Of non-Smalltalk languages, the only one I can think of with anything like that is Erlang. You could easily enough build a code server in Ruby, but you'd have to explicitly include the library that implements it in your project, and start up a server thread to expose it to an IDE that wanted to talk to it, etc. And because of that, it wouldn't be "part of the language" to the point where tooling (like IDEs) would be built to expect it.
The real problem, though, is that people are coding in dynamic languages with no live image connected to the editing session at all: instead, the code is just dead text until they want to test it, at which point it gets injected into a fresh session, run once, and then the session is immediately discarded (creating what is possibly a completely different path-dependent monkey-patch execution sequence than would happen in production, or in a REPL, or...).
For some languages this happens out of necessity, but for most, it's just an artifact of the batch-processing mentality. All e.g. Light Table gives you, when you think about it, is a text editor with a connection to a live Clojure or Python image; and yet to many it seems to be a completely foreign interaction paradigm for programming.
