> Lastly, because S-expressions can represent everything that is representable in SGML/XML/(X)HTML, but more succinctly, we could have basically had Scheme inst

> Lastly, because S-expressions can represent everything that is representable in SGML/XML/(X)HTML, but more succinctly, we could have basically had Scheme instead of HTML. I suggest (along with David Moon (Lisp Machine)) that a key disadvantage of sexp with respect to *ML, is that there's no place to hang on "extra stuff". Many lisps allow you to decorate the nodes with properties once the nodes are read, but the properties lack a printed representation. It's a homoiconicity fail. Sort of like not allowing comments in JSON might be, if a common case was then to attach comments to the objects after they're loaded. That very isn't common, so the restrictiveness is worth it. It's not clear that's the case with sexp.