[topicmapmail] LTM 1.3 Change Proposal

[Murray Altheim]

Lars Marius Garshol wrote:
> (Note: while this may look like a discussion between Steve and me,
> this email is really a summary of the discussions we had at an
> internal Ontopia meeting today. So Steve was stating his opinion, but
> I'm summarizing the result of meeting attended by Steve, me, and
> others. Throughout "we" refers to the meeting consensus.)
[...]
> | * untyped associations and occurrences
> | * untyped association roles
> 
> We strongly feel that this should not have been in XTM 1.0 to begin
> with, and we very much do not want this to be supported by LTM.

This seems to entirely forget the impetus that intelligently lead
to the decision taken in XTM 1.0 to not require typing on
associations and occurrences, as well as a number of other optional
but generally necessary features. It was (to my recollection)
considered by the group the domain of a constraint language, not an
interchange syntax, to prohibit this sort of thing. Nor to my recol-
lection were these "strong feelings" voiced during the development
of XTM. I seem to remember everyone understanding the reasoning
behind not constraining XTM 1.0 any more than we did. Interchange
syntax, not constraint language.

During many stages of a Topic Map's life cycle there are things that
are simply unknown. For example, we allow empty <member> objects
simply because it's got to be possible to create an empty association
before one can populate it. By the same token, not all associations
or occurrences have known types. Sometimes, one simply knows that a
given resource is an occurrence of a Topic -- the type may be added
later, or not at all. Providing no way to specify typeless associations
or occurrences just leads users to create dummy types in order to
create a workaround for the (at that point, inappropriate) constraint.

If we prohibit incomplete information, we just make it much more
difficult for users to finally fill that information in. This kind of
constraint is even more of a problem for LTM as an authoring language,
where people may just be beginning to create a Topic Map and not have
all the pieces together yet. If one wants to write a feature into an
Topic Map application that flags untyped associations and occurrences,
that's one thing, but it doesn't belong in either an authoring or
interchange syntax. I also think the world of Topic Maps is a heck of
a lot larger than these kind of constraints would seem to imply.

Murray

......................................................................
Murray Altheim                    http://kmi.open.ac.uk/people/murray/
Knowledge Media Institute
The Open University, Milton Keynes, Bucks, MK7 6AA, UK               .

                  Empty handed, holding a hoe,
                  Walking, riding a water buffalo,
                  A man is crossing over a bridge;
                  The bridge, not the water, flows.

                         -- Mahasattva Fu, The Blue Cliff Record [96]