Add Context#call

lib/execjs/external_runtime.rb

@@ -9,6 +9,12 @@ module ExecJS
         @script  = ""
       end
 
+      def <<(script)
+        @script << script
+        @script << "\n"
+        self
+      end
+
       def eval(source, options = {})
         if /\S/ =~ source
           exec("return eval(#{"(#{source})".to_json})")
@@ -16,9 +22,10 @@ module ExecJS
       end
 
       def exec(source, options = {})
-        if !options[:pure]
-          @script << source
-          @script << "\n"
+        if options[:pure]
+          source = @script + source
+        else
+          self << source
           source = @script
         end
 
@@ -27,6 +34,10 @@ module ExecJS
         end
       end
 
+      def call(properties, *args)
+        eval "#{properties}.apply(this, #{args.to_json})"
+      end
+
       protected
         def compile_to_tempfile(source)
           tempfile = Tempfile.open("execjs")

lib/execjs/ruby_racer_runtime.rb

@@ -23,6 +23,16 @@ module ExecJS
         end
       end
 
+      def call(properties, *args)
+        unbox @v8_context.eval(properties).call(*args)
+      rescue ::V8::JSError => e
+        if e.value["name"] == "SyntaxError"
+          raise RuntimeError, e
+        else
+          raise ProgramError, e
+        end
+      end
+
       def unbox(value)
         case value
         when ::V8::Function

lib/execjs/ruby_rhino_runtime.rb

@@ -23,6 +23,16 @@ module ExecJS
         end
       end
 
+      def call(properties, *args)
+        unbox @rhino_context.eval(properties).call(*args)
+      rescue ::Rhino::JavascriptError => e
+        if e.message == "syntax error"
+          raise RuntimeError, e
+        else
+          raise ProgramError, e
+        end
+      end
+
       def unbox(value)
         case value
         when ::Rhino::NativeFunction

test/test_execjs.rb

@@ -28,4 +28,21 @@ class TestExecJS < Test::Unit::TestCase
     context = ExecJS.compile("foo = function() { return \"bar\"; }")
     assert_equal "bar", context.eval("foo()", :pure => true)
   end
+
+  def test_context_call
+    context = ExecJS.compile("id = function(v) { return v; }")
+    assert_equal "bar", context.call("id", "bar")
+  end
+
+  def test_nested_context_call
+    context = ExecJS.compile("a = {}; a.b = {}; a.b.id = function(v) { return v; }")
+    assert_equal "bar", context.call("a.b.id", "bar")
+  end
+
+  def test_context_call_missing_function
+    context = ExecJS.compile("")
+    assert_raises ExecJS::ProgramError do
+      context.call("missing")
+    end
+  end
 end

test/test_runtimes.rb

@@ -33,6 +33,7 @@ module TestRuntime
     context = @runtime.compile("foo = function() { return \"bar\"; }")
     assert_equal "bar", context.exec("return foo()")
     assert_equal "bar", context.eval("foo()")
+    assert_equal "bar", context.call("foo")
   end
 
   def test_this_is_global_scope