RFR 8015978: Incorrect transformation of XPath expression "string(-0)"

[David Chase]

Wouldn't be more efficient to do the following, assuming that the full Java compilation chain respects the trickiness of 0 vs -0:

   if (d == 0.0) { 
        d=0.0 // Jam -0 == +0 to +0, per http://www.w3.org/TR/xpath/#function-string

   }

Division's plenty more expensive than assigning a constant, especially on platforms that lack hardware FP division.

David

On 2013-06-07, at 2:03 AM, huizhe wang <huizhe.wang at oracle.com> wrote:

> Hi Aleksej,
> 
> According to XPath spec, both positive and negative zero are converted to the string 0, so it seems doesn't matter. But if you want to detect the negative zero, you may do the following:
>    if (d == 0.0 && 1/d < 0.0) {
>         d=0.0
>    }
> 
> Recognizing that (-0.0 == 0.0), and (1/(-0.0) == -Infinity).
> 
> -Joe