Prolog is excellent for the task for which
it was designed - which is deduction.
Some tasks just turn out to be so much
easier in Prolog than Lisp. Generally
I would consider it useful in an expert
systems context.
Lisp is a more flexible tool all round than
Prolog. It suffers from a lack of features
common in more modern FPLs such
as pattern-directed list handling and types.
Prolog in Lisp might be your solution.
You should know though that Prolog-in-Lisp
will be slower than the best commercial
Prolog such as Sicstus. If you don't mind
losing a little speed - its a solution.
There is a Prolog in Lisp in Qi - does from
100-400 KLIPs under CLisp. The top level
syntax handler needs a little work but it
does go.
Mark
As an undergraduate studying AI I used prolog... it has a natural
syntax for a lot of the course on predicate calculus, logic, NLP,
expert systems etc.
Prolog hides a lot of the work involved with systems that make
deductions, or represent recursive data structures.
However I prefer lisp as a general purpose language and there's a mass
of literature on using it for AI.
Have a look also at Paul Graham's online book "On lisp" which has a
chapter on how to make prolog in lisp and is pretty interesting
reading.
Justin