bind

open suspend fun Cont<R, B>.bind(): B

Runs the Cont to finish, returning B or shift in case of R.

fun <E, A> Either<E, A>.toCont(): Cont<E, A> = cont {
  fold({ e -> shift(e) }, ::identity)
}

suspend fun test() = checkAll(Arb.either(Arb.string(), Arb.int())) { either ->
  cont<String, Int> {
    val x: Int = either.toCont().bind()
    x
  }.toEither() shouldBe either
}

open suspend fun Either<R, B>.bind(): B

Folds Either into Cont, by returning B or a shift with R.

suspend fun test() = checkAll(Arb.either(Arb.string(), Arb.int())) { either ->
  cont<String, Int> {
    val x: Int = either.bind()
    x
  }.toEither() shouldBe either
}

open suspend fun Validated<R, B>.bind(): B

Folds Validated into Cont, by returning B or a shift with R.

suspend fun test() = checkAll(Arb.validated(Arb.string(), Arb.int())) { validated ->
  cont<String, Int> {
    val x: Int = validated.bind()
    x
  }.toValidated() shouldBe validated
}

open suspend fun Result.bind(transform: (Throwable) -> R): B

Folds Result into Cont, by returning B or a transforming Throwable into R and shifting the result.

private val default = "failed"
suspend fun test() = checkAll(Arb.result(Arb.int())) { result ->
  cont<String, Int> {
    val x: Int = result.bind { _: Throwable -> default }
    x
  }.fold({ default }, ::identity) shouldBe result.getOrElse { default }
}

open suspend fun Option.bind(shift: () -> R): B

Folds Option into Cont, by returning B or a transforming None into R and shifting the result.

private val default = "failed"
suspend fun test() = checkAll(Arb.option(Arb.int())) { option ->
  cont<String, Int> {
    val x: Int = option.bind { default }
    x
  }.fold({ default }, ::identity) shouldBe option.getOrElse { default }
}