significance of function type in Go

tags: learning go programming

content

in Go, a type can have method:

type MyInt int
func (i MyInt) Double() int {
	return int(i) * 2
}

but a func cannot have method
- below just doesn’t work

func hello() { ... }
func (h hello) doSomething() { ... }

BUT, if we define a function type, then a function can have method

type MyFunc func(int)int

here we define a type
the type is a function with some specific signature

Note

basically, it’s a named type whose value is a function

because it’s a named type, it could have method:

type MyFunc func(int)int
func (f MyFunc) DoSomething(a int) int {
	return f(a)
}

irl example go’s http.HandlerFunc

type HandlerFunc func(http.ResponseWriter, *http.Request)
func (f HandlerFunc) ServeHTTP(w http.ResponseWriter, r *http.Request) {
	f(w, r)
}

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