[Python-Dev] PEP 435 -- Adding an Enum type to the Python standard library
ethan at stoneleaf.us
Sat Apr 27 04:59:23 CEST 2013
On 04/26/2013 11:17 AM, Eli Bendersky wrote:
> I feel that this thread has lost track of it long ago. Some time back in the Enum discussions (some 350 messages ago or
> so), there was a proposal to have this:
> class Color(Enum):
> RED, BLUE, GREEN
> By doing some crazy-cool shenanigans. Although the syntax is great, it was rejected on the basis of being too magic.
Although explicit reasons were not mentioned (and perhaps not even consciously recognized -- *sigh* someday I hope to be
there are very good ones beyond "being too magic" -- way too easy to introduce bugs: name lookup success looks exactly
like name lookup failure, but the consequences were drastically different:
BLACK in MoreColor is a bug that cannot easily be detected as it is a successful name lookup; the consequence is that
CYAN, MAGENTA, and YELLOW are now off by one.
Not being Dutch, I had to smack into that one before I gave up on the idea.
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