One of the reasons that APL and now J have been so appealing to me is that they adhere to mathematics more than to computers. The developers have hidden the peculiarities of particular hardware platforms while maintaining reasonable efficiency. Taking advantage of peculiarities of IEEE floating point is simply locking one into a particular hardware platform. Ok, IEEE floating point is common to many platforms and probably on all that J support, but there are platforms that represent floating point differently. And IEEE floating point may be superseded in some future hardware. But if one really wants to take advantage of the peculiarities of IEEE then there are bunches of goodies in it beyond having both a positive and negative zero. Personally, I am glad that J does not.
I have not followed this discussion too closely because it is trying to take advantage of a hardware peculiarity, but really - zero is not a positive number and neither is it a negative number. Just because it is internally formatted as a positive or negative number internally is just a convenience of a hardware design. ---------------------------------------------------------------------- For information about J forums see http://www.jsoftware.com/forums.htm
