[Haskell-beginners] Re: \x -> x < 0.5 && x > -0.5

Michael Mossey wrote:

Is there a nifty way to write

filter (\x -> x < 0.5 && x > -0.5) xs

without explicitly using x?

Maybe arrows? I have a vague understanding that arrows can "send" an argument to more than one computation.

That's a job for the reader monad. Lambda Fu, form 53 - silent reader of truth import Control.Monad import Control.Monad.Reader filter (liftM2 (&&) (< 0.5) (> -0.5)) xs Regards, apfelmus -- http://apfelmus.nfshost.com