xml-dev - Re: Public Identifiers

[Paul Grosso <pgrosso@arbortext.com>]

At 07:14 2000 07 25 -0700, Joe English wrote:
>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).

It is true that XML requires a system id, but the rest of what you
say does not follow.

If any tool is going to be able to use the public id to access an
actual resource, there needs to be some way to resolve it such as
a catalog.  Given that your tool needs to have catalog support,
you can specify in your catalog that public identifiers should be
preferred over system identifiers.  Then, you can give any system
id to satisfy XML, and the public id will be used.

The caveat is that all the tools you use need to have catalog support,
and many XML processors don't yet.  But, as per my earlier postings [1],
adding catalog support may not be that difficult (and I hope that more
XML and XSLT and similar processors add catalog support--maybe xml-dev
can help push this request).

paul

[1] http://lists.xml.org/archives/xml-dev/200007/msg00241.html