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From: ok@goanna.cs.rmit.oz.au (Richard A. O'Keefe)
Newsgroups: comp.lang.prolog
Subject: Re: Turbo Prolog 2.0 tip
Message-ID: <4177@goanna.cs.rmit.oz.au>
Date: 1 Nov 90 08:26:19 GMT
References: <1990Nov1.100235.3213@csc.anu.oz.au>
Organization: Comp Sci, RMIT, Melbourne, Australia
Lines: 60

In article <1990Nov1.100235.3213@csc.anu.oz.au>, ada612@csc.anu.oz.au writes:
> How does ALS prolog stack up against PDC/Turbo w.r.t.
>  a) compactness of compiled code

I don't know.  Since Turbot Prolog can't run Prolog code, it's rather
difficult to make a meaningful comparison.

>  b) efficiency of storage of structures (where `reference' variables
>     are being used all over the place)

The one thing where it is likely to do worse than Turbot is that it will
take a full cell for a functor (name/arity pair) instead of a single byte.
Otherwise, I'd expect as good or better.  I would be surprised if it was
a problem.  I have noted that the Turbot programs I have seen tend to use
poorly chosen data structures (such as strings), that's more likely to be
a problem.

>  c) pleasant-to-use IO, including windows, etc.

I honestly can't describe Turbot IO as pleasant-to-use.  (Interlisp-D,
now _that's_ pleasant to use.)  Reading and writing characters and data
structures is easy to do (and compatible with other systems).  Windows
are dead simple on a Mac; what they're like on a PC I don't know because
I've got the low end student edition.

>  d) ability to store terms in EMS, on hard disks, etc.

I've got the low end student edition, which doesn't include that.
(On the other hand, my computational linguistics students haven't
told me they needed it.)  I do know that the "professional" version
supports data storage on disc very nicely indeed; I've _heard_ of
ALS programs with 10Mb of clauses.

>  e) price

The low-end "student" version was something over A$100, I've forgotten
the exact figure.  Ask ALS for a price list (and a feature list).

> These questions are apropos of shoehorning LFG systems for use by linguistics
> students into the confines of PCs without blowing personal or departmental
> budgets.

One of _my_ reasons for picking ALS Prolog was so that my students could
write code using DCGs and XGs and chart parsers and the like, and the
code would run unchanged on their PCs (without hard disc), our PCs (with
hard disc), Macintoshes ditto, the UNIX system where I actually develop
this stuff (any of several Prolog systems).

One thing I regard as important about using real Prolog is the ease
with which you can write preprocessors (e.g. XG + feature structures
-> kernel Prolog).

I personally would be *very* interested in hearing what you and your
linguistics students are doing with LFG.

>  Avery Andrews (ada612@csc.anu.oz.au)

-- 
The problem about real life is that moving one's knight to QB3
may always be replied to with a lob across the net.  --Alasdair Macintyre.