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Type-assignment (was Re: Are we losing out because of grammars?)

James Clark wrote:

> - You seem to think type-assignment is very important.  Why?

First, to implement ID/IDREF/IDREFS, we need type-assignment, 
or at least have to unambiguate relevant parts of the grammar.

Second, Relaxer generates a Java class for each elementRule.  
(To be precise, we have to merge elementRules sharing the same 
role and label, and have to consider tag/attPool as well.)

James Clark wrote:

> It's not in general easy, unless you restrict the grammar.  For example,
> consider the following TREX pattern:

Right.  Kawaguchi-san's another algorithm determines if a RELAX module is 
already such a restricted grammar.

James Clark  wrote:

> It depends how you restrict the grammar.  If you restrict the grammar as
> much as W3C's schemas, type assignment is significantly simpler than
> validation (since I believe I am correct in saying that for W3C schemas
> the type of an element depends only on its name and the names of its
> parents).

I believe so too.  On the other hand, because of this restriction, XML Schema 
is not closed under boolean operations, and cannot prohibit the first para 
from containing footnotes while allowing the other para to contain footnotes.
(I have to admit that this concern is rather theoretical.)