Waht do you think about my repeated_timer class

[Chris Angelico]

On Thu, 3 Feb 2022 at 15:43, Cecil Westerhof via Python-list
<python-list at python.org> wrote:
>
> Chris Angelico <rosuav at gmail.com> writes:
>
> >> > (Side point: The OP's code is quite inefficient, as it creates a new
> >> > thread for each reiteration, but there's nothing wrong with that if
> >> > you're looking for something simple.)
> >>
> >> It is just something I wrote fast. How could I do this in a better way?
> >
> > I'll answer your question, but first and foremost: Your code was fine,
> > and if something does what it's supposed to, that is the most
> > important. Everything else is minor.
>
> I like to write efficient code and it never hurts to write better code
> as just doing what it is supposed to do. ;-)
>
> And in my case interval is .5 seconds and when someone is going to use
> it with an even smaller interval …
>
>
> > But for other ways to do things, I would recommend creating a single
> > thread function and spawning a single thread to run it, and then
> > having that function call the target every N seconds. Also, consider
>
> Have to be careful that timing keeps correct when target takes a 'lot'
> of time.
> Something to ponder about, but can wait.

Ah. In that case, I would recommend a different look at things.
Instead of waiting X time, then firing the event, then waiting X time,
consider instead an interval timer based on monotonic time:

https://docs.python.org/3/library/time.html#time.monotonic

When the timer starts, record the current monotonic time, and sleep
one interval. After the function returns, sleep the remainder of one
interval. It's up to you what happens if you ever find that the next
time point has already passed - do you call the function immediately,
or skip and wait for the next moment?

Interval timers have some complexity to them, but it's worth putting
in the time (pun intended) to figure out how these things work :)

ChrisA