- From: Steen Lehmann <slehmann@silverstream.com>
- Date: Wed, 10 Oct 2001 19:40:39 +0200
- To: "'Eric van der Vlist'" <vdv@dyomedea.com>, "'Gary Robertson'" <gazinyork@hotmail.com>
- Cc: <xmlschema-dev@w3.org>
Hi,
Just a comment on the restriced XPath syntax in XML Schema:
> -----Original Message-----
> From: xmlschema-dev-request@w3.org
> [mailto:xmlschema-dev-request@w3.org] On Behalf Of Eric van der Vlist
> Sent: 10. oktober 2001 16:54
> To: Gary Robertson
> Cc: xmlschema-dev@w3.org
> Subject: Re: Illegal use of unique? I need it. Microsoft
> supports it. Alternatives?
[...]
> > <xs:unique name="StateNamesUniqueWithinAnObject">
> > <xs:selector xpath="../State"/>
> > <xs:field xpath="@name"/>
> > </xs:unique>
> > </xs:element>
> > </xs:sequence>
> > </xs:extension>
> > </xs:complexContent>
> > </xs:complexType>
> >
> > However, note use of parent node syntax (..) in the
> selector xpath. Is
> > this illegal?
>
>
> Yes.
Actually this is not legal as far as I can tell. The selector XPath
syntax is
defined as follows (from XML Schema Part 1):
[1] Selector ::= Path ( '|' Path )*
[2] Path ::= ('.//')? Step ( '/' Step )*
[3] Step ::= '.' | NameTest
[4] NameTest ::= QName | '*' | NCName ':' '*'
As you can see there is no way the Selector can begin with '..'
-- Steen
slehmann@silverstream.com
Received on Wednesday, 10 October 2001 13:38:01 UTC