Re: #1047 Path-identity: A proposal (perhaps)

[Frank Ellermann <nobody@xxxxxxxxxxxxxxxxx>]

Bruce Lilly wrote:

> That still permits foo!!tail-entry, foo!MISMATCH!tail-entry

Yes, and I wasn't consequent with the [FWS], next attempt:

 path-list      = [FWS] path-identity [FWS]
                  *( path-delimiter [FWS] path-identity [FWS] )
                  ( "!" [ "POSTED!" ] ) [FWS] tail-entry [FWS]

 path-delimiter = "!" [[ "MISMATCH" / "POSTED" ] "!" ]

That's a bit convoluted, maybe a simple list of delimiters is
better, see above: 
                  ( "!" / "!POSTED!" ) [FWS] tail-entry [FWS]

 path-delimiter = "!" / "!!" / "!MISMATCH!" / "!POSTED!"

> doesn't address (no pun intended) where IP address literals
> are or are not allowed.

It was based on Charles' revised syntax for a <path-identity>:

| path-identity = ( ALPHA / DIGIT )
|                 *( ALPHA / DIGIT / "-" / "." / "_" ) /
|                 IPv4address / IPv6address    ; see [RFC 3986]

> I made some quick notes this morning:
> path-identity "!POSTED" needs to be a group

Okay, path-identity "!POSTED!" tail-entry catches the normal
case, path-identity "!POSTED!" path-list is for reinjection.

> path-identity "!!" path-identity needs to be a group

Also okay, I have path-identity "!!" path-list, and no way to
combine it with a tail-entry.

> "MISMATCH!" path-identity needs to be a group

Dito as path-identity "!MISMATCH!" path-list, not with a tail.

> That text (and the draft ABNF) implies that
>   Path: MISMATCH!example.net!tail-entry
> is a valid complete field, which might not be what is
> intended; the text doesn't say that there needs to be
> anything to the left of MISMATCH.

Then it was wrong, "!MISMATCH!" is the same idea as "!!", only
for a mismatch.  In my hardcore nitpicking mode it should be:

path-identity "!" path-identity "!MISMATCH!" path-list

a!b!MISMATHCH!c!...!not-for-mail as in "I got this starting
with c!... but I think it should be b, anyway I am a, enjoy".

Or should this be a!!b!MISMATCH!c!...!not-for-mail (?)  Bye.