[zmmmmm]

> Functional languages have been around for years and have never owned more than a niche market due to their complexity

I think the problem is that writing in a functional way almost requires a purist approach, so the only way in is to completely buy into the "dogma" of it. That makes adoption hard to impossible.

Groovy is almost completely the opposite - every practical whim is catered for, almost to a fault - there's all kinds of crazy stuff shoved into it. But boy is it easy to adopt. It's a quite stunning achievement how much is in Groovy and yet still - it remains almost source compatible with Java.