[NNTP] LIST EXTENSIONS (again)

[Clive D.W. Feather]

Okay, let me have another go, this time assuming that we only want a
minimal version indication for LIST EXTENSIONS. Here's a proposal:

(0) Adopt the "restrict characters in command names and extension labels
proposal".

(1) Make LIST EXTENSIONS mandatory.

(2) Require a version entry in the output from LIST EXTENSIONS. However,
rather than "NNTPv2", I would suggest:

    _RFC_ 3977

(this assumes that _ is not a permitted character); 3977 is the number of
the final RFC for NNTP. [This approach has been used successfully in other
standards, and allows more flexibility than just an arbitrary string.]

(3) A conforming server MUST NOT advertise any extension label, other
than one beginning with X, not in the IANA registry.

(4) Any specification in extensions should be phrased along the lines of:

    This specification requires that the server conform to [NNTP],
    indicated by "_RFC_ 3977" or some higher number in the output from
    LIST EXTENSIONS.

or:

    If the server conforms to [NNTP], indicated by "_RFC_ 3977" or some
    higher number in the output from LIST EXTENSIONS, then ....
    Otherwise ....

(5) I'd *like* to see this entry also used to indicate at least some
of the optional things that are in the core protocol. For example:

    _RFC_ 3977 MODE_READER         indicates MODE READER is significant

    _RFC_ 3977 LIST_OPTIONAL       indicates all four optional LIST
                                   commands (excludes OVERVIEW.FMT) are
                                   supported

[Actually, those are the only two significant options I can think of.] But
don't let this derail the previous points.

-- 
Clive D.W. Feather  | Work:  <clive at demon.net>   | Tel:    +44 20 8495 6138
Internet Expert     | Home:  <clive at davros.org>  | Fax:    +44 870 051 9937
Demon Internet      | WWW: http://www.davros.org | Mobile: +44 7973 377646
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