1) Unlike YAML or JSON this doesn't parse into a simple array structure, but a library dependent object hierarchy?
2) Is the API of the libraries also part of the language spec?
3) Can I assume that document.lookup() will be available as document->lookup() in the PHP library?
4) What about programming language specifics that may differ between languages? Will the PHP objects implement the Iterable interface? Or the ArrayAccess interface? (There are probably similar but slightly different concepts in other languages).
5) There is eno.parse(), but is there some kind of reverse mechanism to create a new Eno document? Like document.addList([...]).addSection('hey', 2) or something.