content: -- |
  -- Module: Data.Set.Optics
  -- Description: Optics for working with 'Set's.
  --
  -- This module defines optics for constructing and manipulating finite 'Set's.
  --
  module Data.Set.Optics
    ( setmapped
    , setOf
    ) where
  
  import Data.Set (Set)
  import qualified Data.Set as Set
  
  import Optics.Fold
  import Optics.Optic
  import Optics.Setter
  
  -- $setup
  -- >>> import qualified Data.Set as Set
  -- >>> import Optics.Core
  
  -- | 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 'Optics.Traversal.Traversal' for a 'Set', but
  -- you can manipulate it by reading using 'Optics.Fold.folded' and reindexing it
  -- via 'setmapped'.
  --
  -- >>> over setmapped (+1) (Set.fromList [1,2,3,4])
  -- fromList [2,3,4,5]
  setmapped :: Ord b => Setter (Set a) (Set b) a b
  setmapped = sets Set.map
  {-# INLINE setmapped #-}
  
  -- | Construct a set from a fold.
  --
  -- >>> setOf folded ["hello","world"]
  -- fromList ["hello","world"]
  --
  -- >>> setOf (folded % _2) [("hello",1),("world",2),("!!!",3)]
  -- fromList [1,2,3]
  setOf :: (Is k A_Fold, Ord a) => Optic' k is s a -> s -> Set a
  setOf l = foldMapOf l Set.singleton
  {-# INLINE setOf #-}
  