README added

Author: dapper91

README.md

@@ -0,0 +1,76 @@
+=========
+crontools
+=========
+
+Features:
+
+- crontab expression parser
+- optional seconds field support
+- optional year field support
+- crontab fire time sequential iteration support
+
+Installation
+------------
+
+You can install crontools with pip:
+
+.. code-block:: console
+
+    $ pip install crontools
+
+
+Quickstart
+----------
+
+On the server side everything is also pretty straightforward:
+
+.. code-block:: python
+
+    import datetime as dt
+    import crontools as ct
+
+    tz = dt.timezone.utc
+    now = dt.datetime.fromisoformat('2021-02-01 00:00:00+00:00')
+    ct = ct.Crontab.parse(
+        '30 30 12-16/2 1,2 JAN SAT,SUN *',
+        seconds_ext=True,
+        years_ext=True,
+        tz=tz,
+    )
+
+    cron_iter = ct.iter(start_from=now)
+    for n, fire_datetime in zip(range(1, 31), cron_iter):
+        print("{n:2}: {dt}".format(n=n, dt=fire_datetime))
+
+    output:
+
+     1: 2022-01-01 12:30:30+00:00
+     2: 2022-01-01 14:30:30+00:00
+     3: 2022-01-01 16:30:30+00:00
+     4: 2022-01-02 12:30:30+00:00
+     5: 2022-01-02 14:30:30+00:00
+     6: 2022-01-02 16:30:30+00:00
+     7: 2022-01-08 12:30:30+00:00
+     8: 2022-01-08 14:30:30+00:00
+     9: 2022-01-08 16:30:30+00:00
+    10: 2022-01-09 12:30:30+00:00
+    11: 2022-01-09 14:30:30+00:00
+    12: 2022-01-09 16:30:30+00:00
+    13: 2022-01-15 12:30:30+00:00
+    14: 2022-01-15 14:30:30+00:00
+    15: 2022-01-15 16:30:30+00:00
+    16: 2022-01-16 12:30:30+00:00
+    17: 2022-01-16 14:30:30+00:00
+    18: 2022-01-16 16:30:30+00:00
+    19: 2022-01-22 12:30:30+00:00
+    20: 2022-01-22 14:30:30+00:00
+    21: 2022-01-22 16:30:30+00:00
+    22: 2022-01-23 12:30:30+00:00
+    23: 2022-01-23 14:30:30+00:00
+    24: 2022-01-23 16:30:30+00:00
+    25: 2023-01-01 12:30:30+00:00
+    26: 2023-01-01 14:30:30+00:00
+    27: 2023-01-01 16:30:30+00:00
+    28: 2023-01-02 12:30:30+00:00
+    29: 2023-01-02 14:30:30+00:00
+    30: 2023-01-02 16:30:30+00:00