Smart Modules for Java-like Languages

We present SmartJavaMod, a language of mixin modules supporting compositional compilation, and constructed on top of the Java language. More in detail, this means that basic modules are collections of Java classes which can be typechecked in isolation, inferring constraints on missing classes and allowing safe reuse of the module in as many contexts as possible. Furthermore, it is possible to write structured module expressions by means of a set of module operators, and a type system at the module level ensures type safety, in the sense that we can always reduce a module expression to a well-formed collection of Java classes. What we obtain is a module language which is extremely flexible and allows the encoding (without any need of enriching the core level, that is, the Java language) of a variety of constructs supporting software reuse and extensibility.