What software was used to write real-world haskell?
formatting, haskell, layout, web
Solution
http://www.realworldhaskell.org/blog/2008/11/25/real-world-haskell-is-shipping/
From this blog post (read the comments), it seems they used DocBook.
Problem
Title pretty much sums it up; I'm looking to start a book on programming and I love that approach.