Added F1Functions#dimap (profunctor pattern)

jbgi · jbgi · commit d2bd8cb2e91d · 2016-06-19T16:20:45.000+02:00
diff --git a/core/src/main/java/fj/F1Functions.java b/core/src/main/java/fj/F1Functions.java
@@ -677,4 +677,11 @@ public static <A, B, C> F<C, B> contramap(F<A, B> target, F<C, A> f) {
         return andThen(f, target);
     }
 
+    /**
+     * Both map (with g) and contramap (with f) the target function. (Profunctor pattern)
+     */
+    public static <A, B, C, D> F<C, D> dimap(F<A, B> target, F<C, A> f, F<B, D> g) {
+        return c -> g.f(target.f(f.f(c)));
+    }
+
 }

Original file line number	Diff line number	Diff line change
`@@ -677,4 +677,11 @@ public static <A, B, C> F<C, B> contramap(F<A, B> target, F<C, A> f) {`
`677`	`677`	`return andThen(f, target);`
`678`	`678`	`}`
`679`	`679`
	`680`	`+ /**`
	`681`	`+ * Both map (with g) and contramap (with f) the target function. (Profunctor pattern)`
	`682`	`+ */`
	`683`	`+ public static <A, B, C, D> F<C, D> dimap(F<A, B> target, F<C, A> f, F<B, D> g) {`
	`684`	`+ return c -> g.f(target.f(f.f(c)));`
	`685`	`+ }`
	`686`	`+`
`680`	`687`	`}`