#!/usr/bin/env python3
# File: src/scitex_etc/wait_key.py
import multiprocessing
import time
import readchar
def wait_key(p, *, read_key=None, printer=print):
"""Block until the user presses ``q``, then terminate process ``p``.
Echoes each key as it is pressed; on ``q`` prints a notice and calls
``p.terminate()``.
Parameters
----------
p
A process-like object exposing ``terminate()``.
read_key : callable, optional
Zero-arg callable returning the next key as a string. Defaults to
``readchar.readchar``. Injectable as a test seam (no mocks).
printer : callable, optional
Output sink, defaults to the builtin ``print``. Injectable so tests
can record output without patching ``builtins.print``.
"""
if read_key is None:
read_key = readchar.readchar
key = "x"
while key != "q":
key = read_key()
printer(key)
printer("q was pressed.")
p.terminate()
[docs]
def count(*, printer=print, sleeper=time.sleep):
"""Print an incrementing counter forever, sleeping 1s between values.
Parameters
----------
printer : callable, optional
Output sink, defaults to the builtin ``print``. Injectable test seam.
sleeper : callable, optional
One-arg sleep callable, defaults to ``time.sleep``. Injectable so
tests can run without real delay and bound the loop.
"""
counter = 0
while True:
printer(counter)
sleeper(1)
counter += 1
if __name__ == "__main__":
p1 = multiprocessing.Process(target=count)
p1.start()
wait_key(p1)
print("aaa")
# EOF