Re: using namespaces to version

[David Carlisle <davidc@nag.co.uk>]

> It is (needlessly) harder to get
> this to work properly if the one namespace URI applies to all versions of a
> schema.

But I think the mistake there is to tie the schema to the namespace.
It is helpful that in all versions of HTML the paragraph element is
called p. It gives a level of compatibility between versions.
If HTML2's paragraph had been <p-v2> and HTML3.2's was <p-v32>
then life would be more complicated, but you would still be able to get
by by stripping off the pars of names after the -.

Changing a namespace _only_ changes the names of the elements: it doesn't
do anything else, and in particular it doesn't do anything about schema.
You can get by by breaking apart the name into its local name but that
is more or less identical to splitting on "-" as above, and not much
more convenient in Xpath (for example).

DTD's can be specified by DOCTYPE and Schema can be specified by
schemaLocation or other means. If you want to specify a different schema
it is perfectly possible to do so without changing all your element
names by changing the DTD.

David

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