Module

Data.Validation.Semiring

This module defines a variant of applicative validation with an Alt instance, for validators which support errors with multiple alternatives.

#V 

newtype V err result

The V functor, used for alternative validation

The Alternative instance collects multiple failures in an arbitrary Semiring.

For example:

import Data.Semiring.Free

validate r :: Person -> V (Free Error) Person
validate person = { first: _, last: _, contact: _}
  <$> validateName person.first
  <*> validateName person.last
  <*> (validateEmail person.contact <|> validatePhone person.contact)

Instances

#unV 

unV :: forall err result r. (err -> r) -> (result -> r) -> V err result -> r

Unpack the V type constructor, providing functions to handle the error and success cases.

#invalid 

invalid :: forall err result. err -> V err result

Fail with a validation error.

#isValid 

isValid :: forall err result. V err result -> Boolean

Test whether validation was successful or not.

#toEither 

toEither :: forall err result. V err result -> Either err result

Modules