- From: C. M. Sperberg-McQueen <cmsmcq@acm.org>
- Date: 26 Jul 2005 07:54:04 -0600
- To: Alain Frisch <Alain.Frisch@inria.fr>
- Cc: W3C XML Schema Comments list <www-xml-schema-comments@w3.org>
- Message-Id: <1122386044.7893.5.camel@localhost>
[Apologies for the slow response; your mail did not appear on the list until today, owing to undiagnosed problems in the list moderation system.] On Tue, 2005-07-26 at 07:17, Alain Frisch wrote: > > > Hello, > > I'd need some clarification about the status of non-primitive built-in > simple types. > > Reading paragraph 2.5.3 of XML Schema Part 2, I thought that these types > were only predefined for convenience, which means that equivalent types > could be defined by users. Now, a closer look at the definition for e.g. > integer makes me believe this is not the case: > > << > integer is ·derived· from decimal by fixing the value of > ·fractionDigits· to be 0and disallowing the trailing decimal point. > >> > > (btw, there is a missing whitespace after 0) > > The facet fractionDigits only restricts the value space, not directly > the lexical space, so setting it to 0 does not disallow the trailing > decimal point. This could be done using the pattern facet, but the > definition does not mention this facet. > > So, I guess my question is: Are derived built-in types really > conceptually the same as user-derived types, or is there some additional > magic in their definition? In principle, the goal is to eliminate magic in the non-primitive built-in types as far as possible. In practice, here and in some other places the goal seems not to have been achieved. Speaking for myself, I am inclined to think that the WG should systematically ensure that the prose descriptions and the formal definitions of the ordinary non-primitive types are consistent with each other, either by adding pattern facets or by changing the prose. In this case, I think the right thing to do is probably to add the pattern facet. In the related case of unsignedLong and its descendants, I am inclined to think the right thing to do is to correct the prose. -C. M. Sperberg-McQueen World Wide Web Consortium
Received on Tuesday, 26 July 2005 13:55:47 UTC