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-----------------------------------------------------------------------------
--- This simple module defines the const functor known from Haskell's
--- base libraries. It defines a wrapper around a constant value that
--- "ignores" functions mapped over it.
-----------------------------------------------------------------------------

module Data.Functor.Const
  ( Const (..)
  ) where

newtype Const a _ = Const { getConst :: a }
  deriving (Eq, Ord, Read, Show)

instance Functor (Const a) where
  fmap _ (Const x) = Const x