Yes, it's possible with inf-ruby-mode in Emacs; C-x C-e at the end of a definition works the way it does for Clojure, though the actual REPL implementation in E

Yes, it's possible with inf-ruby-mode in Emacs; C-x C-e at the end of a definition works the way it does for Clojure, though the actual REPL implementation in Emacs never feels seamless the way CIDER does (i.e. it generally requires fiddling around with various config settings whereas CIDER basically Just Works™; it feels more like GUD than a proper REPL).