如何在golang中动态地调用方法而不使用反射？

Question

I'm using reflection to do this:

        method_name := CommandMap[command]
    thing := reflect.ValueOf(self).MethodByName(method_name)
    thing_s := fmt.Sprintf("%s", thing)
    if thing_s == "<invalid reflect.Value>" {
        self.writeMessage(550, "not allowed")
    } else {
        thing.Call([]reflect.Value{})
    }

but there must be a better way. The point of the above code was to get rid of:

if command == "this" {
  runThis()
} else if command == "that" {
  runThat()
} etc. etc.

I want to not have a big if else tree. This is an ftp server http://github.com/andrewarrow/paradise_ftp and I need to handle 15 or so commands like "USER" and "PASS" and "QUIT" etc. etc. I want each one to call a method like "handleUser" or "handlePass". But using reflection is a bad idea. It's too slow.

Answer 1

From your linked use case, it appears that having a map of strings to functions will work best. Example:

func MakeCommandMap() map[string]func(*Paradise) {
    m := map[string]func(*Paradise){
        "USER": (*Paradise).HandleUser,
        "PASS": (*Paradise).HandlePass,
    }
    // ...
    return m
}

Calling the functions:

name := "USER"
if fn := m[name]; fn != nil {
    fn(self) // where self is *Paradise
}