No: PEP 238 is (partly) about how integer division is expressed in
Python; not about its semantics. Python's choice for integer
division with negative arguments goes back much further. From
Misc/HISTORY:
==================================
==> RELEASE 0.9.6 (6 Apr 1992) <==
==================================
[...]
New features in 0.9.6:
[...]
- Division and modulo for long and plain integers with negative operands
have changed; a/b is now floor(float(a)/float(b)) and a%b is defined
as a-(a/b)*b. So now the outcome of divmod(a,b) is the same as
(a/b, a%b) for integers. For floats, % is also changed, but of course
/ is unchanged, and divmod(x,y) does not yield (x/y, x%y)...
[...]
Nice! Thanks for sharing.
Personally, I've always liked Python's behaviour in this regard: for
the few times that I've needed an 'x % y' operation that works with
both positive and negative x, more often than not x-y*floor(x/y) turns
out to be what I need. I've lost count of the number times I've had
to write something awkward like:
/* adjust for the exponent; first reduce it modulo _PyHASH_BITS */
e = e >= 0 ? e % _PyHASH_BITS : _PyHASH_BITS-1-((-1-e) % _PyHASH_BITS);
in C.
Wow. I would never write code like that, but you got a fair point.
Cheers,
Xav
(Mark: Sorry, I forgot to reply to the correct list.)