Stepping Through Macros in CIDER

This is another installment in the series of articles about the notable changes in CIDER 2.0. Today’s topic is one of those “ambitious ideas that lay dormant for ages” I keep mentioning: proper interactive macro stepping. The Dream CIDER has had macroexpansion support practically forever - C-c C-m expands the form before point into a dedicated buffer, a feature we inherited spiritually from SLIME. It works, but it has always felt a bit… detached. The expansion lives in another buffer, divorced from the code you’re reading, and for deeply nested macros you end up bouncing between buffers trying to keep your bearings. Emacs Lisp hackers have long had something nicer: macrostep, a brilliant little package that expands macros in place - right where they sit in your code - one step at a time, and collapses them back when you’re done. I’ve wanted a Clojure version of this for years. CIDER 2.0 finally ships one. Standing on shoulders, not on top of them I’m hardly the first person to want…