Tune extensions for streams with variance annotation (out). (#13)

koptional-reactor-extensions/src/main/kotlin/com/gojuno/koptional/reactor/reactor.kt

@@ -15,7 +15,7 @@ private inline fun <reified R : Any> Flux<*>.ofType(): Flux<R> = ofType(R::class
  * @return a Flux that emits `Some.value` of those items emitted by the source Flux that are `Some`.
  * @see <a href="http://reactivex.io/documentation/operators/filter.html">ReactiveX operators documentation: Filter</a>
  */
-fun <T : Any> Flux<Optional<T>>.filterSome(): Flux<T> = ofType<Some<T>>().map { it.value }
+fun <T : Any> Flux<out Optional<T>>.filterSome(): Flux<T> = ofType<Some<T>>().map { it.value }
 
 /**
  * Filters items emitted by a Flux by only emitting those that are `None`.
@@ -25,4 +25,4 @@ fun <T : Any> Flux<Optional<T>>.filterSome(): Flux<T> = ofType<Some<T>>().map {
  * @return a Flux that emits `Unit` for each item emitted by the source Flux that is `None`.
  * @see <a href="http://reactivex.io/documentation/operators/filter.html">ReactiveX operators documentation: Filter</a>
  */
-fun <T : Any> Flux<Optional<T>>.filterNone(): Flux<Unit> = ofType<None>().map { Unit }
+fun <T : Any> Flux<out Optional<T>>.filterNone(): Flux<Unit> = ofType<None>().map { Unit }

koptional-reactor-extensions/src/test/kotlin/com/gojuno/koptional/reactor/ReactorExtensionsSpec.kt

@@ -1,6 +1,7 @@
 package com.gojuno.koptional.reactor
 
 import com.gojuno.koptional.None
+import com.gojuno.koptional.Optional
 import com.gojuno.koptional.Some
 import org.jetbrains.spek.api.Spek
 import org.jetbrains.spek.api.dsl.context
@@ -10,7 +11,7 @@ import reactor.test.StepVerifier
 
 class ReactorExtensionsSpec : Spek({
 
-    val stream by memoized {
+    val stream: Flux<out Optional<String>> by memoized {
         Flux.just(Some("a"), None, Some("b"), Some("c"), None)
     }
 

koptional-rxjava2-extensions/src/main/kotlin/com/gojuno/koptional/rxjava2/rxjava2.kt

@@ -25,7 +25,7 @@ private inline fun <reified R : Any> Single<*>.ofType(): Maybe<R> = filter { it
  * @return an Observable that emits `Some.value` of those items emitted by the source ObservableSource that are `Some`.
  * @see <a href="http://reactivex.io/documentation/operators/filter.html">ReactiveX operators documentation: Filter</a>
  */
-fun <T : Any> Observable<Optional<T>>.filterSome(): Observable<T> = ofType<Some<T>>().map { it.value }
+fun <T : Any> Observable<out Optional<T>>.filterSome(): Observable<T> = ofType<Some<T>>().map { it.value }
 
 /**
  * Filters items emitted by a Publisher by only emitting those that are `Some`.
@@ -39,7 +39,7 @@ fun <T : Any> Observable<Optional<T>>.filterSome(): Observable<T> = ofType<Some<
  * @return an Flowable that emits `Some.value` of those items emitted by the source Publisher that are `Some`.
  * @see <a href="http://reactivex.io/documentation/operators/filter.html">ReactiveX operators documentation: Filter</a>
  */
-fun <T : Any> Flowable<Optional<T>>.filterSome(): Flowable<T> = ofType<Some<T>>().map { it.value }
+fun <T : Any> Flowable<out Optional<T>>.filterSome(): Flowable<T> = ofType<Some<T>>().map { it.value }
 
 /**
  * Filters items emitted by an MaybeSource by only emitting those that are `Some`.
@@ -53,7 +53,7 @@ fun <T : Any> Flowable<Optional<T>>.filterSome(): Flowable<T> = ofType<Some<T>>(
  * @return an Maybe that emits `Some.value` of those items emitted by the source MaybeSource that are `Some`.
  * @see <a href="http://reactivex.io/documentation/operators/filter.html">ReactiveX operators documentation: Filter</a>
  */
-fun <T : Any> Maybe<Optional<T>>.filterSome(): Maybe<T> = ofType<Some<T>>().map { it.value }
+fun <T : Any> Maybe<out Optional<T>>.filterSome(): Maybe<T> = ofType<Some<T>>().map { it.value }
 
 /**
  * Filters items emitted by an SingleSource by only emitting those that are `Some`.
@@ -67,7 +67,7 @@ fun <T : Any> Maybe<Optional<T>>.filterSome(): Maybe<T> = ofType<Some<T>>().map
  * @return an Maybe that emits `Some.value` of those items emitted by the source SingleSource that are `Some`.
  * @see <a href="http://reactivex.io/documentation/operators/filter.html">ReactiveX operators documentation: Filter</a>
  */
-fun <T : Any> Single<Optional<T>>.filterSome(): Maybe<T> = ofType<Some<T>>().map { it.value }
+fun <T : Any> Single<out Optional<T>>.filterSome(): Maybe<T> = ofType<Some<T>>().map { it.value }
 
 /**
  * Filters items emitted by an ObservableSource by only emitting those that are `None`.
@@ -81,7 +81,7 @@ fun <T : Any> Single<Optional<T>>.filterSome(): Maybe<T> = ofType<Some<T>>().map
  * @return an Observable that emits `Unit` for each item emitted by the source ObservableSource that is `None`.
  * @see <a href="http://reactivex.io/documentation/operators/filter.html">ReactiveX operators documentation: Filter</a>
  */
-fun <T : Any> Observable<Optional<T>>.filterNone(): Observable<Unit> = ofType<None>().map { Unit }
+fun <T : Any> Observable<out Optional<T>>.filterNone(): Observable<Unit> = ofType<None>().map { Unit }
 
 /**
  * Filters items emitted by an Publisher by only emitting those that are `None`.
@@ -95,7 +95,7 @@ fun <T : Any> Observable<Optional<T>>.filterNone(): Observable<Unit> = ofType<No
  * @return an Flowable that emits `Unit` for each item emitted by the source Publisher that is `None`.
  * @see <a href="http://reactivex.io/documentation/operators/filter.html">ReactiveX operators documentation: Filter</a>
  */
-fun <T : Any> Flowable<Optional<T>>.filterNone(): Flowable<Unit> = ofType<None>().map { Unit }
+fun <T : Any> Flowable<out Optional<T>>.filterNone(): Flowable<Unit> = ofType<None>().map { Unit }
 
 /**
  * Filters items emitted by an MaybeSource by only emitting those that are `None`.
@@ -109,7 +109,7 @@ fun <T : Any> Flowable<Optional<T>>.filterNone(): Flowable<Unit> = ofType<None>(
  * @return an Maybe that emits `Unit` for each item emitted by the source MaybeSource that is `None`.
  * @see <a href="http://reactivex.io/documentation/operators/filter.html">ReactiveX operators documentation: Filter</a>
  */
-fun <T : Any> Maybe<Optional<T>>.filterNone(): Maybe<Unit> = ofType<None>().map { Unit }
+fun <T : Any> Maybe<out Optional<T>>.filterNone(): Maybe<Unit> = ofType<None>().map { Unit }
 
 /**
  * Filters items emitted by an SingleSource by only emitting those that are `None`.
@@ -123,4 +123,4 @@ fun <T : Any> Maybe<Optional<T>>.filterNone(): Maybe<Unit> = ofType<None>().map
  * @return an Maybe that emits `Unit` for each item emitted by the source SingleSource that is `None`.
  * @see <a href="http://reactivex.io/documentation/operators/filter.html">ReactiveX operators documentation: Filter</a>
  */
-fun <T : Any> Single<Optional<T>>.filterNone(): Maybe<Unit> = ofType<None>().map { Unit }
+fun <T : Any> Single<out Optional<T>>.filterNone(): Maybe<Unit> = ofType<None>().map { Unit }

koptional-rxjava2-extensions/src/test/kotlin/com/gojuno/koptional/rxjava2/RxJava2ExtensionsSpec.kt

@@ -17,7 +17,7 @@ class RxJava2ExtensionsSpec : Spek({
 
     context("Observable") {
 
-        val stream by memoized {
+        val stream: Observable<out Optional<String>> by memoized {
             Observable.just(Some("a"), None, Some("b"), Some("c"), None)
         }
 
@@ -70,7 +70,7 @@ class RxJava2ExtensionsSpec : Spek({
 
     context("Flowable") {
 
-        val stream by memoized {
+        val stream: Flowable<out Optional<String>> by memoized {
             Flowable.just(Some("a"), None, Some("b"), Some("c"), None)
         }
 
@@ -124,8 +124,8 @@ class RxJava2ExtensionsSpec : Spek({
     context("Maybe") {
 
         context("Stream with Some") {
-            val stream by memoized {
-                Maybe.just(Some("a") as Optional<String>)
+            val stream: Maybe<out Optional<String>> by memoized {
+                Maybe.just(Some("a"))
             }
 
             context("filterSome") {
@@ -177,8 +177,8 @@ class RxJava2ExtensionsSpec : Spek({
         }
 
         context("Stream with None") {
-            val stream by memoized {
-                Maybe.just(None as Optional<String>)
+            val stream: Maybe<out Optional<String>> by memoized {
+                Maybe.just(None)
             }
 
             context("filterSome") {
@@ -232,8 +232,8 @@ class RxJava2ExtensionsSpec : Spek({
     context("Single") {
 
         context("Stream with Some") {
-            val stream by memoized {
-                Single.just(Some("a") as Optional<String>)
+            val stream: Single<out Optional<String>> by memoized {
+                Single.just(Some("a"))
             }
 
             context("filterSome") {
@@ -285,8 +285,8 @@ class RxJava2ExtensionsSpec : Spek({
         }
 
         context("Stream with None") {
-            val stream by memoized {
-                Single.just(None as Optional<String>)
+            val stream: Single<out Optional<String>> by memoized {
+                Single.just(None)
             }
 
             context("filterSome") {