    {-# LANGUAGE Safe #-}

    -- |
    --
    -- Module      :  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 Data.Ix
        (-- *  The 'Ix' class
         Ix(range, index, inRange, rangeSize),
         -- *  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.Data.Ix