From 62e40d8450b9c78346ec3617de7fe3f0ad381510 Mon Sep 17 00:00:00 2001 From: Ethan Furman Date: Tue, 22 Sep 2020 00:05:27 -0700 Subject: [PATCH] Enum: add extended AutoNumber example (GH-22349) --- Doc/library/enum.rst | 26 ++++++++++++++++++++++++++ Misc/ACKS | 1 + 2 files changed, 27 insertions(+) diff --git a/Doc/library/enum.rst b/Doc/library/enum.rst index 843d961afc4..3e9b1f9db35 100644 --- a/Doc/library/enum.rst +++ b/Doc/library/enum.rst @@ -925,6 +925,32 @@ Using an auto-numbering :meth:`__new__` would look like:: >>> Color.GREEN.value 2 +To make a more general purpose ``AutoNumber``, add ``*args`` to the signature:: + + >>> class AutoNumber(NoValue): + ... def __new__(cls, *args): # this is the only change from above + ... value = len(cls.__members__) + 1 + ... obj = object.__new__(cls) + ... obj._value_ = value + ... return obj + ... + +Then when you inherit from ``AutoNumber`` you can write your own ``__init__`` +to handle any extra arguments:: + + >>> class Swatch(AutoNumber): + ... def __init__(self, pantone='unknown'): + ... self.pantone = pantone + ... AUBURN = '3497' + ... SEA_GREEN = '1246' + ... BLEACHED_CORAL = () # New color, no Pantone code yet! + ... + >>> Swatch.SEA_GREEN + + >>> Swatch.SEA_GREEN.pantone + '1246' + >>> Swatch.BLEACHED_CORAL.pantone + 'unknown' .. note:: diff --git a/Misc/ACKS b/Misc/ACKS index 01ee1cb42d3..e4bd3da6b6c 100644 --- a/Misc/ACKS +++ b/Misc/ACKS @@ -1723,6 +1723,7 @@ Févry Thibault Lowe Thiderman Nicolas M. Thiéry James Thomas +Reuben Thomas Robin Thomas Brian Thorne Christopher Thorne