OCL21 — Issue: Virtual machine

Description: The OCL 2.0 specification should be behaviour-oriented and not implementation-oriented (see section 4.3).
Rationale: The idea of using OCL to describe itself is interesting from the research point of view, but unfortunately OCL is not a suitable metalanguage to define the meaning of other textual languages. I think that the best thing to do is to define a virtual machine and to describe the behaviour of the virtual machine using natural language. This technique was successfully used for languages like C, C+, Java, C#, and Prolog. I see no reasons why such a technique would fail for OCL. After all, OCL is less complex than modern programming language like C+, Java, or C#.
A proper description and implementation of the OCL virtual machine will create all the conditions to have a language that is platform/tool independent.

The specification can no doubt be improved. Most criticisms concern inconsistency and lack of formaility. Moving to "natural language" seems a retrograde approach. Work in progress attempts to remove inconsistency from auto-generation from models, and to improve formality by using an exposition of the semantics that can be checked by Isabelle.
Disposition: Closed, no change