如何使用变体选项在 rescript 中键入函数参数？

Question

我想做以下事情。但似乎我无法使用变体选项之一键入函数参数。在 rescript 中实现这一目标的正确方法是什么？

Here is a playground

  type subject = Math | History

  type person =
    | Teacher({firstName: string, subject: subject})
    | Student({firstName: string})
  
  let hasSameNameThanTeacher = (
    ~teacher: Teacher, // syntax error here
    ~student: Person,
  ) => {
    teacher.firstName == student.firstName
  }

Answer 1

Teacher 和 Student 本身不是类型，而是构造 person 类型值的构造函数。如果您希望它们具有不同的类型，则必须明确说明：

module University = {
  type subject = Math | History

  type teacher = {firstName: string, subject: subject}
  type student = {firstName: string}
  type person =
    | Teacher(teacher)
    | Student(student)
  
  let hasSameNameThanTeacher = (
    ~teacher: teacher,
    ~student: student,
  ) => {
    teacher.firstName == student.firstName
  }
}