- From: Jeff Heflin <heflin@cse.lehigh.edu>
- Date: Thu, 06 Jun 2002 16:11:28 -0400
- To: "Peter F. Patel-Schneider" <pfps@research.bell-labs.com>
- CC: webont <www-webont-wg@w3.org>
Here is my official review: In general I like the document, but have a few issues. 1) I think section 1 (2nd to last paragraph) needs a few sentences that describe the particular flavor of BNF you're using. In particular, it should explain the difference between [stuff] and {stuff}. I didn't even notice these the first time through, and only recently realized that [] probably means optional and {} probably means 0,1, or many. 2) Section 3.1: Replace "conjunction of a collection of superclasses, property restrictions, and descriptions" with "conjunction of descriptions (which are described in section 3.3)." 3) Did you mean for <dataLiteral> ::= <datatypeId> <lexical-form> to imply that all literals must be explicitly typed? If so, I am strongly opposed to this. 4) Section 3.3: Need to add [super=<classId>] here since you removed it from the axiom production in 3.1. Even though this is logically equivalent to SubClass with a description UnionOf(<classId>) or IntersectionOf(<classId>), I think it's an important. 5) Section 4: If <fact> ::= <individualFact> then why even have this production? It has no impact on the syntax. Was this intended to avoid the recursion Herman mentioned? If so, this is not the effect. I think his confusion is that <fact> (and now <individualFact>) both correspond to a collections of assertions about an individual (each of which seems like it could be called a fact). We need to find a better name for this collection. RDF calls it a description, but that would probably add to the confusion, since we're using description elsewhere. We could have classDescription and IndDescription Finally, I do not feel that some of my concerns originally raised in my first response were addressed: 6) I'd like to see the syntax for classes really simplified. In stead of EquivalentClass and SubClass, why not just have Class and a qualifier "equivalent" or "complete" or whatever name is approriate? In the XML syntax, this can become an optional attribute, with the most common alternative (I assume SubClass) as the default. That is, have <axiom> ::= Class ( [equivalent | subclass] <classID> {<description>} ) replace the first to axioms in 3.1. 7) Having to write DataProperty or IndividualProperty seems really awkward to me. Why can't we just write Property and let a parser figure out which one it is? It should be easy enough. If the range is a dataRange then its a DataProperty, otherwise its an IndividualProperty. This would change the the beginning of each of the first two axioms in 3.2 to : <axiom> ::= Proprerty ( ... but otherwise leave them unchanged. I believe this preserves the desired separation between classes and datatypes but reduces the cognitve load of the user by forcing parsers to be a little smarter in determing which properties are of which type. Jeff "Peter F. Patel-Schneider" wrote: > > Here is the current version of the Feature Synopsis document. > > Changes have been made to address comments from the WG. In particular, > there has been some renaming of constructs, some extraneous material has > been removed, some sections have been reordered, and some explanations have > been added (although not all the ones called for). Also some of the > productions have been simplified and a bug in the productions for > individuals has been fixed. > > This document is also accessible at > http://www-db.research.bell-labs.com/user/pfps/owl/owl.html > > peter > > ------------------------------------------------------------------------ > Name: owl.html > owl.html Type: Hypertext Markup Language (Text/Html) > Encoding: 7bit
Received on Thursday, 6 June 2002 16:11:31 UTC