Interface Annotations
An interface defines a class that is the base for both the implementation and the automatically created reference class. It is possible to add annotations to the interface to change the behaviour of the 源处理器 when creating the reference class.
Annotations are added as comments in this form:
// @MAXON_ANNOTATION{refclass=false}Annotations can be added to the interface itself. These annotations define the overall creation of the reference class.
Annotations can also be added to single functions of the interface.
Special annotations for COW interfaces are:
Annotations are used on the definition of the interface.
// This example shows an interface with additional annotations.// --------------------------------------------------------------------- // The reference class should be named GenericElementArrayRef // @MAXON_ANNOTATION{refprefix=Generic} // --------------------------------------------------------------------- class ElementArrayInterface : MAXON_INTERFACE_BASES (maxon::ObjectInterface) { MAXON_INTERFACE (ElementArrayInterface, MAXON_REFERENCE_NORMAL , "net.maxonexample.interfaces.elementarray" );
// --------------------------------------------------------------------- // This function should not be added to the reference class. // @MAXON_ANNOTATION{refclass=false} // --------------------------------------------------------------------- MAXON_METHOD Element* GetElement( maxon::Int index);
// --------------------------------------------------------------------- // This function should be used instead. // --------------------------------------------------------------------- MAXON_FUNCTION maxon::Result<Element*> GetElementResult( maxon::Int index) { Element* e = GetElement(index); if (e == nullptr ) return maxon::IllegalArgumentError( MAXON_SOURCE_LOCATION , maxon::String ( "Invalid Index." )); return e; }
// --------------------------------------------------------------------- // This function returns a clone of the array and returns an object of // the currently used reference class type. // @MAXON_ANNOTATION{refclassParameter=REFCLASS} // --------------------------------------------------------------------- template < typename REFCLASS> MAXON_FUNCTION maxon::Result<REFCLASS> CloneArray() const { iferr_scope ; maxon::ObjectInterface * o = Clone() iferr_return ; return REFCLASS(static_cast<typename REFCLASS::ReferencedType*>(o)); } };
The behaviour of the created reference class is defined by the annotations.
// This example uses the reference class defined with various annotations.// create a NullValue GenericElementArrayRef nullValue;
// since FindIndex() is not implemented it should // return the defined return value const maxon::Int index = nullValue.FindIndex( nullptr ); if (index == maxon::InvalidArrayIndex ) DiagnosticOutput ( "Could not find element." );
// create proper instance const maxon::Class<GenericElementArrayRef> componentClass = maxon::Classes::Get<GenericElementArrayRef>( id ); const GenericElementArrayRef elementArray = componentClass.Create() iferr_return ;
// use some functions GenericElementArrayRef elements = elementArray.CloneArray() iferr_return ; Element* const e = elementArray.GetElementResult(-1) iferr_return ;
