> For the beginner, there isn't enough syntax on offer to discern who's doing what to whom here.

If you throw a beginner at any non-trivial code in any language without teaching them anything about the language, then, yeah, it'll be hard for them to figure it out. That says nothing about the language itself, though. That's pretty obvious to everybody.

> Is there a "function signatures for dummys" somewhere?

Yeah, of course. There's actual beginner material, here's one example:

https://learnyouahaskell.github.io/types-and-typeclasses.htm...

Not hard to find, and not the only introduction to the language that covers this material. I guess you never bothered to look, or even to ask Gemini.