🚀 go-pugleaf

> In article <1992Aug25.202004.8511@vax.oxford.ac.uk>,
> popx@vax.oxford.ac.uk writes:
> > I'm looking for ... a meta-interpreter for implementing coroutines.
> >
> Have you seen L.M. Pereira's "Logic control with logic" in
> _Implementations of Prolog_, J.A. Campbell editor, Ellis Horwood
> Limited, 1984? Section 2.2 of the paper is entitled "An Interpreter to
> Control Coroutining".
>
> John E. Kreznar, jkreznar@ininx.com, uunet!ininx!jkreznar
>
Yes I have, thanks for the reference. I was hoping to get a reply from
someone who had used such a meta-interpreter seriously, and who had
optimised it. The code in Pereira's article is easy to read, but (for
that reason), not as efficient as it could be.

Pereira gives a listing, and then says "Although this rendering of the
interpreter is clearer than others, it is not very efficient as it
stands. Use of the cut, more indexing, and non-normalised resolvents
and clause bodies permit much more efficient versions, even surpassing
in efficiency compiled Prolog in the case of programs that do benefit
much from the special control. They also surpass lower-level
implementations (see Filgueiras, M: "On the implementation of control
in logic programming languages", Research Report, Departmento de
Informa'tica, Universidade Nova de Lisboa, 1984).

I want my meta-interpreter to be capable of co-routining _large_
programs (animal "brains", containing production systems, planners,
etc), so time and space efficiency is important.

Jocelyn Paine