What are some open source programs that use Haskell and can be considered to be good quality modern Haskell? The larger the code base, the better.
I want to learn from their source code. I feel I'm past the point of learning from small code examples, which are often to esoteric and small-world. I want to see how code is structured, how monads interact when you have a lot of things going on (logging, I/O, configuration, etc.).
Darcs is an open source, source code management system. It should give you a nice idea for Haskell.
What I recommend.
Read code by people from different grad schools in the 1990s
Read code by
the old masterscertain people (incomplete list)Note that people like me, Coutts, Mitchell, O'Sullivan, Lynagh, etc. learned our Haskell style from these guys.
Read some applications
The source code to the Yesod Web Platform is fairly complex, well thought out, and well written. You will learn a lot from the persistence library that comes with it as well.
Haskell: Functional Programming with Types
Joeri van Eekelen, et al. | Wikibooks Published in 2007, 290 pages
Learn You a Haskell for Great Good!
Miran Lipovaca | LearnYouaHaskell.com Published in 2010, 176 pages
Real World Haskell
B. O'Sullivan, J. Goerzen, D. Stewart | O'Reilly Media, Inc. Published in 2008, 710 pages
The Haskell Road to Logic, Maths and Programming
Kees Doets, Jan van Eijck | College Publications Published in 2004, 449 pages
If you care about Web-programming I would recommend Chris Done's lpaste project.
GHC is probably the biggest or one of the biggest projects written in Haskell that is open source. When I say biggest, I do not just mean in terms of source size, but also impact, use, innovation, robustness. GHC can teach you a lot about writing Haskell.