[sc34wg3] CTM templates - A proposal

Murray Altheim murray06 at altheim.com
Fri Aug 11 00:22:21 EDT 2006

Quoting Steve Pepper <pepper at ontopia.net>:

> Hi Murray,
> Thanks for your comment on templates. Based on your extensive experience
> with LTM, we would appreciate more detailed comments on the rest of the CTM
> spec [1] as well.
> | *  actually a slightly modified LTM that permits superclass-subclass
> |     associations to be expressed using a ';' rather than the ':' for
> |     class-instance.
> Could you post a snippet of a topic map that uses the ';' syntax
> extensively? I think it might help us design a syntax that would meet the
> kind of requirements you and others might have in this respect.

Hi Steve,

You can ask Lars Marius, as he knows all about it. I'd tried to talk
him into adopting it since the current syntax only supports one of the
two available XTM 1.0 association types.

In a nutshell, it's just a semicolon where a colon would normally be:

   [Fido : Dog]

   "Fido is an instance of the class "Dog"

so I have augmented the syntax to permit:

   [Dog ; Mammal]

   "Dog is a subclass of the class "Mammal"

The three fundamental relation types in Ceryle (there a few others,
but the three main ones) are:

    IsA     class-instance (or in a collection or mereological model,
            as in Cyc's #$Collection, this would express something
            akin to #$Individual)

    KindOf  superclass-subclass (or in a collection model, #$Collection)

    Has     (aka HasFacet) expresses a facet, characteristic, or
            property relation. In XTM this is expressed as a typed
            occurrence stating a property of its parent Topic.

I never bothered to create an LTM syntax for the "Has" association
template, as the existing LTM isn't particularly onerous:

   HasFacet( [TemporalThing] : Faceted, [Start] : Facet ) / Facet
   HasFacet( [TemporalThing] : Faceted, [End] : Facet ) / Facet

but this *certainly* could have a shortcut, as it's not particularly
pretty either.


Murray Altheim <murray06 at altheim.com>                              ===  = =
http://www.altheim.com/murray/                                     = =  ===
SGML Grease Monkey, Banjo Player, Wantanabe Zen Monk               = =  = =

        In the evening
        The rice leaves in the garden
        Rustle in the autumn wind
        That blows through my reed hut.  -- Minamoto no Tsunenobu

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