🚀 go-pugleaf

In article <1897@ubc-cs.UUCP>, voda@ubc-cs (Paul Voda) writes:
{ criticising Prolog }
> Quite often the state is encoded by a list, but even if it is a functor
> or a tree there is a significant amount of copying to be done in order
> to create a new state.

{ praising Trilogy }
> Trilogy is careful to preserve the logic in similar situation by copying out the
> value of y into the variable x.				   ^^^^^^^

When does Trilogy require copying?  Does it use reference counting,
as SETL used to, or is it a compile time analysis?

> Trilogy does not require the concept of worlds to to allow the
> updates to the data bases. The input-output variables are used with the
> advantage here.

But the Bowen approach permits the manipulation of several worlds at once.
(Something which isn't possible in vanilla Prolog either.)