[sc34wg3] The TMCL schema topic

Lars Heuer heuer at semagia.com
Mon Mar 16 10:37:26 EDT 2009

Hi Lars,

> The schema topic which represents an entire TMCL schema has  
> disappeared in the last draft. This topic is important for being able
> to attach metadata to schemas, such as name, creator, version number,
> source URL, etc etc. It is also important in order to provide an easy
> mechanism for detecting whether or not a given topic map actually  
> contains a TMCL schema.

May I ask why the schema topic was dropped? Sorry, I missed the
discussion, any hints appreciated. :)

To the schema topic: *If* we have a schema topic, I wonder if we
couldn't attach the constraints like "tmcl:topictype-constraint", and
"tmcl:associationtype-constraint" to that topic.

If I understood TMCL correctly, these kind of constraints enable /
disable some behaviour of the TMCL processor. I.e. if a topic which is
an instance of "tmcl:topictypeconstraint" exists, the validator has to
reject any topic which is used as topic type but is not an instance of

If my understanding (described above) is correct, I think it would be
much more nicely if we can attach this kind of information to the
schema topic (i.e. via associations where the schema topic plays a
role) instead of this keeping this:

    ttc isa topictype-constraint.

we could enable it via templates:

Best regards,

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