Re: Escher could have drawn it (Re: XML Schema and Entities)

[David Brownell <david-b@pacbell.net>]

> >But... they're called Processing Instructions!
> 
> A historical curiosity. It refers to processing the document *after* 
> SGML has finished with it (eg typesetting).

Whatever SGML says is NOT part of the XML spec, and
it's inappropriate to rely on SGML-isms (except as a source
of historical curiousities :).  XML certainly permits what Alaric
initially sketched.


>     The whole point about PIs is that they are NOT part 
> of the structure of the document.

I expect you mean to say that PI locations aren't constrained
by the DTD (or W3C Schema etc) ... they are most certainly
part of the document structure.  Look at the XML and Infoset
specs; they both clearly show that.

Applications see data, including PIs, and they get to choose
what do do with it.  PIs are good when you want to do things
that elements or attributes don't easily permit, likely because
of some DTD/Schema/... related constraint.

- Dave