content: {-# LANGUAGE Trustworthy #-}
  
  -----------------------------------------------------------------------------
  -- |
  -- Module      :  GHC.Internal.Data.Ix
  -- Copyright   :  (c) The University of Glasgow 2001
  -- License     :  BSD-style (see the file libraries/base/LICENSE)
  --
  -- Maintainer  :  libraries@haskell.org
  -- Stability   :  stable
  -- Portability :  portable
  --
  -- The 'Ix' class is used to map a contiguous subrange of values in
  -- type onto integers.  It is used primarily for array indexing
  -- (see the array package).  'Ix' uses row-major order.
  --
  -----------------------------------------------------------------------------
  
  module GHC.Internal.Data.Ix
      (
      -- * The 'Ix' class
          Ix
            ( range
            , index
            , inRange
            , rangeSize
            )
      -- Ix instances:
      --
      --  Ix Char
      --  Ix Int
      --  Ix Integer
      --  Ix Bool
      --  Ix Ordering
      --  Ix ()
      --  (Ix a, Ix b) => Ix (a, b)
      --  ...
  
      -- * Deriving Instances of 'Ix'
      -- | Derived instance declarations for the class 'Ix' are only possible
      -- for enumerations (i.e. datatypes having only nullary constructors)
      -- and single-constructor datatypes, including arbitrarily large tuples,
      -- whose constituent types are instances of 'Ix'.
      --
      -- * For an enumeration, the nullary constructors are assumed to be
      -- numbered left-to-right with the indices being 0 to n-1 inclusive. This
      -- is the same numbering defined by the 'Enum' class. For example, given
      -- the datatype:
      --
      -- >        data Colour = Red | Orange | Yellow | Green | Blue | Indigo | Violet
      --
      -- we would have:
      --
      -- >        range   (Yellow,Blue)        ==  [Yellow,Green,Blue]
      -- >        index   (Yellow,Blue) Green  ==  1
      -- >        inRange (Yellow,Blue) Red    ==  False
      --
      -- * For single-constructor datatypes, the derived instance declarations
      -- are as shown for tuples in chapter 19, section 2 of the Haskell 2010 report:
      -- <https://www.haskell.org/onlinereport/haskell2010/haskellch19.html>.
  
      ) where
  
  import GHC.Internal.Ix
  