Re: Jabber-ID header field

Graham Klyne wrote:

> why allow the obsolete folding-whitespace (obs-FWS)?

It's more like "inherited" than "allow", it's what you
get if you remove the "F" from ... [FWS] CRLF

Clearly nobody should fold trailing white-space before
the CRLF, that's a MUST NOT in 2822.  The FWS-syntax is:

| FWS =  ([*WSP CRLF] 1*WSP) /   ; Folding white space
|        obs-FWS

With that you inherit obs-FWS (MUST NOT generate etc.)
as soon as you say FWS.  If you then remove the bogus 
folding from ... [FWS] CRLF the rest is the same as
... [ 1*WSP / obs-FWS ] CRLF   

Where "obs" stands for MUST accept + MUST NOT generate.

Getting rid of it would work best in a future 2822bis,
until then obsolete gateways could try strange foldings.

For another attempt to nail this oddity see
<http://permalink.gmane.org/gmane.ietf.rfc.interest/110>

Frank