module Main where

    data Letter a =
          A a
        | B a
        | C String
        deriving (Show)

    -- getConstructor :: String -> (a -> Letter ?) -- <==
    getConstructor x
        | x == "a"  = A
        | x == "b"  = B
        | otherwise = C


    main = print $ theType
        where theType = (getConstructor "b") "its b!"