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  1. OMG Issue

UML14 — UML 1.4 RTF issue: OCL: grammar is ambigous

  • Key: UML14-1025
  • Legacy Issue Number: 3389
  • Status: closed  
  • Source: Anonymous
  • Summary:

    In OCL versions prior to UML 1.3, type names had to begin with a
    upper-case character. This was changed, and the rules for typeName and
    name are now identical.
    Unfortunately, this introduces an ambiguity into the OCL grammar rule
    pathName := (<typeName> | <name>) ("::" (<typeName> | <name>))*

    This problem could be solved by dropping the distinction between names
    and type name completely. The path name rule could be changed to:
    pathName := <name> ("::" <name>)*

    Now, the problem arises that it is not possible to distinguish between
    property accesses and type literals if they have the same name. For
    example, consider the following UML model:

    • Classes TypeA, typeB, TypeC
    • Association between TypeA and TypeC, association end at TypeC is
      named typeB.
      The expression "typeB" in the context of "TypeA" might either be
      interpreted as a navigation to the association end
      "typeB", and hence result in an object of "TypeC", or as the type
  • Reported: UML 1.2 — Wed, 1 Mar 2000 05:00 GMT
  • Disposition: Resolved — UML 1.3
  • Disposition Summary:

    No Data Available

  • Updated: Fri, 6 Mar 2015 21:37 GMT