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17.5.3 TemplateBinding


   A template binding represents a relationship between a templateable element and a template. A template binding specifies the substitutions of actual parameters for the formal parameters of the template.



    DirectedRelationship (from Kernel ) on page 62


   TemplateBinding is a directed relationship from a bound templateable element to the template signature of the target template. A TemplateBinding owns a set of template parameter substitutions.


   No additional attributes


   • parameterSubstitution : TemplateParameterSubstitution [*] The parameter substitutions owned by this template binding. Subsets Element::ownedElement.

Issue 8513 -add subsets constraint for ‘Element::owner’ and fix font; also change ‘template’ to ‘signature’


   [1] Each parameter substitution must refer to a formal template parameter of the target template signature.

   parameterSubstitution ->forAll(b | template.parameter->includes(b.formal))

   [2] A binding contains at most one parameter substitution for each formal template parameter of the target template signature.

   template.parameter->forAll(p | parameterSubstitution ->select(b | b.formal = p)->size() <= 1)


   The presence of a TemplateBinding relationship implies the same semantics as if the contents of the template owning the target template signature were copied into the bound element, substituting any elements exposed as formal template parameters by the corresponding elements specified as actual parameters in this binding. If no actual parameter is specified in this binding for a formal parameter, then the default element for that formal template parameter (if specified) is used.

   Semantic Variation Points

   It is a semantic variation point


   if all formal template parameters must be bound as part of a binding (complete binding), or


   if a subset of the formal template parameters may be bound in a binding (partial binding).

   In case of complete binding, the bound element may have its own formal template parameters, and these template parameters can be provided as actual parameters of the binding. In case of partial binding, the unbound formal template parameters are formal template parameters of the bound element.


   A TemplateBinding is shown as a dashed arrow with the tail on the bound element and the arrowhead on the template and the keyword «bind». The binding information is generally displayed as a comma-separated list of template parameter substitutions:

   <template-param-substitition> ::= <template-param-name> ‘->’ <actual-template-parameter>

   where the syntax of <template-param-name> depends on the kind of ParameteredElement for this template parameter substitution and the kind of <actual-template-parameter> depends upon the kind of element. See ParameterableElement (from Templates) on page 647 (and its subclasses).


Issue 8513 -add proper cross-references

   For examples of templates, the reader is referred to those sections that deal with specializations of TemplateableElement, in particular ClassifierTemplates on page 656 and PackageTemplates on page 664.