Tell me the truth

[Mikael Olofsson]

francois.petitjean at bureauveritas.com wrote:
> If I take into account the fact that 'True' and 'False' are singletons
> (guaranteed ?) :
>  (not not x) is bool(x)  # should be always True.
> [snip code and results of code]
>   
Consider the following:

 >>> def ok1(x):
    return (not not x) is bool(x)

 >>> def ok2(x):
    return (not not x) is bool(x) is True

 >>> def ok3(x):
    return ok1(x) is True

 >>> def ok4(x):
    return ((not not x) is bool(x)) is True

 >>> def ok5(x):
    return ((not not x) is bool(x)) and (bool(x) is True)

 >>> for x in [False, True]:
    print x,ok1(x), ok2(x), ok3(x), ok4(x), ok5(x)

   
False True False True True False
True True True True True True

Note that ok2(x) and ok5(x) exhibit the same behaviour.

HTH
/MiO