I’m not blaming them, mostly, but I am pointing out that what they’ve put their effort is not consistent with industry usage. Parsec is neat, but parsing is a relatively niche industrial need, and lens sits somewhere between PL research and “solving problems that only Haskell has”.

They’re fine libraries, they’re just not what I want to see if you’re trying to convince me to replace Java with Haskell at work. If I was looking to write a compiler however...