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  1. OMG Issue

OCL25 — Satisfaction of Operation Specifications (3)

  • Key: OCL25-69
  • Legacy Issue Number: 6550
  • Status: open  
  • Source: Anonymous
  • Summary:

    Author: Hubert Baumeister (baumeist@informatik.uni-muenchen.de),
    Rolf Hennicker (hennicke@informatik.uni-muenchen.de),
    Alexander Knapp (knapp@informatik.uni-muenchen.de)
    Description: Change Definition A.34 to allow the precondition to be weakened
    It is commonly accepted that a program S satisfying an operation specification may weaken the precondition. This corresponds to Bertrand Meyer's view of software specifications as contracts between clients of a program and program provider. This is in accordance with the explanation following Def. A.34: "In other words, the program S accepts each environment satisfying the precondition as input and produces an environment that satisfies the postcondition." This sentence admits the possibility that S may be defined for environments not satisfying the precondition.
    However Def. A.34 requires S to be defined exactly on the environments for which the precondition holds. Therefore, we propose to replace Def. A.34 by:
    An operation specification with pre- and postconditions is satisfied by a program S in the sense of total correctness if the computation of S is a function fS such that the restriction of fS to the domain of R is a total function fS|_dom(R): dom(R) -> im(R) and graph(fS|_dom(R)) \subseteq R.

  • Reported: OCL 2.0b2 — Tue, 11 Nov 2003 05:00 GMT
  • Updated: Thu, 8 Oct 2015 14:12 GMT