R函数是对A方法的封装

$user = new UserController;  ===      $user=A(“User”);

$user = new UserController;

$user->fun();               === R(“User/fun”);

跨模块调用

R(“Home/User/fun”);

R(“Book://Home/User/fun”); 

原文：http://www.cnblogs.com/8000cabbage/p/6253839.html