KerML 1.1b1 RTF Avatar
  1. OMG Issue

KERML11 — End feature cannot be used in a feature chain expression

  • Key: KERML11-68
  • Status: open  
  • Source: Model Driven Solutions ( Mr. Ed Seidewitz)
  • Summary:

    According to 8.4.4.9.6 Operator Expressions, under "Control Functions":

    Given the above, a FeatureChainExpression of the form

    src.f
    

    (where src is an Expression) is semantically equivalent to the Expression

    expr : ControlFunctions::'.' subsets Performances::evaluations { 
        feature redefines ControlFunctions::'.'::source = src {
            feature redefines ControlFunctions::'.'::source::target 
                redefines f;
        }
        alias for f;
        return subsets source.f;
    }
    

    Note that the redefining feature for ControlFunctions::'.'::source::target also redefines the feature f. However, according to the constraint validateRedefinitionEndConformance (see 8.3.3.3.8 Redefinition), if a redefinedFeature is an end feature, then the redefiningFeature must be, too. But this prevents an end feature from being used as the target (i.e., f above) of a feature chain expression.

    This is particularly problematic, because, in the Kernel Semantic Library model StatePerformances, the declaration of StateTransitionBehavior::transitionLinkTarget has the feature value transitionLink.laterOccurrence, which is a feature chain expression that targets the end feature laterOccurrence.

  • Reported: KerML 1.0b2 — Sun, 22 Jun 2025 22:41 GMT
  • Updated: Sun, 22 Jun 2025 22:41 GMT