public function setSource($src, $path = null)
    {
        $this->_prepared = false;
        $this->_functionName = null;
        $this->_codeFile = null;
        $this->_source = new PHPTAL_StringSource($src, $path);
        $this->_path = $this->_source->getRealPath();
        $this->_context->_docType = null;
        $this->_context->_xmlDeclaration = null;
        return $this;
    }