private function checkCompileInput()
    {
        
        $defaults = array('extension' => null,
                          'language' => null,
                          'input' => dirname(__FILE__) . '/../../' . $this->options['extension'] . '/' . self::DEF_INPUT_DIR,
                          'output' => dirname(__FILE__) . '/../../' . $this->options['extension'] . '/' . self::DEF_OUTPUT_DIR);
                          
        $this->options = array_merge($defaults, $this->options);
        
        if ($this->options['extension'] == null){
            $this->err("Please provide the 'extension' parameter.", true);
        }
        else if ($this->options['language'] == null){
            $this->err("Please provide the 'language' parameter.", true);
        }
        
    }