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Article View: comp.lang.prolog
Article #2400

Re: Why can't integers become principal functors?

#2400
From: marques
Date: Thu, 21 Jan 1993 11:42
30 lines
1885 bytes
In article <CHIK.93Jan14104559@ss38.icot.or.jp>, chik@icot.or.jp (Takashi Chikayama) writes:
> Thank you very much to those who responded to my question posted in
> article <CHIK.93Jan7114812@ss38.icot.or.jp>.  I'd like to thank you
> all and summarize the responses here.
> 
> My original question was:
> 
>> Can somebody explain why integers cannot be the principal functor of
>> non-atomic functors?  Are there any theoretical reasons?  Any
>> implementational difficulties?  Or just for compatibility with
>> previous implementations?
[Stuff removed]
> Thank you again to all those who responded.
> 
> Takashi Chikayama
> ICOT

A few years back I wrote a little prolog interpreter for my Commodore 64.
Now it stored atom names in a hash table.  Each entry in this table also 
had other pointers to the procedure corresponding to this name, the operator
settings etc.  Numbers were not stored in the hash table and this could
explain why some implementations don't allow numbers, since under the above
scheme there would be no way to get from the number to its procedures, or
any other useful information that had to be common to all instances of the same
number.  Anyway my interpreter did support arbitary functor names, you
could create something like f(f(a))(x, y) but you got an error if you tried
to use it in call().
-- 
Jose Marques, Systems Programmer
 %INCLUDE STDDIS; /* Standard Disclaimer */
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Message-ID: <1993Jan21.114237.11426@vax.oxford.ac.uk>
Path: arc1-ca.pugleaf.net!sparky!uunet!mcsun!uknet!comlab.ox.ac.uk!oxuniv!marques
References: <CHIK.93Jan7114812@ss38.icot.or.jp> <CHIK.93Jan14104559@ss38.icot.or.jp>

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Path: arc1-ca.pugleaf.net!sparky!uunet!mcsun!uknet!comlab.ox.ac.uk!oxuniv!marques
From: marques@vax.oxford.ac.uk
Newsgroups: comp.lang.prolog
Subject: Re: Why can't integers become principal functors?
Message-ID: <1993Jan21.114237.11426@vax.oxford.ac.uk>
Date: 21 Jan 93 11:42:37 GMT
References: <CHIK.93Jan7114812@ss38.icot.or.jp> <CHIK.93Jan14104559@ss38.icot.or.jp>
Distribution: comp
Organization: Oxford University Library Automation Team
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