Why isn't Null a constant in Blitz?

Blitz3D Forums/Blitz3D Programming/Why isn't Null a constant in Blitz?

Actually, I take that back. It's great that it works and it's possible to do, but it's hardly the kind of elegant program construction that I've generally found possible with Blitz3D.

Is there anywhere in particular that hidden functions like Handle() have been collected and documented?