Abstract
From its beginnings, OCL is based on a strict semantics for undefinedness, with the exception of the logical connectives of type Boolean that constitute a three-valued propositional logic. Recent versions of the OCL standard added a second exception element, which, similar to the null references in object-oriented programming languages, is given a non-strict semantics. Unfortunately, this extension has been done in an ad hoc manner, which results in several inconsistencies and contradictions.
In this paper, we present a consistent formal semantics (based on our HOL-OCL approach) that includes such a non-strict exception element. We discuss the possible consequences concerning class diagram semantics as well as deduction rules. The benefits of our approach for the specification-pragmatics of design level operation contracts are demonstrated with a small case-study.
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Brucker, A.D., Krieger, M.P., Wolff, B. (2010). Extending OCL with Null-References. In: Ghosh, S. (eds) Models in Software Engineering. MODELS 2009. Lecture Notes in Computer Science, vol 6002. Springer, Berlin, Heidelberg. https://doi.org/10.1007/978-3-642-12261-3_25
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DOI: https://doi.org/10.1007/978-3-642-12261-3_25
Publisher Name: Springer, Berlin, Heidelberg
Print ISBN: 978-3-642-12260-6
Online ISBN: 978-3-642-12261-3
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