47 lines
1.5 KiB
Kotlin
47 lines
1.5 KiB
Kotlin
/* Copyright 2017 Andrew Dawson
|
|
*
|
|
* This file is a part of Tusky.
|
|
*
|
|
* This program is free software; you can redistribute it and/or modify it under the terms of the
|
|
* GNU General Public License as published by the Free Software Foundation; either version 3 of the
|
|
* License, or (at your option) any later version.
|
|
*
|
|
* Tusky is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even
|
|
* the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General
|
|
* Public License for more details.
|
|
*
|
|
* You should have received a copy of the GNU General Public License along with Tusky; if not,
|
|
* see <http://www.gnu.org/licenses>. */
|
|
|
|
package com.keylesspalace.tusky.util
|
|
|
|
/**
|
|
* Created by charlag on 05/11/17.
|
|
*
|
|
* Class to represent sum type/tagged union/variant/ADT e.t.c.
|
|
* It is either Left or Right.
|
|
*/
|
|
sealed class Either<out L, out R> {
|
|
data class Left<out L, out R>(val value: L) : Either<L, R>()
|
|
data class Right<out L, out R>(val value: R) : Either<L, R>()
|
|
|
|
fun isRight() = this is Right
|
|
|
|
fun isLeft() = this is Left
|
|
|
|
fun asLeftOrNull() = (this as? Left<L, R>)?.value
|
|
|
|
fun asRightOrNull() = (this as? Right<L, R>)?.value
|
|
|
|
fun asLeft(): L = (this as Left<L, R>).value
|
|
|
|
fun asRight(): R = (this as Right<L, R>).value
|
|
|
|
inline fun <N> map(crossinline mapper: (R) -> N): Either<L, N> {
|
|
return if (this.isLeft()) {
|
|
Left(this.asLeft())
|
|
} else {
|
|
Right(mapper(this.asRight()))
|
|
}
|
|
}
|
|
} |