Newsgroups: comp.lang.prolog
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From: fjh@munta.cs.mu.OZ.AU (Fergus Henderson)
Subject: Re: Time for a standardized, pure, "modern" successor to Prolog?
Message-ID: <9514917.13672@mulga.cs.mu.OZ.AU>
Sender: news@cs.mu.OZ.AU (CS-Usenet)
Organization: Computer Science, University of Melbourne, Australia
References: <3qagtr$70l@borg.cs.waikato.ac.nz>
Date: Mon, 29 May 1995 07:42:39 GMT
Lines: 42

dsmith@borg.cs.waikato.ac.nz (Don Smith) writes:

>Is it time to start serious work on a standardized, "modern", purely
>declarative successor to Prolog?

Yes.  In fact I started serious work on this topic about two years ago.
It's called Mercury ;-)

>Perhaps not.  Perhaps it is
>premature to standardize at this stage. Perhaps a pure, side-effect
>free logic programming language would be unworkable with current
>techniques.  On the other hand, even attempting the task might be
>useful for focussing research efforts and clarifying the issues.  I
>know there are several disconnected projects under way: Goedel,
>Mercury, Oz, Life, CLP(_), ccp, KLIC/KL1, and various DB query
>languages (not all of these are pure). But there is nothing like the
>massive, world-wide cooperative work that is being done by the Haskell
>community.  Why?

The problem is not that current techniques are insufficient - Mercury
is an existance proof of a workable, pure, side-effect free logic
programming language.

I think the problem is there is a lack of concensus in the logic
programming community.

The functional programming community (or at least the Haskell community)
were in agreement about some fundamental things: the lambda calculus
as the underlying theoretical model, a strong Hindley/Milner style type
system, lazy evaluation.

The logic programing community seems to be still divided on the issues
of type systems, mode systems, coroutining, and so forth.  Even the underlying
theoretical model differs dramatically between the systems named above.

But seriously, I think it might be a good idea to start a conference on
pure, side-effect free logic programming languages.

-- 
Fergus Henderson
fjh@cs.mu.oz.au
http://www.cs.mu.oz.au/~fjh
