Object oriented module interconnection languages

The authors discuss two approaches to a module interconnection language (MIL) for object components. They first look at a prototypical programming language which makes the connectivity between objects explicit by making the specification of the object type identify not just the methods it provides but also those it requires. They then propose an algebra of objects which enables new objects (components) to be built from old and, because the algebra is closed, the new components themselves can be used to build further components