A nice solution was used during development of the Go language: a tool for <i>code rewriting</i> (it was called &quot;go fix&quot;). It allowed the language authors to quickly and easily transform large swaths of code in the standard library, and also let everybody execute the same transformations in any third-party code. Thus enabling rapid and extremely painless iterations. [I&#x27;m consciously simplifying the story a bit to make it shorter and more concise, but I&#x27;m not hurting the core message I believe.]