Fwiw, this is less and a less a problem with static languages. In the Scala ecosystem, for example, on-the-fly compilation is available with Play, or any framework that uses SBT [1] (Lift, Scalatra, etc). Edit, save, and your edits (and only your edits) are automatically recompiled and reloaded.

> more boilerplate

Not sure about that. Lift at least (maybe Play too, not sure) is about the same lines of code as Rails, less if you include tests.

1. github.com/harrah/xsbt