support exposing clojure functions to rhino

README.rest

@@ -81,6 +81,23 @@ handy convertions::
         user=> (js/from-js (js/eval sc "o = {name: 'spongebob', friends: ['patrick', 'sandy']};"))
         {:friends ["patrick" "sandy"], :name "spongebob"}
 
+exposing clojure functions to rhino::
+
+        user=> (require '[clj-rhino :as js])
+        nil
+
+        user=> (defn add [ctx scope this [a b]] (+ a b))
+        #'user/add
+
+        user=> (def scope (js/new-safe-scope))
+        #'user/scope
+
+        user=> (js/set! scope "add" (js/make-fn add))
+        nil
+
+        user=> (js/eval scope "add(1, 2)")
+        3.0
+
 license?
 --------
 

src/clj_rhino.clj

@@ -1,6 +1,7 @@
 (ns clj-rhino
   (:refer-clojure :exclude (eval get get-in set!))
-  (:import [org.mozilla.javascript Context UniqueTag NativeArray NativeObject]))
+  (:import [org.mozilla.javascript Context UniqueTag NativeArray NativeObject
+            BaseFunction]))
 
 (defprotocol RhinoConvertible
   (-to-rhino [object scope ctx] "convert a value to a rhino compatible type"))
@@ -198,3 +199,13 @@
                              (.compileFunction ctx scope code 
                                               (or filename "<eval>")
                                               (or line-number 1) sec-domain))))
+
+(defn make-fn [fun]
+  "return an object that can be used as a function in rhino,
+  fun must receive the following arguments [ctx scope this args]
+  args will be passed through from-js before calling fun and the result 
+  through to-js"
+
+  (proxy [BaseFunction] []
+    (call [ctx scope this args]
+      (to-js (fun ctx scope this (from-js args)) scope ctx))))

test/clj_rhino/core_test.clj

@@ -80,7 +80,8 @@
              (is (= (js/get scope "b") false))))
 
   (testing "to-js works"
-           (js/with-context (fn [ctx]
+           (js/with-context
+             (fn [ctx]
                (let [scope (js/new-safe-scope)]
 
                  (is (= (js/to-js nil scope ctx) nil))
@@ -101,7 +102,8 @@
                  (is (= (get (js/to-js {:name "mariano" :age 27} scope ctx) "age") 27))))))
 
   (testing "to-js works on complex nested structures"
-           (js/with-context (fn [ctx]
+           (js/with-context
+             (fn [ctx]
                (let [scope (js/new-safe-scope)
                      obj {:name "bob"
                           :age 27
@@ -117,7 +119,8 @@
                  (is (= (get-in js-obj ["friends" "sandy"]) "squirrel"))))))
 
   (testing "unknown types throw exception when converting to-js"
-           (js/with-context (fn [ctx]
+           (js/with-context
+             (fn [ctx]
                (let [scope (js/new-safe-scope)]
                  (is (thrown? Exception (js/to-js (atom {}) scope ctx)))))))
 
@@ -154,5 +157,13 @@
                  (assert-simetric-convertion {:b {"c" {:d [{"e" 4}]}}} scope ctx
                                              {:b {:c {:d [{:e 4}]}}})
                  ))))
-  )
+
+  (testing "native clojure functions can be added"
+           (js/with-context
+             (fn [ctx]
+               (let [scope (js/new-safe-scope)]
+                 (js/set! scope "add" (js/make-fn (fn [ctx scope this [a b]] (+ a b))))
+                 (is (= (js/eval scope "add(1, 2)") 3.0))))))
+
+)