I find this article to be excellent description of what makes a great REPL and what makes REPL development powerful. Coding in Clojure with Emacs CIDER - with

I find this article to be excellent description of what makes a great REPL and what makes REPL development powerful. Coding in Clojure with Emacs CIDER - with it's integrated code editor and REPL - is the most fun I've ever had with programming. The immediate feedback, the incremental building up of functionality, the ability to interactively evaluate nested expressions at any depth - it all feels very fluid and natural and immediate once you learn a few keyboard shortcuts. Seriously, it was what finally got my programming mojo back after going stale from decades of C++ & Java. In my search for "something better" I also had good experiences with Ruby, Python, and Groovy and I also used their REPLs occasionally, but those REPLs never became central to the coding experience as it is with Clojure. (maybe I was missing out)