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At 11:55 PM -0400 4/26/04, Amelia A Lewis wrote:
>Problem: schema languages other than DTD are increasingly popular, for
>very good reasons, offering facilities not available or difficult of
>attainment in DTDs. However, without a DTD (if only an internal subset),
>entities may not be used.
There's a faulty assumption here that a document can have only one
schema ort can use only one schema language. That is not true. It is
completely possible to use a DTD to define entities without using it
to validate. In fact, I wish entity definition and validation had not
been conflated in XML 1.0. They are two very different tasks.
However, now that people are moving to RELAX NG, it seems possible
that much simpler DTDs that merely serve to define entities will
become prevalent, and we will effectively have two nice, cleanly
separated mechanisms, one for entity definition and one for
validation, each of which perform their specified task well.
If you wish to argue that a new entity definition mechanism is
necessary, you're going to need to do better than noting that a DTD
is not preferred for validation. You need to demonstrate that it is
flawed from the perspective of entity definition, irrespective of and
orthogonal to any issues involved in validation.
Elliotte Rusty Harold
Effective XML (Addison-Wesley, 2003)