From 09ff093dc86b455e3090ce3612c5e01f3b5bada6 Mon Sep 17 00:00:00 2001
From: fogus <mefogus@gmail.com>
Date: Fri, 30 Sep 2011 14:37:58 -0400
Subject: [PATCH] CLJS-26: Added this-as macro and extend-object fn to provide
 standard ways to reference this

---
 src/clj/cljs/core.clj   |  6 ++++++
 src/cljs/cljs/core.cljs | 11 +++++++++++
 2 files changed, 17 insertions(+)

diff --git a/src/clj/cljs/core.clj b/src/clj/cljs/core.clj
index 6c3221be53..5448654fd0 100644
--- a/src/clj/cljs/core.clj
+++ b/src/clj/cljs/core.clj
@@ -643,3 +643,9 @@
          ret# ~expr]
      (prn (str "Elapsed time: " (- (.getTime (js/Date.) ()) start#) " msecs"))
      ret#))
+
+(defmacro this-as
+  "Defines a scope where JavaScript's implit this is bound to the name provided."
+  [name & body]
+  `(let [~name (~'js* "this")]
+     ~@body))
diff --git a/src/cljs/cljs/core.cljs b/src/cljs/cljs/core.cljs
index aedfe0067f..9efefd2cb5 100644
--- a/src/cljs/cljs/core.cljs
+++ b/src/cljs/cljs/core.cljs
@@ -3265,3 +3265,14 @@ reduces them without incurring seq initialization"
 (defn prefers
   "Given a multimethod, returns a map of preferred value -> set of other values"
   [multifn] (-prefers multifn))
+
+(defn extend-object
+  "Takes a JavaScript object and a map of names to functions and
+  attaches said functions as methods on the object.  Any references to
+  JavaScript's implict this (via the this-as macro) will resolve to the 
+  object that the function is attached."
+  [obj fn-map]
+  (doseq [[key-name f] fn-map]
+    (let [str-name (name key-name)]
+      (js* "~{obj}[~{str-name}] = ~{f}")))
+  obj)