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From: hadden@ella.SRC.Honeywell.COM (George D. Hadden)
Newsgroups: comp.binaries.ibm.pc.d,comp.sys.ibm.pc
Subject: Re: Computer Algebra in Prolog uploaded to Simtel20
Message-ID: <1528@cfa.cfa.harvard.EDU>
Date: 20 Apr 89 21:58:49 GMT
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In-reply-to: jk0@sun.soe.clarkson.edu's message of 19 Apr 89 17:51:28 GMT


>From article <20671@srcsip.UUCP>, by hadden@ella.SRC.Honeywell.COM (George D. Hadden):
>> naturally, one well-known problem (some might call this a feature :-)
>> of turbo prolog is that it's not prolog.

>	  in what way is turbo prolog NOT prolog?  because it forces
>  you to define the types?  personally i consider this a feature
>  because it makes debugging and tracing easier.
>
>	  of course, turbo prolog does have it limitations i DO
>  conceed.  but, it's limitation FAR exceed those of pd-prolog.
>  also, you can buy turbo- prolog for $40 from an educational
>  institution.  at that price, there just isn't an arguement.
>
>--
>Jason Coughlin

oh, i'd say there's an argument.  in fact, i think you've answered
your own question.  although you might consider the above-mentioned
characteristic a feature, that only confirms the claim that turbo
prolog is not, in fact, prolog.  i'm not sure what it is but it's NOT
prolog.  please note that this is not a value judgement regarding its
worth -- i'm NOT in the prolog fan club.  however, what i AM in is a
position of teaching prolog to graduate students at the university of
minnesota (in the context of an AI Programming Techniques course) and
feel an acute responsibility to prepare them for the prolog questions
on the qualifying exam.  pdprolog, whatever its other shortcomings may
be, at least runs the examples in the prolog texts that i use (bratko,
c&m).

I quote here from the review of Turbo Prolog 2.0 in the October 1988 
Byte:

   Turbo Prolog 2.0 stretches the language even more than did the
   original Turbo Prolog 1.0 ... Borland's Prologs enforce strong
   typing of objects and relations (Edinburgh Prolog, the de facto
   standard, doesn't) and limit the assert and retracdt mechanism to
   facts alone (Edinburgh supports dynamic modification of facts,
   predicates that define relations, and rules involving those
   predicates). 

   ...

   Like its predecessor, Turbo Prolog 2.0 isn't a traditional Prolog;
   the language is strongly typed and doesn't let you dynamically
   assert and retract rules. 

because of this and other misfeatures of this language, i don't allow
my students to use it for their programming assignments.

-geo
---
George D. Hadden, Honeywell Systems and Research Center
PHONE:  (612)782-7769
MAIL:   3660 Technology Drive MN65-2100, Minneapolis, MN 55418
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