Re: DOM and SAX parsing in Ada

[Nick Roberts <nick.roberts@acm.org>]

Simon Wright <simon@pushface.org> wrote:

> > Regarding objective (1), I need a package that can read a DTD (a very
> > big and hairy one, in fact) and expand the general entities declared in
> > it.
> 
> I'm not completely up to speed on this, but aren't DTDs a bit old-hat? (of
> course there are many varieties of schema, I suppose old-hat-but-standard
> is better than was-current-five-years-back)

You're dead right, Simon, but OASIS uses a DTD (a whopper) for the
validation of DocBook/XML documents (see http://docbook.sourceforge.net/),
presumably because there are still more tools out there, currently, which
support DTD validation (only) rather than XML Schema validation. Perhaps
also of significance is that the DTD is used to declare appropriate default
values for various attributes and all the many DocBook character entities.

There are certain useful things that can be done by DTD (internal or
external) which, to my knowledge, cannot be done any other way. For example,
I have a need to break up a big source document into many files, and then
include them in a (logically single) DocBook document as entities.

I suspect that a lot of other people will need DTD support (if not actual
validation) for a while to come, for various reasons. It probably doesn't
hurt, if an XML processor supports DTDs at all, for it to validate. (It
/must/ also support standalone documents with no DTD!)

-- 
Nick Roberts