pub enum Result<T, E> {
    /// Contains the success value
    #[lang = "Ok"]
    #[stable(feature = "rust1", since = "1.0.0")]
    Ok(#[stable(feature = "rust1", since = "1.0.0")] T),

    /// Contains the error value
    #[lang = "Err"]
    #[stable(feature = "rust1", since = "1.0.0")]
    Err(#[stable(feature = "rust1", since = "1.0.0")] E),
};

fn test(path:String)->Result<&str,&str> {
      if path == "d" {
            Ok("我是成功了")
       }else{
           Error("我失败了")
       }

}

match test {
    Ok(s) =>{

    },
    Error(x)=>{

    }
}