SHRDLU was written in Lisp, albeit a pre-CL list. So it was quite easy to bring up by writing macros that make CL work like older Lisps. We did the same thing with Bernie Cosell's ELIZA:
https://sites.google.com/view/elizagen-org/eliza-clones
Although IPL is a direct Lisp predecessor, it can't be easily mapped to Lisp. Indeed, Lisp and IPL-V were contemporaneous for about 5 years, but Lisp was so much simpler and more elegant that it rapidly supplanted IPL. As a result, Ed Feigenbaum and I are probably the only living person who know IPL (and I only barely know it as I just learned it in the past few months!), whereas Lisp has been essentially endemic for 60 years! (I'm hoping I'm wrong that Ed and I are the only folks who know IPL. If you know of a native IPL speaker who I could talk to, I'd love you to DM me!)
