Wouldn't it be better to make an instance of the Boolean class for functions, that way you could just write: filter ((< 0.5) && (> -0.5)) xs Not sure about the syntax, as the Haskell site is down. Also it will require that you install and import the Boolean class. One could ask if any of these methods are more readable than the original though. Paul Heinrich Apfelmus wrote:
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
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