Xavier Leroy

A concurrent, generational garbage collector for a multithreaded implementation of ML

This paper presents the design and implementation of a “quasi real-time” garbage collector for Concurrent Caml Light, an implementation of ML with threads. This two-generation system combines a fast, asynchronous copying collector on the young generation with a non-disruptive concurrent marking collector on the old generation. This design crucially relies on the ML compile-time distinction between mutable and immutable objects.

Polymorphic type inference and assignment

We present a new approach to the polymorphic typing of data accepting in-place modiflcation in ML-like languages. This approach is based on restrictions over type generalization, and a reflned typing of functions. The type system given here leads to a better integration of imperative programming style with the purely applicative kernel of ML. In particular, generic functions that allocate mutable data can safely be given fully polymorphic types. We show the soundness of this type system, and give a type reconstruction algorithm.

Dynamics in ML

Objects with dynamic types allow the integration of operations that essentially require run-time type-checking into statically-typed languages. This paper presents two extensions of the ML language with dynamics, based on what has been done in the CAML implementation of ML, and discusses their usefulness. The main novelty of this work is the combination of dynamics with polymorphism.