Free Monads

We'll meet for dinner and drinks at Uni-Pizzeria at ~19:00 and then walk over to M006 from there at ~20:00. You can of course also join us just for the presentation.

Lars will talk about free monads and free functors.

IO in Haskell (or GHC, more specifically), is deeply magical. A function returning IO a can perform any effect, and a caller does not know what is going on: Just printing something to the terminal, calling a web service or launching the missiles. But it doesn't have to be that way: Using free monads, we can construct tiny subsets of IO functionality, combine them together and even pick the concrete interpreter depending on the environment.