Re: Strawman DAML+OIL Query Language Proposal

From: pat hayes ([email protected])
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/

---------------------------------------------------------------------
(650)859 6569 w
(650)494 3973 h (until September)
[email protected] 
http://www.coginst.uwf.edu/~phayes


This archive was generated by hypermail 2.1.4 : 04/02/02 EST