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From: imlah@canon.co.uk (Bill Imlah)
Newsgroups: comp.lang.prolog
Subject: Re: converting ascii character lists to functors
Message-ID: <1991Apr22.102405.18983@canon.co.uk>
Date: 22 Apr 91 10:24:05 GMT
References: <EIVERSON.91Apr19200202@aigyptos.nmsu.edu>
Distribution: comp
Organization: Kenny's Fish Bar (Turbot with a Smile)
Lines: 27

eiverson@nmsu.edu (Eric Iverson) writes:

>>| ?- name('loves(John,Mary,John)',X),functor_chars(F,X).
>X = [108,111,118,101,115,40,74,111,104,110,44,77,97,114,121,44,74,111,104,110,41],
>F = loves(_3569,_3590,_3569) ;

>Can you think of a way to do this which does not involve writing to,
>reading from, and then removing a file? 

      From the unification of args 1 & 3 in your example output,
      I assume you want to parse the whole term rather than just 
      get the functor.

      If you can't force Quintus to parse it, you could analyse 
      the term yourself and avoid i/o completely. However, if the form 
      of the term is unconstrained you will find yourself implementing 
      a prolog parser (you may be able to get hold of such code in a s/w 
      library or textbook).

      Alternatively, some prologs provide access to the parser.
      Eg. BIMprolog's sread/2 reads a term from an atom. 

--------------------------------------------------------
Bill Imlah                             imlah@canon.co.uk
Canon Research Centre Europe,  17/20 Frederick Sanger Rd.
The Surrey Research Park, Guildford, Surrey, GU2 5YD, UK.
Disclaimer: I ain't no Quintus expert.