Title: RE: [xri] Initial proposed XRI 1.1 ABNF and issues analysis
It
seems to me that if we drop xri-path-delim (absorb those characters back into
xri-sub-delim), and include xri-auth-delim in xri-gen-delim (and correct the
relevent productions), we solve Dave's first concern. Fixing the XRI
authority to support "@!" (as well as the rest of the GCS characters)
is actually really easy in a consistent way -- just add an optional
xri-auth-delims after the gcs-char in the XRI-authority production (see below
for the updated ABNF productions). Changing the production would allow for
"@*" as well. While we can probably consider this as the default meaning
of a single GCS character (such as "@"), I like the regularity of supporting it
explicity.
The
problem that I have with allowing the characters in xri-sub-delims both delimit
a sub-segment and to be part of a sub-segment (by being part of xri-pchar) is
that it creates an ambiguity as to what constitutes a sub-segment. For
example, is the local path in the following xri composed of 2 or 3
sub-segments?
xri://@corp/a;b;c
According to the ABNF (if xri-sub-delims are both used
in the xri-path-segment production and in the xri-pchar production), one could
consider the sub-segments to be (1) a, b, and c, (2) a;b and c, or (3) a and
b;c. I'd prefer to avoid introducing the ambiguity if at all
possible.
My
recommendation is to make the changes below and also exclude xri-sub-delims from
the xri-pchar production.
Mike
Updated Changes to
ABNF
---------------------------------------
xri-sub-delims = "&" / ":" / ";" / "," /
"'"
xri-auth-delims = "!" /
"*"
xri-gen-delims = "/" / "?" / "#" /
"[" / "]" / "@" / "(" /
"(" / ")" / "$" / "+" / "=" / xri-auth-delims
xri-auth-segment = auth-sub-segment *(
xri-auth-delims auth-sub-segment )
xri-path-segment =
path-sub-segment *( xri-sub-delims path-sub-segment
)
XRI-authority = ( gcs-char [xri-auth-delims] [
xri-auth-segment ] ) / xref-authority
relative-path =
xri-path-segment * ( "/" xri-path-segment ) [ "?" xri-query
]
[ "#" xri-fragment ]
xref-authority = xref *(
xri-auth-delims auth-sub-segment )
auth-sub-segment = (
1*xri-pchar / xref )
path-sub-segment = ( *xri-pchar / xref
)
xri-pchar =
xri-unreserved / pct-encoded / xri-sub-delims
-----Original Message-----
From: Drummond Reed
[mailto:]
Sent: Wednesday, August 18, 2004
4:20 PM
To: 'Dave McAlpin'; Lindelsee, Mike ;
Subject: RE: [xri] Initial proposed XRI 1.1
ABNF and issues analysis
Agreed. Then, Dave,
do you agree with Mike's suggestion of creating a new "delims" category for
xri-auth-delims?
I'm beginning to
wonder if the generalized treatment of subsegments in the proposed XRI 1.1
path is worth the trouble. Would it be simpler to just define * and ! as the
two sub-delimins and then let the other subdelims be part of the path? That
way they will be available for all producer-specific algorithms
anyway
Mike, do you think it
would be simpler to just have an "xri-path-delim" production for * and ! ? In
that case the XRI authority segment and the path segments could go back to
being the same.
Mike, one thing that
occurred to me this morning: we can't eliminate null subsegments in the XRI
authority segment without knocking out using ! after a GCS character (e.g.,
"@!1234"), as by the current BNF, ! is proceeded by a null subsegment. We'd
either have to otherwise change the BNF to support that (taking us back into
"decorator" land) or simply have tight resolution rules about null
subsegments.
=Drummond
From: Dave
McAlpin [mailto:]
Sent: Wednesday, August 18, 2004 2:51 PM
To: Lindelsee, Mike ;
Subject: RE: [xri] Initial proposed XRI
1.1 ABNF and issues analysis
Unless there's a compelling reason to do otherwise,
I'd suggest that we move "*" and "!" back to
xri-gen-delims.
Dave
-----Original Message-----
From:
Lindelsee, Mike [mailto:]
Sent: Wed
8/18/2004 1:13 PM
To:
Subject: RE: [xri]
Initial proposed XRI 1.1 ABNF and issues analysis
Do you think that we
should place "*" and "!" in gen-delims then? Or are my proposed changes
ok as they stand?
Mike
-----Original Message-----
From: Dave
McAlpin [mailto:]
Sent:
Wednesday, August 18, 2004 12:58 AM
To: Lindelsee, Mike ;
Subject: RE: [xri] Initial proposed XRI 1.1 ABNF
and issues analysis
I intentionally included xri-sub-delims in
xri-pchar, and this was correct in the original ABNF. Since then, someone
moved sub-segment delimiters from xri-gen-delims to xri-sub-delims. I think
this is just a misunderstanding of what I intended for xri-sub-delims. The
idea (borrowed from 2396bis), is that xri-gen-delims are delimiters for which
we define semantics and are reserved for the purpose defined in the spec. In
contrast, xri-sub-delims are reserved as delimiters with no defined semantics,
intended for processor specific
algorithms.
Dave
-----Original Message-----
From:
Lindelsee, Mike [ mailto:]
Sent: Tue
8/17/2004 4:23 PM
To:
Subject: [xri] Initial
proposed XRI 1.1 ABNF and issues analysis
I've taken a look at the
proposed ABNF and would like to recommend a couple of changes. First, I
think we should be relatively strict in the authority part and restrict the
segment delimiters to only those that are valid delimiters. My concern
is that showing other delimeters in the authority part will imply to people
reading the ABNF that those delimiters might have some sort of meaning.
The second change is to remove the support for null segments in the authority
part. While there is an XDI use for null segments in the path part, it
doesn't seem to be needed in the authority part. And not allowing null
segments in the authority part helps to keep resolution as simple as
possible.
I also noticed what might be a bug -- the inclusion of
xri-sub-delims in the xri-pchar production. This allows segment
delimiters to be embedded within segments. I don't think that this makes
sense (Dave, please correct me if I'm wrong on
this).
Mike
Proposed changes to the updated XRI
ABNF
----------------------------------------
(change)
xri-sub-delims = xri-auth-delims /
xri-path-delims
(add)
xri-auth-delims = "!" /
"*"
(add)
xri-path-delims = "&" / ":" / ";" / "," /
"'"
(remove)
xri-segment
= sub-segment *( xri-sub-delims sub-segment
)
(add)
xri-auth-segment =
auth-sub-segment *( xri-auth-delims auth-sub-segment
)
(add)
xri-path-segment =
path-sub-segment *( xri-sub-delims path-sub-segment
)
(change)
XRI-authority = ( gcs-char [ xri-auth-segment ] ) /
xref-authority
(change)
relative-path = xri-path-segment * ( "/" xri-path-segment )
[ "?" xri-query
]
[ "#" xri-fragment ]
(change)
xref-authority = xref *( xri-auth-delims auth-sub-segment
)
(remove)
sub-segment
= ( *xri-pchar / xref
)
(add)
auth-sub-segment = (
1*xri-pchar / xref
)
(add)
path-sub-segment = ( *xri-pchar / xref
)
(change-bug)xri-pchar
= xri-unreserved /
pct-encoded
To unsubscribe from
this mailing list (and be removed from the roster of the OASIS TC), go to http://www.oasis-open.org/apps/org/workgroup/xri/members/leave_workgroup.php.
