{-# LANGUAGE CPP #-} {-# LANGUAGE FlexibleInstances #-} {-# LANGUAGE MultiParamTypeClasses #-} {-# LANGUAGE RankNTypes #-} {-# LANGUAGE TypeFamilies #-} {-# OPTIONS_GHC -fno-warn-orphans #-} module Data.RAVec.Tree.DF.Lens ( -- * Indexing ix, ) where import Control.Applicative ((<$>)) import Data.Wrd (Wrd (..)) import Prelude () import qualified Control.Lens as L import qualified Data.Type.Nat as N import Data.RAVec.Tree.DF -- $setup -- >>> import Control.Lens ((^.), (&), (.~), (^?), (#)) -- >>> import Prelude -- >>> import Data.RAVec.Tree.DF -- >>> import Data.Wrd (Wrd (..)) ------------------------------------------------------------------------------- -- Indexing ------------------------------------------------------------------------------- -- | Index lens. -- -- >>> let tree = Node (Node (Leaf 'a') (Leaf 'b')) (Node (Leaf 'c') (Leaf 'd')) -- >>> tree & ix (W1 $ W0 WE) .~ 'z' -- Node (Node (Leaf 'a') (Leaf 'b')) (Node (Leaf 'z') (Leaf 'd')) -- ix :: Wrd n -> L.Lens' (Tree n a) a ix WE f (Leaf x) = Leaf <$> f x ix (W0 is) f (Node x y) = (`Node` y) <$> ix is f x ix (W1 is) f (Node x y) = (x `Node`) <$> ix is f y ------------------------------------------------------------------------------- -- Instances ------------------------------------------------------------------------------- #if !MIN_VERSION_lens(5,0,0) instance N.SNatI n => L.FunctorWithIndex (Wrd n) (Tree n) where imap = imap instance N.SNatI n => L.FoldableWithIndex (Wrd n) (Tree n) where ifoldMap = ifoldMap ifoldr = ifoldr ifoldl = ifoldl instance N.SNatI n => L.TraversableWithIndex (Wrd n) (Tree n) where itraverse = itraverse #endif instance N.SNatI n => L.Each (Tree n a) (Tree n b) a b type instance L.Index (Tree n a) = Wrd n type instance L.IxValue (Tree n a) = a instance L.Ixed (Tree n a) where ix i = ix i