I'm a bit out of my depth, but I think I recall Gerald Sussman talking about dealing with a similar problem using an operator that indicated that evaluated to e

I'm a bit out of my depth, but I think I recall Gerald Sussman talking about dealing with a similar problem using an operator that indicated that evaluated to exactly one out of a finite set of elements but can be evaluated to any in the set. If I'm recalling, it was ok because each of the elements of the set were differentiable functions, but the operator produces a set of possible results, but doesn't specify which. Sort of like a monad, it seemed. I want to say he was referring to a quadrature, but I honestly can't recall and wont be able to spare the time to hunt down the talk until later. Coincidentally, I just got a copy of structure and interpretation of classical mechanics just the other day, so hopefully I'll get some more appreciation for the problem. [0] https://mitpress.mit.edu/9780262553452/structure-and-interpretation-of-classical-mechanics/ https://mitpress.mit.edu/9780262553452/structure-and-interpr...