Vedran Čačić added the comment: Ok, so let me try to summarize.
Some people realized that & and | on bools are overridden to return bools instead of ints, and thought it would be nice if ~ acted as negation on bools (~False being True and ~True being false) instead of mapping them to -1 and -2 as it currently does. A (weak, IMO) counterargument is that currently int(a op b) == int(a) op int(b) for all ints a and b, even those ints that are also bools. But of course str(True) != str(1), so of course _some_ special methods can be overridden with a different behavior (returning non-equal things). A better (again IMO) counterargument is that those (&, |, ~) operators are meant to be bitwise, that is, threaded over all the bits in the operands. In that case, bool with that ~ implementation should not be looked at as a subclass of int* qua long in Py2 (infinite number of bits to the left), but as a subclass of "int1" in the sense of Py2 int being int32 (fixed number of bits). But if we are to drive this to the natural conclusion, then True == -1 when upcasted to int, not 1, and that would probably break too much code. Also, there are bitwise operators (<<, >>) which don't have a nice analogue on int1 (except always returning 0, which is not interesting). Also (wasn't mentioned in the thread, but probably worth mentioning), Python 3 really tries to not have fixed-length ints anywhere. For example, indexing bytes gives ints, and they are not int8, but ordinary int*: ~b'a'[0] is -98, not 158. Bools might be special, but they are probably not _that_ special. We have worked long and hard to remove fixed-length ints from Python, it would be very counterproductive to add them back again. The only reason I'm bringing this here, is that Guido said at some moment > So we're either going to introduce it in 3.6 and tell people about it in case their code might break, or we're never going to do it. and I would feel bad to tell future learners of Python "that feature was considered, but we simply forgot about it and the opportunity closed". :-O If the sentiment has really crystallized to "we shouldn't do this" in the meantime, no problem. But it seems no pronouncement was made. ---------- _______________________________________ Python tracker <rep...@bugs.python.org> <http://bugs.python.org/issue27754> _______________________________________ _______________________________________________ Python-bugs-list mailing list Unsubscribe: https://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com
