- From: Hassan Aït-Kaci <hak@ilog.com>
- Date: Tue, 20 Mar 2007 09:31:22 -0700
- To: W3C RIF WG <public-rif-wg@w3.org>
It is inherently ambiguous to define a language where lexical categories and syntactic categories may have the same form. For ex., if predicates, sorts, and constants may be uris, how do you disambiguate an expression like uri1(uri2,uri3)? If you answer, "thanks its grammatical position: it appears where a predicate, constant, etc., is expected", then you haven't written a parser lately... Indeed, the way to know the what *syntactic* category is expected is using the *lexical* category of a token. So my question is, when you read a uri off the input stream, what is its lexical category? If uri is a *lexical* category (like 'variable' starting with a ?, or 'number' being made of numerical digits), do you return "URI" or "CONSTANT", or "SORT", what? (This is the lexical level, remember!). -hak -- Hassan Aït-Kaci ILOG, Inc. - Product Division R&D tel/fax: +1 (604) 930-5603 - email: hak @ ilog . com http://koala.ilog.fr/wiki/bin/view/Main/HassanAitKaci
Received on Tuesday, 20 March 2007 16:33:42 UTC