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From: ok@goanna.cs.rmit.oz.au (Richard A. O'Keefe)
Newsgroups: comp.lang.prolog
Subject: Re: "Embedded Prolog" in C code
Message-ID: <6199@goanna.cs.rmit.oz.au>
Date: 10 Jun 91 12:05:08 GMT
References: <1991May26.231138.13000@brolga.cc.uq.oz.au> <644@fudd.dataco.UUCP> <653@fudd.dataco.UUCP>
Organization: Comp Sci, RMIT, Melbourne, Australia
Lines: 42

In article <653@fudd.dataco.UUCP>, campbell@dataco.UUCP (Duncan Campbell) writes:
> Well, Ted, out here in the real world _REAL_ Prolog isn't much use to
> anyone.  Indeed, if I were required to use a "pure" language, I simply
> would not bother with prolog at all: Scheme _IS_ a far superior language.

I'm currently using Scheme a lot.  I have three observations to make
about Scheme.
(1) I like it.
(2) One day it will catch up with where Pop-2 was years ago, but
    don't hold your breath.  (Scheme has precisely two things that
    Pop-2 didn't:  lexical scoping and full continuations.  These
    days Pop has lexical scoping.)
(3) Unless the Prolog standard has a radically different result from
    the Scheme standard, the whole standardisation effort will have
    been a waste of time.  I have access to 5 Scheme implementations
    (later this year to be 6), and there is no non-trivial program
    that I can move from one to another without either rewriting or
    an extensive library of compatibility code (currently standing at
    >2000 lines and growing fast).

> The fact remains that PDCProlog provides much of the
> functionality of "pure" Prolog and possesess the features like
> timers, static typing and execution speed (*10 faster than "pure"
> prolog) needed for real-time applications.

Static typing has been available as an option for Edinburgh-compatible
since 1983 or 1984.  If people didn't pick it up, that's not my fault.
(NU Prolog comes with _four_ type checkers...)  And it seems rather odd
for someone claiming static type checking as an important advantage to
advocate Scheme.

I do not have access to a PDC Prolog, but Borland's last offering of
it did not provide any execution time advantage.  Perhaps you have some
interpreter in mind.  If you want a logic-based language, and don't
mind total incompatibility with Prolog, then you might like to try
Trilogy, which is about as fast as Turbo Prolog was, and has a GREATLY
superior type system, and isn't really any less compatible with Prolog
than Turbo Prolog was.
-- 
Should you ever intend to dull the wits of a young man and to
incapacitate his brains for any kind of thought whatever, then
you cannot do better than give him Hegel to read.  -- Schopenhauer.