Hi Brett, I like having mercury-minimal I think that’s pretty considerate.
To use (ice-9 match) you will need to add it to the list of #:modules in the arguments field then use-module in your phase. I.E.: (arguments `( #:modules ,(cons '(ice-9 match) %gnu-build-system-modules) ... Then in your phase: (lambda ... (use-modules (ice-9 match)) ... A phase should work well for this purpose, as long as the submodule does not include any binaries. If it does, you should use the snippets field of the origin record instead. Happy to help, and good luck, John