Tim Golden napisa (a):
> It's only a moment before the metaclass and
> the Twisted solution come along. :)
I couldn't resist. It's not as elegant as I hoped, but hey, at least
it memoizes the intermediate classes :-)
class fact_0(object):
value = 1
class fact_meta(object):
def __new__(cls, name, bases, attrs):
n = attrs['n']
class_name = 'fact_%i' % n
try:
return globals()[class_name]
except KeyError:
new_class = type(class_name, bases, {})
new_class.value = n * fact(n - 1).value
new_class.__str__ = lambda self: str(self.value)
globals()[class_name] = new_class
return new_class
class fact(object):
def __new__(self, n_):
class spanish_inquisition(object):
__metaclass__ = fact_meta
n = n_
return spanish_inquisition()
print fact(5)
print fact(3)
print fact(1)
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