[topicmapmail] Should resourceData have a MIME type?

[Robert Barta]

On Sat, Jan 11, 2003 at 04:13:28PM -0500, Thomas B. Passin wrote:
> I have noticed that some people put markup into the resourceData element of
> an occurrence.  One example is Kal Ahmed's nice topic map of the TM4J API.
...
> Presumably for a resourceRef, the application can find out the MIME type
> when it retrieves the resource, but not so for resource data.

Thomas,

Not all protocols give you some object meta data. HTTP does, SMTP can do,
FTP, file: do not.

> It would be clumsy to define different occurrence types to hold different
> types of resource data.  It would be very complex to specify each instance
> as being of some type that holds the right data type.

Whether it is clumsy may depend on the notation you are using. In
AsTMA= I would write

  holidays subclasses time-interval
  bn: Holidays
  in: sleeping, drinking, eating, programming
  in (text-html) : <b>sleeping, drinking, eating, programming</b>

and reify text-html with the appropriate PSI (if there is one) or the
HTML standard. But occurrence types do not feel to be the right thing
to use here (?).

I had a similar problem with a topic map of references for TM
literature. There I chose to use scopes:

  graham01 (article)
  bn        : RDF and Topic Maps - An Exercise in Convergence
  bn @ latex: {RDF} and {Topic Maps} - An Exercise in Convergence
  ...

When run through the processor it will first look for a LaTeX variant
to give better results. Not overly hi-tech but it works.

Another option would be to reify the occurrence data itself and to
associate it with a MIME type. While the MIME type is meta data and
this seems the right thing to this approach is quite error prone.

Another would be to tuck this away into a variant section:

 <variant>
     <parameters><topicRef xlink:href="#text-html"/></parameters>
     <variantName>
        <resourceData><html:b>sleeping, drinking, eating, programming</html:b></resourceData>
     </variantName>
 </variant>

But these - I reckon - are more thought as an extension mechanism for
naming and not so much attaching values to a topic.

> It would be very simple to add an optional attribute to resourceData that
> would specify the MIME type.  Then my app could get an occurrence of Kal's
> data, discover that it is intended to be HTML, and display it accordingly.
> Even inline images could be included, along with the other MIME types.

Yes, there is something missing. Maybe because introducing something
would have opened another box of Pandora (she had a few): What about
other "data types"?

    - Integer,
    - float,
    - ...
    - building new data types (record of a text, a float and one integer)

Or would you restrict it to text data?

[ There was recently a suggestions for a typing system floating by (Murray?) ]

> This would be so useful and so simple - and backwards compatible - that I
> urge its adoption in the next version of the ISO standard.

Useful, yes. Simple, hopefully.

\rho