Adding Type Constructor Parameterization to Java
Vincent Cremet and Philippe Altherr: Adding Type Constructor Parameterization to Java, JOT vol. 7, no. 5.
We present a generalization of Java’s parametric polymorphism that enables parameterization of classes and methods by type constructors, i.e., functions from types to types. Our extension is formalized as a calculus called FGJ?. It is implemented in a prototype compiler and its type system is proven safe and decidable. We describe our extension and motivate its introduction in an object-oriented context through two examples: the definition of generic data-types with binary methods and the definition of generalized algebraic data-types. The Coq proof assistant was used to formalize FGJ? and to mechanically check its proof of type safety.
FGJ? is a simple extension of (Featherweight) Java’s generics, where type parameters may be type constructors (functions from types to types). This very readable paper finally made me understand GADTs.
(Previously: Generics of a Higher Kind on Scala’s support for the same idea.)
- First-class modules: hidden power and tantalizing promises
- Erasure and Polymorphism in Pure Type Systems
- Recent Apple Java Update Doesn’t Fix Critical Java Flaw Claims Researcher
- Amazon Courts Windows Developers by Adding .Net to its Elastic Beanstalk
- New Java Vulnerability Found Affecting Java 5, 6, and 7 SE