___         ___ _
  / _ \ /\  /\/ __(_)
 / /_\// /_/ / /  | |      GHC Interactive, version 5.03, for Haskell 98.
/ /_\\/ __  / /___| |      http://www.haskell.org/ghc/
\____/\/ /_/\____/|_|      Type :? for help.

Loading package std ... linking ... done.
Prelude> -- testing :info
Prelude> :info +
-- + is a method in class Num
infixl 6 +
(+) :: forall a. (Num a) => a -> a -> a
Prelude> :info (+)
-- + is a method in class Num
infixl 6 +
(+) :: forall a. (Num a) => a -> a -> a
Prelude> :info Complex.:+
-- Complex.:+ is a data constructor
infix 6 Complex.:+
(Complex.:+) :: forall a. (RealFloat a) =>
		a -> a -> Complex.Complex a
Prelude> :info (Complex.:+)
-- Complex.:+ is a data constructor
infix 6 Complex.:+
(Complex.:+) :: forall a. (RealFloat a) =>
		a -> a -> Complex.Complex a
Prelude> :info RealFloat
-- RealFloat is a class
class (RealFrac a, Floating a) => RealFloat a where {
    floatRadix :: a -> Integer;
    floatDigits :: a -> Int;
    floatRange :: a -> (Int, Int);
    decodeFloat :: a -> (Integer, Int);
    encodeFloat :: Integer -> Int -> a;
    exponent :: a -> Int {- has default method -};
    significand :: a -> a {- has default method -};
    scaleFloat :: Int -> a -> a {- has default method -};
    isInfinite :: a -> Bool;
    isDenormalized :: a -> Bool;
    isNegativeZero :: a -> Bool;
    isIEEE :: a -> Bool;
    isNaN :: a -> Bool;
    atan2 :: a -> a -> a {- has default method -};
    }
Prelude> :info []
-- [] is a data constructor
[] :: forall a. [a]

-- [] is a type constructor
data [] a = [] | (:) a [a]
Prelude> :info ()
-- () is a data constructor
() :: ()

-- () is a type constructor
data () = ()
Prelude> :info (,)
-- (,) is a data constructor
(,) :: forall a b. a -> b -> (a, b)

-- (,) is a type constructor
data (,) a b = (,) a b
Prelude> :info `List.isPrefixOf`
-- List.isPrefixOf is a variable
List.isPrefixOf :: forall a. (Eq a) => [a] -> [a] -> Bool
Prelude> Leaving GHCi.