RecursiveResult#invert returns a new RecursiveResult

jnape · jnape · commit 3da90978f1d7 · 2018-05-13T14:11:14.000-05:00
diff --git a/CHANGELOG.md b/CHANGELOG.md
@@ -6,6 +6,7 @@ The format is based on [Keep a Changelog](http://keepachangelog.com/).
 ## [Unreleased]
 ### Changed
 - `ToMap` accepts an `Iterable` covariant in `Map.Entry`
+- `RecursiveResult#invert` is also a `RecursiveResult`
 
 ### Added
 - `Upcast` for safely casting up a type hierarchy
diff --git a/src/main/java/com/jnape/palatable/lambda/functions/recursion/RecursiveResult.java b/src/main/java/com/jnape/palatable/lambda/functions/recursion/RecursiveResult.java
@@ -23,6 +23,11 @@ public abstract class RecursiveResult<A, B> implements CoProduct2<A, B, Recursiv
     private RecursiveResult() {
     }
 
+    @Override
+    public RecursiveResult<B, A> invert() {
+        return match(RecursiveResult::terminate, RecursiveResult::recurse);
+    }
+
     @Override
     @SuppressWarnings("unchecked")
     public <C> RecursiveResult<C, B> biMapL(Function<? super A, ? extends C> fn) {
diff --git a/src/test/java/com/jnape/palatable/lambda/functions/recursion/RecursiveResultTest.java b/src/test/java/com/jnape/palatable/lambda/functions/recursion/RecursiveResultTest.java
@@ -1,6 +1,5 @@
 package com.jnape.palatable.lambda.functions.recursion;
 
-import com.jnape.palatable.lambda.functions.recursion.RecursiveResult;
 import com.jnape.palatable.traitor.annotations.TestTraits;
 import com.jnape.palatable.traitor.framework.Subjects;
 import com.jnape.palatable.traitor.runners.Traits;
@@ -10,9 +9,9 @@
 import testsupport.traits.MonadLaws;
 import testsupport.traits.TraversableLaws;
 
-import static com.jnape.palatable.traitor.framework.Subjects.subjects;
 import static com.jnape.palatable.lambda.functions.recursion.RecursiveResult.recurse;
 import static com.jnape.palatable.lambda.functions.recursion.RecursiveResult.terminate;
+import static com.jnape.palatable.traitor.framework.Subjects.subjects;
 
 @RunWith(Traits.class)
 public class RecursiveResultTest {
