#55 Added map and contramap for F and F2

mperry · mperry · commit 985a1cf0e0da · 2014-07-24T13:23:20.000+10:00
diff --git a/core/src/main/java/fj/F1Functions.java b/core/src/main/java/fj/F1Functions.java
@@ -840,4 +840,12 @@ static public <A, B, E extends Exception> F<A, Validation<E, B>> toF1(final TryC
         };
     }
 
+    static public <A, B, C> F<A, C> map(F<A, B> target, F<B, C> f) {
+        return andThen(target, f);
+    }
+
+    static public <A, B, C> F<C, B> contramap(F<A, B> target, F<C, A> f) {
+        return andThen(f, target);
+    }
+
 }
diff --git a/core/src/main/java/fj/F2Functions.java b/core/src/main/java/fj/F2Functions.java
@@ -363,4 +363,20 @@ static public <A, B, C, E extends Exception> F2<A, B, Validation<E, C>> toF2(fin
         };
     }
 
+    static public <A, B, C, Z> F2<Z, B, C> contramapFirst(F2<A, B, C> target, F<Z, A> f) {
+        return (z, b) -> target.f(f.f(z), b);
+    }
+
+    static public <A, B, C, Z> F2<A, Z, C> contramapSecond(F2<A, B, C> target, F<Z, B> f) {
+        return (a, z) -> target.f(a, f.f(z));
+    }
+
+    static public <A, B, C, X, Y> F2<X, Y, C> contramap(F2<A, B, C> target, F<X, A> f, F<Y, B> g) {
+        return contramapSecond(contramapFirst(target, f), g);
+    }
+
+    static public <A, B, C, Z> F2<A, B, Z> map(F2<A, B, C> target, F<C, Z> f) {
+        return (a, b) -> f.f(target.f(a, b));
+    }
+
 }

Original file line number	Diff line number	Diff line change
`@@ -840,4 +840,12 @@ static public <A, B, E extends Exception> F<A, Validation<E, B>> toF1(final TryC`
`840`	`840`	`};`
`841`	`841`	`}`
`842`	`842`
	`843`	`+ static public <A, B, C> F<A, C> map(F<A, B> target, F<B, C> f) {`
	`844`	`+ return andThen(target, f);`
	`845`	`+ }`
	`846`	`+`
	`847`	`+ static public <A, B, C> F<C, B> contramap(F<A, B> target, F<C, A> f) {`
	`848`	`+ return andThen(f, target);`
	`849`	`+ }`
	`850`	`+`
`843`	`851`	`}`