Rules for determining the order of keyboard events? (Python)

I currently have a situation like this:

keyboard.on_press(Function1)
keyboard.on_press_key(';', Function2)
keyboard.on_press_key('/', Function3) 

Through trial I’ve found that the on_press_key() events always happen first (and the logic of my program is dependent on it) but I have no idea why, or if it’s a hardware- or OS- specific thing that could be inconsistent and break if used on other systems (?).

I’ve tried searching but couldn’t find anything on this. Is there a reliable way to know the order in which the events are triggered, or force them to be triggered in a particular order?

Answer

Looking at the source code, the flow of control is as follows:

• keyboard.on_press adds an entry in the handlers object stored in the global _listener obj.
• keyboard.on_press_key adds an entry in the nonblocking_keys dict.

When a key event is raised, process is called, which calls pre_process_event (itself calling all callbacks in the nonblocking_keys dict) BEFORE calling the handlers.

    def process(self):
        """
        Loops over the underlying queue of events and processes them in order.
        """
        assert self.queue is not None
        while True:
            event = self.queue.get()
            if self.pre_process_event(event):
                self.invoke_handlers(event)
            self.queue.task_done()

However this is just an implementation detail which might evolve with new versions, you’d better not rely on it. Could you for ex call Function1 in Function2 and Function3 ?