_If_ one is using a firmware which supports that.

Grbl, which many of the 3D printer firmwares are based on, does not (and no variables, or loops, or branching).

And weirdly, neither does Klipper, despite having all the resources in the world to do so. Just not a priority since slicers don't produce code like that, and 99.999% of Klipper's job is to eat whatever a slicer sends it.

So suppose I attached an extruder to a Haas mill or something...