- From: Henry S. Thompson <ht@cogsci.ed.ac.uk>
- Date: 12 Feb 2001 10:15:50 +0000
- To: James Clark <jjc@jclark.com>
- Cc: XML Schema Comments <www-xml-schema-comments@w3.org>
James Clark <jjc@jclark.com> writes:
> Why does XML Schema Part 2 require me to write for example
>
> <xsd:simpleType>
> <xsd:list>
> <xsd:simpleType>
> <xsd:union memberTypes="xsd:NCName">
> <xsd:simpleType>
> <xsd:restriction base="xsd:token">
> <xsd:enumeration value="#default"/>
> </xsd:restriction>
> </xsd:simpleType>
> </xsd:union>
> </xsd:simpleType>
> </xsd:list>
> </xsd:simpleType>
>
> instead of simply:
>
> <xsd:list>
> <xsd:union memberTypes="xsd:NCName">
> <xsd:restriction base="xsd:token">
> <xsd:enumeration value="#default"/>
> </xsd:restriction>
> </xsd:union>
> </xsd:list>
>
> ?
>
> The extra simpleType elements are completely unnecessary, as far as I
> can see, and serve only to obfuscate the meaning of the Schema.
Not obfuscate, rather make explicit. A union is a union of simple
types: you can either refer to them or provide them. Similarly for
lists. We choose the more verbose syntax intentionally because it was
clearer.
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 Monday, 12 February 2001 05:15:54 UTC