RE: [xml-dev] Re: determining ID-ness in XML

[Leigh Dodds <ldodds@ingenta.com>]

> -----Original Message-----
> From: Jeff Rafter [mailto:jeffrafter@defined.net]
> Sent: 05 November 2001 01:09
> To: xml-dev@lists.xml.org
> Subject: Re: [xml-dev] Re: determining ID-ness in XML
>
[...]
> In general, if we accept the argument that IDs *are* orthogonal to both
> Validation and Well-Formedness then removing them to an xml:id attribute
> would be the best solution. I am struggling to juxtapose this notion with
> the use of the xml:idatts approach. It seems that declaring which
> attributes are ID attributes brings us back to step one...

Can you elaborate? Why does xml:idatts take us back to step one?

xml:id = this element has an identifier, this is what it is.
xml:idatts = this element (and its children) has an identifier. It's in an
attribute called X.

Don't both of these solve the problem?

The second has an extra level of indirection which gives the flexibility to
potentially have >1 identifying attribute (as you note), and allows that
attribute
to have different types.

This flexibility seems to be a Good Thing, but raises another issue:
whether the identifier is an ID [1].

- we can't have >1 ID per element type in a DTD
- we can't have integers as IDs in a DTD (not a Name)

Of course we can say that the attributes identified by xml:idatts must
be of type ID, and accept the restrictions. We could also say that the
identifier contained in an xml:id attribute does/doesn't have to be
an ID. Where exactly does 80/20 lie here?

It strikes me that we've circled the problem, laid out some good
options and identified some of the issues [2]. But we've not started
to weigh up the different options in light of these.

I'm sure there's all sorts of things still to yet to creep out of the
woodwork:
For example, what about cross-referencing? xml:idref? xml:idrefatts? If
we're
recreating identifiers separate from DTDs, then surely cross-referencing
is also an issue...?

L.

[1]. http://weblogs.userland.com/eclectic/xml-identifiers.html#ID-Type
[2]. http://weblogs.userland.com/eclectic/xml-identifiers.html#issues


--
Leigh Dodds, Research Group, Ingenta | "Pluralitas non est ponenda
http://weblogs.userland.com/eclectic |    sine necessitate"
http://www.xml.com/pub/xmldeviant    |     -- William of Ockham