Re: Quantifier syntax in KIF
Message-id: <>
Date: Thu, 8 Apr 1993 15:24:46 +0000
To: macgregor@ISI.EDU, genesereth@cs.Stanford.EDU
Subject: Re: Quantifier syntax in KIF
Cc: sowa <>,,
        interlingua@ISI.EDU, srkb@ISI.EDU
Comment on extension as requested. I don't like the double-nested syntax,
and see no need for it. What is ambiguous about

        (forall (?var term) ...)    ?

The use of the question-mark-prefix notation for variables is exactly to
remove any ambiguity between variables and other expressions; and one needs
some way of making this distinction in any case.

The problem with the double-nest syntax is that it violates the usual
conventions for recursive syntactic structure. 

Many alternatives are possible, for example:

        (forall (term: ?var...)
        (forall (term ?var...)
        (forall (term (?var...))  or  (forall ((?var...)term)

I kind of like the last one, if one insists on having extra brackets, since
it gives the outer pair something useful to do.

Pat Hayes

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