Macros in Lisp during compilation often extend the compile-time environment and another purpose is to register information in the Lisp IDE (record source code,

Macros in Lisp during compilation often extend the compile-time environment and another purpose is to register information in the Lisp IDE (record source code, record source locations, ...). > but with a much simpler feature (which is just running code at compile time) Common Lisp does that with the EVAL-WHEN construct, which allows to run arbitrary code at compile time.