Detail

Flexible Type-Safe Linking of Components for Java-Like Languages

We define a framework of components based on Java-like languages,
where components are binary mixin modules. Basic components
can be obtained from a collection of classes by compiling such classes in
isolation; for allowing that, requirements in the form of type constraints
are associated with each class. Requirements are specified by the user
who, however, is assisted by the compiler which can generate missing
constraints essential to guarantee type safety.
Basic components can be composed together by using a set of expressive
typed operators; thanks to soundness results, such a composition is
always type safe.
The framework is designed as a separate layer which can be instantiated
on top of any Java-like language; a prototype implementation is
available for a small Java subset.
Besides safety, the approach achieves great flexibility in reusing components
for two reasons: (1) type constraints generated for a single component
exactly capture all possible contexts where it can be safely used;
(2) composition of components is not limited to conventional linking,
but is achieved by means of a set of powerful operators typical of mixin
modules.