catch (Throwable t) { rethrow(t);
catch (RuntimeException e) { rethrow(e, RuntimeException.class);
  public Value execute(Env env)    throws Throwable  {    try {      env.setValue(_var.getName(), env.getGlobalVar(_var.getName()));    }    catch (Throwable t) {      rethrow(t);    }    return null;  }