[jzwinck]

You mention that R doesn't deserve the bad rap it had 5 years ago. Less than two years ago I learned the hard way that R reference counting had only three possible counter values. 0, 1, and 2+. So if you took a second reference to something then deleted it, that object's reference count would stay at 2+ forever. Then if you modified it, Copy On Write would kick in, even though there was only one reference living. This was the source of crippling inefficiency in production code. I asked about it back then and the reply was yeah, R does that, hopefully it won't soon. Broken Copy On Write was not acceptable to me in 2014.