Random date string

gistfile1.hs

randomMonth :: (RandomGen g) => State g String
randomMonth = 
    let monthNames = [ "January", "February", "March"
                     , "April", "May", "June"
                     , "July", "August", "September"
                     , "October", "November", "December"
                     ]
    in (monthNames !!) <$> randomNumber (1,11)

randomNumber :: (RandomGen g) => (Int,Int) -> State g Int
randomNumber = state . randomR

randomDateString :: (RandomGen g) => State g String
randomDateString = 
    let day = randomNumber (1,28)
        year = randomNumber (1940,2020)
        display d month y = show d ++ " " ++ month ++ " " ++ show y
    in liftM3 display day randomMonth year