F#对象表达式

//When typename is a class:
{ new typename [type-params]arguments with
    member-definitions
    [ additional-interface-definitions ]
}
//When typename is not a class:
{ new typename [generic-type-args] with
    member-definitions
    [ additional-interface-definitions ]
}

let ex =
 {
      new System.Exception() with member x.ToString() = "Hello FSharp" 
 }
printfn "%A" ex