- From: Henry S. Thompson <ht@cogsci.ed.ac.uk>
- Date: 26 Jun 2003 14:26:22 +0100
- To: <Simon.Cox@csiro.au>
- Cc: <xmlschema-dev@w3.org>, <fellah@pcigeomatics.com>
<Simon.Cox@csiro.au> writes: <snip/> > Now XSD's "redefine" does apply to model groups, so I guess we could extend > the group with the additional facets required, and then these would become > available within localSimpleType. > > But this would involve tinkering with components in the XSD namespace. > That doesn't look like such a smart idea. For what you want, it's not completely unreasonable. > Is there another mechanism that we could use? > Maybe declare a new facet and add it to a substitution-group headed > by one of the existing facets? Whether or not it's a good idea, you _can't_ actually do this -- the sForS has "blockDefault='#all'", which means after-the-fact substitution groups won't work. > [N.B. There is an annotation on the facets group: > <xs:annotation> > <xs:documentation> > We should use a substitution group for facets, but > that's ruled out because it would allow users to > add their own, which we're not ready for yet. > </xs:documentation> > </xs:annotation> > So obviously the W3C WG have at least briefly considered this use-case. > What to do while waiting for them to revisit this issue?] Sometimes we surprise ourselves :-). I think you'd be better off extending localSimpleType to produce a type in your own namespace with the additional facets likewise in your own namespace. But that would mean defining everything _else_ you had in mind to use (xs:union, xs:restriction, etc.) to eventually allow the new type instead of the old. . . So you either do that, extending XML Schema types as you go, but losing exact name correspondence (which may be no bad thing, since your elements _don't_ have the semantics of the schema ones, or use redefine and be guilty of tag abuse. ht -- Henry S. Thompson, HCRC Language Technology Group, University of Edinburgh Half-time member of W3C Team 2 Buccleuch Place, Edinburgh EH8 9LW, SCOTLAND -- (44) 131 650-4440 Fax: (44) 131 650-4587, e-mail: ht@cogsci.ed.ac.uk URL: http://www.ltg.ed.ac.uk/~ht/ [mail really from me _always_ has this .sig -- mail without it is forged spam]
Received on Thursday, 26 June 2003 09:26:24 UTC