This is great to see. The IPython project has grown to be much more than just a collection of nice interactive interfaces to Python. It is a well-designed JSON-based protocol between interactive interfaces and execution kernels – which can execute any language, not just Python. The fact that you can do things like IHaskell and IJulia is a testament to how well the IPython team has designed the protocol.

The best part about this project is that it stands to reduce much of the duplicated / wasted effort that goes into recreating the same interface functionality for every single programming language. This is already allowing Julia (and now Haskell) to reap the benefits of the amazing browser UI work that's gone into the IPython Notebook – all for the very low cost of implementing a rather simple ZMQ message server.