Has Harper actually done any real programming of significance? I am an "industry programmer" who has a pretty strong theoretical bent (have a math degree rather than CS, have read most of Harper's papers on the type theory and semantics of module systems), but when I read his blog posts I get the feeling that when it comes to programming he doesn't really know what's up.
I dunno, I just TA for the guy. I suspect it depends on what you mean by "real programming of significance". I can tell you that Harper is really damn smart. I'd be truly surprised if he was bad at programming. But his actual experience, I don't know. He hasn't written any code for the course itself, but that's not really his role.
