Go function type, reusable function signatures

How to learn a new programming language by having the compiler yelling at you

I was looking for a way to reuse a common signature in various functions in Golang, googling for while I had no luck.

I tried the “heuristic way” of writing random code to let the compiler give me some hopefully useful hints so I started with what I felt could be right.

And after a couple tries……. it worked.

You can declare a function signature as a type

type myFunctionType = func(a, b string) string

An example:

package main
import "fmt"
type myFunctionType = func(a, b string) string
func main() {
 var explicit myFunctionType = func(a, b string) string {
  return fmt.Sprintf("%s %s", a, b)
 }
implicit := func(a, b string) string {
  return fmt.Sprintf("%s %s", b, a)
 }
functionTypeConsumer(explicit)
functionTypeConsumer(implicit)
functionTypeConsumer(func(a, b string) string {
 return fmt.Sprintf("%s %s!", a, b)
})}
func functionTypeConsumer(fn myFunctionType) {
 s := fn("hello", "world")
 fmt.Println(s)
}

Here a working example on Go playground

The Go Playground