Joining and leaving classes

[Cubical]

is there an event called when joining and/or leaving classes? Something along the lines of onJoinedClass(); and onLeaveClass();.

I'm at work right now so I cannot provide an exact example of what I'm currently doing but it's something along the lines of the following.

PHP Code:

functions loadClassData(temp.obj, temp.classlist) {
  for (temp.classname: temp.classlist) {
    if (temp.classname in temp.obj.joinedclasses) {
      temp.obj.(temp.classname @ "::onJoined")();
    } else {
      temp.obj.join(temp.classname);
      temp.obj.(temp.classname @ "::onJoined")();
    }
  }
} 


I did a quick search and didn't see anything that stuck out.