diff --git a/lib/execjs.rb b/lib/execjs.rb
index 88242a8..7cd0288 100644
--- a/lib/execjs.rb
+++ b/lib/execjs.rb
@@ -18,6 +18,10 @@ module ExecJS
     runtime.eval(source)
   end
 
+  def self.compile(source)
+    runtime.compile(source)
+  end
+
   def self.runtimes
     Runtimes.runtimes
   end
diff --git a/lib/execjs/external_runtime.rb b/lib/execjs/external_runtime.rb
index 7583807..f19ed63 100644
--- a/lib/execjs/external_runtime.rb
+++ b/lib/execjs/external_runtime.rb
@@ -3,6 +3,56 @@ require "tempfile"
 
 module ExecJS
   class ExternalRuntime
+    class Context
+      def initialize(runtime)
+        @runtime = runtime
+        @script  = ""
+      end
+
+      def eval(source)
+        if /\S/ =~ source
+          exec("return eval(#{"(#{source})".to_json})")
+        end
+      end
+
+      def exec(source)
+        @script << source
+        @script << "\n"
+
+        compile_to_tempfile(@script) do |file|
+          extract_result(@runtime.exec_runtime(file.path))
+        end
+      end
+
+      protected
+        def compile_to_tempfile(source)
+          tempfile = Tempfile.open("execjs")
+          tempfile.write compile(source)
+          tempfile.close
+          yield tempfile
+        ensure
+          tempfile.close!
+        end
+
+        def compile(source)
+          @runtime.runner_source.dup.tap do |output|
+            output.sub!('#{source}', source)
+            output.sub!('#{json2_source}') do
+              IO.read(ExecJS.root + "/support/json2.js")
+            end
+          end
+        end
+
+        def extract_result(output)
+          status, value = output.empty? ? [] : JSON.parse(output)
+          if status == "ok"
+            value
+          else
+            raise ProgramError, value
+          end
+        end
+    end
+
     attr_reader :name
 
     def initialize(options)
@@ -15,22 +65,39 @@ module ExecJS
       @binary      = locate_binary
     end
 
-    def eval(source)
-      if /\S/ =~ source
-        exec("return eval(#{"(#{source})".to_json})")
-      end
+    def exec(source)
+      context = Context.new(self)
+      context.exec(source)
     end
 
-    def exec(source)
-      compile_to_tempfile(source) do |file|
-        extract_result(exec_runtime(file.path))
-      end
+    def eval(source)
+      context = Context.new(self)
+      context.eval(source)
+    end
+
+    def compile(source)
+      context = Context.new(self)
+      context.exec(source)
+      context
     end
 
     def available?
       @binary ? true : false
     end
 
+    def runner_source
+      @runner_source ||= IO.read(@runner_path)
+    end
+
+    def exec_runtime(filename)
+      output = sh("#{@binary} #{filename} 2>&1")
+      if $?.success?
+        output
+      else
+        raise RuntimeError, output
+      end
+    end
+
     protected
       def locate_binary
         if binary = which(@command)
@@ -55,37 +122,6 @@ module ExecJS
         end
       end
 
-      def compile(source)
-        runner_source.dup.tap do |output|
-          output.sub!('#{source}', source)
-          output.sub!('#{json2_source}') do
-            IO.read(ExecJS.root + "/support/json2.js")
-          end
-        end
-      end
-
-      def runner_source
-        @runner_source ||= IO.read(@runner_path)
-      end
-
-      def compile_to_tempfile(source)
-        tempfile = Tempfile.open("execjs")
-        tempfile.write compile(source)
-        tempfile.close
-        yield tempfile
-      ensure
-        tempfile.close!
-      end
-
-      def exec_runtime(filename)
-        output = sh("#{@binary} #{filename} 2>&1")
-        if $?.success?
-          output
-        else
-          raise RuntimeError, output
-        end
-      end
-
       if "".respond_to?(:force_encoding)
         def sh(command)
           output, options = nil, {}
@@ -108,14 +144,5 @@ module ExecJS
           end
         end
       end
-
-      def extract_result(output)
-        status, value = output.empty? ? [] : JSON.parse(output)
-        if status == "ok"
-          value
-        else
-          raise ProgramError, value
-        end
-      end
   end
 end
diff --git a/lib/execjs/ruby_racer_runtime.rb b/lib/execjs/ruby_racer_runtime.rb
index fac00c8..3c9bc0b 100644
--- a/lib/execjs/ruby_racer_runtime.rb
+++ b/lib/execjs/ruby_racer_runtime.rb
@@ -1,26 +1,63 @@
 module ExecJS
   class RubyRacerRuntime
+    class Context
+      def initialize
+        @v8_context = ::V8::Context.new
+      end
+
+      def exec(source)
+        if /\S/ =~ source
+          eval "(function(){#{source}})()"
+        end
+      end
+
+      def eval(source)
+        if /\S/ =~ source
+          unbox @v8_context.eval("(#{source})")
+        end
+      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
+          nil
+        when ::V8::Array
+          value.map { |v| unbox(v) }
+        when ::V8::Object
+          value.inject({}) do |vs, (k, v)|
+            vs[k] = unbox(v) unless v.is_a?(::V8::Function)
+            vs
+          end
+        else
+          value
+        end
+      end
+    end
+
     def name
       "therubyracer (V8)"
     end
 
     def exec(source)
-      if /\S/ =~ source
-        eval "(function(){#{source}})()"
-      end
+      context = Context.new
+      context.exec(source)
     end
 
     def eval(source)
-      if /\S/ =~ source
-        context = ::V8::Context.new
-        unbox context.eval("(#{source})")
-      end
-    rescue ::V8::JSError => e
-      if e.value["name"] == "SyntaxError"
-        raise RuntimeError, e
-      else
-        raise ProgramError, e
-      end
+      context = Context.new
+      context.eval(source)
+    end
+
+    def compile(source)
+      context = Context.new
+      context.exec(source)
+      context
     end
 
     def available?
@@ -29,21 +66,5 @@ module ExecJS
     rescue LoadError
       false
     end
-
-    def unbox(value)
-      case value
-      when ::V8::Function
-        nil
-      when ::V8::Array
-        value.map { |v| unbox(v) }
-      when ::V8::Object
-        value.inject({}) do |vs, (k, v)|
-          vs[k] = unbox(v) unless v.is_a?(::V8::Function)
-          vs
-        end
-      else
-        value
-      end
-    end
   end
 end
diff --git a/lib/execjs/ruby_rhino_runtime.rb b/lib/execjs/ruby_rhino_runtime.rb
index 1803273..48923a3 100644
--- a/lib/execjs/ruby_rhino_runtime.rb
+++ b/lib/execjs/ruby_rhino_runtime.rb
@@ -1,26 +1,61 @@
 module ExecJS
   class RubyRhinoRuntime
+    class Context
+      def initialize
+        @rhino_context = ::Rhino::Context.new
+      end
+
+      def exec(source)
+        if /\S/ =~ source
+          eval "(function(){#{source}})()"
+        end
+      end
+
+      def eval(source)
+        if /\S/ =~ source
+          unbox @rhino_context.eval("(#{source})")
+        end
+      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
+          nil
+        when ::Rhino::NativeObject
+          value.inject({}) do |vs, (k, v)|
+            vs[k] = unbox(v) unless v.is_a?(::Rhino::NativeFunction)
+            vs
+          end
+        else
+          value
+        end
+      end
+    end
+
     def name
       "therubyrhino (Rhino)"
     end
 
     def exec(source)
-      if /\S/ =~ source
-        eval "(function(){#{source}})()"
-      end
+      context = Context.new
+      context.exec(source)
     end
 
     def eval(source)
-      if /\S/ =~ source
-        context = ::Rhino::Context.new
-        unbox context.eval("(#{source})")
-      end
-    rescue ::Rhino::JavascriptError => e
-      if e.message == "syntax error"
-        raise RuntimeError, e
-      else
-        raise ProgramError, e
-      end
+      context = Context.new
+      context.eval(source)
+    end
+
+    def compile(source)
+      context = Context.new
+      context.exec(source)
+      context
     end
 
     def available?
@@ -29,19 +64,5 @@ module ExecJS
     rescue LoadError
       false
     end
-
-    def unbox(value)
-      case value
-      when ::Rhino::NativeFunction
-        nil
-      when ::Rhino::NativeObject
-        value.inject({}) do |vs, (k, v)|
-          vs[k] = unbox(v) unless v.is_a?(::Rhino::NativeFunction)
-          vs
-        end
-      else
-        value
-      end
-    end
   end
 end
diff --git a/test/test_execjs.rb b/test/test_execjs.rb
index eaec324..751a544 100644
--- a/test/test_execjs.rb
+++ b/test/test_execjs.rb
@@ -17,4 +17,10 @@ class TestExecJS < Test::Unit::TestCase
     runtime = ExecJS::ExternalRuntime.new(:command => "ruby")
     assert runtime.available?
   end
+
+  def test_compile
+    context = ExecJS.compile("foo = function() { return \"bar\"; }")
+    assert_equal "bar", context.exec("return foo()")
+    assert_equal "bar", context.eval("foo()")
+  end
 end
diff --git a/test/test_runtimes.rb b/test/test_runtimes.rb
index 673d758..d27a196 100644
--- a/test/test_runtimes.rb
+++ b/test/test_runtimes.rb
@@ -29,6 +29,12 @@ module TestRuntime
     assert_equal "café", @runtime.eval("'café'")
   end
 
+  def test_compile
+    context = @runtime.compile("foo = function() { return \"bar\"; }")
+    assert_equal "bar", context.exec("return foo()")
+    assert_equal "bar", context.eval("foo()")
+  end
+
   def test_this_is_global_scope
     assert_equal true, @runtime.eval("this === (function() {return this})()")
     assert_equal true, @runtime.exec("return this === (function() {return this})()")