SAX and delayed entity loading

Simon St.Laurent simonstl at
Thu Dec 3 19:39:43 GMT 1998

At 02:17 PM 12/3/98 -0500, John Cowan wrote:
>I think it is important to distinguish between the use of unparsed
>entities (which involves notations) and the use of notations.
>Notations that govern elements through the use of a NOTATION attribute
>are a powerful feature for describing
>the syntax of what's in the element, as is shown by the repeated
>attempts to reinvent them in various schema proposals.  As stated in my
reply to Eliot, they
>provide a distributed registry as opposed to the centralized registry
>plus private use mechanism of MIME, but sacrifice MIME's declarative
>features that allow partial interpretation of unknown types.

I still argue that notations are a waste of time based on the misguided
notion that information about dependencies (of whatever type) actually
belongs in the document.  

Let the dependent pieces be self-describing (MIME or something better), and
you'll have a far more manageable system.  Keep as little information in
the document as possible, and remember that there are other tools out there
that can describe non-XML data types.  XML can focus on XML, which is what
is does best, and leave the rest of this out of it.

If the dependencies are within the document, then that's a case for
meaningful and flexible schemas, not for notations.  If schemas won't cut
it, then maybe you can turn to an external source for information on
element types, but it seems like you've really gone too far at that point.

>> How
>> would I apply a MIME type to an attribute?  More important, why one earth
>> would I want to?  Seems like some pretty heavy overkill.
>To say what the internal syntax of the attribute value is.

Er, yes, that's overkill, like I said.  Nuclear weapons to kill gnats and
all that.  Seems like a schema could crush that gnat quite nicely, and even
use MIME types if necessary, without resorting to notations.

Simon St.Laurent
XML: A Primer / Cookies
Sharing Bandwidth (December)
Building XML Applications (January)

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