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Diffstat (limited to 'foldables/h1.hs')
| -rw-r--r-- | foldables/h1.hs | 6 |
1 files changed, 6 insertions, 0 deletions
diff --git a/foldables/h1.hs b/foldables/h1.hs new file mode 100644 index 0000000..16b22ac --- /dev/null +++ b/foldables/h1.hs @@ -0,0 +1,6 @@ +-- What is the type of foldMap . foldMap? Or foldMap . foldMap . foldMap, etc.? What do they do? + +foldMap :: Monoid m => (a -> m) -> t a -> m + +foldMap . foldMap :: (Foldable t, Foldable t1, Monoid m) => (a -> m) -> t (t1 a) -> m +-- They fold for multi-level of foldables |