diff options
| -rw-r--r-- | libraries/base/Data/Foldable.hs | 6 | ||||
| -rw-r--r-- | libraries/base/changelog.md | 2 |
2 files changed, 8 insertions, 0 deletions
diff --git a/libraries/base/Data/Foldable.hs b/libraries/base/Data/Foldable.hs index f5f3112138..cc0f348e47 100644 --- a/libraries/base/Data/Foldable.hs +++ b/libraries/base/Data/Foldable.hs @@ -130,6 +130,12 @@ class Foldable t where -- This INLINE allows more list functions to fuse. See Trac #9848. foldMap f = foldr (mappend . f) mempty + -- | A variant of 'foldMap' that is strict in the accumulator. + -- + -- @since 4.13.0.0 + foldMap' :: Monoid m => (a -> m) -> t a -> m + foldMap' f = foldl' (\ acc a -> acc <> f a) mempty + -- | Right-associative fold of a structure. -- -- In the case of lists, 'foldr', when applied to a binary operator, a diff --git a/libraries/base/changelog.md b/libraries/base/changelog.md index 3709a0a1a2..bfa8cb9e18 100644 --- a/libraries/base/changelog.md +++ b/libraries/base/changelog.md @@ -10,6 +10,8 @@ a representational one. There is really no reason to care about the type of the underlying object. + * Add `foldMap'`, a strict version of `foldMap`, to `Foldable`. + ## 4.12.0.0 *TBA* * Bundled with GHC *TBA* |