Ask HN: Want to build Ruby irb for iOS in RubyMotion with me?

I was on the train this morning, and wanted to double-check a Ruby concept I was thinking about, and thought it would be cool if I had irb on my phone. A couple of apps appear to exist, but I think it'd be a cool project to try with RubyMotion. Either way, would love to hear any thoughts on how to approach this. Thanks!