specialmap.go

// The trouble with specialized map types... I need a better name.
package main

import "fmt"

type I interface {
	M()
}

type IFunc func()

func (fn IFunc) M() {
	fn()
}

func printi(s string, impl I) {
	fmt.Println(s)
	impl.M()
}

func map1(m map[string]I) {
	for s, impl := range m {
		printi(s, impl)
	}
}

func map2(m map[string]IFunc) {
	for s, fn := range m {
		printi(s, fn)
	}
}

func map3(m Map) {
	for s, fn := range m {
		printi(s, fn)
	}
}

type Map map[string]I
type MapFunc map[string]IFunc
type Map2 map[string]I

func main() {
	map1(Map{"ok": IFunc(func() { fmt.Println("boom") })})
	map2(MapFunc{"ok": func() { fmt.Println("boom") }})
	map3(map[string]I{"ok": IFunc(func() { fmt.Println("boom") })})
	//map3(Map2{"ok": IFunc(func() { fmt.Println("boom") })}) // compilation error
}