Look into ControlSpec, to translate from range 0-1 to any range.
Example:
~mySpec = ControlSpec(-10, 5); // map to any desired range
// take the value, and map it to the desired range:
~mySpec.map(aSlider.value);
Example of a gist: https://gist.github.com/vasilisioakeimidis
But: We want git repos.