In reply to @b:chreekat.net

Probably not the right room to be asking (sorry), and I'm not sure there is an option that's more idiomatic. But I'll give my own recommendations and heuristics:

1. Always use explicit export lists so you only export the things you want exported. It's helpful to the compiler as well as your future self
2. Anything that needs a do block usually goes on the top level
3. lets and wheres are good for one-line unpacking or manipulating of function arguments, but it gets confusing if you can't see the place where the arguments are declared on the same screen
4. I usually put top-level helpers after the function they are helping, and I usually use let instead of where.
5. Nesting lets and wheres is awful