WIP: upgrade to arrow 2.0

gradle/libs.versions.toml

@@ -1,5 +1,5 @@
 [versions]
-arrow = "1.2.4"
+arrow = "2.0.0-alpha.2"
 dokka = "1.9.20"
 junit = "5.10.2"
 kotest = "5.8.1"

lib/module.md

@@ -12,7 +12,7 @@ available from Arrow.
 # Package app.cash.quiver
 Custom types (e.g. [`Outcome`](app.cash.quiver.Outcome))
 
-# Package app.cash.quiver.continuations
+# Package app.cash.quiver.effects
 Continuations for working with custom types (e.g. [`Outcome`](app.cash.quiver.Outcome))
 
 ```kotlin

lib/src/main/kotlin/app/cash/quiver/Outcome.kt

@@ -8,14 +8,12 @@ import arrow.core.Either.Right
 import arrow.core.None
 import arrow.core.Option
 import arrow.core.Some
-import arrow.core.Validated
 import arrow.core.flatMap
 import arrow.core.getOrElse
 import arrow.core.identity
 import arrow.core.left
 import arrow.core.right
 import arrow.core.some
-import arrow.core.valid
 import app.cash.quiver.extensions.orThrow
 import app.cash.quiver.raise.OutcomeRaise
 import app.cash.quiver.raise.outcome
@@ -292,12 +290,6 @@ fun <E, EE, A> Outcome<E, Either<EE, A>>.sequence(): Either<EE, Outcome<E, A>> =
   is Present -> this.value.map(::Present)
 }
 
-fun <E, EE, A> Outcome<E, Validated<EE, A>>.sequence(): Validated<EE, Outcome<E, A>> = when (this) {
-  Absent -> Absent.valid()
-  is Failure -> this.valid()
-  is Present -> this.value.map(::Present)
-}
-
 fun <E, A> Iterable<Outcome<E, A>>.sequence(): Outcome<E, List<A>> =
   outcome { map { it.bind() } }
 
@@ -307,5 +299,3 @@ inline fun <E, A, B> Outcome<E, A>.traverse(f: (A) -> Option<B>): Option<Outcome
 @OptIn(ExperimentalTypeInference::class)
 @OverloadResolutionByLambdaReturnType
 inline fun <E, EE, A, B> Outcome<E, A>.traverse(f: (A) -> Either<EE, B>): Either<EE, Outcome<E, B>> = this.map(f).sequence()
-inline fun <E, EE, A, B> Outcome<E, A>.traverse(f: (A) -> Validated<EE, B>): Validated<EE, Outcome<E, B>> =
-  this.map(f).sequence()

lib/src/main/kotlin/app/cash/quiver/effects/OutcomeEagerEffectScope.kt

@@ -0,0 +1,55 @@
+package app.cash.quiver.effects
+
+import app.cash.quiver.Absent
+import app.cash.quiver.Failure
+import app.cash.quiver.Outcome
+import app.cash.quiver.Present
+import arrow.core.Either
+import arrow.core.left
+import arrow.core.merge
+import arrow.core.raise.Raise
+import arrow.core.raise.eagerEffect
+import arrow.core.raise.effect
+import arrow.core.raise.fold
+import arrow.core.right
+
+@JvmInline
+value class OutcomeEffectScope<E>(private val cont: Raise<Either<Failure<E>, Absent>>) :
+  Raise<Either<Failure<E>, Absent>> {
+
+  suspend fun <B> Outcome<E, B>.bind(): B =
+    when (this) {
+      Absent -> raise(Absent.right())
+      is Failure -> raise(this.left())
+      is Present -> value
+    }
+
+  override fun raise(r: Either<Failure<E>, Absent>): Nothing = cont.raise(r)
+}
+
+@JvmInline
+value class OutcomeEagerEffectScope<E>(private val cont: Raise<Either<Failure<E>, Absent>>) :
+  Raise<Either<Failure<E>, Absent>> {
+
+  fun <B> Outcome<E, B>.bind(): B =
+    when (this) {
+      Absent -> raise(Absent.right())
+      is Failure -> raise(this.left())
+      is Present -> value
+    }
+
+  override fun raise(r: Either<Failure<E>, Absent>): Nothing = cont.raise(r)
+}
+
+@Suppress("ClassName")
+object outcome {
+  inline fun <E, A> eager(crossinline f: OutcomeEagerEffectScope<E>.() -> A): Outcome<E, A> =
+    eagerEffect {
+      f.invoke(OutcomeEagerEffectScope<E>(this))
+    }.fold({ it.merge() }, ::Present)
+
+  suspend inline operator fun <E, A> invoke(crossinline f: suspend OutcomeEffectScope<E>.() -> A): Outcome<E, A> =
+    effect {
+      f.invoke(OutcomeEffectScope<E>(this))
+    }.fold({ it.merge() }, ::Present)
+}

lib/src/main/kotlin/app/cash/quiver/extensions/Option.kt

@@ -6,9 +6,10 @@ import arrow.core.Either
 import arrow.core.None
 import arrow.core.Option
 import arrow.core.Some
-import arrow.core.ValidatedNel
 import arrow.core.getOrElse
+import arrow.core.left
 import arrow.core.nonEmptyListOf
+import arrow.core.right
 import kotlin.experimental.ExperimentalTypeInference
 import app.cash.quiver.extensions.traverse as quiverTraverse
 
@@ -38,7 +39,10 @@ inline fun <A> Option<A>.forEach(f: (A) -> Unit) {
  * If it's a None, will return a Nel of the error function passed in
  */
 inline fun <T, E> Option<T>.toValidatedNel(error: () -> E): ValidatedNel<E, T> =
-  ValidatedNel.fromOption(this) { nonEmptyListOf(error()) }
+  this.fold(
+    { nonEmptyListOf(error()).left() },
+    { it.right() }
+  )
 
 /**
  * Map some to Unit. This restores `.void()` which was deprecated by Arrow.

lib/src/main/kotlin/app/cash/quiver/extensions/Validated.kt

@@ -1,23 +1,20 @@
-@file:Suppress("TYPEALIAS_EXPANSION_DEPRECATION", "DEPRECATION")
-
 package app.cash.quiver.extensions
 
 import arrow.core.Either
-import arrow.core.ValidatedNel
+import arrow.core.NonEmptyList
 import arrow.core.flatMap
 import arrow.core.getOrElse
-import arrow.core.invalidNel
 import arrow.core.left
+import arrow.core.nonEmptyListOf
 import arrow.core.right
-import arrow.core.validNel
-import arrow.core.zip
+
+typealias ValidatedNel<E, A> = Either<NonEmptyList<E>, A>
 
 /**
  * Turns your Validated List into an Either, but will throw an exception in the Left hand case.
  */
 fun <E, A> ValidatedNel<E, A>.attemptValidated(): Either<Throwable, A> =
-  this.toEither()
-    .mapLeft { errors -> RuntimeException(errors.toString()) }
+  this.mapLeft { errors -> RuntimeException(errors.toString()) }
 
 /**
  * Given a predicate and an error generating function return either the original value in a ValidNel if the
@@ -28,7 +25,7 @@ fun <E, A> ValidatedNel<E, A>.attemptValidated(): Either<Throwable, A> =
  *
  */
 inline fun <ERR, A> A.validate(predicate: (A) -> Boolean, error: (A) -> ERR): ValidatedNel<ERR, A> =
-  if (predicate(this)) this.validNel() else error(this).invalidNel()
+   if (predicate(this)) this.right() else nonEmptyListOf(error(this)).left()
 
 /**
  * Given a predicate and an error generating function return either the original value in a Right if the
@@ -46,28 +43,24 @@ inline fun <ERR, A> A.validateEither(predicate: (A) -> Boolean, error: (A) -> ER
  * to pair them. takeLeft will return the value of the left side iff both validations
  * succeed.
  *
- * eg.
+ * eg:
  *
  * Valid("hi").takeLeft(Valid("mum")) == Valid("hi")
  */
 fun <ERR, A> ValidatedNel<ERR, A>.takeLeft(other: ValidatedNel<ERR, A>): ValidatedNel<ERR, A> =
-  this.zip(other) { a, _ ->
-    a
-  }
+  this.zip(other) { a, _ -> a }
 
 /**
  * Often you have two validations that return the same thing, and you don't want necessarily
  * to pair them. takeRight will return the value of the right side iff both validations
  * succeed.
  *
- * eg.
+ * eg:
  *
  * Valid("hi").takeRight(Valid("mum")) == Valid("mum")
  */
 fun <ERR, A> ValidatedNel<ERR, A>.takeRight(other: ValidatedNel<ERR, A>): ValidatedNel<ERR, A> =
-  this.zip(other) { _, b ->
-    b
-  }
+  this.zip(other) { _, b -> b }
 
 /**
  * Given a mapping function and an error message, return either the result of the function in a
@@ -77,7 +70,7 @@ inline fun <ERR, A, B> A.validateMap(
   f: (A) -> Either<Throwable, B>,
   error: (A, Throwable) -> ERR
 ): ValidatedNel<ERR, B> =
-  f(this).map { it.validNel() }.getOrElse { error(this, it).invalidNel() }
+  f(this).map { it.right() }.getOrElse { nonEmptyListOf(error(this, it)).left() }
 
 /**
  * The Validated type doesn't natively support flatMap because of the monad laws that it breaks. But this
@@ -93,4 +86,4 @@ inline fun <ERR, A, B> A.validateMap(
  * result == ValidNel("$jackjack")
  */
 inline fun <ERR, A, B> ValidatedNel<ERR, A>.concatMap(f: (A) -> ValidatedNel<ERR, B>): ValidatedNel<ERR, B> =
-  this.withEither { either -> either.flatMap { f(it).toEither() } }
+  this.flatMap { f(it) }

lib/src/test/kotlin/app/cash/quiver/OutcomeTest.kt

@@ -1,28 +1,21 @@
-@file:Suppress("DEPRECATION")
-
 package app.cash.quiver
 
 import app.cash.quiver.arb.outcome
+import app.cash.quiver.effects.outcome
 import app.cash.quiver.matchers.shouldBeAbsent
 import app.cash.quiver.matchers.shouldBeFailure
 import app.cash.quiver.matchers.shouldBePresent
 import arrow.core.Either
 import arrow.core.None
 import arrow.core.Option
 import arrow.core.Some
-import arrow.core.Validated
-import arrow.core.invalid
 import arrow.core.left
 import arrow.core.right
 import arrow.core.some
-import arrow.core.valid
-import app.cash.quiver.continuations.outcome
-import io.kotest.assertions.arrow.core.shouldBeInvalid
 import io.kotest.assertions.arrow.core.shouldBeLeft
 import io.kotest.assertions.arrow.core.shouldBeNone
 import io.kotest.assertions.arrow.core.shouldBeRight
 import io.kotest.assertions.arrow.core.shouldBeSome
-import io.kotest.assertions.arrow.core.shouldBeValid
 import io.kotest.assertions.fail
 import io.kotest.assertions.throwables.shouldThrow
 import io.kotest.common.runBlocking
@@ -354,19 +347,6 @@ class OutcomeTest : StringSpec({
     absent.sequence().shouldBeSome().shouldBeAbsent()
   }
 
-  "Validated sequence/traverse" {
-    Present(1.valid()).sequence().shouldBeValid().shouldBePresent().shouldBe(1)
-    Present(1.valid()).sequence() shouldBe Present(1).traverse { a: Int -> a.valid() }
-
-    val bad: Outcome<String, Validated<String, Int>> = "bad".failure()
-    bad.sequence().shouldBeValid().shouldBeFailure().shouldBe("bad")
-
-    val absent: Outcome<String, Validated<String, Int>> = Absent
-    absent.sequence().shouldBeValid().shouldBeAbsent()
-
-    Present("bad".invalid()).sequence().shouldBeInvalid()
-  }
-
   "List sequence/traverse" {
     Present(listOf(1, 2, 3)).sequence().shouldBe(listOf(1.present(), 2.present(), 3.present()))
     Present(listOf(1, 1)).sequence() shouldBe Present(1).traverse { a: Int -> listOf(a, a) }

lib/src/test/kotlin/app/cash/quiver/extensions/MapTest.kt

@@ -1,16 +1,19 @@
 package app.cash.quiver.extensions
 
 import arrow.core.Either
+import arrow.core.NonEmptyList
 import arrow.core.None
 import arrow.core.Some
 import arrow.core.left
-import arrow.core.maybe
 import arrow.core.right
 import arrow.core.some
+import arrow.core.toNonEmptyListOrNull
 import io.kotest.core.spec.style.StringSpec
 import io.kotest.matchers.shouldBe
 import io.kotest.property.Arb
+import io.kotest.property.arbitrary.filter
 import io.kotest.property.arbitrary.int
+import io.kotest.property.arbitrary.list
 import io.kotest.property.arbitrary.map
 import io.kotest.property.arrow.core.nonEmptyList
 import io.kotest.property.checkAll
@@ -129,7 +132,7 @@ class MapTest : StringSpec({
   }
 
   "traverse Option short-circuits" {
-    checkAll(Arb.nonEmptyList(Arb.int())) { ints ->
+    checkAll(arbNel(Arb.int())) { ints ->
       val acc = mutableListOf<Int>()
       val evens = ints.quiverTraverse {
         if (it % 2 == 0) {
@@ -143,4 +146,12 @@ class MapTest : StringSpec({
       evens.fold({ Unit }) { it shouldBe ints }
     }
   }
-})
+}) {
+  companion object {
+    // TODO(hugom): remove in favour of Arb.nonEmptyList once kotest-extensions-arrow has been upgraded to arrow 2.0.0
+    private fun <A> arbNel(a: Arb<A>): Arb<NonEmptyList<A>> =
+      Arb.list(a).filter(List<A>::isNotEmpty).map {
+        it.toNonEmptyListOrNull() ?: throw IndexOutOfBoundsException("Empty list")
+      }
+  }
+}

lib/src/test/kotlin/app/cash/quiver/extensions/OptionTest.kt

@@ -15,6 +15,12 @@ import io.kotest.property.checkAll
 import app.cash.quiver.extensions.traverse as quiverTraverse
 import app.cash.quiver.extensions.traverseEither as quiverTraverseEither
 import app.cash.quiver.extensions.ifPresent
+import arrow.core.NonEmptyList
+import io.kotest.assertions.arrow.core.shouldBeLeft
+import io.kotest.assertions.arrow.core.shouldBeRight
+import io.kotest.assertions.arrow.core.shouldHaveSize
+import io.kotest.matchers.shouldHave
+import io.kotest.matchers.types.shouldBeInstanceOf
 
 class OptionTest : StringSpec({
 
@@ -79,6 +85,13 @@ class OptionTest : StringSpec({
     sideEffectRun shouldBe false
   }
 
+  "toValidatedNel converts an option to a ValidatedNel" {
+    val errorList = None.toValidatedNel { IllegalStateException("Empty!") }.shouldBeLeft()
+    errorList.first().shouldBeInstanceOf<IllegalStateException>()
+
+    Some(42).toValidatedNel { IllegalStateException("Invalid") }.shouldBeRight(42)
+  }
+
   @Suppress("UNREACHABLE_CODE")
   "traverse to iterable of None returns an empty list" {
     None.quiverTraverse { listOf(it) } shouldBe emptyList()