#!/usr/bin/env python3
+# © Copyright 2021-2022, Scott Gasch
+
+"""A simple stopwatch decorator / context for timing things."""
+
+import contextlib
import time
-from typing import Callable
+from typing import Callable, Literal
-class Timer(object):
+class Timer(contextlib.AbstractContextManager):
"""
- with timer.Timer() as t:
- do_the_thing()
+ A stopwatch to time how long something takes (walltime).
+
+ e.g.
- walltime = t()
- print(f'That took {walltime}s.')
+ with stopwatch.Timer() as t:
+ do_the_thing()
+
+ walltime = t()
+ print(f'That took {walltime} seconds.')
"""
def __init__(self) -> None:
- self.start = None
- self.end = None
+ self.start = 0.0
+ self.end = 0.0
def __enter__(self) -> Callable[[], float]:
+ """Returns a functor that, when called, returns the walltime of the
+ operation in seconds.
+ """
self.start = time.perf_counter()
self.end = 0.0
return lambda: self.end - self.start
- def __exit__(self, *args) -> bool:
+ def __exit__(self, *args) -> Literal[False]:
self.end = time.perf_counter()
- return True
+ return False