[Cosi1125]

Good point. I'd add complex numbers and "everything is a vector" to that.

Of course that doesn't make it a DSL. It simply means that R was designed with a particular application in mind. So was Perl (regular expressions as first-class citizens) or Javascript (DOM manipulation). Not to mention PHP.

[nequo]

That is true. Also Erlang with the actor model, and Go with its goroutines for network services.

[SomeoneFromCA]

This is why I said "de facto", not "by design". Yes, you can use it outside stats domain, but it will suck big time for that. PHP used to be like that as well, but later versions look more usable for general scripting.