@ramin_hal9001
Nice article, imagining monads as alternate-universe eval-when special forms in lisp terms?
In Waters' package and chapter in Steele's Common lisp the language 2 book, Waters took the Macro Hard On Fire approach. So Waters' package shadows LET and so forth, and opportunistically wires "online and offline Series ports" together to create "lazy" DOLISTs at macroexpand time. I guess Waters' offline Series ports are an idea of von Neumann bottlenecks.