diff --git a/include/json/writer.h b/include/json/writer.h
index 3abf2ea..94582d9 100644
--- a/include/json/writer.h
+++ b/include/json/writer.h
@@ -9,21 +9,37 @@ namespace Json {
 
    class Value;
 
+   /** \brief Abstract class for writers.
+    */
+   class JSON_API Writer
+   {
+   public:
+      virtual ~Writer();
+
+      virtual std::string write( const Value &root ) = 0;
+   };
+
    /** \brief Outputs a Value in <a HREF="http://www.json.org">JSON</a> format without formatting (not human friendly).
     *
     * The JSON document is written in a single line. It is not intended for 'human' consumption,
     * but may be usefull to support feature such as RPC where bandwith is limited.
     * \sa Reader, Value
     */
-   class JSON_API FastWriter
+   class JSON_API FastWriter : public Writer
    {
    public:
-      std::string write( const Value &root );
+      FastWriter();
+
+      void enableYAMLCompatibility();
+
+   public: // overridden from Writer
+      virtual std::string write( const Value &root );
 
    private:
       void writeValue( const Value &value );
 
       std::string document_;
+      bool yamlCompatiblityEnabled_;
    };
 
    /** \brief Writes a Value in <a HREF="http://www.json.org">JSON</a> format in a human friendly way.
@@ -49,11 +65,12 @@ namespace Json {
    public:
       StyledWriter();
 
+   public: // overridden from Writer
       /** \brief Serialize a Value in <a HREF="http://www.json.org">JSON</a> format.
        * \param root Value to serialize.
        * \return String containing the JSON document that represent the root value.
        */
-      std::string write( const Value &root );
+      virtual std::string write( const Value &root );
 
    private:
       void writeValue( const Value &value );
diff --git a/src/jsontestrunner/main.cpp b/src/jsontestrunner/main.cpp
index 1d43720..a576564 100644
--- a/src/jsontestrunner/main.cpp
+++ b/src/jsontestrunner/main.cpp
@@ -115,7 +115,8 @@ rewriteValueTree( const std::string &rewritePath,
                   const Json::Value &root, 
                   std::string &rewrite )
 {
-//   Json::FastWriter writer;
+   //Json::FastWriter writer;
+   //writer.enableYAMLCompatibility();
    Json::StyledWriter writer;
    rewrite = writer.write( root );
    FILE *fout = fopen( rewritePath.c_str(), "wt" );
diff --git a/src/lib_json/json_writer.cpp b/src/lib_json/json_writer.cpp
index f1d8168..47577fa 100644
--- a/src/lib_json/json_writer.cpp
+++ b/src/lib_json/json_writer.cpp
@@ -67,10 +67,29 @@ std::string valueToQuotedString( const char *value )
    return std::string("\"") + value + "\"";
 }
 
+// Class Writer
+// //////////////////////////////////////////////////////////////////
+Writer::~Writer()
+{
+}
+
 
 // Class FastWriter
 // //////////////////////////////////////////////////////////////////
 
+FastWriter::FastWriter()
+   : yamlCompatiblityEnabled_( false )
+{
+}
+
+
+void 
+FastWriter::enableYAMLCompatibility()
+{
+   yamlCompatiblityEnabled_ = true;
+}
+
+
 std::string 
 FastWriter::write( const Value &root )
 {
@@ -106,33 +125,34 @@ FastWriter::writeValue( const Value &value )
       break;
    case arrayValue:
       {
-         document_ += "[ ";
+         document_ += "[";
          int size = value.size();
          for ( int index =0; index < size; ++index )
          {
             if ( index > 0 )
-               document_ += ", ";
+               document_ += ",";
             writeValue( value[index] );
          }
-         document_ += " ]";
+         document_ += "]";
       }
       break;
    case objectValue:
       {
          Value::Members members( value.getMemberNames() );
-         document_ += "{ ";
+         document_ += "{";
          for ( Value::Members::iterator it = members.begin(); 
                it != members.end(); 
                ++it )
          {
             const std::string &name = *it;
             if ( it != members.begin() )
-               document_ += ", ";
+               document_ += ",";
             document_ += valueToQuotedString( name.c_str() );
-            document_ += " : ";
+            document_ += yamlCompatiblityEnabled_ ? ": " 
+                                                  : ":";
             writeValue( value[name] );
          }
-         document_ += " }";
+         document_ += "}";
       }
       break;
    }
diff --git a/test/runjsontests.py b/test/runjsontests.py
index a5284fb..de7bd9d 100644
--- a/test/runjsontests.py
+++ b/test/runjsontests.py
@@ -83,7 +83,7 @@ if __name__ == '__main__':
         sys.exit( 1 )
 
     jsontest_executable_path = os.path.normpath( os.path.abspath( sys.argv[1] ) )
-    if len(sys.argv) > 1:
+    if len(sys.argv) > 2:
         input_path = os.path.normpath( os.path.abspath( sys.argv[2] ) )
     else:
         input_path = None