Links
Writing Mac and iOS Apps Shouldn’t Be So Difficult
inessential.com
You could write an entire static blog publishing system and the UI to go with it without ever restarting the app. Click a thing, then see what happens in the app — and if it’s not right you’d edit the script, which would be automatically recompiled when called the next time.
In other words, there was absolutely no friction when it came to iteration. Write some code without restarting and see your changes immediately.