Question

编辑：我更新了以下代码示例，以更好地说明问题。

比方说，我有2个仅用于字段的结构，不需要任何功能。

假设它们代表数据库中两种相似的数据：

type Boy struct {
    Name          string
    FavoriteColor string
    BirthDay      time.Time
}

type Girl struct {
    Name           string
    FavoriteFlower string
    BirthDay       time.Time
}

我为Boy结构编写了一个函数，该函数根据给定的日期和男孩的信息打印问候语。

假定这是一个更为复杂的函数的占位符，该函数基于time.Time字段执行某操作，并返回一个int并将在应用程序的其他地方使用：

func CheckBirthDayBoy(date time.Time, boy Boy) int {
    numDays := 0

    if date.Before(boy.BirthDay) {
        // Greet how many days before birthday
        numDays = int(boy.BirthDay.Sub(date).Hours() / 24)
        fmt.Println("Hi, " + boy.Name + "! Only " + strconv.Itoa(numDays) + " days until your birthday! I hear your favorite color is " + boy.FavoriteColor + "!")
    } else if date.Equal(boy.BirthDay) {
        // Greet happy birthday
        fmt.Println("Happy birthday, " + boy.Name + "! I brought you something " + boy.FavoriteColor + " as a present!")
    } else {
        // Greet belated birthday
        numDays = int(date.Sub(boy.BirthDay).Hours() / 24)
        fmt.Println("Sorry I'm " + strconv.Itoa(numDays) + " days late, " + boy.Name + "! Here is something " + boy.FavoriteColor + " to cheer you up!")
    }

    return numDays
}

现在，由于Go是一种强类型语言，并且没有泛型，所以我最终不得不为Girl结构编写一个重复函数：

func CheckBirthDayGirl(date time.Time, girl Girl) int {
    numDays := 0

    if date.Before(girl.BirthDay) {
        // Greet how many days before birthday
        numDays = int(girl.BirthDay.Sub(date).Hours() / 24)
        fmt.Println("Hi, " + girl.Name + "! Only " + strconv.Itoa(numDays) + " days until your birthday! I hear your favorite flower is a " + girl.FavoriteFlower + "!")
    } else if date.Equal(girl.BirthDay) {
        // Greet happy birthday
        fmt.Println("Happy birthday, " + girl.Name + "! I brought you a " + girl.FavoriteFlower + " as a present!")
    } else {
        // Greet belated birthday
        numDays = int(date.Sub(girl.BirthDay).Hours() / 24)
        fmt.Println("Sorry I'm " + strconv.Itoa(numDays) + " days late, " + girl.Name + "! Here is a " + girl.FavoriteFlower + " to cheer you up!")
    }

    return numDays
}

有没有一种方法可以避免像上面那样的简单结构的代码重复？我不想为要为其实现的每个新结构复制函数。

~~接口在这里不是一个选择，因为两个结构都没有任何功能可言（并且为满足接口而添加虚拟功能听起来像是我的倒退解决方案）。~~

编辑：在考虑了我接受的解决方案之后，我现在认为接口也是针对此问题的有效解决方案。感谢@ThunderCat带来了它！

Answer 1

正如ThunderCat在评论中提到的：将通用代码放入单独的函数中并调用。

func CheckBirthday(date, birthdate time.Time, name, gift string) (numDays int) {
    if date.Before(birthdate) {
        // Greet how many days before birthday
        numDays = int(birthdate.Sub(date).Hours() / 24)
        fmt.Printf("Hi, %s! Only %d days until your birthday! I hear your favorite is %s!\n", name, numDays, gift)
    } else if date.Equal(birthdate) {
        // Greet happy birthday
        fmt.Printf("Happy birthday, %s! I brought you a %s as a present!\n", name, gift)
    } else {
        // Greet belated birthday
        numDays = int(date.Sub(girl.birthday).Hours() / 24)
        fmt.Printf("Sorry I'm %d days late, %s! Here is a %s to cheer you up!\n", numDays, name, gift)
    }

    return
}

func CheckBirthdayBoy(date time.Time, boy Boy) int {
    return CheckBirthday(date, boy.BirthDay, boy.Name, boy.FavoriteColor)
}

func CheckBirthdayGirl(date time.Time, girl Girl) int {
    return CheckBirthday(date, girl.BirthDay, girl.Name, girl.FavoriteFlower)
}

Answer 2

类型开关对您有用吗？

func CheckBirthDay(date time.Time, i interface{}) int {
    switch v := i.(type) {
    case Boy:
      CheckBirthDay(date, v.Birthday)
    case Girl:
      CheckBirthDay(date, v.Birthday)
    default:
      DoSomething()
    }
}

func CheckBirthDay(date time.Time, bday time.Time) int {
    ...
}

防止仅字段结构在Go中重复功能

2 个答案: