Data.Either.Valid

Documentation

data Valid e a

Like the Either type, but its instances accumulates its errors. As such, there is no Monad instance for Valid.

The Invalid constructor takes precedence over Valid when used with classes that combine two values.

Note: There are a lot of packages that implement this data type, but finding a well-maintained one with minimal dependencies proved difficult.

Constructors

Invalid !e

Valid !a

Instances

Bifunctor Valid

Defined in Data.Either.Valid

Methods

bimap :: (a -> b) -> (c -> d) -> Valid a c -> Valid b d

first :: (a -> b) -> Valid a c -> Valid b c

second :: (b -> c) -> Valid a b -> Valid a c

Functor (Valid e)

Defined in Data.Either.Valid

Methods

fmap :: (a -> b) -> Valid e a -> Valid e b

(<$) :: a -> Valid e b -> Valid e a

Semigroup e => Applicative (Valid e)

Defined in Data.Either.Valid

Methods

pure :: a -> Valid e a

(<*>) :: Valid e (a -> b) -> Valid e a -> Valid e b

liftA2 :: (a -> b -> c) -> Valid e a -> Valid e b -> Valid e c

(*>) :: Valid e a -> Valid e b -> Valid e b

(<*) :: Valid e a -> Valid e b -> Valid e a

Monoid e => Alternative (Valid e)

Defined in Data.Either.Valid

Methods

empty :: Valid e a

(<|>) :: Valid e a -> Valid e a -> Valid e a

some :: Valid e a -> Valid e [a]

many :: Valid e a -> Valid e [a]

(Eq e, Eq a) => Eq (Valid e a)

Defined in Data.Either.Valid

Methods

(==) :: Valid e a -> Valid e a -> Bool

(/=) :: Valid e a -> Valid e a -> Bool

(Ord e, Ord a) => Ord (Valid e a)

Defined in Data.Either.Valid

Methods

compare :: Valid e a -> Valid e a -> Ordering

(<) :: Valid e a -> Valid e a -> Bool

(<=) :: Valid e a -> Valid e a -> Bool

(>) :: Valid e a -> Valid e a -> Bool

(>=) :: Valid e a -> Valid e a -> Bool

max :: Valid e a -> Valid e a -> Valid e a

min :: Valid e a -> Valid e a -> Valid e a

(Show e, Show a) => Show (Valid e a)

Defined in Data.Either.Valid

Methods

showsPrec :: Int -> Valid e a -> ShowS

show :: Valid e a -> String

showList :: [Valid e a] -> ShowS

(Semigroup e, Semigroup a) => Semigroup (Valid e a)

Defined in Data.Either.Valid

Methods

(<>) :: Valid e a -> Valid e a -> Valid e a

sconcat :: NonEmpty (Valid e a) -> Valid e a

stimes :: Integral b => b -> Valid e a -> Valid e a

(Semigroup e, Monoid a) => Monoid (Valid e a)

Defined in Data.Either.Valid

Methods

mempty :: Valid e a

mappend :: Valid e a -> Valid e a -> Valid e a

mconcat :: [Valid e a] -> Valid e a

fromEither :: Either e a -> Valid e a

Convert an Either value to Valid.

toEither :: Valid e a -> Either e a

Convert a Valid value to Either.

valid :: (e -> r) -> (a -> r) -> Valid e a -> r

Consume a Valid by handling errors and valid values.