safe and flexible objects
We design a calculus where objects are created by instantiating classes, as well as mixins. Mixin-instantiated objects are "incomplete objects", that can be completed in object-based fashion. The combination of class-based features with object-based ones offers some flexible programming solutions. The fact that all objects are created from fully-typed constructs is a guarantee of controlled (therefore reasonably safe) behavior.
mixins incomplete objects types language design