[topicmapmail] Should resourceData have a MIME type?

[Nikita Ogievetsky]

Kal wrote:
> On Monday 13 January 2003 15:17, Nikita Ogievetsky wrote:
> > Thinking about this issue again I must say that neither occurrence type,
> > nor scope, nor variant (which is not there yet) are the proper
syntactical
> > places
> > for expressing resourceData MIME type.
> > I am saying this because all off the above allow expressing properties
of
> > occurrence assertion. And MIME type is the property of the resource
itself,
> > not occurrence!
> >
>
> Thats a good point. We discussed this on IRC and it seems that we are
> converging on reification as the solution here. I agree with you that what
> should be reified is the occurrence resource itself (if you have a
resource
> rather than resource data) or the resourceData element (if your data is
> contained in-line).
>
> Of course, we should have PSIs for "resource-has-media-type" and for MIME
> types in general.

I like this. But I also wonder whether "class-instance" may be used here.
What are your reservations against it?

> We also discussed how this might be related to datatyping - it feels at
least
> as though data-typing is a similar issue and that a similar approach
*might*
> solve that too - although only for simple data types.
>
> In addition, it would appear that TMCL needs to take this into
consideration
> as it would be desirable to be able to constrain the media/data type of a
> class of occurrences (e.g. all "Picture" occurrences must be a PNG, GIF or
> JPG image; all "Age" occurrences must be media-type=text and
> data-type=integer)
>

That is an interesting idea. However this constraints should definitely be
optional
and customizable/extendable to allow for new MIME types as they arrive.
(like SVG, for example)
It is also interesting to keep a taxonomy of MIME types and have PSIs for
various image classes.  For example:
image->raster image->JPEG
        ->vector image->SVG
xml ->SVG

Than one can reference one of the MIME classes (or use DAML-like
expressions)
in the TMCL pattern rather than enumerating all applicable MIME types.

All the best,

--Nikita.

Nikita Ogievetsky, nogievet@cogx.com;
Cogitech Inc.        http://www.cogx.com
Topic Maps Tutorials and Consulting.
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