Defining a function that returns Any type in Golang-CodePudding

I would like to define a function type (what we call delegate in C#) whose return value can be anything (is unknown at compile type) and after reading Golang docs (it's just been 3 days since I started learning Golang) I found that the current version of the language does not support generics. After searching StackOverflow I came across a post suggesting that the return type can be set as interface{} which implies that any type can be returned by that function. Then I wrote the following code to test how it works:

type Consumer func() interface {}

func TestConsumer() Consumer {
    return func() string {
         return "ok"
    }
}

But I got the following error

cannot use func literal (type func() string) as type Consumer in return argument

This is while when I change the return type of Consumer to string, it works without any problem.

The question is what is that I am doing wrong and how can I achieve writing a function type (delegate) that can return anything and assign an actual functions to that?

CodePudding user response：

func TestConsumer() interface{} {
    return func() string {
         return "ok"
    }
}

Please try with this one

CodePudding user response：

The issue is that the function type func() string does not conform to the function type func() interface{}.

The reason for this is because the function type func() interface{} means a function that explicitly returns a value of type interface{}, and while a string can be easily casted to an interface{}, the overall function signatures are not the same.

The correct code would be:

type Consumer func() interface {}

func TestConsumer() Consumer {
    return func() interface{} {
         return "ok"
    }
}

The string gets implicity casted to the interface{} type, and the function signatures are the same.