Where does UML explicitly intend String Expression elements to be used?

In the Unified Modeling Language (UML) specification, a StringExpression is a specialized ValueSpecification used to compute dynamic names via string manipulation and parameter substitution. Specifically, UML defines StringExpression to be used as the value specification for the nameExpression property owned by NamedElement (and by extension ParameterableElement) when elements are part of template specifications. During template instantiation, the StringExpression evaluates expressions that incorporate template parameters to dynamically generate the resulting element names. Because ParameterableElements within template specifications rely on nameExpression to determine their names upon binding, UML explicitly intends StringExpression elements to serve as the ValueSpecifications for these nameExpressions within template definitions.

B: UML explicitly restricts StringExpression usage to nameExpression properties within templates rather than allowing arbitrary, custom dynamically-generated name specifications for any general NamedElement.

C: StringExpression is a concrete subclass of Expression (and ValueSpecification), not a form of OpaqueExpression, which uses body strings and languages for general evaluation.

D: StringExpression is a valid, standard metaclass defined in the UML specification (under the Expressions and Templates packages).

1. Object Management Group (OMG). "OMG Unified Modeling Language (OMG UML), Version 2.5.1." Section 7.4.4 (StringExpression) and Section 9.2 (Templates), pp. 71-73, 105-108.

2. Object Management Group (OMG). "OMG Unified Modeling Language (OMG UML), Superstructure, Version 2.4.1." Section 7.3.55 (StringExpression), pp. 143-144.