Nice write up!

When I see stuff like this, personally, I don't try to understand it, as code like this emerges from basically three motivations:

- The other person wanted to write in some other more (functional|object oriented|stack) language but couldn't, so they did this.

- The person couldn't be bothered to learn idioms for the target language and didn't care about others being able to read the program.

- The person intentionally wanted to obfuscate the program.

And none of these are good reasons to write code in a particular way. Code is about communication. Code like this is the equivalent to saying "I know the grammatical convention in English is subject-verb-object but I feel like speaking verb-object-subject and other people will have to just deal with it"—which, obviously, is a horrible way to communicate if you actually want to share ideas/get your point across.

That all said, the desire to have logic expressed more compactly and declaratively definitely resonates. Unfortunately C style verbosity and impurity remains dominant.