Wow, that project sounds like a total dumpster fire. Not that I know any of the details, of course, but I find it hard to believe that it saved any effort to try to write a compiler and a custom language/type system/code generator/etc versus just embarking on a rewrite of the code in question. To be honest I’m surprised that even in hindsight he seems to think it was a good idea, as I read it as a cautionary tale.