isn't differentiable programming a concept that has existed under one shape or another since the 80s, likely earlier ? e.g. https://dl.acm.org/doi/abs/10.1145/322609.322611

Like, I'm pretty sure writing a generic "differential function" is one of the first things you teach to undergrads taking a LISP class - isn't "differential programming" as mentioned here just the same concept baked in PLs ?