> not evolving one bit for the next 6 years [...] would be grounds for moving to a different language
I'd never heard of Guile until you mentioned it. I looks like Scheme. If moving to a lisp-like language, Clojure, which you mention, would be a better choice. It's backers claim they'll be there for the long-term, and it has innovative concurrency constructs.
As for Groovy, it appears to be dying. Oracle went to a lot of trouble to create Nashorn, a zippy Javascript bundled with Java 8, and you can bet they'll be promoting it heavily in the "scripting Java" space to dislodge Groovy. Grails is losing adoption bigtime, getting replaced by Node.js, Play!, Django, and even Rails. When Gradle upgrades to version 2, they'll likely bundle some other JVM languages for their API, e.g. Nashorn.
I'd never heard of Guile until you mentioned it. I looks like Scheme. If moving to a lisp-like language, Clojure, which you mention, would be a better choice. It's backers claim they'll be there for the long-term, and it has innovative concurrency constructs.
As for Groovy, it appears to be dying. Oracle went to a lot of trouble to create Nashorn, a zippy Javascript bundled with Java 8, and you can bet they'll be promoting it heavily in the "scripting Java" space to dislodge Groovy. Grails is losing adoption bigtime, getting replaced by Node.js, Play!, Django, and even Rails. When Gradle upgrades to version 2, they'll likely bundle some other JVM languages for their API, e.g. Nashorn.