My research interests include type systems and operational semantics for programming languages, especially module systems, functional and, more recently, object-oriented languages (I must be going native). I also work on concurrency and parallelism.
I obtained my PhD in Computer Science under the supervision of Don Sannella at the LFCS, at the University of Edinburgh. Before joining Microsoft in 2000, I briefly worked for Harlequin Ltd. on their Dylan compiler. I designed and implemented the extended module system of Moscow ML, a popular byte-code compiler for Standard ML. I was also a post-doc researcher under Andrew Pitts at the University of Cambridge Computer Laboratory. At Microsoft, together with Andrew Kennedy and Nick Benton, I developed SML.NET, a Standard ML compiler with object oriented extensions, that targets the Common Language Runtime and is integrated with Visual Studio .NET. Working with Andrew Kennedy and Don Syme, I contributed to the design and implementation of Generics on the Common Language Runtime, focussing on verification. I was also responsible for the implementation of the concurrency constructs in Cω, an extension of C# with native support for join patterns as well as type-safe manipulation of XML and SQL-like data. Combining Generics and Cω led to my implementation of the Joins library, an efficient combinator library for Cω-style join patterns implemented in C# 2.0 and easily usable from (at least) C# 2.0 and Visual Basic 8.0.
The original (lock-based) joins library served as the runtime for Concurrent Basic - a natural extension of Visual Basic 9.0 with join pattern style concurrency. Thanks to Erik Meijer and Lucian Wischik for their support.
Separately, Dimitrios Vytiniotis and I have used Coq to study type inference for QML, a simple variant of ML with impredicative polymorphism (think System F extended with ML's implicit let-polymorphism).
Aaron Turon and I came up with novel, non-blocking implementation of join patterns (a re-implemenation of the lock-based C# Joins Library) that scales well on multi-core processors. This new implementation offers high-level, declarative synchronization (as before) with good parallel performance (the new bit).
Very recently, I worked with Gavin Bierman, Geoffrey Mainland, Erik Meijer and Mads Torgersen to give a high-level operational semantics for C#'s latest feature, asynchronous methods. Asynchronous methods make it easy to write asynchronous, concurrent code without resorting to explicit continuation passing style. See our forthcoming ECOOP 2012 paper.
Against all odds, I'm now working on probabilistic programming, including the Infer.NET Fun project.
Here is my list of publications.
I organized the The 2007 ACM SIGPLAN Workshop on ML.