Representing Objects as strings in VBA

I am working an a more meaningful way to print objects in VBA. The desired result should look something like this.

Console.PrintLine List.Create(1, 2, 3)
List(1, 2, 3)

The concept is that objects implementing an IPrintable interface are printed as their ToString property. Primitive data types are printed as is

Console.PrintLine "a"
a

And other objects are represented as "TypeName(&ObjPtr)"

Console.PrintLine New Collection
Collection(&150653720)

But the issue that is gunking up my design is that I want nested objects to represent themselves

Console.PrintLine List.Create(1, List.Create(), New Collection)
List(1, List(), Collection(&150653384))

My solution is to use an auxiliary helper methods, located in a standard module called cast, which in a way provides a default implementation of IPrintable

Public Function ToString(ByVal x As Variant) As String

    Dim result As String

    If TypeOf x Is IPrintable Then
        result = x.ToString
    ElseIf IsObject(x) Then
        result = DefaultObjectToString(x)
    Else
        result = CStr(x)
    End If

    ToString = result

End Function
Private Function DefaultObjectToString(ByVal x As Object) As String

    DefaultObjectToString = ObjectToString(x, cast.CArray(Array("&" & ObjPtr(x))))

End Function
Public Function ObjectToString(ByVal o As Object, ByRef members() As Variant, _
        Optional ByVal delim As String = ", ") As String

    Dim stringMembers() As String
    If LBound(members) <= UBound(members) Then
        ReDim stringMembers(LBound(members) To UBound(members))
    End If

    Dim i As Long
    For i = LBound(members) To UBound(members)
        stringMembers(i) = ToString(members(i))
    Next i

    ObjectToString = TypeName(o) & "(" & Join(stringMembers, delim) & ")"

End Function

I would want this to be located in the IPrintable class but that must be empty to use it as an interface.

Now any method that is printing the objects can just use cast.ToString like console does

Public Sub PrintLine(Optional ByVal x As Variant)

    If IsMissing(x) Then
        Debug.Print vbNullString
    Else
        Debug.Print cast.ToString(x)
    End If

End Sub

Also here is how List implements IPrintable (ToArray is just an array version of the list.)

Public Property Get ToString(Optional delim As String = ", ") As String

    ToString = cast.ObjectToString(Me, ToArray, delim)

End Property
Public Property Get IPrintable_ToString() As String

    IPrintable_ToString = ToString()

End Property

If I had a BinaryTree object it would look like this.

Public Property Get ToString() As String

    ToString = cast.ObjectToString(Me, Array(LeftTree, RightTree), ", ")

End Property