Path: utzoo!attcan!uunet!lll-winken!lll-tis!helios.ee.lbl.gov!pasteur!ucbvax!decwrl!labrea!sri-unix!teknowledge-vaxc!shardy
From: shardy@teknowledge-vaxc.ARPA (Steve Hardy)
Newsgroups: comp.lang.prolog
Subject: Re: Knowledge representation and Prolog
Message-ID: <23253@teknowledge-vaxc.ARPA>
Date: 17 Jun 88 02:44:14 GMT
References: <121@quintus.UUCP> <6648@burdvax.PRC.Unisys.COM>
Organization: Teknowledge, Inc., Palo Alto CA
Lines: 49
In-reply-to: finin@antares.PRC.Unisys.COM's message of 16 Jun 88 18:13:38 GMT

Jerry Harper asks about knwoledge representation languages
written in Prolog (besides APES.)

Teknowledge developed a prolog-based expert system shell called
M.1.  It was released in June 1984 and has sold close to 4,000
copies.

M.1 is unusual in that it is a complete logic programming
language as well as being an easy-to-use expert system shell.

For example:

/* --- simple EMYCIN-like heuristic rule --- */

	if main-component-of-meal = beef
		then best-color-of-wine = red cf 75.

/* --- list processing --- */

	infix <>.		/* for "append" */

	[] <> LIST = LIST.

	if LIST1 <> LIST2 = LIST3
	   then [ITEM|LIST1] <> LIST2 = [ITEM|LIST3].

/* --- objects and inheritance --- */

	issquare(obj-22).
	size(obj-22) = 5.

	if isrectangle(X) and
		height(X) = H and width(X) = W and H * W = R
	    then area(X) = R.

	if issquare(X) then isrectangle(X).
	if issquare(X) and size(X) = S then height(X) = S.
	if issquare(X) and size(X) = S then width(X) = S.

After releasing four versions of M.1 in Prolog, Teknowledge
recoded the system in C.  This led to the system being
approximately five times faster and able to handle knowledge
systems five times larger (up to 2000 rules on a 640K IBM-PC.)

It was easier to work out the design of M.1 with Prolog than it
would have been with C.

Steve Hardy, Teknowledge Inc., (415) 424-0500
DISCLAIMER: My opinioins are not necessarily those of
Teknowledge.