Kotlin utilities/it.czerwinski.kotlin.util/Either

Either

sealed class Either<out L, out R>

Disjoint union. The instance might be either Left or Right.

This type is based on scala.Either.

Parameters

Type of Left

Type of Right

Functions

all

inline fun all(predicate: (R) -> Boolean): Boolean

Returns the result of applying the predicate to the value if this is Right or true if this is Left.

any

inline fun any(predicate: (R) -> Boolean): Boolean

Returns the result of applying the predicate to the value if this is Right or false if this is Left.

contains

abstract operator fun contains(element: Any): Boolean

Returns true if the element is equal to the value of this Either, or false otherwise.

filter

inline fun filter(predicate: (R) -> Boolean): Either<L, R>?

Returns the same Right if the predicate is satisfied for the value. Otherwise returns null.

filterIsInstance

inline fun <T> filterIsInstance(): Either<L, T>?

Returns the same Right casted to type T if it is T. Otherwise returns null.

filterIsInstanceToOption

inline fun <T> filterIsInstanceToOption(): Option<Either<L, T>>

Returns Some containing the same Right casted to type T if it is T. Otherwise returns None.

filterNot

inline fun filterNot(predicate: (R) -> Boolean): Either<L, R>?

Returns the same Right if the predicate is not satisfied for the value. Otherwise returns null.

filterNotToOption

inline fun filterNotToOption(predicate: (R) -> Boolean): Option<Either<L, R>>

Returns Some containing the same Right if the predicate is not satisfied for the value. Otherwise returns None.

filterToOption

inline fun filterToOption(predicate: (R) -> Boolean): Option<Either<L, R>>

Returns Some containing the same Right if the predicate is satisfied for the value. Otherwise returns None.

fold

inline fun <T> fold(leftTransform: (L) -> T, rightTransform: (R) -> T): T

Transforms Left with leftTransform or Right with rightTransform.

forEach

inline fun forEach(action: (R) -> Unit)

Runs action if this is a Right. Returns Unit without any action if this is a Left.

get

fun get(): R

Gets value of this Right.

getOrNull

fun getOrNull(): R?

Gets value of this Right or null if this is Left.

map

inline fun <T> map(transform: (R) -> T): Either<L, T>

Maps value of this Right using transform.

none

inline fun none(predicate: (R) -> Boolean): Boolean

Returns false if the predicate is met by the value if this is Right or true otherwise.

swap

abstract fun swap(): Either<R, L>

Swaps Left to Right and Right to Left.

toOption

fun toOption(): Option<R>

Returns a Some containing the Right value if it exists, or a None if this is a Left.

Properties

isLeft

abstract val isLeft: Boolean

Returns true if this is a Left or false if this is Right.

isRight

abstract val isRight: Boolean

Returns true if this is a Right or false if this is Left.

left

val left: LeftProjection<L, R>

Projects Either as Left.

right

~~val~~ ~~right~~: RightProjection<L, R>

Projects Either as Right.

Inheritors

Left

Right

Extensions

filterNotNull

fun <L, R> Either<L, R?>.filterNotNull(): Either<L, R>?

Returns the same Right if its value is not null. Otherwise returns null.

filterNotNullToOption

fun <L, R> Either<L, R?>.filterNotNullToOption(): Option<Either<L, R>>

Returns Some containing the same Right if its value is not null. Otherwise returns None.

filterOrElse

inline fun <L, R> Either<L, R>.filterOrElse(predicate: (R) -> Boolean, zero: () -> L): Either<L, R>

Returns the same Right if the predicate is satisfied for the value, Left(zero) if the predicate is not satisfied for the value, or the same Left if this is Left.

flatMap

inline fun <L, R, T> Either<L, R>.flatMap(transform: (R) -> Either<L, T>): Either<L, T>

Maps value of this Right to a new Either using transform.

getOrElse

inline fun <L, R> Either<L, R>.getOrElse(default: () -> R): R

Gets value of this Right or default value if this is Left.

joinLeft

fun <L, R> Either<Either<L, R>, R>.joinLeft(): Either<L, R>

Returns this if this is Right. Otherwise returns value of Left.

joinRight

fun <L, R> Either<L, Either<L, R>>.joinRight(): Either<L, R>

Returns this if this is Left. Otherwise returns value of Right.

merge

fun <T> Either<T, T>.merge(): T

Merges Left and Right of the same type to a single value.