Checking if a string is null

[Manfred Nowak]

Regan Heath wrote

> This all boils down to the empty vs null string debate where some
> people want to be able to distinguish between them and some see no
> point. 

I haven't seen such a debate.

Does it mean that it is not possible to implement a Kleene Algebra for 
strings in D because there is no neutral element for the alternative 
operator?

Hail to communities with academic rigor :-(

-manfred