How should I generate a roguelike dungeon in haskell?

I'm new in Haskell and I'm making a roguelike.
The point is, I don't know how to build the dungeon in Haskell.
I know the basics in Python but Python is imperative and not functional like Haskell.
When I've searched, I find out that Haskell isn't really popular in roguelike development.

Can you tell me some tips, explain me how it should work, etc? But please don't post there any hole code because I want to write the code by myself.

Thanks in advance