XSchema Spec Section 2.2, Draft 1

John Cowan cowan at locke.ccil.org
Thu Jun 11 01:48:33 BST 1998

Paul Prescod wrote:

> Anyhow: when I first started using SGML, it really bothered me that
> attribute constraint declarations were not buried in element type
> declarations. But now I think that it is better to strictly separate them.
> It should be possible to attach attributes to any list of elements
> (including ALL). I think that SGML and XML had it right, and we should go
> back to that way of doing it.

I assume this is an error for "SGML had it right".  In XML, there
is no reason to assume that the "id ID #IMPLIED" attribute in one
element has anything to do with the "id ID #IMPLIED" attribute
in another.  There is no way of declaring in XML DTDs that two
elements have the *very same* attribute, only that they have
attributes that agree in name and type.  XML DTDs do not reify

> If we want to allow nesting of attribute constraint declarations in
> element constraint declarations, it should be a short-hand for the
> expanded version.

I disagree.  I am willing to accept a shorthand, either by way
of general entities in XSchemas or otherwise, for copying
attribute declarations from one element to another by way of
shorthand, but not for reifying attributes independently of the
elements they are attached to.

Perhaps the practical result would be the same, but the theoretical
implications are very different.
John Cowan	http://www.ccil.org/~cowan		cowan at ccil.org
	You tollerday donsk?  N.  You tolkatiff scowegian?  Nn.
	You spigotty anglease?  Nnn.  You phonio saxo?  Nnnn.
		Clear all so!  'Tis a Jute.... (Finnegans Wake 16.5)

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