question about jit.anim.drive - generic parameter possible?

hi -

I'm using jit.anim.drive with the moveto and rotateto messages to animate a jit.gl.camera & some jit.gl.lights, and I'd like to coordinate various parameters that aren't part of the object transform - for instance, the lens_angle of the camera and the spot_angle of the light.

I can handle this myself (for instance by triggering a line object when I start the moveto) but then I don't get all the nice easein & easeout curves - and while I can recreate these manually, it's a lot of work.

Couldn't jit.anim.drive (and jit.anim.path) have an attribute that would tell it to dump out a generic 0. to 1. parameter as it progresses through the current animation that could then be used to drive an arbitrary variable?

It would be essentially the opposite of jit.anim.path's eval message - instead of feeding the object a 0. to 1. message, the object reports its progress from 0. to 1.