Re: Pros and cons of high-level intermediate languages

>[one can write more-or-less continuation passing C code with this loop:]
> while (TRUE) { cont = (*cont)(); }


Everybody knows about this technique. We are actually using in Prolog.
We are calling the above loop the "motor". But to split a program in as
many C functions as there are storable control points is not reallistic.


E.g. in Prolog, it is fair to map every predicate onto a C function, but
to go further is a non-sense as far as efficiency is concerned. One wants
to be able to goto from a clause to another one inside a predicate, yet
one also want to store and read a clause label for handling bactracking.


Furthermore, some useful improvements come easily if C functions
correspond to a high-level semantical unit. E.g. in Prolog, (I suppose
something similar can be done for a functional language) left-recursive
clauses need not return to the motor, they merely have to loop.
Left-recursion translates to iteration.


Splitting into too small bits also hinders any chance for locality.


Olivier Ridoux
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