shorter way to one pan value to another

I have built a tour containing many panos and hotspots and we would like to have a transition during which the camera is animated. The camera will zoom and center to the hotspot you have just clicked before going to the other scene.

I have a solution that works pretty well but there is a problem when the hotspot is near pan value or 180.0. For instance if hotspot pan is 170.0 and the camera pan is at -170.0 when the user click on the hotspot, my ramp will make the camera do a 340° from -170.0 to 170.0 instead of taking the shorter way from -170 to -190 (equivalent to 190 down to 170). I have tried to find a formula with many getProperty, max, min, abs and so on this has proved to be quickly overcomplicated for a pretty simple and usual need.

A good solution would be to have a simple function that would be usable with in value expression used by setProperty. The function I suggest would work in the following way :

The return tDelta values would always gives the shorter angle from aAngle1 to aAngle2, expressed between -180 and +180

I would then be able to adjust value2 of my ramp to value1+tDelta as returned by my function.

A more generic to implement this would be to let us define our own lingo function usable in expression within a xml node, that you would add to Spi-V dynamically setting the scriptText of a new movie scripts.
Sometimes, things that are easy to program with a few if then else or repeat loops are impossible to express with a single math expression.