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Diffstat (limited to 'applicative/h1.hs')
-rw-r--r-- | applicative/h1.hs | 14 |
1 files changed, 14 insertions, 0 deletions
diff --git a/applicative/h1.hs b/applicative/h1.hs new file mode 100644 index 0000000..b13c33d --- /dev/null +++ b/applicative/h1.hs @@ -0,0 +1,14 @@ +import Control.Applicative + +data MyMaybe a = MyNothing | MyJust a + deriving (Show) + +instance Functor MyMaybe where + fmap _ MyNothing = MyNothing + fmap f (MyJust x) = MyJust (f x) + +instance Applicative MyMaybe where + pure x = MyJust x + MyNothing <*> _ = MyNothing + _ <*> MyNothing = MyNothing + (MyJust f) <*> (MyJust g) = MyJust (f g) |