Add the haskell book

Haskell-book/11/Vehicle.hs

@@ -0,0 +1,40 @@
+module Vehicle where
+
+data Price = Price Integer deriving (Eq, Show)
+
+data Size = Size Integer deriving (Eq, Show)
+
+data Manufacturer = Mini
+                  | Mazda
+                  | Tata
+                  deriving (Eq, Show)
+
+data Airline = PapuAir
+             | CatapultsR'Us
+             | TakeYourChancesUnited
+             deriving (Eq, Show)
+
+data Vehicle = Car Manufacturer Price
+             | Plane Airline Size
+             deriving (Eq, Show)
+
+myCar = Car Mini (Price 14000)
+urCar = Car Mazda (Price 20000)
+clownCar = Car Tata (Price 7000)
+doge = Plane PapuAir (Size 1234)
+
+isCar :: Vehicle -> Bool
+isCar (Car _ _) = True
+isCar _         = False
+
+isPlane :: Vehicle -> Bool
+isPlane (Plane _ _) = True
+isPlane _           = False
+
+areCars :: [Vehicle] -> [Bool]
+areCars = map isCar
+
+getManu :: Vehicle -> Manufacturer
+getManu (Car m _) = m
+
+data Example = MakeExample Int deriving Show