IPython creator here, just to say I'm thrilled to see this! We've wanted more languages to follow this route, and while we have only had time to work directly with the Julia team, it's fabulous to see others following up with the idea.

Please don't hesitate to ask us on the dev mailing list if you run into any problems. For one thing, we're planning on making some updates to the protocol spec soon, based mostly on the experience of the IJulia work. It would be great to have your input there as well, in case you spot something that wouldn't fit well the patterns you saw while doing the Haskell port.

And besides, this means I now have one less excuse to get off my butt and learn Haskell! :)