From: pat hayes (phayes@ai.uwf.edu)
Date: 09/07/01
>Richard Fikes wrote:
> >
> > As I mentioned yesterday in the telecon, a student of mine, Yulin Li,
> > and I have designed a simple language for querying DAML+OIL knowledge
> > bases. The language is specified as a DAML+OIL ontology so that both
> > queries and the results obtained from asking a query are represented in
> > DAML+OIL.
>
>I appreciate the effort of specifying the language as a DAML+OIL
>ontology.
Well, I wonder what the point of this effort was, and would like to
raise this as an issue for discussion. It seems to me to be:
(a) completely pointless, in the strict sense that it provides no
useful functionality or understanding of the language (ie the query
language) to describe its syntax in DAML+OIL as opposed to, say, BNF.
All that this enables a hypothetical DAML reasoner to do is to parse
the expressions of the query language. Using an ontology language for
parsing seems a very poor design decision; at the least, one that
should be discussed on its merits rather than simply assumed to be
somehow a Good Thing.
(b) actively misleading, in the sense that it suggests that the
purpose of DAML+OIL is to be a syntax specification language, which
as far as I was aware wasn't ever even close to the intended goal of
the project;
(c) based on a basic misapprehension about the nature of descriptive
languages, in that part of the very idea of a *syntactic*
specification is that it describes domains of recursively defined
finite entities to which results such as the second recursion theorem
apply, whereas descriptive (assertional) languages like DAML+OIL (and
RDF and FOL) have an extensional semantics which is (because of
Goedel incompleteness) inherently unable to fully capture the notion
of finiteness or recursion.
>We chuckled on the phone about what an obscure mechanism it is
>for communication in the group...
>but I hope each of us has at his/her disposal some tools
>that render DAML+OIL intelligible to us in some familiar
>notation/interface.
I'm afraid I do not have access to any that I know how to use. I
wish there was one, indeed. Do you know of any?
>My tool of choice barfed... so I submitted the attached
>ontology to our new RDF validation service
> http://www.w3.org/RDF/Validator/
>and I got:
>
>Error: {E201} Syntax error when processing rdf:parseType. Cannot have
>rdf:parseType in this context.[Line = 41, Column = 58]
>Error: {E201} Syntax error when processing rdf:parseType. Cannot have
>rdf:parseType in this context.[Line = 118, Column = 58]
>Error: {E201} Syntax error when processing rdf:parseType. Cannot have
>rdf:parseType in this context.[Line = 216, Column = 58]
>Error: {E201} Syntax error when processing rdf:parseType. Cannot have
>rdf:parseType in this context.[Line = 354, Column = 58]
>
>I'm in the process of fixing these errors... I'll share
>the results when I have them.
>
>[...]
> > ------------------------------------------------------------------------
> > Name: query-answer.daml
> > query-answer.daml Type: Plain Text (text/plain)
> > Encoding: 7bit
>
>--
>Dan Connolly, W3C http://www.w3.org/People/Connolly/
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