- (ir-macro-rules (sym ...) (code0 xpr0) (code1 xpr1) ...)syntax
pairs the differnt macro-codes code0 code1 ... with expressions xpr0 xpr1 ..., which usually evalute to backquoted templates in the scope of injected symbols sym ....
This macro is unhygienic by design, it introduces the two symbols inject and compare? into its scope.