- From: Henry S. Thompson <ht@cogsci.ed.ac.uk>
- Date: 25 Jan 2001 08:20:01 +0000
- To: Michael Anderson <michael@research.canon.com.au>
- Cc: francis@redrice.com, Adalbert Wysocki <waldi@imediation.com>, xmlschema-dev@w3.org
Michael Anderson <michael@research.canon.com.au> writes: > Francis Norton wrote: > <snip> > > > The second question has to do with defaults. "fixed" and "default" only > > apply to attribute declarations (see > > http://www.w3.org/TR/xmlschema-0/#ref36) and are specified via the "use" > > and "value" attributes, eg you could add: > > > > <xsd:attribute name="weather" use="fixed" value="wet" /> > > > > after the </xsd:sequence> above, and while both XML Spy 3.5 and xsv will > > allow the "weather" attribute to be absent, neither will allow it to be > > empty or to have any value but "wet". > > Sorry, my previous mail was a bit verbose. My main problem has to do with > the above example applied to an element. If I have: > > <xsd:element name="weather" fixed="wet"/> > > and an information item > > <weather></weather> > > Is the "weather" content considered to be absent, thus be allowed, and given > a value of "wet"? > OR > Is the "weather" content considered empty, thus not be allowed? There is no difference between absent and empty. The infoset for that element has no children. So following clauses [1] [2] will apply, _provided_ the element has a simple type definition, e.g. you need to modify your example slightly to <xs:element name="weather" type="xs:token" fixed="wet"/> If the declaration has a {value constraint}, then provided clause 1.2.2 has not obtained . . . 3.2 If the {value constraint} is fixed, the element information item must have no element information item [children], and the normalized value must be either empty or match the string of the {value constraint}; If an element information item is valid with respect to an element declaration as per Element Locally Valid (Element) (§3.3) and the {value constraint} is present, but clause 1.2.2 of Element Locally Valid (Element) (§3.3) above does not obtain and the element information item has no element or character information item [children], the post-schema-validation infoset has the {value constraint}'s string as the item's [schema normalized value] property and its [specified] is set to schema. Otherwise, the item's [specified] is set to instance. ht [1] http://www.w3.org/TR/xmlschema-1/#cvc-elt [2] http://www.w3.org/TR/xmlschema-1/#sic-eltDefault -- 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 Thursday, 25 January 2001 03:20:36 UTC