Glad you like it! We spent all weekend hacking away on this - really excited to show it to everyone.
Behind the scenes we're running iOS apps on Macs and streaming the screen to you - sort of like a remote-desktop connection into a running app. We've built up a bunch of infrastructure to do that for our main product.
To make the RubyMotion REPL magic happen, we looked at the how RubyMotion launcher worked. RubyMotion apps expose the REPL over a UNIX socket, and you can write expressions and read results from there. So, we connect into that.
If anyone is curious, here's a DTrace script for peeking at the traffic going over the RubyMotion REPL socket: https://gist.github.com/2624774
Behind the scenes we're running iOS apps on Macs and streaming the screen to you - sort of like a remote-desktop connection into a running app. We've built up a bunch of infrastructure to do that for our main product.
To make the RubyMotion REPL magic happen, we looked at the how RubyMotion launcher worked. RubyMotion apps expose the REPL over a UNIX socket, and you can write expressions and read results from there. So, we connect into that.
If anyone is curious, here's a DTrace script for peeking at the traffic going over the RubyMotion REPL socket: https://gist.github.com/2624774