# Re: Quantifier syntax in KIF

phayes@cs.uiuc.edu
Message-id: <199304082023.AA02914@uxc.cso.uiuc.edu>
Sender: phayes@dante.cs.uiuc.edu
Reply-To: cg@cs.umn.edu
Date: Thu, 8 Apr 1993 15:24:46 +0000
To: macgregor@ISI.EDU, genesereth@cs.Stanford.EDU
From: phayes@cs.uiuc.edu
Subject: Re: Quantifier syntax in KIF
Cc: sowa <sowa@turing.pacss.binghamton.edu>, cg@cs.umn.edu,
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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