For my spreadsheet project, I had to redo something I had forgotten about: cell displacement. I did that once when the formula language was python.
Since I have lots of other things to do, I decided to do it the same way, and wrote the equivalent of regurgitate for Traxter, my formula language.
It turns out it was not really hard, but I had to redo parts of the parser so it kept more information about the source.
After that it was simple, you see, Traxter compiles to Python. That means all I had to do was another (very similar) backend, and there it is, a Traxter-to-Traxter compiler. Or decompiler. Or something. And relative cell references are working again (and now with the right syntax).