Ummmm yes & no. It has a REPL, but it sure isn't easy to use and very few C# coders actually use it. Contrast that with a dynamic language like Python where people basically live in the REPL. Common Lisp takes this to a whole new level. You really can't equate C#'s REPL to Common Lisp's. This is one of those things where the sum of the thing is greater than its parts. Note that I'm not saying C# isn't a decent language, just very very different than what you get with languages like Smalltalk & Lisp.