he result from an 'IndexedGetter' or 'IndexedLens').
-- See also ('^@?').
--
-- @
-- 'ipreviews' = 'views' '.' 'ipre'
-- @
--
-- This is usually applied in the 'Control.Monad.Reader.Reader'
-- 'Control.Monad.Monad' @(->) s@.
--
-- @
-- 'ipreviews' :: 'IndexedGetter' i s a     -> (i -> a -> r) -> s -> 'Maybe' r
-- 'ipreviews' :: 'IndexedFold' i s a       -> (i -> a -> r) -> s -> 'Maybe' r
-- 'ipreviews' :: 'IndexedLens'' i s a      -> (i -> a -> r) -> s -> 'Maybe' r
-- 'ipreviews' :: 'IndexedTraversal'' i s a -> (i -> a -> r) -> s -> 'Maybe' r
-- @
--
-- However, it may be useful to think of its full generality when working with
-- a 'Control.Monad.Monad' transformer stack:
--
-- @
-- 'ipreviews' :: 'MonadReader' s m => 'IndexedGetter' i s a     -> (i -> a -> r) -> m ('Maybe' r)
-- 'ipreviews' :: 'MonadReader' s m => 'IndexedFold' i s a       -> (i -> a -> r) -> m ('Maybe' r)
-- 'ipreviews' :: 'MonadReader' s m => 'IndexedLens'' i s a      -> (i -> a -> r) -> m ('Maybe' r)
-- 'ipreviews' :: 'MonadReader' s m => 'IndexedTraversal'' i s a -> (i -> a -> r) -> m ('Maybe' r)
-- @
ipreviews :: MonadReader s m => IndexedGetting i (First r) s a -> (i -> a -> r) -> m (Maybe r)
ipreviews l f = asks (getFirst . ifoldMapOf l (\i -> First #. Just . f i))
{-# INLINE ipreviews #-}

------------------------------------------------------------------------------
-- Preuse
----
ipreviews :: MonadReader s m => IndexedGetting i (First r) s a -> (i -> a -> r) -> m (Maybe r)
ipreviews l f = asks (getFirst . ifoldMapOf l (\i -> First #. Just . f i))
ipreviews l f = asks (getFirst . ifoldMapOf l (\i -> First #. Just . f i))