Adds OutcomeOf::asResult with an onAbsent conversion (#114)

* Adds OutcomeOf::asResult with an onAbsent conversion * Updates lib.api
block · Nov 22, 2024 · e7a5252 · e7a5252
1 parent fa94f56
commit e7a5252
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Showing 3 changed files with 29 additions and 6 deletions.
diff --git a/lib/api/lib.api b/lib/api/lib.api
@@ -37,6 +37,7 @@ public final class app/cash/quiver/OutcomeKt {
 	public static final fun asOption (Lapp/cash/quiver/Outcome;)Larrow/core/Option;
 	public static final fun asOutcome (Larrow/core/Either;)Lapp/cash/quiver/Outcome;
 	public static final fun asResult (Lapp/cash/quiver/Outcome;)Ljava/lang/Object;
+	public static final fun asResult (Lapp/cash/quiver/Outcome;Lkotlin/jvm/functions/Function0;)Ljava/lang/Object;
 	public static final fun failure (Ljava/lang/Object;)Lapp/cash/quiver/Outcome;
 	public static final fun filter (Lapp/cash/quiver/Outcome;Lkotlin/jvm/functions/Function1;)Lapp/cash/quiver/Outcome;
 	public static final fun flatMap (Lapp/cash/quiver/Outcome;Lkotlin/jvm/functions/Function1;)Lapp/cash/quiver/Outcome;

diff --git a/lib/src/main/kotlin/app/cash/quiver/Outcome.kt b/lib/src/main/kotlin/app/cash/quiver/Outcome.kt
@@ -3,6 +3,10 @@
 package app.cash.quiver
 
 import app.cash.quiver.extensions.OutcomeOf
+import app.cash.quiver.extensions.orThrow
+import app.cash.quiver.extensions.toResult
+import app.cash.quiver.raise.OutcomeRaise
+import app.cash.quiver.raise.outcome
 import arrow.core.Either
 import arrow.core.Either.Left
 import arrow.core.Either.Right
@@ -14,14 +18,10 @@ import arrow.core.flatMap
 import arrow.core.getOrElse
 import arrow.core.identity
 import arrow.core.left
+import arrow.core.raise.catch
 import arrow.core.right
 import arrow.core.some
 import arrow.core.valid
-import app.cash.quiver.extensions.orThrow
-import app.cash.quiver.extensions.toResult
-import app.cash.quiver.raise.OutcomeRaise
-import app.cash.quiver.raise.outcome
-import arrow.core.raise.catch
 import kotlin.experimental.ExperimentalTypeInference
 
 /**
@@ -247,6 +247,18 @@ inline fun <E, A> Outcome<E, A>.asEither(onAbsent: () -> E): Either<E, A> =
  */
 fun <A> OutcomeOf<A>.asResult(): Result<Option<A>> = inner.toResult()
 
+/**
+ * Converts an OutcomeOf<A> to a Result<A>, converting Absent to a Failure.
+ */
+inline fun <A> OutcomeOf<A>.asResult(onAbsent: () -> Throwable): Result<A> =
+  inner.toResult()
+    .flatMap { maybeValue ->
+      maybeValue.fold(
+        { Result.failure(onAbsent()) },
+        { Result.success(it) }
+      )
+    }
+
 inline fun <E, A, B> Outcome<E, A>.foldOption(onAbsent: () -> B, onPresent: (A) -> B): Either<E, B> =
   inner.map { it.fold(onAbsent, onPresent) }
 

diff --git a/lib/src/test/kotlin/app/cash/quiver/OutcomeTest.kt b/lib/src/test/kotlin/app/cash/quiver/OutcomeTest.kt
@@ -31,6 +31,7 @@ import io.kotest.assertions.throwables.shouldThrow
 import io.kotest.common.runBlocking
 import io.kotest.core.spec.style.StringSpec
 import io.kotest.matchers.result.shouldBeFailure
+import io.kotest.matchers.result.shouldBeSuccess
 import io.kotest.matchers.shouldBe
 import io.kotest.property.Arb
 import io.kotest.property.arbitrary.int
@@ -40,6 +41,7 @@ import io.kotest.property.arrow.core.either
 import io.kotest.property.arrow.core.option
 import io.kotest.property.checkAll
 import kotlinx.coroutines.coroutineScope
+import java.lang.IllegalStateException
 
 class OutcomeTest : StringSpec({
   "Present flatMap" {
@@ -475,6 +477,7 @@ class OutcomeTest : StringSpec({
       absent.recover { fallback.bind() }.shouldBeAbsent()
     }
   }
+
   "recover can recover from Failure" {
     checkAll(Arb.either(Arb.long(), Arb.int())) { either ->
       val failed: Outcome<String, Int> = "failure".failure()
@@ -495,9 +498,16 @@ class OutcomeTest : StringSpec({
     }
   }
 
-  "Converting to Result" {
+  "converting to Result" {
     Absent.asResult() shouldBe Result.success(None)
     1.present().asResult() shouldBe Result.success(Some(1))
     Throwable("sad").failure().asResult().shouldBeFailure().message shouldBe "sad"
   }
+
+  "asResult converts to Either converting Absent to an error" {
+    1.present().asResult { IllegalStateException("nup") }.shouldBeSuccess(1)
+    Absent.asEither { IllegalStateException("nup") }.shouldBeLeft().message shouldBe "nup"
+    "bad".failure().asEither { IllegalStateException("nup") }.shouldBeLeft("bad")
+  }
+
 })