@worldsendless (Please don't tell him that `clojure.core/let` is a macro 🤫)
@greenCoder absolutely. The built-in macros are built in and often thought of as justa part of the language. They are stable, standard, and even instrumented. But library-defined macros can be a head-ache, and macros made on a project level are inherently expensive because of the rules they are re-writing.