Implement exclusions in a contourplot[ ]?

Questions
1

ContourPlot[(x - y)/(x + y), {x, -10, 10}, {y, -10, 10},
Exclusions → {x + y == 0}, Automatic, Frame → True,
Axes → Automatic, AxesOrigin → {0, 0}, AxesStyle → GrayLevel[0.5],
PlotPoints → 200, ContourLabels → False, ContourStyle → Red,
ContourShading → False]

I want to exclude the line x+y == 0, and I don’t know how to do it. Tried various things, but nothing works.

Can anyone help me ?

Chiel Geeraert, Netherlands

2

Hi Chiel

Instead of Exclusions, have you tried using RegionFunction? e.g.

RegionFunction -> (#1 + #2 != 0 &)
3

No, I didn’t try beforehand. But just a minute ago I gave a try, but alas, an error.
To be sure I checked options[contourplot] and exclusions is part of the options there. Somehow I do something wrong, but it should be possible.