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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