xml-dev - Re: Public Identifiers

[Joe English <jenglish@flightlab.com>]

Paul Grosso <pgrosso@arbortext.com> wrote:

> Of course, public identifiers have to be resolved before they
> can be used, so some kind of catalog support would be needed
> in the tools you use

Not necessarily.  Heck, even URLs don't need to be resolved
before they're used; consider namespace URIs and RDF.

It would be perfectly reasonable for a processor with
built-in knowledge of particular DTDs to simply examine the
PUBLIC id to determine how to handle incoming documents.
If it already "knows" what the PUBLIC ID means, it
doesn't need the text of the DTD.

[ begin gripe ]

Except that PUBLIC IDs are somewhat less-than-useful in XML.
I'd really like to use:

    <?xml version='1.0' standalone='yes'?>
    <!DOCTYPE foo PUBLIC "-//ORG//Well Known DTD">

like I do with SGML, but XML makes me add a system identifier.
Since about half the XML tools I use seem to ignore the standalone
declaration and try to read the DTD anyway, it has to be a valid one.

So I can either use "http://org.org/well-known.dtd"
(and then I can't process the document on my laptop
while on the train), or I can use "/usr/local/lib/xml/well-known.dtd"
(and then nobody else can use the document).

So I end up halfway-tempted to do things the "XML way",
with namespaces:

    <foo xmlns="http://org.org/well-known.dtd">...</foo>

(a URI that *no* processor will attempt to resolve),
and then I can't use any SGML or DTD-aware XML tools.

Sigh.

[ end gripe ]

--Joe English

  jenglish@flightlab.com