Remove references to remit from the documentation

src/Control/Lens/Fold.hs

@@ -1276,7 +1276,7 @@ hasn't l = getAll #. foldMapOf l (\_ -> All False)
 
 -- | This converts a 'Fold' to a 'Getter' that returns the first element if it
 -- exists as a 'Maybe'.
-pre :: Getting (Endo r) s t a b -> Getting r s t (Maybe a) (Maybe b)
+pre :: Getting (Leftmost r) s t a b -> Getting r s t (Maybe a) (Maybe b)
 pre l f = (Accessor #. flip appEndo (runAccessor (f Nothing)) .# runAccessor) `rmap` l (dimap Just (Accessor #. Endo #. const .# runAccessor) f)
 
 ------------------------------------------------------------------------------
@@ -1311,8 +1311,8 @@ pre l f = (Accessor #. flip appEndo (runAccessor (f Nothing)) .# runAccessor) `r
 -- 'preview' :: 'MonadReader' s m => 'Iso'' s a       -> m ('Maybe' a)
 -- 'preview' :: 'MonadReader' s m => 'Traversal'' s a -> m ('Maybe' a)
 -- @
-preview :: MonadReader s m => Getting (Endo (Maybe a)) s t a b -> m (Maybe a)
-preview l = asks (foldrOf l (\x _ -> Just x) Nothing)
+preview :: MonadReader s m => Getting (Leftmost a) s t a b -> m (Maybe a)
+preview l = asks (getLeftmost . foldMapOf l LLeaf)
 {-# INLINE preview #-}
 
 -- | Retrieve a function of the first value targeted by a 'Fold' or
@@ -1394,7 +1394,7 @@ preuses l f = gets (previews l f)
 -- This has no practical impact on a 'Getter', 'Setter', 'Lens' or 'Iso'.
 --
 -- /NB:/ To write back through an 'Iso', you want to use 'Control.Lens.Isomorphic.from'.
--- Similarly, to write back through an 'Prism', you want to use 'Control.Lens.Prism.remit'.
+-- Similarly, to write back through an 'Prism', you want to use 'Control.Lens.Review.re'.
 backwards :: (Profunctor p, Profunctor q) => Overloading p q (Backwards f) s t a b -> Overloading p q f s t a b
 backwards l f = forwards #. l (Backwards #. f)
 {-# INLINE backwards #-}

src/Control/Lens/Internal/Fold.hs

@@ -20,6 +20,7 @@ module Control.Lens.Internal.Fold
   , Sequenced(..)
   , Max(..), getMax
   , Min(..), getMin
+  , Leftmost(..), getLeftmost
   , Rightmost(..), getRightmost
   ) where
 
@@ -110,9 +111,32 @@ getMax (Max a) = Just a
 {-# INLINE getMax #-}
 
 ------------------------------------------------------------------------------
--- Rightmost
+-- Leftmost and Rightmost
 ------------------------------------------------------------------------------
 
+-- | Used for 'Control.Lens.Fold.preview'
+data Leftmost a = LPure | LLeaf a | LStep (Leftmost a)
+
+instance Monoid (Leftmost a) where
+  mempty = LPure
+  {-# INLINE mempty #-}
+  mappend x y = LStep $ case x of
+    RPure    -> y
+    RLeaf _  -> x
+    RStep x' -> case y of
+      -- The last two cases make firstOf produce a Just as soon as any element
+      -- is encountered, and possibly serve as a micro-optimisation; this
+      -- behaviour can be disabled by replacing them with _ -> mappend x y'.
+      -- Note that this means that firstOf (backwards folded) [1..] is Just _|_.
+      LPure    -> x'
+      LLeaf a  -> LLeaf $ fromMaybe a (getLeftmost x')
+      LStep x' -> mappend x' y'
+
+getLeftmost :: Leftmost a -> Maybe a
+getLeftmost LPure = Nothing
+getLeftmost (LLeaf a) = Just a
+getLeftmost (LStep x) = getLeftmost x
+
 -- | Used for 'Control.Lens.Fold.lastOf'
 data Rightmost a = RPure | RLeaf a | RStep (Rightmost a)
 
@@ -135,4 +159,3 @@ getRightmost :: Rightmost a -> Maybe a
 getRightmost RPure = Nothing
 getRightmost (RLeaf a) = Just a
 getRightmost (RStep x) = getRightmost x
-

src/Control/Lens/Type.hs

@@ -267,12 +267,12 @@ type Iso' s a = Iso s s a a
 ------------------------------------------------------------------------------
 
 -- | A 'Prism' @l@ is a 0-or-1 target 'Traversal' that can also be turned
--- around with 'Control.Lens.Review.remit' to obtain a 'Getter' in the
+-- around with 'Control.Lens.Review.re' to obtain a 'Getter' in the
 -- opposite direction.
 --
 -- There are two laws that a 'Prism' should satisfy:
 --
--- First, if I 'Control.Lens.Review.remit' or 'Control.Lens.Prism.review' a value with a 'Prism' and then 'Control.Lens.Prism.preview' or use ('Control.Lens.Fold.^?'), I will get it back:
+-- First, if I 'Control.Lens.Review.re' or 'Control.Lens.Prism.review' a value with a 'Prism' and then 'Control.Lens.Prism.preview' or use ('Control.Lens.Fold.^?'), I will get it back:
 --
 -- * @'Control.Lens.Prism.preview' l ('Control.Lens.Prism.review' l b) ≡ 'Just' b@
 --