The last time I checked, it was bootstrapped in OCaml. When I met Graydon several years ago (brilliant dude, PS), he was quite intrigued by OCaml, and strongly recommended I check it out. If ML had any influence at all, it uses variant types instead. About time more languages use them!

Rather than, "oh crap! every single variable could potentially be null at any time!", the few functions that can be null make you check for None / Some 'a, and that's it, no tedious null checks ever again. "Null pointers simplify a lot of error-checking.", my ass.