Chris Angelico wrote: > On Thu, Sep 18, 2014 at 1:34 AM, Ian Kelly <ian.g.ke...@gmail.com> wrote: >> On Wed, Sep 17, 2014 at 9:29 AM, Chris Angelico <ros...@gmail.com> wrote:
>>> Invariant: div*y + mod == x. >>> >>> If mod is NaN, there is no possible value for div that will make the >>> invariant true, ergo it too has to be NaN. >> >> That still doesn't make the invariant true. By this argument div could >> be 42, and the invariant would hold equally well (i.e. not at all). > > Nothing can possibly make it true, so there are only two > possibilities: return NaN, or raise an exception. If nothing can make it true, then it is not an invariant, and your argument is no longer valid. -- Steven -- https://mail.python.org/mailman/listinfo/python-list
