Wait a minute! Can you embed Julia into a C program like Lua? Can it interface with complex C types cleanly?? This might be the scripting language I'v been looking for in my side project!
One big pain point so far is that it won't be easy to actually embed Julia into my app. So users of my app will have to install Julia (probably via homebrew) before they can script the app with it.
I foresee Julia overtaking PyObjC, RubyCocoa, Nu, and MacRuby as the scripting language of Mac apps. This looks incredibly perfect. You don't lose performance, so you can even do the hard stuff in Julia. Which makes bridging much less painful. Hoorah!