diff --git a/lib/src/lambda_context.dart b/lib/src/lambda_context.dart
index fd180d1..84b6d04 100644
--- a/lib/src/lambda_context.dart
+++ b/lib/src/lambda_context.dart
@@ -57,8 +57,12 @@
   /// Evaluate the string as a mustache template using the current context.
   String renderSource(String source) {
     _checkClosed();
-    //FIXME
-    throw new UnimplementedError();
+    var sink = new StringBuffer();
+    var node = _parse(source, _renderer._lenient, _renderer._templateName);
+    var renderer = new _Renderer.lambda(
+        _renderer, node, source, _renderer._indent, sink);
+    renderer.render();
+    return sink.toString();
   }
 
   /// Lookup the value of a variable in the current context.
diff --git a/lib/src/template.dart b/lib/src/template.dart
index e13113e..0ad6ec2 100644
--- a/lib/src/template.dart
+++ b/lib/src/template.dart
@@ -138,7 +138,24 @@
            renderer._templateName,
            renderer._indent,
            renderer._source);
-	
+
+	  _Renderer.lambda(
+	      _Renderer renderer,
+	      _Node node,
+	      String source,
+	      String indent,
+	      StringSink sink)
+       : this(node,
+           sink,
+           renderer._values,
+           renderer._stack,
+           renderer._lenient,
+           renderer._htmlEscapeValues,
+           renderer._partialResolver,
+           renderer._templateName,
+           renderer._indent + indent,
+           source);
+	 
 	final _Node _root;
   final StringSink _sink;
   final _values;