recurring event type

alert.py

from typing import Awaitable

from cocotb.triggers import Trigger, _Event


class Alert(Awaitable[None]):
    def __init__(self) -> None:
        self._pending = []

    def set(self) -> None:
        triggers = self._pending[:]
        self._pending = []
        for t in triggers:
            t()

    def _prime_trigger(self, trigger: Trigger, callback) -> None:
        self._pending.append(trigger)

    def __await__(self) -> Trigger:
        return _Event(self)