Basic observer pattern

package Observer

type (
    Event struct {
        Content interface{}
        Response chan<- float32
    }
    Monitor chan<- Event
    Target interface{
        Add(monitor Monitor)
        Remove(monitor Monitor) bool
    }
    repeater []Monitor
)

func (self *repeater) Add(m Monitor) {
    *self = append(*self, m)
}

func (self *repeater) Remove(m Monitor) bool {
    for i, which := range *self {
        if which == m {
            copy((*self)[i:], (*self)[i + 1:])
            return true
        }
    }
    return false
}

func (self *repeater) repeat(source <-chan Event) {
    for e := range source {
        for _, m := range *self {
            m <- e
        }
    }
}

func NewTarget(source <-chan Event) Target {
    t := &repeater{}
    go t.repeat(source)
    return &t
}