I've thought about codebase conversions quite a bit while working on the decaffeinate project [1] to help speed up the conversion from CoffeeScript to JavaScrip

I've thought about codebase conversions quite a bit while working on the decaffeinate project [1] to help speed up the conversion from CoffeeScript to JavaScript at my work. I've also given some advice on different strategies [2][3], although some of that is specific to the CoffeeScript -> JavaScript problem, which is easier than other situations since the languages can interop easily and are so similar. The "1 hour per 100 lines" rough number from the article is probably optimistic, at least in some settings. As one example, a coworker of mine manually converted a complex 500-line file, and it took two days to convert, one day to go through code review, and introduced two bugs. Probably any reasonable strategy needs to find a way to work incrementally and focus on the most valuable parts first. For example, if you focus your efforts on converting files that are the most active, then you may be able to culturally move your team to the new language even if there's still a lot of legacy code in the old language. In terms of the three phases from the article, I'm hoping that decaffeinate can become stable enough that it completely automates step 1 and avoids the need for step 2, but step 3 will always take time. In my case, my plan is to do a fully-automated conversion over the ~150k lines of code (broken up into maybe 10 chunks), call the style issues tech debt, and slowly clean those up as we work through each part of the code. [1] https://github.com/decaffeinate/decaffeinate https://github.com/decaffeinate/decaffeinate [2] https://github.com/decaffeinate/decaffeinate/blob/master/docs/conversion-guide.md#converting-a-whole-project https://github.com/decaffeinate/decaffeinate/blob/master/doc... [3] https://github.com/codecombat/codecombat/issues/4276#issuecomment-291954686 https://github.com/codecombat/codecombat/issues/4276#issueco...