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| author | Joe Zhao <ztuowen@gmail.com> | 2015-08-24 15:45:45 -0600 |
|---|---|---|
| committer | Joe Zhao <ztuowen@gmail.com> | 2015-08-24 15:45:45 -0600 |
| commit | 6588473adf96a3eb7cfac55820ec022d4533fcbf (patch) | |
| tree | dcc6d21e7ce8ed368eda73a7fd74eca5340355ed /foldables/h1.hs | |
| parent | 3cf3e36b1498271f3c9162576809d886482e6d97 (diff) | |
| download | typeclass-6588473adf96a3eb7cfac55820ec022d4533fcbf.tar.gz typeclass-6588473adf96a3eb7cfac55820ec022d4533fcbf.tar.bz2 typeclass-6588473adf96a3eb7cfac55820ec022d4533fcbf.zip | |
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 |