>
> But the biggest thing missing is precise semantics. Saying "exactly
> the same semantics as with Python 2.5" doesn't cut it (those semantics
> are incredibly hairy and sometimes surprising, and their
> implementation was a nightmare -- I've rarely been as relieved as when
> I was able to cut those out of the implementation).
Why is that so? I might be being naive, but what is wrong with something
like this:
def cmp(a, b):
if hasattr(a, '__cmp__'):
return a.__cmp__(b)
elif hasattr(b, '__cmp__'):
return -1 * b.__cmp__(a)
elif hasattr(a, '__le__') and hasattr(a, '__ge__'):
x = a <= b
y = a >= b
if x and y:
return 0
elif x:
return -1
elif y:
return 1
elif hasattr(b, '__le__') and hasattr(b, '__ge__'):
x = b <= a
y = b >= a
if x and y:
return 0
elif x:
return 1
elif y:
return -1
elif hasattr(a, '__eq__'):
if a == b:
return 0
if hasattr(a, '__lt__'):
if a < b:
return -1
else:
return 1
elif hasattr(a, '__gt__'):
if a > b:
return 1
else:
return -1
else:
raise NotImplemented()
elif hasattr(b, '__eq__'):
if a == b:
return 0
if hasattr(b, '__lt__'):
if b < a:
return 1
else:
return -1
elif hasattr(b, '__gt__'):
if b > a:
return -1
else:
return 1
else:
raise NotImplemented()
else:
raise NotImplemented()
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