arrow-core/arrow.core.continuations/eagerEffect

eagerEffect

fun <R, A> eagerEffect(f: suspend EagerEffectScope<R>.() -> A): EagerEffect<R, A>(source)

DSL for constructing EagerEffect<R, A> values

import arrow.core.Either
import arrow.core.None
import arrow.core.Option
import arrow.core.Validated
import arrow.core.continuations.eagerEffect
import io.kotest.assertions.fail
import io.kotest.matchers.shouldBe

fun main() {
  eagerEffect<String, Int> {
    val x = Either.Right(1).bind()
    val y = Validated.Valid(2).bind()
    val z = Option(3).bind { "Option was empty" }
    x + y + z
  }.fold({ fail("Shift can never be the result") }, { it shouldBe 6 })

  eagerEffect<String, Int> {
    val x = Either.Right(1).bind()
    val y = Validated.Valid(2).bind()
    val z: Int = None.bind { "Option was empty" }
    x + y + z
  }.fold({ it shouldBe "Option was empty" }, { fail("Int can never be the result") })
}