My email was sent more as a warning: "abandon hope, all ye who enter here", because normal algebraic facts about 0.0=-0.0 no longer hold true.
Everything about -0.0 needs to be special-cased.
If you admit -0.0, then plan on grepping the entire Maxima corpus & finding all tests for zero; then find all places in Maxima where you now have to _add_ tests for -0.0.
At 12:08 PM 12/3/2012, Robert Dodier wrote:
>On 2012-12-03, Henry Baker <hbaker1 at pipeline.com> wrote:
>
>> More succinctly, -0.0 violates the concept of "referential
>> transparency"; i.e., the ability to substitute equals for equals.
>
>I agree that signed zero is algebraically strange, and also that it
>might be useful in some contexts. But that general discussion is beyond
>consideration, so long as we remain within the scope of portable Common
>Lisp code.
>
>best
>
>Robert Dodier