Path: utzoo!utgpu!news-server.csri.toronto.edu!cs.utexas.edu!sun-barr!lll-winken!uunet!mcsun!ub4b!kulcs!icarus.cs.kuleuven.ac.be
From: bimandre@icarus.cs.kuleuven.ac.be (Andre Marien)
Newsgroups: comp.lang.prolog
Subject: nice prolog code
Message-ID: <1642@n-kulcs.cs.kuleuven.ac.be>
Date: 30 Jan 91 12:45:33 GMT
Sender: news@cs.kuleuven.ac.be
Organization: Dept. of Computer Science (K.U.Leuven)
Lines: 23
Originator: bimandre@icarus

Recently, I saw a nice piece of code in a program used to benchmark
prolog systems. I am not going to copy it here, just give a similar piece of code.
(no, this is not about benchmarks, although that would be interesting)
(no, this is not artificially created)

	p(T) :-
		T =.. [F|AL],
		length(AL,AR),
		q(F/AR,AL,R) .

	q(+/2,[X,Y],R) :- R is X + Y .
	q(+/1,[R],R) .
	q(*/2,[X,Y],R) :- R is X * Y .

(I may have the order of the arguments to length wrong; the reason I found this
beauty was that I was curious what length/2 was used for)

As long as people use prolog this way when they try it out (which was NOT the case
for the programer who wrote this, I am afraid) prolog has no chance of being
accepted by the rest of computer science. Suggestions for remedies are invited.

Andre' Marien
bimandre@cs.kuleuven.ac.be