[docs] Code, test, and doc review for PEP-0435 Enum (issue 17947)

[ethan at stoneleaf.us]

http://bugs.python.org/review/17947/diff/8131/Lib/enum.py
File Lib/enum.py (right):

http://bugs.python.org/review/17947/diff/8131/Lib/enum.py#newcode103
Lib/enum.py:103: enum_class = type.__new__(metacls, cls, bases,
classdict)
On 2013/05/14 00:01:06, isoschiz wrote:
> On 2013/05/13 20:32:37, stoneleaf wrote:
> > On 2013/05/13 19:25:49, isoschiz wrote:
> > > Shouldn't this technically be a use of super()? Not that I guess
complex
> type
> > > hierarchies of Metaclasses are common.
> > 
> > __new__ is one of the few things (the only thing?) that cannot be
shared --
> you
> > can only create an object once.
> 
> And yet in this instance you are deferring to your superclass'
__new__. If
> someone mixes in an extension type with a custom __new__ as well as
Enum, then
> this will break. Using super() will make that possible.

I don't understand.  Can you provide an example?

http://bugs.python.org/review/17947/diff/8131/Lib/enum.py#newcode114
Lib/enum.py:114: if not isinstance(value, tuple):
On 2013/05/14 00:01:06, isoschiz wrote:
> On 2013/05/13 20:32:37, stoneleaf wrote:
> > On 2013/05/13 19:25:49, isoschiz wrote:
> > > Doesn't this produce weird behaviour for the following definition:
> > > 
> > > class MyEnum(Enum):
> > >     FOO = 7
> > >     BAR = (42, 8)
> > >     BAZ = "hello"
> > 
> > Did you try it?
> > """
> > --> class MyEnum(Enum): FOO = 7; BAR = (42, 8); BAZ = "hello"
> > ... 
> > --> MyEnum
> > <enum 'MyEnum'>
> > --> list(MyEnum)
> > [<MyEnum.FOO: 7>, <MyEnum.BAR: (42, 8)>, <MyEnum.BAZ: 'hello'>]
> > --> MyEnum.BAR
> > <MyEnum.BAR: (42, 8)>
> > --> MyEnum.BAR.value == (42, 8)
> > True
> > """
> > 
> > Looks good to me. ;)
> 
> I must confess I didn't try it - apologies. :-)
> 
> Although as a corollary, the code is dense enough that I can't work
out in a
> straightforward way why this works! Perhaps some more comments would
help?

Probably because it doesn't work straight-forwardly. ;-)

I'll add some comments when I get some time, and figure out how to
detail the convoluted path involved.

http://bugs.python.org/review/17947/