-- Extended exercise: supermarket billing
-- ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

-- Types of names, prices (pence) and bar-codes.

type Name    = String
type Price   = Int
type BarCode = Int

-- The database linking names prices and bar codes.

type Database = [ (BarCode,Name,Price) ]

-- The example database we use is

codeIndex :: Database
codeIndex = [ (4719, "Fish Fingers" , 121),
              (5643, "Nappies" , 1010),
              (3814, "Orange Jelly", 56),
              (1111, "Hula Hoops", 21),
              (1112, "Hula Hoops (Giant)", 133),
              (1234, "Dry Sherry, 1lt", 540)]

-- The lists of bar codes, and of Name,Price pairs.

type TillType = [BarCode]
type BillType = [(Name,Price)]

-- The length of a line in the bill.

lineLength :: Int
lineLength = 30