One Method, multiple tasks

[David Roberts]

For members experienced with objects the following is probably 'old hat' but I couldn't find anything in the documentation mentioning its use.

It is a simple way to have a single statement do more than one task depending upon the assigned Class.

The 'trick' is to duplicate both an Interface name and a method name.

The following snippet illustrates the concept.

#Compile  Exe
#Dim All

Macro CreateObj(ObjectName, ClassName) = ObjectName = Class ClassName
Macro DestroyObj(ObjectName) = ObjectName=Nothing

Class CShortDisplay
  
  Interface IDisplay: Inherit IUnknown
  
    Method Table() As Long
      ? "ShortDisplay"
    End Method
  
  End Interface
  
End Class

Class CFullDisplay
  
  Interface IDisplay: Inherit IUnknown
  
    Method Table() As Long
      ? "FullDisplay"
    End Method
  
  End Interface
  
End Class

Global ShowMy As IDisplay

Function PBMain( ) As Long
                          
  CreateObj(ShowMy, "CShortDisplay")
  
  ShowMy.Table
  
  DestroyObj(ShowMy)
  
  CreateObj(ShowMy, "CFullDisplay")
  
  ShowMy.Table
  
  DestroyObj(ShowMy)

'  Waitkey$

End Function