[ZPT] Do people use local versions of tal, metal dtd's?

Evan Simpson evan@digicool.com
Thu, 31 May 2001 13:51:12 -0500


From: "Lynn Walton" <waltonl@franklin.edu>
> Do people who are using ZPT (or really in general any externally
> referenence dtd file) usually really reference the dtd on the external
> site as in
> <html xmlns:tal="http://xml.zope.org/namespaces/tal"
>       xmlns:metal="http://xml.zope.org/namespaces/metal"
>       metal:define-macro="master">
> or do they obtain the dtd and store it locally?

A couple notes about namespace declarations:

1. They're only used for DTD validation, or in the case of ZPT,
identifying a namespace.

2. A URN such as "http://xml.zope.org/namespaces/tal" is *not* required
to be a URL for the actual DTD.  As with TAL and METAL (which *have no*
DTD!) they are convenient ways to construct a unique name.

3. If you need a DTD for any reason, you should keep a local copy,
indexed by its URN.  Unlike web pages, DTDs are meant to be utterly
static: a new DTD had better have a new URN.

That's my understanding, anyway.

Cheers,

Evan @ digicool