From aef4e185182ed5addd9e3fc147bcd16cfb1f477f Mon Sep 17 00:00:00 2001
From: Rob Rix <rob.rix@github.com>
Date: Fri, 23 Oct 2015 17:19:07 -0400
Subject: [PATCH] Map over Syntax.

---
 prototype/UI/index.html | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/prototype/UI/index.html b/prototype/UI/index.html
index 21d8c1065..dbcb9d77a 100644
--- a/prototype/UI/index.html
+++ b/prototype/UI/index.html
@@ -239,6 +239,13 @@
         return this;
     }
 
+    // forall a b. Syntax a -> (a -> b) -> Syntax b
+    Syntax.prototype.map = function(transform) {
+        if (this.indexed != null) { return new Syntax(this.indexed, transform); }
+        if (this.keyed != null) { return new Syntax(this.keyed, transform); }
+        if (this.leaf != null) { return new Syntax(this.leaf, transform); }
+    }
+
     function Diff(json) {
         if (json.pure != null) {
             this.pure = new Patch(json.pure);