Public Class Memory
Protected Shared _X As Double

Public Shared Property X()

End Class

Public Class Command
 
    Public Shared Sub Multiply()
        Memory.LastX = Memory.X
        Memory.X = Memory.Y * Memory.X
        Call StackDown()
        Memory.MakeStackUp = True
    End Sub

End Class

Public Shared Sub

Function

Public Class Taschenrechner

Dim Typ As Byte

Long, Double, Decimal, Complex, String, Vektor2, Vektor3 , Date

Memory.X.Typ=1
Memory.X.IntegerVar = 25
Memory.Y=Memory.X

Memory.X = Multiply(Memory.Y, Memory.X)

Public Shared Function Multiply(X As RegisterVariant, Y As RegisterVariant) As _
  RegisterVariant

Select Case

X.Typ

Y.Typ