This final chapter will list out generally useful Haskell libraries. As with any programming language ecosystem, libraries are a very important part of it. Good, modular, and extensible libraries are what really make for productive programming. The Haskell ecosystem has libraries of multiple varieties, from bad to outstanding. All of the libraries listed here are considered robust and safe and recommended for use in production.
It's an unfortunate fact that choosing a good Haskell library for your needs is no easy task. There are ways to compare and weigh libraries: When was the package last updated? Is its maintainer active? Is the library present in the newest Stackage snapshot? Still, it's easy to miss an excellent library for your specific use. Sometimes there might be a niche, not well-maintained library that fits just your need. Then use that, and refactor later if necessary. Haskell gives guarantees that make refactoring easy, so it's no big deal...