{-# LANGUAGE Rank2Types #-} ----------------------------------------------------------------------------- -- | -- Module : Data.Set.Lens -- Copyright : (C) 2012-14 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 Data.Set as Set -- $setup -- >>> :set -XNoOverloadedStrings -- >>> import Control.Lens -- | 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) (fromList [1,2,3,4]) -- fromList [2,3,4,5] setmapped :: (Ord i, 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 #-}