I can't really think of a application of lerp or clamp with just that.
You could clamp the vertical velocity so that it doesn't fall too fast?
set vy to clamp(vy, -100, 100)
I may have bungled the order of the parameters though.
You could limit the y position for some kind of ground too:
set y to min(self.y, 400)
Thanks! I will try it out. The game axis are xyz actually, and jump direction and strength can be controlled similar to Mario. I asked about Lerp and Clamp, because I want the longer the fall the faster you'd go and also I'd want to have jump height dependent on how long you press button with a limit. I would do it myself, but it would take me more events than necessary, and someone like you is very good at keeping things simple. :)