bool behavior in Python 3000?
stargaming at gmail.com
Wed Jul 11 16:05:00 CEST 2007
Alan Isaac schrieb:
> Miles wrote:
>> What boolean operation does '-' represent?
> And as usual, a-b is to be interpreted as a+(-b).
> In which case the desired behavior is
> False-True = False+(-True)=False+False = False
I always thought, at least in a Python context, A-B would trigger
A.__sub__(B), while A+(-B) triggers A.__add__(B.__neg__()). A better
choice could be A+~B (A.__add__(B.__invert__())) because it's always
unary (and IMO slightly more visible).
> In response to Stargaming, Steve is making
> a point about the incoherence of certain arguments,
> not proposing an implementation.
Why should it be incoherent? Bjoern is pointing out an important aspect
of how Python handles binary algebra (correctly). In contrast, Steven
tries to invert his argument. Following, I showed why Steven's proof is
wrong because his implementation fails at some aspects where the current
one works. So I cannot see how Bjoern's argument is either wrong or not
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