Module

Data.Validation.Semiring

Package: purescript-validation
Repository: purescript/purescript-validation

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

The API is equivalent to Data.Validation, but uses Semiring instead of Semigroup.

#V Source

data V err res

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

(Eq err, Eq result) => Eq (V err result)
(Ord err, Ord result) => Ord (V err result)
(Show err, Show result) => Show (V err result)
Functor (V err)
Bifunctor V
(Semiring err) => Apply (V err)
(Semiring err) => Applicative (V err)
(Semiring err, Semigroup a) => Semigroup (V err a)
(Semiring err, Monoid a) => Monoid (V err a)
(Semiring err) => Alt (V err)
(Semiring err) => Plus (V err)
(Semiring err) => Alternative (V err)

#unV Source

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

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

#invalid Source

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

Fail with a validation error

#isValid Source

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

Test whether validation was successful or not

Modules: Data.Validation.Semigroup; Data.Validation.Semiring