Semantics of Method Call Interception

From an object-oriented programming perspective, an important class of aspects (in the sense of aspect-oriented programming) can be modelled via method call interception (MCI). This concept allows us to intercept transitions from a caller to a callee in a way that extra functionality can be superimposed on the actual method call. We describe fundamental language constructs for MCI. The style of Natural semantics is used to specify the meaning of the constructs. The semantical formulation (as opposed to a formulation based on program transformation) shows that static type safety and separate compilation can be preserved when MCI is added to an object-oriented language.