[Hygiene] Use Action.onEvent syntax. (#346)

formula-android/src/main/java/com/instacart/formula/android/FragmentFlowStore.kt

@@ -76,7 +76,7 @@ class FragmentFlowStore @PublishedApi internal constructor(
         return Evaluation(
             output = state,
             actions = context.actions {
-                events(lifecycleEventStream) { event ->
+                lifecycleEventStream.onEvent { event ->
                     val fragmentId = event.fragmentId
                     when (event) {
                         is FragmentLifecycleEvent.Removed -> {
@@ -106,7 +106,7 @@ class FragmentFlowStore @PublishedApi internal constructor(
                     }
                 }
 
-                events(visibleContractEventStream) {
+                visibleContractEventStream.onEvent {
                     if (state.visibleIds.contains(it)) {
                         // TODO: should we log this duplicate visibility event?
                         none()
@@ -115,7 +115,7 @@ class FragmentFlowStore @PublishedApi internal constructor(
                     }
                 }
 
-                events(hiddenContractEventStream) {
+                hiddenContractEventStream.onEvent {
                     transition(state.copy(visibleIds = state.visibleIds.minus(it)))
                 }
 

formula-android/src/main/java/com/instacart/formula/android/internal/CompositeBinding.kt

@@ -48,7 +48,7 @@ internal class CompositeBinding<ParentComponent, ScopedComponent>(
                 output = Unit,
                 actions = context.actions {
                     val isInScope = input.activeFragments.any { binds(it.key) }
-                    events(Action.onData(isInScope)) {
+                    Action.onData(isInScope).onEvent {
                         if (isInScope && component == null) {
                             transition(State(component = scopeFactory.invoke(input.component)))
                         } else if (!isInScope && component != null) {
@@ -60,7 +60,7 @@ internal class CompositeBinding<ParentComponent, ScopedComponent>(
                         }
                     }
 
-                    events(Action.onTerminate()) {
+                    Action.onTerminate().onEvent {
                         transition { component?.dispose() }
                     }
                 }

formula/src/main/java/com/instacart/formula/ActionBuilder.kt

@@ -39,19 +39,6 @@ abstract class ActionBuilder<out Input, State>(
         transition: Transition<Input, State, Event>,
     )
 
-    /**
-     * Adds an [Action] as part of this [Evaluation]. [Action] will be initialized
-     * when it is initially added and cleaned up when it is not returned
-     * as part of [Evaluation].
-     *
-     * @param transition A function that is invoked when [Action] emits an [Event].
-     */
-    abstract fun <Event> onEvent(
-        action: Action<Event>,
-        avoidParameterClash: Any = this,
-        transition: Transition<Input, State, Event>,
-    )
-
     /**
      * Adds an [Action] as part of this [Evaluation]. [Action] will be initialized
      * when it is initially added and cleaned up when it is not returned

formula/src/main/java/com/instacart/formula/internal/ActionBuilderImpl.kt

@@ -21,30 +21,13 @@ internal class ActionBuilderImpl<out Input, State> internal constructor(
         action: Action<Event>,
         transition: Transition<Input, State, Event>,
     ) {
-        add(toBoundStream(action, transition))
-    }
-
-    override fun <Event> onEvent(
-        action: Action<Event>,
-        avoidParameterClash: Any,
-        transition: Transition<Input, State, Event>,
-    ) {
-        add(toBoundStream(action, transition))
+        actions.add(toBoundStream(action, transition))
     }
 
     override fun <Event> Action<Event>.onEvent(
         transition: Transition<Input, State, Event>,
     ) {
-        val stream = this
-        this@ActionBuilderImpl.events(stream, transition)
-    }
-
-    private fun add(action: DeferredAction<*>) {
-        if (actions.contains(action)) {
-            throw IllegalStateException("duplicate stream with key: ${action.keyAsString()}")
-        }
-
-        actions.add(action)
+        events(this, transition)
     }
 
     private fun <Event> toBoundStream(

formula/src/test/java/com/instacart/formula/FormulaRuntimeTest.kt

@@ -885,11 +885,11 @@ class FormulaRuntimeTest(val runtime: TestableRuntime, val name: String) {
     @Test
     fun `same stream declarations are okay`() {
         val formula = OnlyUpdateFormula<Unit> {
-            events(EmptyAction.init()) {
+            EmptyAction.init().onEvent {
                 transition(Unit)
             }
 
-            events(EmptyAction.init()) {
+            EmptyAction.init().onEvent {
                 transition(Unit)
             }
         }
@@ -901,11 +901,11 @@ class FormulaRuntimeTest(val runtime: TestableRuntime, val name: String) {
     @Test
     fun `same observable declarations are okay`() {
         val formula = OnlyUpdateFormula<Unit> {
-            events(RxAction.fromObservable("same") { Observable.just(1) }) {
+            RxAction.fromObservable("same") { Observable.just(1) }.onEvent {
                 none()
             }
 
-            events(RxAction.fromObservable("same") { Observable.just(1) }) {
+            RxAction.fromObservable("same") { Observable.just(1) }.onEvent {
                 none()
             }
         }
@@ -918,7 +918,7 @@ class FormulaRuntimeTest(val runtime: TestableRuntime, val name: String) {
         val formula = OnlyUpdateFormula<Unit> {
             val list = listOf(1, 2, 3)
             list.forEach {
-                events(EmptyAction.init()) {
+                EmptyAction.init().onEvent {
                     none()
                 }
             }
@@ -933,7 +933,7 @@ class FormulaRuntimeTest(val runtime: TestableRuntime, val name: String) {
         val formula = OnlyUpdateFormula<Unit> {
             val list = listOf(1, 2, 3)
             list.forEach {
-                events(EmptyAction.init(it)) {
+                EmptyAction.init(it).onEvent {
                     none()
                 }
             }
@@ -946,13 +946,13 @@ class FormulaRuntimeTest(val runtime: TestableRuntime, val name: String) {
     fun `multiple event streams without key`() {
         var executed = 0
         val formula = OnlyUpdateFormula<Unit> {
-            events(Action.onInit()) {
+            Action.onInit().onEvent {
                 transition {
                     executed += 1
                 }
             }
 
-            events(Action.onInit()) {
+            Action.onInit().onEvent {
                 transition {
                     executed += 1
                 }
@@ -968,11 +968,11 @@ class FormulaRuntimeTest(val runtime: TestableRuntime, val name: String) {
     fun `multiple events with input and without key`() {
         var executed = 0
         val formula = OnlyUpdateFormula<Int> {
-            events(Action.onData(it)) {
+            Action.onData(it).onEvent {
                 transition { executed += 1 }
             }
 
-            events(Action.onData(it)) {
+            Action.onData(it).onEvent {
                 transition { executed += 1 }
             }
         }
@@ -987,7 +987,7 @@ class FormulaRuntimeTest(val runtime: TestableRuntime, val name: String) {
         val formula = OnlyUpdateFormula<Unit> {
             val list = listOf(0, 1, 2)
             list.forEach {
-                events(Action.onInit()) {
+                Action.onInit().onEvent {
                     none()
                 }
             }
@@ -1041,7 +1041,7 @@ class FormulaRuntimeTest(val runtime: TestableRuntime, val name: String) {
         var emissions = 0
         var terminateCallback = -1
         val formula = OnlyUpdateFormula<Int> { input ->
-            events(Action.onTerminate()) {
+            Action.onTerminate().onEvent {
                 transition {
                     emissions += 1
                     terminateCallback = input
@@ -1204,7 +1204,7 @@ class FormulaRuntimeTest(val runtime: TestableRuntime, val name: String) {
     @Test
     fun `emit error`() {
         val formula = OnlyUpdateFormula<Unit> {
-            events(Action.onInit()) {
+            Action.onInit().onEvent {
                 throw java.lang.IllegalStateException("crashed")
             }
         }

formula/src/test/java/com/instacart/formula/subjects/DynamicStreamSubject.kt

@@ -36,7 +36,7 @@ class DynamicStreamSubject(runtime: TestableRuntime) {
                 output = Unit,
                 actions = context.actions {
                     input.forEach { key ->
-                        events(action(key)) {
+                        action(key).onEvent {
                             none()
                         }
                     }

formula/src/test/java/com/instacart/formula/subjects/EventFormula.kt

@@ -29,7 +29,7 @@ class EventFormula<EventT : Any>(
         return Evaluation(
             output = state,
             actions = context.actions {
-                events(stream) {
+                stream.onEvent {
                     val newState = state + 1
                     transition(newState) {
                         captured(Event(newState, it))

formula/src/test/java/com/instacart/formula/subjects/ExtremelyNestedFormula.kt

@@ -19,7 +19,7 @@ object ExtremelyNestedFormula {
             return Evaluation(
                 output = state + childValue,
                 actions = context.actions {
-                    events(Action.onInit()) {
+                    Action.onInit().onEvent {
                         transition(state + 1)
                     }
                 }

formula/src/test/java/com/instacart/formula/subjects/FromObservableWithInputFormula.kt

@@ -29,7 +29,7 @@ class FromObservableWithInputFormula : StatelessFormula<FromObservableWithInputF
                 val fetchItem = RxAction.fromObservable(key = input.itemId) {
                     repo.fetchItem(input.itemId)
                 }
-                events(fetchItem) {
+                fetchItem.onEvent() {
                     transition { input.onItem(it) }
                 }
             }

formula/src/test/java/com/instacart/formula/subjects/RemovingTerminateStreamSendsNoMessagesFormula.kt

@@ -17,7 +17,7 @@ class RemovingTerminateStreamSendsNoMessagesFormula : StatelessFormula<RemovingT
             actions = context.actions {
                 val onTerminate = input.onTerminate
                 if (onTerminate != null) {
-                    events(Action.onTerminate()) {
+                    Action.onTerminate().onEvent {
                         transition(onTerminate)
                     }
                 }

formula/src/test/java/com/instacart/formula/subjects/StartStopFormula.kt

@@ -31,7 +31,7 @@ class StartStopFormula(runtime: TestableRuntime) : Formula<Unit, State, Output>(
         return Evaluation(
             actions = context.actions {
                 if (state.listenForEvents) {
-                    events(incrementEvents.action()) {
+                    incrementEvents.action().onEvent {
                         transition(state.copy(count = state.count + 1))
                     }
                 }

formula/src/test/java/com/instacart/formula/subjects/SubscribesToAllUpdatesBeforeDeliveringMessages.kt

@@ -21,7 +21,7 @@ object SubscribesToAllUpdatesBeforeDeliveringMessages {
             return Evaluation(
                 output = state,
                 actions = context.actions {
-                    events(initial) {
+                    initial.onEvent {
                         transition { incrementRelay.triggerEvent() }
                     }
 

samples/custom-network-state-stream/src/main/java/com/instacart/formula/samples/networkstate/NetworkStateFormula.kt

@@ -19,7 +19,7 @@ class NetworkStateFormula(
                 status = "Network state: $isConnected"
             ),
             actions = context.actions {
-                events(networkStateStream) {
+                networkStateStream.onEvent {
                     transition(state.copy(isOnline = it.isOnline))
                 }
             }

samples/stopwatch-compose/src/main/java/com/instacart/formula/compose/stopwatch/StopwatchFormula.kt

@@ -33,7 +33,7 @@ class StopwatchFormula : Formula<Unit, StopwatchFormula.State, StopwatchRenderMo
                         Observable.interval(1, TimeUnit.MILLISECONDS).observeOn(AndroidSchedulers.mainThread())
                     }
 
-                    events(incrementTimePassed) {
+                    incrementTimePassed.onEvent {
                         transition(state.copy(timePassedInMillis = state.timePassedInMillis + 1))
                     }
                 }