> I am looking for a replacement programming language to solve small problems for which Python/Ruby would have traditionally been used, good file system, stream

> I am looking for a replacement programming language to solve small problems for which Python/Ruby would have traditionally been used, good file system, stream and networking APIs, but concurrency as a first class citizen, garbage collected, fast startup time. You may want to have a look at ClojureScript, which has come a long way in the last few years. While the tooling is still not as nice as Clojure-on-the-JVM in my opinion, it continues to get better everyday--this week support for a better REPL via NodeJS[1] was introduced, for instance. A lot of smart people are putting good effort into the compiler and ecosystem and I suspect we'll see a continued uptrend in cljs adoption. Anyway, it may be just what you want: an elegant, productive, pragmatic language with first-class support for concurrency (atoms, core.async) and well-suited to short-lived and scripting-domain problems. (Bonus you can write your frontend and backend in the same language if you want!) [1] http://swannodette.github.io/2014/12/29/nodejs-of-my-dreams/ http://swannodette.github.io/2014/12/29/nodejs-of-my-dreams/