Combining subsumption and binary methods: An object calculus with views

We present an object-oriented calculus which allows arbitrary hiding of met hods in prototypes, even in the presence of binary methods and friend funct ions. This combination of features permits complete control of the interfac e a class exposes to the remainder of a program (which is of key importance for program readability, security and ease of maintenance), while still al lowing complex interactions with other classes belonging to the same module or software component. This result is made possible by the use of views. A view is a name that spe cifies an interface to an object. A set of views is attached to each object and a method can be invoked either directly or via a view of the object.