[topicmapmail] LTM 1.3 Change Proposal

[Lars Marius Garshol]

* Murray Altheim
| 
| In XTM 1.0 we specified both class-instance and superclass-subclass
| associations.

Yep. Some background on that can be found here:

<URL: http://www.ontopia.net/topicmaps/materials/syntax-comments-2000-09.html#TOPIC >

| With the XTM shorthand of <instanceOf> we had the ready ability to
| express Topic types, and this showed up in LTM as the colon (':')
| following a Topic ID.
| 
|     [john : human]
| 
| meaning 'john' is an instance of the class 'human'.

Yep.
 
| With the release of Ceryle recently the presence of its variant
| syntax on LTM 1.2 might be noted as a proposal for 1.3 (I think I've
| mentioned this one before). 

You have, yes.

| It's a simple additional shorthand to mirror the colon (':')
| character, only to perform this for the XTM 1.0 superclass-subclass
| association using a semicolon (';') character, e.g.:
| 
|     [human ; mammal]
| 
| meaning 'human' is a subclass of the superclass 'mammal'.

I've given this some thought over the Christmas holidays, and came to
the conclusion that I'm not very keen on a shorthand specifically for
superclass-subclass. I think the idea of being able to express a large
number of associations (of specifiable type) would be useful, and that
this could then be used for superclass-subclass, too.

We also discussed this in an Ontopia meeting today, where most people
were similarly unsympathetic to the idea. It was also mentioned that
this doesn't really make it that easy to build a hierarchy, though
admittedly it's easier than at present.

So on balance I'm against this, even if I'm sympathetic towards the
general idea of making it possible to build large association
structures concisely.

-- 
Lars Marius Garshol, Ontopian         <URL: http://www.ontopia.net >
GSM: +47 98 21 55 50                  <URL: http://www.garshol.priv.no >