I find the solutions from https://github.com/qobi/AD-Rosetta-Stone/ https://github.com/qobi/AD-Rosetta-Stone/ to be very helpful, particularly for representing

I find the solutions from https://github.com/qobi/AD-Rosetta-Stone/ https://github.com/qobi/AD-Rosetta-Stone/ to be very helpful, particularly for representing forward and backward mode automatic differentiation using a functional approach. I used this code as inspiration for a functional-only (without references/pointers) in Mercury: https://github.com/mclements/mercury-ad https://github.com/mclements/mercury-ad