ad VS concat

Maybe ad?

I’ll also link the ad package here in case someone can speak to its value over backprop https://github.com/ekmett/ad

Apologies in advance for disappointing a few people but the [ad] part in the title doesn't mean Automatic Differentiation but rather means "advertisement".

Hi everybody! A couple weeks ago, I made a blog post talking about how recursion and pattern matching could be used to translate Calculus formulas into Haskell. This is a follow-up exploring how to use automatic differentiation to calculate those same derivatives as an example of cool stuff that polymorphism allows us to do. (I learned this idea from the ad package and really fell in love with how elegant it is)

One step further is then (Compiling to Categories)[https://github.com/compiling-to-categories/concat] which tries to make the previous approach more convenient. It aims to overload any Haskell function from a -> b into a Category a b. Then, typeclass instances are used to transfrom those functions into virtually anything. While this project is very interesting, it is probably the most experimental one. You can also take a look at the overloaded package or at this novel categorifier plugin.

I believe it is here: https://github.com/compiling-to-categories/concat

I still dream of an Arrow-inspired contender to the throne of do notation (both for Monads and Applicatives), but proc isn't it, at least not with its current desugaring. Even more exciting to think about a variant of proc that does some concat-like magic and replaces arr with something that still allows complex data routing while exposing more structure than an opaque a -> b.