Ruby, the language, hasn't changed that much from 1.8.x to 1.9.x.
Bullshit. It's changed immensely. Ruby 1.9 has fibers now, there are native threads, there is unicode in fast C, no longer in Ruby. There are actually so many new features in 1.9 people are pissed that it's not named 2.0.
Well I count three majour features:
1) Performance 2) Threads/Fiber 3) Encoding/Unicode
and I can get all of those if I use the JRuby interpreter which is compatible with Ruby 1.8.6. There are, obviously, a few language improvements, but nothing I would consider major changes. The features above are things I think should be there right from the start. Java had them there right from the beginning.
I've been playing with all sorts of new 1.9 features the past few weeks. Sadly one of them is not a working MySQL gem, but it'll catch up at some point I'm sure.
In other words: it isn't mature enough, because there are still a lot of gems that don't work with it.
Do you follow Linux Kernel development at all? It's a cardinal sin to even attempt to change a userland API. Behind the API things evolve immensely, but the API itself, that we as developers build software against, never, ever changes. But then on the rare occasion that it does change, you can bet your ass the version number will move by a lot more than .1.
Well, I wouldn't really compare a kernel with a framework like Rails. The way I see it: the rails framework is in itself a piece of software being developed in an agile fashion, and as we know all softwares developed that way do change, and there are some things that will be removed because they don't actually make sense.. Up until now, the Rails development team have been delivering versions which are quite stable and mature enough for you to develop a stable piece of software.
When the Rails API begins to remain unchanged for even a few releases in a row, maybe then you can start calling it things like "mature".
Well, your concept of "mature" is quite different from mine. I think the versions delivered are quite mature. The API, on the other hand, may not be as mature, but we should expect some maturity with the merge with Merb.
Fidel.