Collection of Unique Functions in Go

Question

I am trying to implement a set of functions in go. The context is an event server; I would like to prevent (or at least warn) adding the same handler more than once for an even

Answer 1

Which functions you mean to be equal? Comparability is not defined for functions types in language specification. reflect.Value gives you the desired behaviour more or less

type EventResponseSet map[reflect.Value]struct{}
set := make(EventResponseSet)
if _, ok := set[reflect.ValueOf(item)]; ok {
    // don't add item
} else {
    // do add item
    set[reflect.ValueOf(item)] = struct{}{}
}

this assertion will treat as equal items produced by assignments only

//for example
item1 := fmt.Println
item2 := fmt.Println
item3 := item1
//would have all same reflect.Value

but I don't think this behaviour guaranteed by any documentation.