Skip to content
Merged
Show file tree
Hide file tree
Changes from all commits
Commits
File filter

Filter by extension

Filter by extension

Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
1 change: 1 addition & 0 deletions CHANGELOG.md
Original file line number Diff line number Diff line change
Expand Up @@ -7,6 +7,7 @@ Notable changes to this project are documented in this file. The format is based
Breaking changes:

New features:
- Added `Semiring` instance (#59)

Bugfixes:

Expand Down
10 changes: 10 additions & 0 deletions src/Data/Maybe.purs
Original file line number Diff line number Diff line change
Expand Up @@ -190,6 +190,16 @@ instance semigroupMaybe :: Semigroup a => Semigroup (Maybe a) where
instance monoidMaybe :: Semigroup a => Monoid (Maybe a) where
mempty = Nothing

instance semiringMaybe :: Semiring a => Semiring (Maybe a) where
zero = Nothing
one = Just one

add Nothing y = y
add x Nothing = x
add (Just x) (Just y) = Just (add x y)

mul x y = mul <$> x <*> y

-- | The `Eq` instance allows `Maybe` values to be checked for equality with
-- | `==` and inequality with `/=` whenever there is an `Eq` instance for the
-- | type the `Maybe` contains.
Expand Down