Data.Merge

Documentation

newtype Merge x a

Describes the merging of two values of the same type into some other type. Represented as a Maybe valued function, one can also think of this as a predicate showing which pairs of values can be merged in this way.

data Example = Whatever { a :: Int, b :: Maybe Bool }
mergeExamples :: Merge Example Example
mergeExamples = Example <$> required a <*> optional b

Constructors

Merge

Fields

• runMerge :: x -> x -> Maybe a

Instances

Profunctor Merge

Defined in Data.Merge

Methods

dimap :: (a -> b) -> (c -> d) -> Merge b c -> Merge a d

lmap :: (a -> b) -> Merge b c -> Merge a c

rmap :: (b -> c) -> Merge a b -> Merge a c

(#.) :: forall a b c q. Coercible c b => q b c -> Merge a b -> Merge a c

(.#) :: forall a b c q. Coercible b a => Merge b c -> q a b -> Merge a c

Monad (Merge x)

Defined in Data.Merge

Methods

(>>=) :: Merge x a -> (a -> Merge x b) -> Merge x b

(>>) :: Merge x a -> Merge x b -> Merge x b

return :: a -> Merge x a

Functor (Merge x)

Defined in Data.Merge

Methods

fmap :: (a -> b) -> Merge x a -> Merge x b

(<$) :: a -> Merge x b -> Merge x a

Applicative (Merge x)

Defined in Data.Merge

Methods

pure :: a -> Merge x a

(<*>) :: Merge x (a -> b) -> Merge x a -> Merge x b

liftA2 :: (a -> b -> c) -> Merge x a -> Merge x b -> Merge x c

(*>) :: Merge x a -> Merge x b -> Merge x b

(<*) :: Merge x a -> Merge x b -> Merge x a

Alternative (Merge x)

Defined in Data.Merge

Methods

empty :: Merge x a

(<|>) :: Merge x a -> Merge x a -> Merge x a

some :: Merge x a -> Merge x [a]

many :: Merge x a -> Merge x [a]

Semigroup a => Semigroup (Merge x a)

Defined in Data.Merge

Methods

(<>) :: Merge x a -> Merge x a -> Merge x a

sconcat :: NonEmpty (Merge x a) -> Merge x a

stimes :: Integral b => b -> Merge x a -> Merge x a

Semigroup a => Monoid (Merge x a)

Defined in Data.Merge

Methods

mempty :: Merge x a

mappend :: Merge x a -> Merge x a -> Merge x a

mconcat :: [Merge x a] -> Merge x a

merge :: (x -> x -> Maybe a) -> Merge x a

The most general combinator for constructing Merges.

optional :: Eq a => (x -> Maybe a) -> Merge x (Maybe a)

Meant to be used to merge optional fields in a record.

required :: Eq a => (x -> a) -> Merge x a

Meant to be used to merge required fields in a record.