Re: #1132: Allowing IP addresses as path-identiites - Poll result

[Frank Ellermann <nobody@xxxxxxxxxxxxxxxxx>]

Charles Lindsey wrote:

>    path-identity = dot-atom-text / bareword

Hi, you can't say <dot-atom-text> here, it contains some
characters we don't like (delimiters for 1036 incl. "!"):

ATEXT: ALNUM ! # $ % & ' * + - / = ? ^ _ ` { | } ~
LDH  : ALNUM                           _

Let's stick to some kind of <ldh-string>.

>    bareword = ALPHA *( [ "-" / "_" ] (ALPHA / DIGIT) )

Yes.  For a "bare" version of <ldh-string> you'd get...

     ldh-fqdn = ALPHA *( [ "-" / "." ] (ALPHA / DIGIT) )

...or similar.  And for an unambiguous bareword without
underscore you'd need the "at least one dot" kludge, i.e.

 path-identity = ( 1*( label "." ) label ) / bareword
 label         = alphanum [ *( alphanum / "-" ) alphanum ]
 alphanum      = ALPHA / DIGIT

There are several cases of ALPHA / DIGIT in USEFOR, so the
additional <alphanum> is justified.

With that version of <label> there's still an unnecessary
ambiguity with <IPv4address>, it can be solved by <toplabel>:

 path-identity = ( 1*( label "." ) toplabel ) / bareword
 label         = alphanum [ *( alphanum / "-" ) alphanum ]
 toplabel      = ALPHA    [ *( alphanum / "-" ) alphanum ]
 alphanum      = ALPHA / DIGIT

IIRC we already had this part of the syntax before in the
discussions.


>    tail-entry = dot-atom-text / bareword

No <dot-atom-text>, just say tail-entry = path-identity

>    source-identity = dot-atom-text / IP-address / bareword

Dito, source-identity = path-identity / IP-address

Actually I don't see the point of bareword here, is that for
POSTED and MISMATCH in this variant ?  You could enumerate it:

     source-identity = ( 1*( label "." ) toplabel )
                     / "MISMATCH" / "POSTED" / IP-address

>    IP-address = IPv4address / IPv6address ;  see [RFC 3986]

Okay.  The latter has always a colon, so that's unambiguous
(add usual dead:beef rant here).  The former has always three
dots and digits, but never an ALPHA => no <toplabel>, no FQDN.


> [2nd version of syntax, making <source-identity>s readily
> distinguishable from <path-identity>s.]
[...]

>    path-identity = dot-atom-text / bareword

See above, better use <label> - in this variant an IPv4 is
always unambiguous, you don't need the <toplabel> detail.

>    tail-entry = dot-atom-text / bareword

See above, tail-entry = path-identity or, as you have it,
just the same syntax, but not the <dot-atom-text> version.

>    path-source = source-identity ( ".SEEN" / ".MATCH" /
>                                    ".MISMATCH" )

>    source-identity = dot-atom-text / IP-address / bareword

Something's wrong here, your syntax aparently allows...

     path-identity!path-identity!POSTED!path-source!
     path-identity!path-identity path-source!
     path-identity!path-identity

The third case is wrong, you want an "!" at the end, always.
The second case is also wrong, missing "!" before the source.

>  Two "!"s in succession are equivelent to
> "!site.example.MATCH!"

Okay, here's the fixed (?) version:

     path-entry = 1*( path-identity "!" )
                  [ "POSTED!" ] [[ path-source ] "!" ]

Skipping the prose, please could somebody else check this ?

                           Bye, Frank