MIME types vs. DOCTYPE (was RE: ANNOUNCE: New XHTML WD)

[David Megginson]

Jonathan Borden writes:

 > excellent. one point: there is no reason to define text/xhtml as
 > opposed to using text/xml and inserting a DOCTYPE or perhaps a
 > default xmlns definition. If a user-agent needs to know the DOCTYPE
 > ... look at it!

Unfortunately, that doesn't work at all -- all DOCTYPE gives me is the
name of the root element, optionally accompanied by an internal DTD
subset and identifiers for an external DTD subset.

The name of the root element is locally-scoped to the document itself,
so it's useless for type discovery (what if my document type and yours
both use "article" as the name of the root element?); the public
identifier (or the system identifier if it is an absolute URI) can
uniquely identify the entity containing the external DTD subset but
not the document type itself.

Both namespaces and architectural forms provide the means for uniquely
identifying the types of at least parts of a document (specific
element and attribute types for namespaces, specific architectural
views for AFs), but why should a client have to go to all that
trouble?  Isn't it easier to identify the resource type externally so
that it can be handed directly to the correct processor?


All the best,


David

-- 
David Megginson                 david at megginson.com
           http://www.megginson.com/

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