Andrew Dunstan <andrew@dunslane.net> writes:
> Regarding your other suggestion, the whole point I have been making is
> that if external modules can invent arbitrary nodes then we can't
> publish an XSD (or RelaxNG or DTD) spec that is worth anything at all.
Well, sure we can. But if you're using any external FDW, you'll need to
consult its documentation to see what additions it makes.
It may be sufficient to say something like "ForeignScan can have
unspecified additional children". Dunno if we can formalize that
in any useful way ...
regards, tom lane