Creating LotusScript formulas with Optional Parameters

[MoGryph]

Does anyone know if there's a way to create a function in lotusscript, that allows for an optional parameter.

Take for example, something like the Mid$ function.

As defined in Help, it's syntax is:
Mid[$](stringVar, start [, length]) = stringExpr

In other words, you may, or may not, include the Length of the characters you want returned.

I know in VB and VB for Apps, you can use the actual 'Optional' keyword in the function declaration, to say that it is an optional. Something like:

Function TestOpt$(stringVar As String, OPTIONAL StringVar2 As String)
TestOpt$ = stringVar & IIf (Not(IsNull(StringVar2)), StringVar2, " None&quot
End Function

Yes, very useless example, but I think it explains what I'm looking for.

Thanks-
MoGryph