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Elliotte Rusty Harold wrote:
> It does not depend on whether *you* are working
> with a schema. It depends on whether *everyone*
> is working with the *same* schema. The assumption
> that there is a single unique schema, which everyone
> agrees to and adheres to is a common fallacy in the XML world.
I see your point, in the abstract, however, I can't help
thinking that we should be able to assume more uniformity than you
suggest. For instance, if an XML document declares a namespace that is
defined by a normative schema, I think that processors of the document
should be able to assume that the rules defined by that schema
actually apply to the document. Or, if someone creates a document that
claims to conform to some specification that includes a normative
schema, we should be able to assume that the rules of the schema apply
in instances of the format.
If we can't make these assumptions then it seems to me that
XML document exchange would always require bi-lateral agreements
between authors and consumers. The alternative would be unilateral
decisions made by both producers and consumers that could result in
widely variant interpretations of the data -- i.e. the value of any
particular XML document would be akin to the tea leaves in a fortune
teller's cup -- any relationship between reality and what is read
would be anecdotal at best. This might work well with poetry, but I
think that such interpretational freedom is probably inappropriate in
many areas of XML usage.
In any case, if you can't rely on a schema having force in
some particular exchange, then the wise implementor might choose
something like X.finfo which does not rely on schema information but
still provides some compactness and speed-of-parsing benefits.