[tutfbhuf]

> 90% of your Ruby code will absolutely not work in Crystal unmodified.

Don't nail me on exact 90%, but for me it does. Nothing rails related though. Good example: https://news.ycombinator.com/item?id=23437035

However, I agree that the fundamentals/underlyings are very different. It's far from being like a python 2 to 3 migration.