long for a class whose __long__ method returns a plain int. This
fixes an interpreter crash (due to long_subtype_new assuming
PyNumber_Long returns a long) when initializing an instance of a long
subclass from an object whose __long__ method returns a plain int.
correctly rounded, using round-half-to-even. This ensures that the
value of float(n) doesn't depend on whether we're using 15-bit digits
or 30-bit digits for Python longs.
the __long__ slot is allowed to return either int or long, but the behaviour of
float objects should not change between 2.5 and 2.6.
Reviewed by Benjamin Peterson
long raise ValueError instead of returning 0. Also, change the error
message for conversion of an infinity to an integer, replacing 'long' by
'integer', so that it's appropriate for both long(float('inf')) and
int(float('inf')).
round included:
* Revert round to its 2.6 behavior (half away from 0).
* Because round, floor, and ceil always return float again, it's no
longer necessary to have them delegate to __xxx___, so I've ripped
that out of their implementations and the Real ABC. This also helps
in implementing types that work in both 2.6 and 3.0: you return int
from the __xxx__ methods, and let it get enabled by the version
upgrade.
* Make pow(-1, .5) raise a ValueError again.
