OCaml:获取值的类型名称 [英] OCaml: get value's type name

问题描述

可以在OCaml中打印值的名称，例如，如果我有

Is is possible to print value's name in OCaml, for example if I have

type my_type =
  | MyType_First of int
  | MyType_Second of string

然后执行类似的操作:

let my_value = MyType_First 0 in
print_string ("my_value is of type " ^ String.from_type my_value ^ ".\n";

我可以得到"my_value的类型为MyType_First吗". ?

can I get "my_value is of type MyType_First." ?

谢谢.

推荐答案

单态解决方案:

let from_type = function
  | MyType_First _ -> "MyType_First"
  | MyType_Second _ -> "MyType_Second"

多态解决方案:无. (AFAIK，即使指定了调试标志，与构造函数相对应的词法标记也不会记录在字节码/二进制文件中.唯一可以做的就是使用一些暗的Obj.magic为构造函数打印整数标识符".)

Polymorphic solution: none. (AFAIK, lexical tokens corresponding to constructors are not recorded in the bytecode/binary, even when debugging flags are specified. The only thing one could do is to print the integer ‘identifier’ for the constructor, using some dark Obj.magic.)

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