On 04/26/2013 09:27 AM, Serhiy Storchaka wrote:
26.04.13 18:50, Larry Hastings написав(ла):
The standard Java documentation on enums:
http://docs.oracle.com/javase/tutorial/java/javaOO/enum.html
This example requires more than features discussed here. It requires
an enum constructor.
class Planet(Enum):
MERCURY = Planet(3.303e+23, 2.4397e6)
[...]
This can't work because the name Planet in the class definition is not
defined.
It can't work because you inserted the word "Planet" there. If you omit
the word "Planet", this would work fine with something like the
metaclass instantiate-all-data-members behavior in flufl.enum 4.
Here is the hack, demonstrated in Python 3:
class Metaclass(type):
def __new__(cls, name, bases, namespace):
result = type.__new__(cls, name, bases, dict(namespace))
for name, value in namespace.items():
if not (callable(value) or name.startswith("__")):
value = result(name, value)
setattr(result, name, value)
return result
class Planet(metaclass=Metaclass):
MERCURY = (3.303e+23, 2.4397e6)
def __init__(self, name, value):
self.mass, self.radius = value
def surfaceGravity(self):
return 6.67300E-11 * self.mass / (self.radius ** 2)
def surfaceWeight(self, otherMass):
return otherMass * self.surfaceGravity()
print("If you weigh 175 pounds, on Mercury you'd weigh",
Planet.MERCURY.surfaceWeight(175))
//arry/
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