Re: comments on OCL



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Heinrich Hussmann (Heinrich.Hussmann@inf.tu-dresden.de)
Mon, 13 Dec 1999 17:30:05 +0200


Dear Hubert, dear Daniel, Hubert Baumeister wrote: > >[text cut out] > > Another solution is to use a least fixpoint operator to achieve this. So the designers of OCL could > have had in mind to always take the > least fixpoint of such an equation, similar to the use of initial models in algebraic > specifications. > > The point here is that there is no formal semantics of OCL; so one can only speculate about the > intentions of the designers of OCL. Thus, what we really need is a agreed upon formal semantics of > OCL which > could be used to discuss these kind of questions. > I remember a very similar informal discussion during the last UML'99 conference (about "recursion in OCL operations"). You should be aware that the OMG people definitely want to have such issues sorted out. So there is no basic objection against, e.g., proposing a least fixpoint operator for OCL. The problem the OMG currently has is that nobody feels really responsible for OCL. Jos Warmer is no longer able to spend much time on OCL. But instead of speculating about the intentions of the original designers, it would be an alternative to ask Jos. For a short email question, one ususally gets a short reponse from him. Best regards Heinrich -- Prof. Dr. Heinrich Hussmann Dresden University of Technology Department of Computer Science Phone +49 351 463 8464 Fax +49 351 463 8459 Email Heinrich.Hussmann@inf.tu-dresden.de


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