{-# LANGUAGE Rank2Types #-} ----------------------------------------------------------------------------- -- | -- Module : Data.IntSet.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.IntSet.Lens ( members , setmapped , setOf ) where import Control.Lens import Data.IntSet as IntSet -- $setup -- >>> :set -XNoOverloadedStrings -- >>> import Control.Lens -- | IntSet isn't Foldable, but this '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 '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 'Traversal' for a 'Set', because the number of -- elements might change but you can manipulate it by reading using 'folded' and -- reindexing it via 'setmapped'. -- -- >>> over setmapped (+1) (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 'Getter', 'Fold', 'Traversal', 'Lens' or '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' :: 'Getter' s 'Int' -> s -> 'IntSet' -- 'setOf' :: 'Fold' s 'Int' -> s -> 'IntSet' -- 'setOf' :: 'Iso'' s 'Int' -> s -> 'IntSet' -- 'setOf' :: 'Lens'' s 'Int' -> s -> 'IntSet' -- 'setOf' :: 'Traversal'' s 'Int' -> s -> 'IntSet' -- @ setOf :: Getting IntSet s Int -> s -> IntSet setOf l = views l IntSet.singleton {-# INLINE setOf #-}