ietf-nntp newsgroup production

Charles Lindsey chl at clw.cs.man.ac.uk
Thu Jul 27 02:17:18 PDT 2000


In <Pine.LNX.3.93.1000726124639.1130C-100000 at one.softml.net> Chin Chee-Kai <cheekai at SoftML.net> writes:

>          13.  Augmented BNF[9] Syntax for NNTP Commands

>          [..........]
>+         The conventions as defined in RFC822 are used.  In addition, the
>+         notation "\", when used in the production rules, denotes exclusion.

No, I son't think you want to invent a special notation just so you can
use it in one situation.

>+           argument = parameter ; excluding sequence ".."
>+           ;;; original production ::  augument = parameter ; excluding sequence ".."

But since 'argument' is not used elsewhere in the syntax, why not leave it
out?

>+           newsgroup = newsgroup-segment *(DOT newsgroup-segment)
>+           newsgroup-segment = parameter \ DOT
>+           DOT = %x2E
>+                   ;;; parameter excluding DOT
>+           ;;; original production ::  newsgroup = parameter
>+           ;;;         which allowed newsgroups like "...."
>+           ;;;         because DOT was a parameter

The USEFOR syntax is:

newsgroup-name  = component *( "." component )
component       = component-start
             *( component-start / component-other )
component-start = Un-lowercase / Un-digit
Un-lowercase    = <Unicode Letter, Lowercase> /
          <Unicode Letter, Other>
Un-digit        = <Unicode Number, Decimal Digit> /
          <Unicode Number, Other>
component-other = "+" / "-" / "_"

The complication arises because of the UTF-8 and a desire to exclude
upparcase letters. I do not think we need quite so much complication in
this document, so I would suggest:

newsgroup	= component *( "." component )
component 	= <a sequence composed of letters, digits,
		  "+", "-" and "_">

Note that the <...> notation is fully compliant with RFC 2234, and could
have been used for the "exlusion" in 'argument'.

-- 
Charles H. Lindsey ---------At Home, doing my own thing------------------------
Email:     chl at clw.cs.man.ac.uk  Web:   http://www.cs.man.ac.uk/~chl
Voice/Fax: +44 161 437 4506      Snail: 5 Clerewood Ave, CHEADLE, SK8 3JU, U.K.
PGP: 2C15F1A9     Fingerprint: 73 6D C2 51 93 A0 01 E7  65 E8 64 7E 14 A4 AB A5



More information about the ietf-nntp mailing list