- From: Henry S. Thompson <ht@cogsci.ed.ac.uk>
- Date: 21 Feb 2001 15:33:59 +0000
- To: Michael Anderson <michael@research.canon.com.au>
- Cc: "xmlschema-dev@w3.org" <xmlschema-dev@w3.org>
Michael Anderson <michael@research.canon.com.au> writes: > "Henry S. Thompson" wrote: > > > Michael Anderson <michael@research.canon.com.au> writes: > > > > > Hi all, > > > Does someone understand clause 1.6 of > > > http://www.w3.org/TR/xmlschema-1/#rcase-NameAndTypeOK ? > > > > > > "R's { type definition } is validly derived given {extension } from B's > > > {type definition} as defined by Type Derivation OK (Complex)(5.11) or > > > Type Derivation OK(Simple)(5.12) as appropriate". > > > > This means that the derivation can't involve {extension} -- it's as if > > B had had block='extension'. The point is that to derive by > > restriction, the type derivation path can't involve extension. > > Thanks for the reply. > > Unfortunately i admit I'm still confused. Having B's block='extension' just > means that substitute groups of B can't have an extended type of B. Sorry not to be clearer -- the {extension} is being used _here_ to constrain the relation between the two types -- the actual constraint used here doesn't know or care _why_ you're checking the two types, it just traces the connection and checks it exists and doesn't use the prohibited derivation methods. ht -- Henry S. Thompson, HCRC Language Technology Group, University of Edinburgh W3C Fellow 1999--2001, part-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/
Received on Wednesday, 21 February 2001 10:34:02 UTC