Pretty much. If you want to use a function that's defined in a class, you'll have to join() that class first. The function also doesn't have to be "public". Public functions can be useful in weapons, though. Let's look at an excerpt of some Atlantis weapons.
-Weather:
PHP Code:
function onCreated() {
weather = this; // I love doing this stuff
}
public function GetWeather() {
return this.sWeather;
}
-DayNight:
PHP Code:
function UpdateSymbols() {
// lots of code here
temp.we = weather.GetWeather();
// a lot more code using the stuff we just got from -Weather
}