Re: [relax-ng] Approaches for defining common attributes

[Martin Bryan <mtbryan@sgml.u-net.com>]

MURATA Makoto wrote:

> On the other hand, the third approach has a big advantage: different
> schemas can easily impose different constraints on attribute values.

We need to distinguish two types of constraints on attribute values:
cardinality and value range constraints. Having a mechanism whereby the
cardinality/optionality of an attribute can be changed for each element in a
DTD a set of common attributes are applied to make sense, as does the
ability to change the default value applied to the attribute for each
element in a DTD, but I'm not sure that allowing the set of valid values to
be changed is such a good idea.

Martin Bryan
IS-Thought: Thinkers for the Information Society
29 Oldbury Orchard, Churchdown, Glos. GL3 2PU, UK
Phone/Fax: 01452 714029 E-mail: martin@is-thought.co.uk

Thought of the week:
Different contexts require different labels for things