Almost every serious Emacser knows by now that John Wiegley has taken over as the Emacs maintainer. Everyone appears united in their belief that this is a good thing and that Wiegley will be a great maintainer.
As you’d expect, Wiegley is an Emacs Lisp export (see this video with Sacha on Elisp development, for example). What you might not be aware of is that Wiegley works primarily in Haskell. There’s a wonderful video of Wiegley discussing the benefits of Haskell and his experience with it. He says that the big strength of Haskell is that it’s hard to write incorrect code that compiles. If you can get the compiler to accept your code then it will likely work as intended.
Haskell isn’t a silver bullet, of course, but according to Wiegley, it does make it easier to write good code. The video is 26 and a half minutes long but worth watching, especially if you’re considering trying out the language. After watching the video, I’m considering trying it out myself. There are a number of open source compilers available. The Glascow Haskell Compiler appears to be the favorite but there are others.