It's an improvement. It's still not pretty, but I guess that's as good as it's going to get...
Maybe this is an instance of Haskell trying to tell me "if you need to write a 20-line do-block in the middle of your function, you're doing it wrong".
20 lines is a lot, but I have smaller ones all the time. You need >4 spaces of indent to continue a let. Here's another way to understand why: f = do let x = some big expression y = another big expression x y If you wonder why "multiple let" syntax is needed, well I don't really know for sure, but consider if x and y were mutually recursive. I was annoyed at first with all the indentation but got used to it. I use 4 space indents so it works out ok. Binding with <- or in where can reduce the indentation but is not always appropriate.