Staging Programs in Haskell

Staging is a programming technique where some parts of your program are annotated to be executed statically, at compilation time, while all execution is still guaranteed to be type-correct. The main advantage is that this gives the programmer much more fine-grained control about performance than is usually the case, in that statically known parts of the program can also be guaranteed to be executed statically. This allows, for example, the creation of efficient domain-specific languages, where (most) abstraction overhead can be eliminated.

In this tutorial, we will discuss the implementation of Staging in the context of Haskell (it is, in fact, available as a relatively little known subset of Template Haskell called “Typed Template Haskell”, even though it still has some practical shortcomings). We will introduce some common techniques that are useful when going from unstaged to staged programs, and look at some simple domain-specific language examples.

Andres Löh

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Andres Löh is a Haskell consultant and co-owner of Well-Typed LLP. He is based in Regensburg, Germany. He started using Haskell in 1997, when being an undergraduate student of mathematics in Konstanz, and has been an enthusiastic functional programmer ever since. Andres obtained a PhD in Computer Science from Utrecht University in 2004, on extending the Haskell language with capabilities for datatype-generic programming. After having been a university lecturer for several years, he joined Well-Typed in 2010.

Andres is very interested in applying functional programming to real-world problems, and in particular in datatype-generic programming, staging and metaprogramming, domain-specific languages, (dependent) type systems, and proving programs correct.