使用回调和函数作为go中的类型

Question

I am attempting to create a sort of function that is similar to the Express (NodeJS) route method in Go:

app.get("route/here/", func(req, res){
    res.DoStuff()
});    

In this example I want "foo" (the type) to be the same as the anonymous function in the above method. Here is one of my failed attempts using Go:

type foo func(string, string)

func bar(route string, io foo) {
        log.Printf("I am inside of bar")
        // run io, maybe io() or io(param, param)?
}

func main() {
        bar("Hello", func(arg1, arg2) {
                return  arg + arg2
        })
}

How might I fix my dilemma? Should I not use a type and use something else? What are my options?

Answer 1

You are on the right track - creating a type for a func on the context you are using it adds clearer design intent and more importantly additional type safety.

You just need to modify you example a bit for it to compile:

package main

import "log"

//the return type of the func is part of its overall type definition - specify string as it's return type to comply with example you have above
type foo func(string, string) string

func bar(route string, io foo) {

    log.Printf("I am inside of bar")
    response := io("param", "param")
    log.Println(response)

}

func main() {

    bar("Hello", func(arg1, arg2 string) string {
        return arg1 + arg2
    })

}