Identifying XML Document Types (was XML media types revisited)

Simon St.Laurent simonstl at
Fri Jan 15 21:22:36 GMT 1999

At 02:27 PM 1/15/99 -0600, W. Eliot Kimber wrote:
>You're correct: none of them are viable, because they do not create
>self-describing objects. What is needed is a mechanism that allows a
>document to unambiguously point to the definition of what it is, from which
>applications can then determine the right thing to do.  MIME types go a
>long way, but they are managed outside the document, leaving open the
>question "how do I know what MIME types to associate with a document?".
>Schema-use declarations (many have been proposed) and architecture use
>declarations (the new PI-based syntax) are examples of workable solutions
>because they point to authoritative definitions of what the rules for the
>document are. Note that architecture use declarations are standardized
>today and trivially easy to implement support for. The external identifier
>for the architecture definition itself can be anything, including public
>IDs and MIME types.

Schemas may be a good answer (if they kill the internal subset escape
hatch), combining an assertion about document type with a way to check it.
Is there any comparable 'architecture validation' process?  Or are they
just assertions?

The only (obvious, anyway) flaw with these options are the need to load the
document before you know if it's worth processing - but that may be seen as
more a flaw of today's limited filesystems and transfer protocols, I suppose.

We're getting there...

Simon St.Laurent
XML: A Primer / Cookies
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Building XML Applications (March)

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