more flexible in what it accepts.
--
-- @
-- 'foldlMOf' l ≡ 'ifoldlMOf' l '.' 'const'
-- @
--
-- @
-- 'ifoldlMOf' :: 'Monad' m => 'IndexedGetter' i s a     -> (i -> r -> a -> m r) -> r -> s -> m r
-- 'ifoldlMOf' :: 'Monad' m => 'IndexedFold' i s a       -> (i -> r -> a -> m r) -> r -> s -> m r
-- 'ifoldlMOf' :: 'Monad' m => 'IndexedLens'' i s a      -> (i -> r -> a -> m r) -> r -> s -> m r
-- 'ifoldlMOf' :: 'Monad' m => 'IndexedTraversal'' i s a -> (i -> r -> a -> m r) -> r -> s -> m r
-- @
ifoldlMOf :: Monad m => IndexedGetting i (Endo (r -> m r)) s a -> (i -> r -> a -> m r) -> r -> s -> m r
ifoldlMOf l f z0 xs = ifoldrOf l f' return xs z0
  where f' i x k z = f i z x >>= k
{-# INLINE ifoldlMOf #-}

-- | Extract the key-value pairs from a structure.
--
-- When you don't need access to the indices in the result, then 'toListOf' is
ifoldlMOf :: Monad m => IndexedGetting i (Endo (r -> m r)) s a -> (i -> r -> a -> m r) -> r -> s -> m r
ifoldlMOf l f z0 xs = ifoldrOf l f' return xs z0
  where f' i x k z = f i z x >>= k

ifoldlMOf l f z0 xs = ifoldrOf l f' return xs z0
  where f' i x k z = f i z x >>= k
