Mon Jul 14 11:24:01 CEST 2008

multi-stack Forth support

Currently i'm using structure type inheritance together with pattern
matching to be able to perform base type operations on derived types:
they simply leave alone the extended state.

This is essentially the same as operating on a stack: each type
extension adds one stack element. Does this have implications on the
implementation level? Is it better to represent state as a stack of
states right from the beginning? This would make the update method
trivial. Current conclusion: Maybe it's best to keep that method