content: {-# LANGUAGE CPP #-}
  {-# LANGUAGE Rank2Types #-}
  
  {-# LANGUAGE Trustworthy #-}
  
  #include "lens-common.h"
  
  -----------------------------------------------------------------------------
  -- |
  -- Module      :  Data.Set.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.Set.Lens
    ( setmapped
    , setOf
    ) where
  
  import Control.Lens.Getter ( Getting, views )
  import Control.Lens.Setter ( setting )
  import Control.Lens.Type
  import qualified Data.Set as Set
  import Data.Set (Set)
  
  
  -- $setup
  -- >>> :set -XNoOverloadedStrings
  -- >>> import Control.Lens
  -- >>> import qualified Data.Set as Set
  
  -- | This 'Setter' can be used to change the type of a 'Set' by mapping
  -- the elements to new values.
  --
  -- Sadly, you can't create a valid 'Traversal' for a 'Set', but you can
  -- manipulate it by reading using 'Control.Lens.Fold.folded' and reindexing it via 'setmapped'.
  --
  -- >>> over setmapped (+1) (Set.fromList [1,2,3,4])
  -- fromList [2,3,4,5]
  setmapped :: Ord j => IndexPreservingSetter (Set i) (Set j) i j
  setmapped = setting Set.map
  {-# INLINE setmapped #-}
  
  -- | Construct a set from a 'Getter', 'Control.Lens.Fold.Fold', 'Control.Lens.Traversal.Traversal', 'Control.Lens.Lens.Lens' or 'Control.Lens.Iso.Iso'.
  --
  -- >>> setOf folded ["hello","world"]
  -- fromList ["hello","world"]
  --
  -- >>> setOf (folded._2) [("hello",1),("world",2),("!!!",3)]
  -- fromList [1,2,3]
  --
  -- @
  -- 'setOf' ::          'Getter' s a     -> s -> 'Set' a
  -- 'setOf' :: 'Ord' a => 'Fold' s a       -> s -> 'Set' a
  -- 'setOf' ::          'Iso'' s a       -> s -> 'Set' a
  -- 'setOf' ::          'Lens'' s a      -> s -> 'Set' a
  -- 'setOf' :: 'Ord' a => 'Traversal'' s a -> s -> 'Set' a
  -- @
  setOf :: Getting (Set a) s a -> s -> Set a
  setOf l = views l Set.singleton
  {-# INLINE setOf #-}
  