Étienne Duris

Dynamic Attribute Grammars

Although Attribute Grammars were introduced long ago, their lack of expressiveness has resulted in limited use outside the domain of static language processing. With the new notion of Dynamic Attribute Grammars defined on top of Grammar Couples, we show that it is possible to extend this expressiveness and to describe computations on structures that are not just trees, but also on abstractions allowing for infinite structures. The result is a language that is comparable in power to most first-order functional languages, with a distinctive declarative character.

Reflection-based implementation of Java extensions: the double-dispatch use-case

Reflection-based libraries could sometimes be used to extend the expressive power of Java without modifying the language nor the virtual machine. In this paper, we present the advantages of this approach together with general guidelines allowing such implementations to be practicable. Then, we show how these principles have been applied to implement an efficient and general double-dispatch solution for Java.

A reflective implementation of Java multi-methods

In Java, method implementations are chosen at runtime by late-binding with respect to the runtime class of just the receiver argument. However, in order to simplify many programming designs, late-binding with respect to the dynamic type of all arguments is sometimes desirable. This behavior, usually provided by multimethods, is known as multipolymorphism. This work presents a new multimethod implementation based on the standard Java reflection mechanism. Provided as a package, it does not require any language extension or any virtual machine modification. The design issues of this reflective implementation are presented together with a new and simple multimethod dispatch algorithm that efficiently supports class loading at runtime. This implementation provides a practicable and fully portable multimethod solution.