code: func CallMeta(l *State, index int, event string) bool {
  	index = l.AbsIndex(index)
  	if !MetaField(l, index, event) {
  		return false
  	}
  	l.PushValue(index)
  	l.Call(1, 1)
  	return true
  }
docs: // CallMeta calls a metamethod.
  //
  // If the object at index has a metatable and this metatable has a field event,
  // this function calls this field passing the object as its only argument. In
  // this case this function returns true and pushes onto the stack the value
  // returned by the call. If there is no metatable or no metamethod, this
  // function returns false (without pushing any value on the stack).