cat.hs

#!/usr/bin/env stack
-- stack --install-ghc runghc -- -Wno-tabs

data Event
		= Noop
		| Noise
		| Pats
	deriving (Show,Read)

data Action
		= Sleep
		| Purr
		| Meow
	deriving (Show,Read)

main :: IO ()
main = interact (unlines . map show . eventLoop . map read . lines)

eventLoop :: [Event] -> [Action]
eventLoop = live cat

live :: (Event -> [Action]) -> [Event] -> [Action]
live style = concat . map style

cat :: Event -> [Action]
cat Pats = [Purr]
cat Noop = [Sleep]
cat Noise = []