I want to compare just the signs of two Fixnums. Right now I am using:

```
c = -c if (a >= 0.0 && b < 0.0) || (a < 0.0 && b >= 0.0)

```

I would like something like:

```
c = -c if a.sign != b.sign

```

or perhaps some other way of comparing only the signs.