protected function initRuntimeVars(ITemplate $tpl)
    {
        $this->runtimePlugins = array();
        $this->scope          = &$this->data;
        $this->scopeTree      = array();
        $this->stack          = array();
        $this->curBlock       = null;
        $this->buffer         = '';
        $this->returnData     = array();
    }