I think just tweaking your parse method to use #'string-append and #'~a would be enough to preserve hygiene for your introduced identifiers. datum->syntax will

I think just tweaking your parse method to use #'string-append and #'~a would be enough to preserve hygiene for your introduced identifiers. datum->syntax will happily work with mixed combinations of syntax-objects and data. And yes, feel free to do anything with that example and share further. Not enough people have had exposure to Racket's implicit expansion macros. (Is that even what they're called?)