Carplay: is it hardware, software, or both?
Sorry if this is posted in the wrong forum section… since it's not out yet I wasn't sure wether I should put it under Mac Software or Hardware 
The thing is, I'm looking for an after-market double din radio, and was leaning towards a Parrot Asteroid Smart. I'd primarily use it for AD2P (and USB) bluetooth audio streaming, calling and Waze.
But ever since Carplay has been announced, and Alpine mentioned it's going to make an after market solution that will fit ány car (with a double din slot anyway), I've been wondering… what is Carplay anyway? Alpine announced that it's going to release an "after market solution" before the end of the year for example, but do I see Carplay as a double din radio, a "module" of some sort to be implemented behind the existing radio, or just software?
Because I currently have a single din radio in my car with a very strong desire to get rid of this 14 year old radio to replace it with a nice double din one (I like gadgets, what can I say), I'm really hoping that Apple will basically make a "Parrot Asteroid Smart" type double din with their own software.
Also, if you don't bring your own iOS device, how will Carplay function? It's also something I haven't found anything about yet. Can we only speculate on the details so far, or did I completely miss the memo on the details?
Thanks!