54f0 100644
--- a/LINQ/LINQ/Interpreter/Expressions/Literals.vb
+++ b/LINQ/LINQ/Interpreter/Expressions/Literals.vb
@@ -30,7 +30,7 @@ Namespace Interpreter.Expressions
             End Select
         End Sub
 
-        Public Overrides Function Exec(env As Environment) As Object
+        Public Overrides Function Exec(context As ExecutableContext) As Object
             Return value
         End Function
 
diff --git a/LINQ/LINQ/Interpreter/Expressions/MemberReference.vb b/LINQ/LINQ/Interpreter/Expressions/MemberReference.vb
index 857447f..a11161d 100644
--- a/LINQ/LINQ/Interpreter/Expressions/MemberReference.vb
+++ b/LINQ/LINQ/Interpreter/Expressions/MemberReference.vb
@@ -21,8 +21,8 @@ Namespace Interpreter.Expressions
             End If
         End Sub
 
-        Public Overrides Function Exec(env As Environment) As Object
-            Dim symbol As Object = Me.symbol.Exec(env)
+        Public Overrides Function Exec(context As ExecutableContext) As Object
+            Dim symbol As Object = Me.symbol.Exec(context)
 
             If symbol Is Nothing Then
                 Throw New NullReferenceException
diff --git a/LINQ/LINQ/Interpreter/Expressions/SymbolReference.vb b/LINQ/LINQ/Interpreter/Expressions/SymbolReference.vb
index e7943be..6e516d5 100644
--- a/LINQ/LINQ/Interpreter/Expressions/SymbolReference.vb
+++ b/LINQ/LINQ/Interpreter/Expressions/SymbolReference.vb
@@ -10,11 +10,15 @@ Namespace Interpreter.Expressions
             Me.symbolName = name
         End Sub
 
-        Public Overrides Function Exec(env As Environment) As Object
-            Dim symbol As Symbol = env.FindSymbol(symbolName)
+        Public Overrides Function Exec(context As ExecutableContext) As Object
+            Dim symbol As Symbol = context.env.FindSymbol(symbolName)
 
             If symbol Is Nothing Then
-                Throw New MissingPrimaryKeyException(symbolName)
+                If context.throwError Then
+                    Throw New MissingPrimaryKeyException(symbolName)
+                Else
+                    Return Nothing
+                End If
             Else
                 Return symbol.value
             End If
diff --git a/LINQ/LINQ/Interpreter/Query/AggregateExpression.vb b/LINQ/LINQ/Interpreter/Query/AggregateExpression.vb
index 41db12e..0b8dcd9 100644
--- a/LINQ/LINQ/Interpreter/Query/AggregateExpression.vb
+++ b/LINQ/LINQ/Interpreter/Query/AggregateExpression.vb
@@ -12,7 +12,7 @@ Namespace Interpreter.Query
             Call MyBase.New(symbol, sequence, exec)
         End Sub
 
-        Public Overrides Function Exec(env As Environment) As Object
+        Public Overrides Function Exec(context As ExecutableContext) As Object
             Throw New NotImplementedException()
         End Function
     End Class
diff --git a/LINQ/LINQ/Interpreter/Query/DataSoruce.vb b/LINQ/LINQ/Interpreter/Query/DataSoruce.vb
index 14a1598..9796ba3 100644
--- a/LINQ/LINQ/Interpreter/Query/DataSoruce.vb
+++ b/LINQ/LINQ/Interpreter/Query/DataSoruce.vb
@@ -16,11 +16,13 @@ Namespace Interpreter.Query
 
         Public MustOverride Function PopulatesData() As IEnumerable(Of Object)
 
-        Public Shared Function CreateDataSet(query As QueryExpression, env As Environment) As DataSet
+        Public Shared Function CreateDataSet(query As QueryExpression, context As ExecutableContext) As DataSet
+            Dim env As Environment = context.env
+
             If query.IsURISource Then
                 Return New URIIteratorDriver(query, query.GetSeqValue(Nothing), env)
             Else
-                Dim seqVal As Object = query.GetSeqValue(env)
+                Dim seqVal As Object = query.GetSeqValue(context)
 
                 If TypeOf seqVal Is String Then
                     Return New URIIteratorDriver(query, seqVal, env)
diff --git a/LINQ/LINQ/Interpreter/Query/ProjectionExpression.vb b/LINQ/LINQ/Interpreter/Query/ProjectionExpression.vb
index e672300..025e1ce 100644
--- a/LINQ/LINQ/Interpreter/Query/ProjectionExpression.vb
+++ b/LINQ/LINQ/Interpreter/Query/ProjectionExpression.vb
@@ -15,9 +15,10 @@ Namespace Interpreter.Query
                 .ToArray
         End Sub
 
-        Public Function RunOptionPipeline(output As IEnumerable(Of JavaScriptObject), env As Environment) As IEnumerable(Of JavaScriptObject)
+        Public Function RunOptionPipeline(output As IEnumerable(Of JavaScriptObject), context As ExecutableContext) As IEnumerable(Of JavaScriptObject)
             Dim raw As JavaScriptObject() = output.ToArray
             Dim allNames As String() = raw(Scan0).GetNames
+            Dim env As Environment = context.env
 
             For Each name As String In allNames
                 If Not env.HasSymbol(name) Then
@@ -26,7 +27,7 @@ Namespace Interpreter.Query
             Next
 
             For Each line As PipelineKeyword In pipeline
-                raw = line.Exec(raw, env).ToArray
+                raw = line.Exec(raw, context).ToArray
             Next
 
             Return raw
@@ -52,20 +53,24 @@ Namespace Interpreter.Query
         ''' <summary>
         ''' 
         ''' </summary>
-        ''' <param name="env"></param>
+        ''' <param name="context"></param>
         ''' <returns>
         ''' array of <see cref="JavaScriptObject"/>
         ''' </returns>
-        Public Overrides Function Exec(env As Environment) As Object
+        Public Overrides Function Exec(context As ExecutableContext) As Object
             Dim projections As New List(Of JavaScriptObject)
-            Dim closure As New Environment(parent:=env)
+            Dim env As Environment = context.env
+            Dim closure As New ExecutableContext With {
+                .env = New Environment(parent:=env),
+                .throwError = context.throwError
+            }
             Dim skipVal As Boolean
-            Dim dataset As DataSet = GetDataSet(env)
+            Dim dataset As DataSet = GetDataSet(context)
 
-            Call closure.AddSymbol(symbol.symbolName, symbol.type)
+            Call closure.env.AddSymbol(symbol.symbolName, symbol.type)
 
             For Each item As Object In dataset.PopulatesData()
-                closure.FindSymbol(symbol.symbolName).value = item
+                closure.env.FindSymbol(symbol.symbolName).value = item
 
                 For Each line As Expression In executeQueue
                     If TypeOf line Is WhereFilter Then
@@ -82,7 +87,7 @@ Namespace Interpreter.Query
                 End If
             Next
 
-            Return opt.RunOptionPipeline(projections, env).ToArray
+            Return opt.RunOptionPipeline(projections, context).ToArray
         End Function
     End Class
 End Namespace
\ No newline at end of file
diff --git a/LINQ/LINQ/Interpreter/Query/Query.vb b/LINQ/LINQ/Interpreter/Query/Query.vb
index 3fac0d4..456ad91 100644
--- a/LINQ/LINQ/Interpreter/Query/Query.vb
+++ b/LINQ/LINQ/Interpreter/Query/Query.vb
@@ -22,12 +22,12 @@ Namespace Interpreter.Query
             Me.executeQueue = execQueue.ToArray
         End Sub
 
-        Public Function GetSeqValue(env As Environment) As Object
-            Return sequence.Exec(env)
+        Public Function GetSeqValue(context As ExecutableContext) As Object
+            Return sequence.Exec(context)
         End Function
 
-        Protected Function GetDataSet(env As Environment) As DataSet
-            Return DataSet.CreateDataSet(Me, env)
+        Protected Function GetDataSet(context As ExecutableContext) As DataSet
+            Return DataSet.CreateDataSet(Me, context)
         End Function
     End Class
 End Namespace
\ No newline at end of file
diff --git a/LINQ/LINQ/LINQ.vbproj b/LINQ/LINQ/LINQ.vbproj
index 32889ca..b68a562 100644
--- a/LINQ/LINQ/LINQ.vbproj
+++ b/LINQ/LINQ/LINQ.vbproj
@@ -155,7 +155,7 @@
     <Import Include="System.Threading.Tasks" />
   </ItemGroup>
   <ItemGroup>
-    <Compile Include="Interpreter\Executable.vb" />
+    <Compile Include="Interpreter\ExecutableContext.vb" />
     <Compile Include="Interpreter\Expressions\BinaryExpression.vb" />
     <Compile Include="Interpreter\Expressions\ArrayExpression.vb" />
     <Compile Include="Interpreter\Expressions\FuncEval.vb" />
diff --git a/LINQ/LINQ/Program.vb b/LINQ/LINQ/Program.vb
index 5cfdcb4..6dca65b 100644
--- a/LINQ/LINQ/Program.vb
+++ b/LINQ/LINQ/Program.vb
@@ -1,4 +1,5 @@
-Imports LINQ.Interpreter.Query
+Imports LINQ.Interpreter
+Imports LINQ.Interpreter.Query
 Imports LINQ.Runtime
 Imports LINQ.Script
 Imports Microsoft.VisualBasic.ApplicationServices.Terminal
@@ -16,7 +17,7 @@ Module Program
         Dim tokens = LINQ.Language.GetTokens(file.ReadAllText).ToArray
         Dim query As ProjectionExpression = tokens.PopulateQueryExpression
         Dim env As New GlobalEnvironment(New Registry)
-        Dim result As JavaScriptObject() = query.Exec(env)
+        Dim result As JavaScriptObject() = query.Exec(New ExecutableContext With {.env = env, .throwError = True})
         Dim table As DataFrame = result.CreateTableDataSet
         Dim text As String()() = table _
             .csv _
diff --git a/LINQ/LINQ/Runtime/Environment.vb b/LINQ/LINQ/Runtime/Environment.vb
index 52e7f35..b9ce6d0 100644
--- a/LINQ/LINQ/Runtime/Environment.vb
+++ b/LINQ/LINQ/Runtime/Environment.vb
@@ -58,7 +58,7 @@ Namespace Runtime
             ElseIf Not parent Is Nothing Then
                 Return parent.FindSymbol(name)
             Else
-                Throw New MissingPrimaryKeyException(name)
+                Return Nothing
             End If
         End Function
 
diff --git a/LINQ/LINQ/Runtime/Math.vb b/LINQ/LINQ/Runtime/Math.vb
index 92d1b32..0bb7d5f 100644
--- a/LINQ/LINQ/Runtime/Math.vb
+++ b/LINQ/LINQ/Runtime/Math.vb
@@ -7,6 +7,7 @@ Namespace Runtime
         Public Shared ReadOnly abs As New Callable(AddressOf stdnum.Abs)
         Public Shared ReadOnly min As New Callable(AddressOf stdnum.Min)
         Public Shared ReadOnly max As New Callable(AddressOf stdnum.Max)
+        Public Shared ReadOnly pow As New Callable(AddressOf stdnum.Pow)
 
     End Class
 End Namespace
\ No newline at end of file
diff --git a/LINQ/LINQ/Script/SyntaxImplements.vb b/LINQ/LINQ/Script/SyntaxImplements.vb
index a18b99f..69d775d 100644
--- a/LINQ/LINQ/Script/SyntaxImplements.vb
+++ b/LINQ/LINQ/Script/SyntaxImplements.vb
@@ -168,6 +168,11 @@ Namespace Script
             End If
         End Function
 
+        <Extension>
+        Private Function IsClosure(tokenList As Token()) As Boolean
+            Return tokenList(Scan0).name = Tokens.Open AndAlso tokenList.Last.name = Tokens.Close
+        End Function
+
         <Extension>
         Public Function ParseExpression(tokenList As Token()) As Expression
             If tokenList.Length = 1 Then
@@ -189,6 +194,12 @@ Namespace Script
                         .Take(tokenList.Length - 2) _
                         .ToArray
                 End If
+            ElseIf blocks.Length = 2 Then
+                Dim name As Expression = ParseExpression(blocks(Scan0))
+
+                If TypeOf name Is SymbolReference AndAlso blocks(1).IsClosure Then
+                    Return New FuncEval(name, blocks(1).Skip(1).Take(blocks(1).Length - 2).GetParameters)
+                End If
             End If
 
             Return tokenList.ParseBinary
diff --git a/LINQ/LINQ/test/Program.vb b/LINQ/LINQ/test/Program.vb
index 5dc357b..f7d99aa 100644
--- a/LINQ/LINQ/test/Program.vb
+++ b/LINQ/LINQ/test/Program.vb
@@ -3,6 +3,7 @@ Imports LINQ.Runtime
 Imports Microsoft.VisualBasic.ComponentModel.DataSourceModel
 Imports LINQ.Interpreter.Query
 Imports Microsoft.VisualBasic.My.JavaScript
+Imports LINQ.Interpreter
 
 Public Module Program
 
@@ -27,7 +28,7 @@ order by y
         Dim query As ProjectionExpression = tokens.PopulateQueryExpression
         Dim env As New GlobalEnvironment(New Registry, New NamedValue(Of Object)("y", 1))
 
-        Dim result As JavaScriptObject() = query.Exec(env)
+        Dim result As JavaScriptObject() = query.Exec(New ExecutableContext With {.env = env, .throwError = True})
         Dim table = result.CreateTableDataSet
 
         Pause()