content: {-# LANGUAGE Rank2Types #-}
  -----------------------------------------------------------------------------
  -- |
  -- Module      :  Data.IntSet.Lens
  -- Copyright   :  (C) 2012-16 Edward Kmett
  -- License     :  BSD-style (see the file LICENSE)
  -- Maintainer  :  Edward Kmett <ekmett@gmail.com>
  -- Stability   :  provisional
  -- Portability :  portable
  --
  ----------------------------------------------------------------------------
  module Data.IntSet.Lens
    ( members
    , setmapped
    , setOf
    ) where
  
  import Control.Lens
  import qualified Data.IntSet as IntSet
  import Data.IntSet (IntSet)
  
  -- $setup
  -- >>> :set -XNoOverloadedStrings
  -- >>> import Control.Lens
  -- >>> import qualified Data.IntSet as IntSet
  
  -- | IntSet isn't Foldable, but this t'Fold' can be used to access the members of an 'IntSet'.
  --
  -- >>> sumOf members $ setOf folded [1,2,3,4]
  -- 10
  members :: Fold IntSet Int
  members = folding IntSet.toAscList
  {-# INLINE members #-}
  
  -- | This t'Setter' can be used to change the contents of an 'IntSet' by mapping
  -- the elements to new values.
  --
  -- Sadly, you can't create a valid t'Traversal' for an 'IntSet', because the number of
  -- elements might change but you can manipulate it by reading using 'folded' and
  -- reindexing it via 'setmapped'.
  --
  -- >>> over setmapped (+1) (IntSet.fromList [1,2,3,4])
  -- fromList [2,3,4,5]
  setmapped :: IndexPreservingSetter' IntSet Int
  setmapped = setting IntSet.map
  {-# INLINE setmapped #-}
  
  -- | Construct an 'IntSet' from a t'Getter', t'Fold', t'Traversal', t'Lens' or t'Iso'.
  --
  -- >>> setOf folded [1,2,3,4]
  -- fromList [1,2,3,4]
  --
  -- >>> setOf (folded._2) [("hello",1),("world",2),("!!!",3)]
  -- fromList [1,2,3]
  --
  -- @
  -- 'setOf' :: t'Getter' s 'Int'     -> s -> 'IntSet'
  -- 'setOf' :: t'Fold' s 'Int'       -> s -> 'IntSet'
  -- 'setOf' :: t'Iso'' s 'Int'       -> s -> 'IntSet'
  -- 'setOf' :: t'Lens'' s 'Int'      -> s -> 'IntSet'
  -- 'setOf' :: t'Traversal'' s 'Int' -> s -> 'IntSet'
  -- @
  setOf :: Getting IntSet s Int -> s -> IntSet
  setOf l = views l IntSet.singleton
  {-# INLINE setOf #-}
  