envy VS hoogle

when you already know how to compile and run single-module interactive console programs, it takes about a day to understand basics of Cabal, and about a week to learn about input parsing and output formatting. Do you need CLI args? Use optparse-applicative. Env vars? Use envy. JSON? Use aeson. Don't think about performance and/or API conventions, that's not what you should be concerned of at this point, as you are just learning to compose things together from indivdual parts.

For what it's worth, I've never used/heard of this function myself, but I used the awesome https://hoogle.haskell.org site and searched by the type signature:

Looks cool.

Maybe it can also search by signature like https://hoogle.haskell.org/ - would be a killer feature for me, but niche :)

As for finding things in those many modules, I usually check hoogle first: https://hoogle.haskell.org/

If the type doesn't make it clear, then I read the docs or source on hackage. To find the right hackage package, I generally use hoogle which can be queried by name or by type!

Cool project and overall I'd say your good is good. There's some stylistic things I might change. Below I've commented on a bunch of random stuff just to give you food for thought and possible leads to look into as a continuing to learn haskell sort of thing. I was pretty bad about citing where functions are from, so I recommend using something like hoogle (https://hoogle.haskell.org/) if it's not clear what function I meant.

Fun fact: Hoogle is actually a thing: https://hoogle.haskell.org

You can search for a type signature on Hoogle. For example, if I wanted to know if there's a function from lists to Maybe I could search for [a] -> Maybe [a]

Haskell has a search engine, called hoogle, for looking up types and functions. It's invaluable for getting familliar with the language. https://hoogle.haskell.org

hoogle