I feel your pain. For what it's worth, I think I went through what you're going through in 2019. After many months of online classes and "independent study" I finally got to the point where I was coding activation functions and back-propagation. After all of that I understood why the bottleneck was data and compute, so I'd always be tied to some kind of API if I wanted to use anything that was relevant. This made me accept and ultimately embrace ML as a black box. In the same way that I'm not familiar with the codebases of most of the tools I use every day in my coding career, I'm not going to be familiar with the ins and outs of ML. It's just another tool but it's a powerful one so it's important that I can use it effectively. Because of that I'm very much in the API camp and as far as APIs go they seem to be pretty darn simple which is nice.

I think this was a perfect demonstration of why classes are the "right" way to write code at scale - at least with our current languages and tools. Early in my career I drank the OOP coolaid and got bitten hard over and over again. After years of abuse from trying to make all code into nouns and fighting mangled nests of inheritance, I rebelled and went full FP (So I just drank the other side's coolaid, sigh). I even purposely flunked an interview challenge once because I wanted to prove that FP was "better". Not my finest moment. I've now come to accept that a lot of code has dependencies that you want to configure prior to calling a function. A class constructor is a very natural way to do this. So now, I still try to write pure functions when it's reasonable but I don't shy away from creating an encapsulating class when a function has a dependency that is unnatural to pass in at call time (e.g. environment variables). Unfortunately, most code does have those kind of dependencies so most my function are now methods on a class. Part of me still wants to create patterns and tools in FP that solve this at least as good as classes do but I think that's just due to my prejudice of OOP. So, Jon, to reiterate, I think you perfectly demonstrated how classes are the preferred way to do DI, so we should be using them. I still avoid the term OOP though ;) Most code is more naturally thought of as verbs, not nouns. Is it even a thing to say I write functional classes?