diff options
Diffstat (limited to 'libraries/base/Data/Foldable.hs')
| -rw-r--r-- | libraries/base/Data/Foldable.hs | 40 |
1 files changed, 29 insertions, 11 deletions
diff --git a/libraries/base/Data/Foldable.hs b/libraries/base/Data/Foldable.hs index e9246f9dc4..ed32879d28 100644 --- a/libraries/base/Data/Foldable.hs +++ b/libraries/base/Data/Foldable.hs @@ -323,36 +323,54 @@ foldlM :: (Foldable t, Monad m) => (b -> a -> m b) -> b -> t a -> m b foldlM f z0 xs = foldr f' return xs z0 where f' x k z = f z x >>= k --- | Map each element of a structure to an action, evaluate --- these actions from left to right, and ignore the results. +-- | Map each element of a structure to an action, evaluate these +-- actions from left to right, and ignore the results. For a version +-- that doesn't ignore the results see 'Data.Traversable.traverse'. traverse_ :: (Foldable t, Applicative f) => (a -> f b) -> t a -> f () traverse_ f = foldr ((*>) . f) (pure ()) --- | 'for_' is 'traverse_' with its arguments flipped. +-- | 'for_' is 'traverse_' with its arguments flipped. For a version +-- that doesn't ignore the results see 'Data.Traversable.for'. +-- +-- >>> for_ [1..4] print +-- 1 +-- 2 +-- 3 +-- 4 for_ :: (Foldable t, Applicative f) => t a -> (a -> f b) -> f () {-# INLINE for_ #-} for_ = flip traverse_ -- | Map each element of a structure to a monadic action, evaluate --- these actions from left to right, and ignore the results. As of --- base 4.8.0.0, 'mapM_' is just 'traverse_', specialized to 'Monad'. +-- these actions from left to right, and ignore the results. For a +-- version that doesn't ignore the results see +-- 'Data.Traversable.mapM'. +-- +-- As of base 4.8.0.0, 'mapM_' is just 'traverse_', specialized to +-- 'Monad'. mapM_ :: (Foldable t, Monad m) => (a -> m b) -> t a -> m () mapM_ f= foldr ((>>) . f) (return ()) --- | 'forM_' is 'mapM_' with its arguments flipped. As of base --- 4.8.0.0, 'forM_' is just 'for_', specialized to 'Monad'. +-- | 'forM_' is 'mapM_' with its arguments flipped. For a version that +-- doesn't ignore the results see 'Data.Traversable.forM'. +-- +-- As of base 4.8.0.0, 'forM_' is just 'for_', specialized to 'Monad'. forM_ :: (Foldable t, Monad m) => t a -> (a -> m b) -> m () {-# INLINE forM_ #-} forM_ = flip mapM_ --- | Evaluate each action in the structure from left to right, --- and ignore the results. +-- | Evaluate each action in the structure from left to right, and +-- ignore the results. For a version that doesn't ignore the results +-- see 'Data.Traversable.sequenceA'. sequenceA_ :: (Foldable t, Applicative f) => t (f a) -> f () sequenceA_ = foldr (*>) (pure ()) -- | Evaluate each monadic action in the structure from left to right, --- and ignore the results. As of base 4.8.0.0, 'sequence_' is just --- 'sequenceA_', specialized to 'Monad'. +-- and ignore the results. For a version that doesn't ignore the +-- results see 'Data.Traversable.sequence'. +-- +-- As of base 4.8.0.0, 'sequence_' is just 'sequenceA_', specialized +-- to 'Monad'. sequence_ :: (Foldable t, Monad m) => t (m a) -> m () sequence_ = foldr (>>) (return ()) |