Re: SUO: OMG, UML and Ontologies
John.Velman@HSC.com wrote:
>
> Francis,
>
> In your earlier messages you said
>
> "For those that dont know, UML is a graphical language that has been
> effectively used for a variety of tasks. It does have a formal semantics,
> which
> is ultimately based on OCL which is a 1st order constraint language, not a
> million miles away from FOL."
>
> Can you be a little more precise than "not a million miles away..?"
I guessed that some people may be confused by the graphical syntax of UML.
Underlying the UML is OCL. OCL is described in ISBN 0-201-37940-6.
I am not completely familiar with it; however it has simple constraints, forall,
implies, types, collections, objects, a lot of stuff.
OCL is the language in which the semantics of UML is expressed, in conjunction
with the MOF (Meta Object Facility). This fact is normally hidden from the
punter; but it is still true.
A logician would probably puke when reading its definition, but that too would
miss the point.
A major point: neither UML 2.0 nor OCL are set in stone. They are subject to
collective bargaining. Furthermore, the groups responsible are actively
canvassing for suggestions.
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