Implement bimapBoth (#174) (#202)

* Implement `bimapBoth` (#174)

* fix style

* notes

CHANGELOG.md

@@ -36,6 +36,9 @@ The changelog is available [on GitHub][2].
  Use `foldr` instead of explicit recursion and `toList`.
 * [#182](https://github.com/kowainik/relude/issues/182):
  Support GHC-8.8.1.
+* [#174](https://github.com/kowainik/relude/issues/187):
+ Implement `bimapBoth` in `Relude.Extra.Tuple` module,
+ mark `mapBoth` as DEPRECATED.
 
 ## 0.5.0 — Mar 18, 2019
 

src/Relude/Extra/Bifunctor.hs

@@ -12,17 +12,31 @@ bar :: IO (a, b)
 
 baz :: Maybe (Either a b)
 qux :: Maybe (a, b)
+
+doo :: (a, a)
+dee :: Either a a
 @
 -}
 
 module Relude.Extra.Bifunctor
- ( bimapF
+ ( bimapBoth
+ , bimapF
  , firstF
  , secondF
  ) where
 
 import Relude
 
+{- | Maps a function over both elements of a bifunctor.
+
+>>> bimapBoth length ("a", "bb")
+(1,2)
+>>> map (bimapBoth not) [Left True, Right False]
+[Left False,Right True]
+-}
+bimapBoth :: Bifunctor f => (a -> b) -> f a a -> f b b
+bimapBoth f = bimap f f
+{-# INLINE bimapBoth #-}
 
 {- | Fmaps functions for nested bifunctor. Short for @fmap (bimap f g)@.
 

src/Relude/Extra/Tuple.hs

@@ -63,6 +63,7 @@ mapToSnd f a = (a, f a)
 -}
 mapBoth :: (a -> b) -> (a, a) -> (b, b)
 mapBoth f (a1, a2) = (f a1, f a2)
+{-# DEPRECATED mapBoth "Use 'bimapBoth' from 'Relude.Extra.Bifunctor' instead" #-}
 {-# INLINE mapBoth #-}
 
 {- | Apply a function that returns a value inside of a functor,