recursive functions

[cicatrix]

I think I managed to adapt HeapPermute algorithm and make a generic class out of it.

Some theory can be found here:
http://www.cut-the-knot.org/do_you_know/AllPerm.shtml

''' <summary>
    ''' A generic class that encapsulates a HeapPermute algorithm (I think)
    ''' </summary>
    ''' <typeparam name="T"></typeparam>
    ''' <remarks>
    ''' With this class you can obtain an IEnumerable which contains all the permutations of the given sequence of values.
    ''' </remarks>
    Class Permuter(Of T)
        ' VS 2010 Auto implemented
        Public Property Sequence As IEnumerable(Of T)
 
        Public Function GetAllPermutations() As IEnumerable(Of IEnumerable(Of T))
            Return GetAllPermutations(_Sequence)
        End Function
 
        Private Function GetAllPermutations(ByVal values As IEnumerable(Of T)) As IEnumerable(Of IEnumerable(Of T))
            Dim ret As New List(Of List(Of T))
 
            Select Case values.Count
                Case 0
                    Return ret
                Case 1
                    ret.Add(New List(Of T) From {values(0)})
                    Return ret
                Case Else
                    Dim GetExcluded = Function(sourcevalues As IEnumerable(Of T), excluded_element As T) As IEnumerable(Of T)
                                          Return From vals In sourcevalues Where Not vals.Equals(excluded_element)
                                      End Function
 
                    For Each value As T In values
                        Dim tempret As IEnumerable(Of IEnumerable(Of T)) = GetAllPermutations(GetExcluded(values, value))
                        For Each tempelement In tempret
                            Dim templist As New List(Of T)
                            templist.Add(value)
                            templist.AddRange(tempelement)
                            ret.Add(templist)
                        Next
                    Next
                    Return ret
            End Select
 
        End Function
    End Class

Test program:

Sub Main()
        Dim p As New Permuter(Of Integer)
        Dim sequence() As Integer = {1, 2, 3, 4}
 
        p.Sequence = sequence
 
        Dim ret As IEnumerable(Of IEnumerable(Of Integer)) = p.GetAllPermutations
 
        For Each permutedsequence In ret
            For Each value As Integer In permutedsequence
                Console.Write(value.ToString & "; ")
            Next
            Console.WriteLine()
        Next
        Console.ReadLine()
    End Sub

Test output:

1; 2; 3; 4;
1; 2; 4; 3;
1; 3; 2; 4;
1; 3; 4; 2;
1; 4; 2; 3;
1; 4; 3; 2;
2; 1; 3; 4;
2; 1; 4; 3;
2; 3; 1; 4;
2; 3; 4; 1;
2; 4; 1; 3;
2; 4; 3; 1;
3; 1; 2; 4;
3; 1; 4; 2;
3; 2; 1; 4;
3; 2; 4; 1;
3; 4; 1; 2;
3; 4; 2; 1;
4; 1; 2; 3;
4; 1; 3; 2;
4; 2; 1; 3;
4; 2; 3; 1;
4; 3; 1; 2;
4; 3; 2; 1;