scalaz

Validation

sealed trait Validation[+E, +A] extends AnyRef

Represents either:

Isomorphic to scala.Either and scalaz.\/. The motivation for a Validation is to provide the instance Applicativea that accumulate failures through a scalaz.Semigroup[E].

scalaz.NonEmptyList is commonly chosen as a type constructor for the type E. As a convenience, an alias scalaz.ValidationNel[E] is provided as a shorthand for scalaz.Validation[NonEmptyList[E]], and a method Validation#toValidationNel converts Validation[E] to ValidationNel[E].

Example:

import scalaz._, std.AllInstances._

def parseInt(s: String): Validation[String, Int] =
  try { Success(s.toInt) } catch { case ex: NumberFormatException => Failure(ex.getMessage) }
val V = Validation.validationNelApplicative[String]

val x: ValidationNel[String, Int] =
  V.map2(parseInt("1.x").toValidationNel, parseInt("1..0").toValidationNel)(_ * _)
  // Failure(NonEmptyList(For input string: "1..0", For input string: "1.x"))
E

The type of the Failure

A

The type of the Success

Source
Validation.scala
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Type Members

  1. sealed trait SwitchingValidation[X] extends AnyRef

Value Members

  1. final def !=(arg0: AnyRef): Boolean

    Definition Classes
    AnyRef
  2. final def !=(arg0: Any): Boolean

    Definition Classes
    Any
  3. final def ##(): Int

    Definition Classes
    AnyRef → Any
  4. def +++[EE >: E, AA >: A](x: ⇒ Validation[EE, AA])(implicit M1: Semigroup[AA], M2: Semigroup[EE]): Validation[EE, AA]

    Sums up values inside validation, if both are success or failure.

    Sums up values inside validation, if both are success or failure. Returns first failure otherwise.

    success(v1) +++ success(v2) ¬ニメ success(v1 + v2)
    success(v1) +++ failure(v2) ¬ニメ failure(v2)
    failure(v1) +++ success(v2) ¬ニメ failure(v1)
    failure(v1) +++ failure(v2) ¬ニメ failure(v1 + v2)
  5. def +|+[EE >: E, AA >: A](x: Validation[EE, AA])(implicit es: Semigroup[EE], as: Semigroup[AA]): Validation[EE, AA]

    If this and that are both success, or both a failure, combine them with the provided Semigroup for each.

    If this and that are both success, or both a failure, combine them with the provided Semigroup for each. Otherwise, return the success. Alias for append

  6. def :?>>[X](success: ⇒ X): SwitchingValidation[X]

    If this validation is success, return the given X value, otherwise, return the X value given to the return value.

  7. final def ==(arg0: AnyRef): Boolean

    Definition Classes
    AnyRef
  8. final def ==(arg0: Any): Boolean

    Definition Classes
    Any
  9. def ===[EE >: E, AA >: A](x: ⇒ Validation[EE, AA])(implicit EE: Equal[EE], EA: Equal[AA]): Boolean

    Compare two validations values for equality.

  10. def @\/[EE, AA](k: (\/[E, A]) ⇒ \/[EE, AA]): Validation[EE, AA]

    Run a disjunction function and back to validation again.

    Run a disjunction function and back to validation again. Alias for disjunctioned

  11. def ap[EE >: E, B](x: ⇒ Validation[EE, (A) ⇒ B])(implicit E: Semigroup[EE]): Validation[EE, B]

    Apply a function in the environment of the success of this validation, accumulating errors.

  12. def append[EE >: E, AA >: A](that: Validation[EE, AA])(implicit es: Semigroup[EE], as: Semigroup[AA]): Validation[EE, AA]

    If this and that are both success, or both a failure, combine them with the provided Semigroup for each.

    If this and that are both success, or both a failure, combine them with the provided Semigroup for each. Otherwise, return the success. Alias for +|+

  13. final def asInstanceOf[T0]: T0

    Definition Classes
    Any
  14. def bimap[C, D](f: (E) ⇒ C, g: (A) ⇒ D): Validation[C, D]

    Binary functor map on this validation.

  15. def bitraverse[G[+_], C, D](f: (E) ⇒ G[C], g: (A) ⇒ G[D])(implicit arg0: Functor[G]): G[Validation[C, D]]

    Binary functor traverse on this validation.

  16. def clone(): AnyRef

    Attributes
    protected[java.lang]
    Definition Classes
    AnyRef
    Annotations
    @throws( ... )
  17. def compare[EE >: E, AA >: A](x: ⇒ Validation[EE, AA])(implicit EE: Order[EE], EA: Order[AA]): Ordering

    Compare two validations values for ordering.

  18. def disjunction: \/[E, A]

    Convert to a disjunction.

  19. def disjunctioned[EE, AA](k: (\/[E, A]) ⇒ \/[EE, AA]): Validation[EE, AA]

    Run a disjunction function and back to validation again.

    Run a disjunction function and back to validation again. Alias for @\/

  20. def ensure[EE >: E](onFailure: ⇒ EE)(f: (A) ⇒ Boolean): Validation[EE, A]

    Ensures that the success value of this validation satisfies the given predicate, or fails with the given value.

  21. final def eq(arg0: AnyRef): Boolean

    Definition Classes
    AnyRef
  22. def equals(arg0: Any): Boolean

    Definition Classes
    AnyRef → Any
  23. def excepting[EE >: E](pf: PartialFunction[A, EE]): Validation[EE, A]

    Return a Validation formed by the application of a partial function across the success of this value:

    Return a Validation formed by the application of a partial function across the success of this value:

    strings map (_.parseInt excepting { case i if i < 0 => new Exception(s"Int must be positive: $i") })
    Since

    7.0.2

  24. def exists(f: (A) ⇒ Boolean): Boolean

    Return true if this validation is a success value satisfying the given predicate.

  25. def filter[EE >: E](p: (A) ⇒ Boolean)(implicit M: Monoid[EE]): Validation[EE, A]

    Filter on the success of this validation.

  26. def finalize(): Unit

    Attributes
    protected[java.lang]
    Definition Classes
    AnyRef
    Annotations
    @throws( classOf[java.lang.Throwable] )
  27. def findSuccess[EE >: E, AA >: A](that: ⇒ Validation[EE, AA])(implicit es: Semigroup[EE]): Validation[EE, AA]

    If this is a success, return it; otherwise, if that is a success, return it; otherwise, combine the failures with the specified semigroup.

  28. def flatMap[EE >: E, B](f: (A) ⇒ Validation[EE, B]): Validation[EE, B]

    Bind through the success of this validation.

  29. def fold[X](fail: (E) ⇒ X, succ: (A) ⇒ X): X

    Catamorphism.

    Catamorphism. Run the first given function if failure, otherwise, the second given function.

  30. def foldRight[B](z: ⇒ B)(f: (A, ⇒ B) ⇒ B): B

    Fold on the success of this validation.

  31. def forall(f: (A) ⇒ Boolean): Boolean

    Return true if this validation is a failure value or the success value satisfies the given predicate.

  32. def foreach[U](f: (A) ⇒ U): Unit

    Run the side-effect on the success of this validation.

  33. final def getClass(): Class[_]

    Definition Classes
    AnyRef → Any
  34. def getOrElse[AA >: A](x: ⇒ AA): AA

    Return the success value of this validation or the given default if failure.

    Return the success value of this validation or the given default if failure. Alias for |

  35. def hashCode(): Int

    Definition Classes
    AnyRef → Any
  36. def isFailure: Boolean

    Return true if this validation is failure.

  37. final def isInstanceOf[T0]: Boolean

    Definition Classes
    Any
  38. def isSuccess: Boolean

    Return true if this validation is success.

  39. def leftMap[C](f: (E) ⇒ C): Validation[C, A]

    Run the given function on the left value.

  40. def loopFailure[EE >: E, AA >: A, X](success: (AA) ⇒ X, failure: (EE) ⇒ \/[X, Validation[EE, AA]]): X

    Spin in tail-position on the failure value of this validation.

  41. def loopSuccess[EE >: E, AA >: A, X](success: (AA) ⇒ \/[X, Validation[EE, AA]], failure: (EE) ⇒ X): X

    Spin in tail-position on the success value of this validation.

  42. def map[B](f: (A) ⇒ B): Validation[E, B]

    Map on the success of this validation.

  43. final def ne(arg0: AnyRef): Boolean

    Definition Classes
    AnyRef
  44. final def notify(): Unit

    Definition Classes
    AnyRef
  45. final def notifyAll(): Unit

    Definition Classes
    AnyRef
  46. def orElse[EE >: E, AA >: A](x: ⇒ Validation[EE, AA]): Validation[EE, AA]

    Return this if it is a success, otherwise, return the given value.

    Return this if it is a success, otherwise, return the given value. Alias for |||

  47. def show[EE >: E, AA >: A](implicit SE: Show[EE], SA: Show[AA]): Cord

    Show for a validation value.

  48. def swap: Validation[A, E]

    Flip the failure/success values in this validation.

    Flip the failure/success values in this validation. Alias for unary_~

  49. def swapped[EE, AA](k: (Validation[A, E]) ⇒ Validation[AA, EE]): Validation[EE, AA]

    Run the given function on this swapped value.

    Run the given function on this swapped value. Alias for ~

  50. final def synchronized[T0](arg0: ⇒ T0): T0

    Definition Classes
    AnyRef
  51. def toEither: Either[E, A]

    Convert to a core scala.Either at your own peril.

  52. def toList: List[A]

    Return an empty list or list with one element on the success of this validation.

  53. def toOption: Option[A]

    Return an empty option or option with one element on the success of this validation.

    Return an empty option or option with one element on the success of this validation. Useful to sweep errors under the carpet.

  54. def toStream: Stream[A]

    Return an empty stream or stream with one element on the success of this validation.

  55. def toString(): String

    Definition Classes
    AnyRef → Any
  56. def toValidationNel[EE >: E, AA >: A]: ValidationNel[EE, AA]

    Wraps the failure value in a scalaz.NonEmptyList

  57. def traverse[G[+_], B](f: (A) ⇒ G[B])(implicit arg0: Applicative[G]): G[Validation[E, B]]

    Traverse on the success of this validation.

  58. def unary_~: Validation[A, E]

    Flip the failure/success values in this validation.

    Flip the failure/success values in this validation. Alias for swap

  59. def valueOr[AA >: A](x: (E) ⇒ AA): AA

    Return the success value of this validation or run the given function on the failure.

  60. final def wait(): Unit

    Definition Classes
    AnyRef
    Annotations
    @throws( ... )
  61. final def wait(arg0: Long, arg1: Int): Unit

    Definition Classes
    AnyRef
    Annotations
    @throws( ... )
  62. final def wait(arg0: Long): Unit

    Definition Classes
    AnyRef
    Annotations
    @throws( ... )
  63. def |[AA >: A](x: ⇒ AA): AA

    Return the success value of this validation or the given default if failure.

    Return the success value of this validation or the given default if failure. Alias for getOrElse

  64. def |||[EE >: E, AA >: A](x: ⇒ Validation[EE, AA]): Validation[EE, AA]

    Return this if it is a success, otherwise, return the given value.

    Return this if it is a success, otherwise, return the given value. Alias for orElse

  65. def ~[EE, AA](k: (Validation[A, E]) ⇒ Validation[AA, EE]): Validation[EE, AA]

    Run the given function on this swapped value.

    Run the given function on this swapped value. Alias for swapped

Inherited from AnyRef

Inherited from Any

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