xml-dev - Re: Tool X (was Re: simple question on namespaces.)

[Jonathan Borden <jborden@mediaone.net>]

Uche Ogbuji wrote:

> Arjun Ray quotes anonymous exchange from internal W3C list:
>
> > : For example, if some company starts using a name space prefix but
> > : doesn't define its vocabulary in some standardized way (so that any
> > : conforming tool can interpret it and validate against it), how can
> > : you ever know if you've handled all their names if you're tryin to
> > : compete with them by providing support for their data elements? You
> > : can't.
>
> Ding ding ding ding!  Now for all those who didn't know what Paul meant by
> "Tool X", this is but one of the possible culprits (and possibly the most
> insidious).  There might also be my example of a tool that retrieves a
> schema and makes processing assumptions differently from a tool that
> doesn't molest the namespace URI.  There are other faces of tool X, and
> all of them are problematic in pratice regardless of the "rightness" of
> their behavior.
>
    I'm not sure that anything in this argument is unique to either
namespaces or whether a schema is retrieved by URL. Isn't this simply a
question: given a document how can you define its vocabulary?

1) look at the DTD indicated by a doctypedef.
2) look at an XML Schema indicated by a schemaLocation URI
3) look at an RDF Schema indicated by a namespace URI.

etc. etc.

The point is that without some type of schema one can never know what
elements might be contained in 'the next' document produced by a particular
tool. Whether the element names are QNames or are all of the form:

wuga-wuga-wuga---foo
wuga-wuga-wuga---bar

is totally irrelevent. Without either a prose specification or a machine
readable schema the vocabulary is not constrained.

Suppose I state:

Documents conformant to XXX must validate against the DTD locatable by a
DOCTYPE definition.

-or-

Documents conformant to YYY must validate against an XSD locatable by the
document element namespace URI.

Leaving aside the public id FPI and assuming we are talking about a system
identifier (for the purposes of constraining this discussion) each mechanism
provides a single system identifier by which a schema is to be located.

What is the functional difference?

Jonathan Borden
The Open Healthcare Group
http://www.openhealth.org