[Haskell] ANNOUNCE: fixpoint 0.1

I'm pleased to announce fixpoint 0.1, a (for now) small generic programming library which allows data types to be manipulated as fixpoints of their underlying functors. The library is mostly based on "Functional Programming with Bananas, Lenses, Envelopes and Barbed Wire" by Erik Meijer, Maarte

Re: [Haskell] MTL violates coverage condition?

Does 'MonadState s m => MonadState s (ReaderT r m)', found in Control.Monad.Reader violate the coverage condition as I believe it does? Yes, it does. Can one write a function using this library to force the type inference engine to loop indefinitely? If not, what mitigating conditions prevent

[Haskell] MTL violates coverage condition?

Hi, A bit of a detailed technical question. I'm writing a library which makes heavy use of the MTL (Monad.State, etc) and monad transformers. I have a monad transformer, MymonadT, which I want to inherit relevant type classes from the monads it transforms, i.e. MonadState s m => MonadState s (

[Haskell] Recruiting functional programmers

Interested in recruiting Haskell programmers from Chalmers/Gothenburg university? As an experiment, I am planning a recruitment event here in December-see www.jobs-in-fp.org for how to take part. John Hughes ___ Haskell mailing list Haskell@haskell.o

[Haskell] Re: ANNOUNCE: fixpoint 0.1

Roman Leshchinskiy wrote: instance Fixpoint [a] where data Pre [a] s = Nil | Cons a s project [] = Nil project (x:xs) = Cons x xs inject Nil = [] inject (Cons x xs) = x : xs With this, we can easily define things like catamorphisms: cata :: Fixpoint t => (Pre t s -> s)

Re: [Haskell] ANNOUNCE: fixpoint 0.1

Good stuff! You might also want to consider including code from Uustalu et al, "Recursion Schemes from Comonads", 2001 http://citeseer.ist.psu.edu/uustalu01recursion.html Chapter 7 has code formatted as Literate Haskell that generalizes cata, ana, hylo (iteration), and para (primitive recursion

[Haskell] Coq Tutorial at POPL 2008: Using Proof Assistants for Programming Language Research

== Tutorial Announcement and Call for Participation Using Proof Assistants for Programming Language Research Or: How to Write Your Next POPL Paper in

[Haskell] recursive deriving

When you want automated deriving of show/read etc., you need all the components of your type also to be instances of show/read but you won't want to *require* them to be automatically generated verions. Standalone deriving does the wrong thing here. Standalone deriving should not cause an ove