xml-dev - Re: Namespace Comments (and dtd encoding)

[james anderson <James.Anderson@mecomnet.de>]

Peter Murray-Rust wrote:
> 
> ...
> 
> The point is - I think - that the DTD parser is completely dumb. It doesn't
> care about colons (except to recognise that they are legal). I assume -
> though I haven't tried it - that this DTD will validate the example with
> any of the current parsers.
> 

i do not understand how such a reduced dtd <em>processor</em> will suffice.
before a dtd definition can be created, the universal name must be known.
otherwise the prefixes have been awarded the status of (temporarily) universal qualifiers.

imagine (to take the inverse tack on mr bourret's example) a situation where
the processor faced with a document streams of which various external entities
contain either "ambiguous" or "undetermined" prefixes.

1. "ambiguous" prefixes would arise where identical prefixes are present in
disjoint external entities and require accompanying attribute declarations in
order to disambiguate them - and thereby otherwise identical local names.

2. "undetermined" prefixes would arise where non-identical prefixes are
present in disjoint external entities, but accompanied with attribute
declarations which map respectively identical local names to the same
universal name.

in order to interpret either of these two cases correctly, the dtd processor
must understand universal names. (i've neglected examples here. if the
problem's not clear i'll put them together)

i think a similar situation could well arise within a single external entity,
but the spec is sufficiently unclear on valid dtd content, that i'm uncertain.
i take the example of disjoint entities since it demonstrates a case where a
combination of independently valid external subsets may or may not be valid
dependant on the prefix<->uri bindings which hold.

i had, until monday, presumed that the prefix-namespace bindings have to be
understood to hold at some point before elements are read, in order that the
effective dtd can be created and am having a hard time understanding how to
delay this binding, so to speak, beyond the close '>' in the doctype form.

i'd really like to know the binding at the point where the respective element
declaration is read, otherwise i have to delay its processing until some (at
the moment poorly specified) later point.

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