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- Subject: Re: Lua minus null (-0)
- From: Dirk Laurie <dpl@...>
- Date: Sun, 5 Jun 2011 23:43:10 +0200
On Sun, Jun 05, 2011 at 10:44:24PM +0200, Henk Boom wrote:
> If I understand the Sebastian properly, he is not complaining that lua
> doesn't differentiate between them, but that these two numbers which
> are not normally differentiated do not print the same:
> On Sun, Jun 05, 2011 at 12:47:39PM +0200, Sebastian wrote:
> > The problem of the output from -0 is that -0 does'nt look good.
> > The user (for example a wow addon user) can be disoriented,
> > when he read the addon output: "(-20) * 0 = -0.
That, too, is not a bug, it's a feature. Reuben's point applies:
Lua relies on the host C compiler and its libraries. Since C converts
a negative zero to the string -0, so does Lua.
It is a good thing, not a bad thing. The Wikipedia article I cited
in my previous post gives several examples why one would wish to have
information on the sign of a zero.
The claim that -0*0 should be 0, not -0 is wrong too. Quoting the
article: "Multiplication and division follow their usual rules for