Data.Maybe.First

newtype First a

Monoid returning the first (left-most) non-Nothing value.

First (Just x) <> First (Just y) == First (Just x)
First Nothing <> First (Just y) == First (Just y)
First Nothing <> Nothing == First Nothing
mempty :: First _ == First Nothing

Constructors

• First (Maybe a)

Instances

• Newtype (First a) _
• (Eq a) => Eq (First a)
• Eq1 First
• (Ord a) => Ord (First a)
• Ord1 First
• (Bounded a) => Bounded (First a)
• Functor First
• Invariant First
• Apply First
• Applicative First
• Bind First
• Monad First
• Extend First
• (Show a) => Show (First a)
• Semigroup (First a)
• Monoid (First a)
• Alt First
• Plus First
• Alternative First
• MonadZero First