LOOP can be cheated a bit with, as it originated in separate semi-portable package AFAIK, just like for CLOS you can use PCL for heavy lifting. Specifically the

LOOP can be cheated a bit with, as it originated in separate semi-portable package AFAIK, just like for CLOS you can use PCL for heavy lifting. Specifically there was MIT LOOP package that wasn't exactly ANSI compliant but got you significant portion of the way there. Also, if you're willing, it's possible to just lift a bunch of code from SBCL/CMUCL due to permissive license. MIT LOOP https://www.cs.cmu.edu/afs/cs/project/ai-repository/ai/lang/lisp/code/iter/loop/mit/0.html https://www.cs.cmu.edu/afs/cs/project/ai-repository/ai/lang/... few other versions including symbolics update to MIT which is supposedly closer to ANSI: https://www.cs.cmu.edu/afs/cs/project/ai-repository/ai/lang/lisp/code/iter/loop/0.html https://www.cs.cmu.edu/afs/cs/project/ai-repository/ai/lang/...