To be honest with you, no, we didn't seriously consider it. Maybe we should have. I do not know if ClojureScript would be able to work with all the dependencies we have (for example, Hadoop client library to talk to HDFS). But it's a good point nevertheless. I'll mention it in https://github.com/Factual/drake/issues/1.
I didn't realise originally that Drake integrated with HDFS. Thats a really awesome feature, and I can see why the JVM made sense in development because of existing HDFS libraries.
Thanks for the response! I ask because I have an idea for a CLI program, and I want to write it in Clojure, but I'm worried about the startup time of the JVM. As I understand it, this issue is mitigated in Drake by the fact that a typical job will crunch lots of data and therefore take lots of time. That's not the case for my program, it needs to be quick.
Yes, startup times are a pain. As of this morning, Drake now works with Drip, which is a nifty tool to bring down start up times. It spins "backup" JVMs, so next time you run the command, JVM is ready. It works great for interactive environments where at least several seconds pass between runs, but won't do much if you need to run Drake several times per second from an automated script.
Another option is Nailgun, but it has its limitations, too.
None if this is ideal. If you want to write a very simple CLI program, keep this in mind. You may want to stay away from JVM.