Talk: 16:15-17:00 (English)

Structuring effectful programs

Historically, Haskell has been using monads to encode effects in programs, and monad transformers to provide a modular way to combine several such effects. More recently, algebraic effects have become increasingly popular as a mechanism to replace monad transformers. Often, discussions about the advantages and disadvantages of the various approaches seem to focus on technical details and not on the bigger question of how scalable effectful applications should actually be designed. In this talk, I am hoping to provide a brief introduction to both monad transformers and algebraic effects and then explain how I believe that effectful programs should be structured in such a way that the choice between these approaches becomes mostly irrelevant.

Andres Löh


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, domain-specific languages, (dependent) type systems, parallel and concurrent programming, and the theory of version control.