Copenhagen Programming Language Seminar

Joint HIPERFIT and COPLAS double presentation:

Giving Haskell a promotion
Supercompilation by evaluation

Simon Peyton-Jones
Microsoft Research (Cambridge, UK)

November 9th, 2011, 11:00 - 12:30
DIKU, Universitetsparken 1, Lille Auditorium


Giving Haskell a promotion

Static type systems strive to be richly expressive while still being simple enough for programmers to use. I'll describe a recent experiment that enriches Haskell's kind system with two features promoted from its type system: data types and polymorphism. The new system has a very good power-to-weight ratio: it offers a significant improvement in expressiveness, but, by re-using concepts that programmers are already familiar with, the system is easy to understand and implement.

Supercompilation by evaluation

Supercompilation is a technique due to Turchin which allows for the construction of program optimisers that are both simple and extremely powerful. Supercompilation is capable of achieving transformations such as deforestation, function specialisation and constructor specialisation. But the papers are jolly hard to understand. I'll show how the a call-by-need supercompilation algorithm can be recast to be based explicitly on an evaluator, and in the process extend it to deal with recursive let-expressions.

Short bio:
Simon Peyton Jones, MA, MBCS, CEng, graduated from Trinity College Cambridge in 1980. After two years in industry, he spent seven years as a lecturer at University College London, and nine years as a professor at Glasgow University, before moving to Microsoft Research (Cambridge) in 1998. His main research interest is in functional programming languages, their implementation, and their application. He has led a succession of research projects focused around the design and implementation of production-quality functional-language systems for both uniprocessors and parallel machines. He was a key contributor to the design of the now-standard functional language Haskell, and is the lead designer of the widely-used Glasgow Haskell Compiler (GHC), for which he, together with his colleague Simon Marlow, received the 2011 ACM SIGPLAN Programming Languages Software Award.

Scientific host: Fritz Henglein Administrative host:Jette Møller. All are welcome.
The Copenhagen Programming Language Seminar (COPLAS) is a collaboration between DIKU, DTU, ITU, and RUC.
COPLAS is part of the FIRST Research School.
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