QVT13 — QVTo: Standard Library return types

• • QVTo Standard Library. Some operation's returned values would better return the TemplateParameterType **
    Several stdlib operations would be better changed to avoid doing unnecessary castings on the returned value of the operation.

For AnyType::oclAsType(oclType) operation I could write:

var aClass : Class := anotherVar.oclAsType(Class);

However, for Model::objectsOfType(OclType) operation I can't do:

var aClassSet : Set(Class) := aModel.objectsOfType(Class);

I have to do the following, instead:

var aClassSet : Set(Class) := aModel.objectsOfType(Class).oclAsType(Set(Class));

Therefore, for end-user usability, I propose exploiting TemplateParameterType and changing some QVTo Standard Library operations

Element::subobjectsOfType(OclType) : Set(T)
Element::allSubobjects(OclType) : Set(T)
Element::subobjectsOfKind(OclType) : Set(T)
Element::allSubobjectsOfKind(OclType) : Set(T)
Element::clone() : T
Element::deepclone() : T
Model::objectsOfType(OclType) : Set(T)
Model::copy() : T
Model::createEmptyModel(): T

Note: this approach is made in the Object::asOrderedTuple() : OrderedTuple(T) operation.

8.3.5.7 createEmptyModel static Model::createEmptyModel() : Model Creates and initializes a model of the given type. This operation is useful when creating intermediate models within a transformation.

QVTo Standard Library. Some operation's returned values would better return the TemplateParameterType **
Several stdlib operations would be better changed to avoid doing unnecessary castings on the returned value of the operation.

For AnyType::oclAsType(oclType) operation I could write:

var aClass : Class := anotherVar.oclAsType(Class);

However, for Model::objectsOfType(OclType) operation I can't do:

var aClassSet : Set(Class) := aModel.objectsOfType(Class);

I have to do the following, instead:

var aClassSet : Set(Class) := aModel.objectsOfType(Class).oclAsType(Set(Class));

Therefore, for end-user usability, I propose exploiting TemplateParameterType and changing some QVTo Standard Library operations

Element::subobjectsOfType(OclType) : Set(T)
Element::allSubobjects(OclType) : Set(T)
Element::subobjectsOfKind(OclType) : Set(T)
Element::allSubobjectsOfKind(OclType) : Set(T)
Element::clone() : T
Element::deepclone() : T
Model::objectsOfType(OclType) : Set(T)
Model::copy() : T
Model::createEmptyModel(): T

Note: this approach is made in the Object::asOrderedTuple() : OrderedTuple(T) operation.

Discussion

subobjectsOfType etc duplicate QVT13-53

clone/deepclone merged into QVT13-53

Model::copy/createEmptyModel - NO. Model is the correct return type.