I'm kind of new to Scheme, but it seems to me constructing code at runtime would be a job for eval. I'm assuming this would end up being something like: (eval (list macro-name (list expr [literal1 val1] [literal2 val2] ...)) <environment>) I'm working from the assumption that macros are essentially functions for writing code and that it would be available at runtime as it is from the REPL. Hope this helps, Kurt