英文:
Error while passing struct in the place of interface{}
问题
所以，我有一个像这样的函数：
func ProcessRequest(requestBody *SignInRequest, response func(SignInResponse) *src.Response, error func(ControllerError) *src.Response) *src.Response {
return error(ControllerError{Code: http.StatusNotImplemented})
}
我试图调用它：
ProcessRequest(payload, myFunction, handler.OnControllerError)
func myFunction(i interface{}) *src.Response {
}
这显示了一个错误：
无法将'type func(i interface{}) *src.Response'用作'type func(SignInResponse) *src.Response'
但是，如果我尝试相同的操作：
type TestStruct struct {
}
func myFunction2(i interface{}) *src.Response {
}
myFunction2(TestStruct{})
那么就不会显示任何错误。
我希望它接受interface{}作为参数，因为我希望myFunction是通用的，可以接受任何struct。
英文:
So, I have a function like this
func ProcessRequest(requestBody *SignInRequest, response func(SignInResponse) *src.Response, error func(ControllerError) *src.Response) *src.Response {
return error(ControllerError{Code: http.StatusNotImplemented})
}
And I'm trying to call this
ProcessRequest(payload, myFunction, handler.OnControllerError)
func myFunction(i interface{}) *src.Response {
}
This is showing me an error
> Cannot use 'myFunction' (type func(i interface{}) *src.Response) as the type func(SignInResponse) *src.Response
But if I try the same thing with
type TestStruct struct {
}
func myFunction2(i interface{}) *src.Response {
}
myFunction2(TestStruct{})
Then it is not showing any error.
I want it to take interface{} as an argument because I want myFucntion to be general which can take any struct.
答案1
得分: 2
你混淆了两件事情。
当你有一个带有签名func (interface{}) *src.Response的函数时，你确实可以在调用时传递任何类型的值，但实际情况并非如此。
实际上，你有另一个函数ProcessRequest，其中一个参数的类型是func (SignInResponse) *src.Response的函数。
当你尝试将类型为func (interface{}) *src.Response的值传递给接受类型为func (SignInResponse) *src.Response的函数时，就会发生错误，因为这些参数的类型显然不兼容。
更新。
要理解为什么参数的类型不兼容，可以考虑SignInResponse和interface{}在内存中具有不同的存储表示方式；基本上，这与[]T和[]interface{}不兼容的原因相同，即使你可以执行t := T{}; var i interface{} = t。这个问题在FAQ中有解释。
至于手头的问题，最简单的方法可能是使用匿名函数将SignInResponse的值“适配”为interface{}：传递类似以下的内容给ProcessResponse
func (r SignInResponse) *src.Response {
return myFunction2(r)
}
英文:
You're confusing two things.
When you have a function with the signaure func (interface{}) *src.Response, you indeed can call it while passing it a value of any type, but that is not what happens.
What happens is that you have another function, ProcessRequest, and one of the types of its arguments is a function with the type func (SignInResponse) *src.Response.
The error happens when you try to pass a value of type func (interface{}) *src.Response to a function which accepts an argument of type func (SignInResponse) *src.Response because the types of these arguments are obviously not compatible.
Update.
To understand why the types of the arguments are not compatible, consider that SignInResponse and interface{} have different storage representation in memory; basically that's the same reason why []T and []interface{} are not compatible even when you can do t := T{}; var i interface{} = t. This one is explained in the FAQ.
As to the problem at hand, supposedly the easiest approach is to use an anonymous function to "adapt" the value SignInResponse to interface{}: pass to ProcessResponse something like
func (r SignInResponse) *src.Response {
return myFunction2(r)
}
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