jchucomponents-core/com.jeluchu.jchucomponents.core.functional/Either

Either

sealed class Either<out L, out R>

Represents a value of one of two possible types (a disjoint union). Instances of Either are either an instance of Left or Right. FP Convention dictates that Left is used for "failure" and Right is used for "success".

Inheritors

Left

Right

Types

Left

data class Left<out L>(val a: L) : Either<L, Nothing>

Right

data class Right<out R>(val b: R) : Either<Nothing, R>

Properties

isLeft

val isLeft: Boolean

Returns true if this is a Left, false otherwise.

isRight

val isRight: Boolean

Returns true if this is a Right, false otherwise.

Functions

flatMap

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

Right-biased flatMap() FP convention which means that Right is assumed to be the default case to operate on. If it is Left, operations like map, flatMap, ... return the Left value unchanged.

fold

fun fold(fnL: (L) -> Any, fnR: (R) -> Any): Any

Applies fnL if this is a Left or fnR if this is a Right.

getOrElse

fun <L, R> Either<L, R>.getOrElse(value: R): R

Returns the value from this Right or the given argument if this is a Left. Right(12).getOrElse(17) RETURNS 12 and Left(12).getOrElse(17) RETURNS 17

left

fun <L> left(a: L): Either.Left<L>

Creates a Left type.

map

fun <T, L, R> Either<L, R>.map(fn: (R) -> T): Either<L, T>

Right-biased map() FP convention which means that Right is assumed to be the default case to operate on. If it is Left, operations like map, flatMap, ... return the Left value unchanged.

right

fun <R> right(b: R): Either.Right<R>