Method values and method expressions play

main.go

// http://play.golang.org/p/YbcN6-hLq-
//
package main

import "fmt"

type Methoder interface{
	Method()
}

type Methodable struct {
	Name string
	methodCalled bool
}

func (m *Methodable) Method() {
	m.methodCalled = true
}

func (m Methodable) WasMethodCalled() bool {
	return m.methodCalled
}

func showMethodableState(m *Methodable) {
	if m.WasMethodCalled() {
		fmt.Printf("Yup! Method() was called on %s\n", m.Name)
	} else {
		fmt.Printf("Nope! No Method() call on %s yet\n", m.Name)
	}
}

func main() {
	m1 := &Methodable{Name: "m1"}
	m2 := &Methodable{Name: "m2"}
	m3 := &Methodable{Name: "m3"}
	
	// create method value from instance
	me1 := m1.Method
		
	// create method expression from type
	me2 := (*Methodable).Method
		
	// create method expression from interface
	me3 := Methoder.Method
	
	methods := []*Methodable{m1, m2, m3}
	
	// Show initial state
	fmt.Println("Initial state:")
	for _, m := range methods {
		showMethodableState(m)
	}
	
	// Call the method value
	me1()
	
	// Call the method expression.
	// Require the receiver as the first parameter
	me2(m2) 
	me3(m3)
	
	// Show final state
	fmt.Println("Final state:")
	for _, m := range methods {
		showMethodableState(m)
	}
}