在OCaml中键入构造函数相等性

Question

我是OCaml的新手。我试图找到一种方法来检查模式匹配中构造函数类型（联合类型？）的相等性。

type team = BRAZIL | KOREA;;
type tourn = LEAF of team | NODE of tourn * tourn ;;
let iter t d = 
  match t with 
    NODE ( (LEAF k), (LEAF i) ) when k = d -> "Yes"
  | _                                      -> "No"
;;

iter (NODE ( (LEAF KOREA), (LEAF BRAZIL) ) KOREA         (* returns "No" *)

Answer 1

它运行正常，但你测试错了。如果您在最后一行再次查看，则会看到)丢失。

 # iter (NODE (LEAF KOREA, LEAF BRAZIL)) KOREA ;;
 - : string = "Yes"