Andres Löh
Hi everyone.
I'll follow Simon's lead, and ask a similar question with a similar motivation. I'm going to talk about free monads at the upcoming Haskell eXchange next Wednesday. I'll not limit myself to a particular library, and I'm open to related approaches (e.g. "operational") as well.
I'm also looking for as many compelling examples as possible. Like Simon, I don't want to know anything secret or anything that you wouldn't like me to include in my talk. Most useful are pointers to existing libraries using free monads that I might have missed (for example, because they're new or very specialized).
Thanks a lot for your help in advance.
Cheers, Andres
I my "pianola" package, I use a free monad (in module Pianola.Protocol) to abstract away the connection details of RPC calls, along with the reading/writing from the handles. I use another free monad (in module Pianola.Pianola, but not exported) to sequence observational interactions with an external object accessed through the network. The functor is the Kleisli arrow of a monad. The observations can return no results, or more than one result. Depending on the interpreter, more than one result can be treated as an error, or at least merit a warning. The current interpreter just chooses the first result and keeps going. Cheers. http://hackage.haskell.org/package/pianola-0.1.1 http://hackage.haskell.org/package/pianola-0.1.1/docs/Pianola-Protocol.html http://hackage.haskell.org/package/pianola-0.1.1/docs/src/Pianola- Pianola.html