purity police, arrest this man

CNEx.hs

{-# LANGUAGE DeriveDataTypeable #-}
module CNEx where

import Prelude hiding (catch)
import Data.Typeable
import Control.Exception
import System.Random
import System.IO.Unsafe

data ChuckNorris = ChuckNorris deriving (Typeable)

instance Show ChuckNorris where
  {-# NOINLINE show #-}
  show _ = unsafePerformIO $ do
    i <- randomRIO (0, length phrases - 1)
    return $ phrases !! i
    where phrases =
            ["You cannot throw Chuck Norris... Chuck Norris throws YOU!",
             "Chuck Norris wrote Hello World once... it was called Unix",
             "Chuck Norris will functionally KICK YOUR ASS"]

instance Exception ChuckNorris where
  toException = SomeException
  fromException _ = Nothing -- nope

test =
  throw ChuckNorris
  `catch` \ChuckNorris -> error "can't be caught"

Chuck Norris exceptions really seems to be popular now...
https://github.com/criso/ChuckNorrisException

Haha, that’s what I was referencing. :3