[Python-Dev] Enumeration item arguments?
pjenvey at underboss.org
Tue Apr 30 04:30:24 CEST 2013
On Apr 29, 2013, at 3:25 PM, Eli Bendersky wrote:
> On Mon, Apr 29, 2013 at 2:59 PM, Ethan Furman <ethan at stoneleaf.us> wrote:
> In the Planet example we saw the possibility of specifying arguments to enum item __init__:
> class Planet(Enum):
> MERCURY = (3.303e+23, 2.4397e6)
> VENUS = (4.869e+24, 6.0518e6)
> EARTH = (5.976e+24, 6.37814e6)
> MARS = (6.421e+23, 3.3972e6)
> JUPITER = (1.9e+27, 7.1492e7)
> SATURN = (5.688e+26, 6.0268e7)
> URANUS = (8.686e+25, 2.5559e7)
> NEPTUNE = (1.024e+26, 2.4746e7)
> def __init__(self, mass, radius):
> self.mass = mass # in kilograms
> self.radius = radius # in meters
> Do we want to support this?
> I'm -1, and this is yet another bad sign of conflating enums with classes. If planets want to have attributes and behaviors, let them be normal classes. If they want a PlanetId *enum member*, that's OK, but there's no need to intermix the two.
You may be right about the Planet example, but I wouldn't go that far. Additional metadata on Enum instances can be a handy feature in some cases, like documentation, e.g.:
HOPOPT = 0, "IPv6 Hop-by-Hop Option"
ICMP = 1, "Internet Control Message"
IGMP = 2, "Internet Group Management"
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