kotlin-stdlib/com.javiersc.kotlin.stdlib/Either

Either

sealed class Either<out A, out B>

Inheritors

Left

Right

Types

Left

data class Left<out A>(val value: A) : Either<A, Nothing>

The left side of the disjoint union, as opposed to the Right side.

Right

data class Right<out B>(val value: B) : Either<Nothing, B>

The right side of the disjoint union, as opposed to the Left side.

Functions

combine

fun <A, B> Either<A, B>.combine(other: Either<A, B>, combineLeft: (A, A) -> A, combineRight: (B, B) -> B): Either<A, B>

Combine two Either values. If both are Right then combine both B values using combineRight or if both are Left then combine both A values using combineLeft, otherwise return the sole Left value (either this or other).

compareTo

operator fun <A : Comparable<A>, B : Comparable<B>> Either<A, B>.compareTo(other: Either<A, B>): Int

flatMap

inline fun <A, B, C> Either<A, B>.flatMap(f: (right: B) -> Either<A, C>): Either<A, C>

Binds the given function across Right, that is, Map, or transform, the right value B of this Either into a new Either with a right value of type C. Returns a new Either with either the original left value of type A or the newly transformed right value of type C.

flatten

fun <A, B> Either<A, Either<A, B>>.flatten(): Either<A, B>

fold

inline fun <C> fold(ifLeft: (left: A) -> C, ifRight: (right: B) -> C): C

Transform an Either into a value of C. Alternative to using when to fold an Either into a value C.

getOrElse

infix inline fun <A, B> Either<A, B>.getOrElse(default: (A) -> B): B

Get the right value B of this Either, or compute a default value with the left value A.

getOrNull

fun getOrNull(): B?

Returns the unwrapped value B of Either.Right or null if it is Either.Left.

handleErrorWith

fun <A, B, C> Either<A, B>.handleErrorWith(f: (A) -> Either<C, B>): Either<C, B>

Binds the given function across Left, that is, Map, or transform, the left value A of this Either into a new Either with a left value of type C. Returns a new Either with either the original right value of type B or the newly transformed left value of type C.