Internal Channels Pattern

External.go

func main() {
    t := NewThing(0)
    var r int
    for i := 0; i < 10; i++ {
        r = t.inc()
    }
}

Internal.go

type Thing struct {
    state    int
    internal chan message
}

type message struct {
    f   func(int) int
    ret chan int
}

func NewThing(i int) Thing{
    t := new(Thing)
    t.state = i
    t.internal = make(chan message)
    go t.run()
    return t
}

func (t Thing) run() {
    for m := range t.internal {
        t.i = m.f(t.i)
        m.ret <- t.i
    }
}

func (t Thing) Inc() int{
    m := new(message)
    m.f = func(i int){ return i + 1 }
    m.ret = make(chan int)
    t.internal <- m
    return <- m.ret
}