On Apr 26, 2017, at 19:12, Adam Roach <adam@xxxxxxxxxxx> wrote:
>
> This has the reciprocal problem that using quotes with (e.g.) sz and hreflang is a violation of the ABNF in RFC6690.
Yes. Using ABNF for the serialization of an item that should be described at the data model level (as in 5988bis) is now generally considered a mistake. To stay compatible with the letter of RFC 6690 (which probably continues to be a good idea), the reference implementation in Appendix A of links-json uses the quote-less form whenever the value is a ptoken, i.e. a sequence of one or more ptokenchar characters(*). Should we require this, and if yes, should this be a SHOULD or a MUST?
Grüße, Carsten
(*)
ptoken = 1*ptokenchar
ptokenchar = "!" / "#" / "$" / "%" / "&" / "'" / "("
/ ")" / "*" / "+" / "-" / "." / "/" / DIGIT
/ ":" / "<" / "=" / ">" / "?" / "@" / ALPHA
/ "[" / "]" / "^" / "_" / "`" / "{" / "|"
/ "}" / "~"