Message-Id: <4.3.2.20000707184050.00b85de0@mail.bayarea.net>
Date: Sat, 08 Jul 2000 03:19:59 +0100
To: drums@cs.utk.edu
From: Dave Crocker <dcrocker@brandenburg.com>
Subject: ABNF sets and sequences
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Folks,

Some issues just won't go away.

The fact that some parameter lists are ordered and others are not is 
problematic for ABNF-based specifications.  We end up relying on obscure 
text in the prose and/or on community memory.

We hassled this within Drums quite a bit but I want to raise it again.

Simply put, the goal is to permit "concatenation" -- ie, lists -- to be 
labeled as unordered sets or ordered sequences.  The default would be 
ordered, as it is now.  The modification to ABNF would be from:

         group          =  "(" *c-wsp alternation *c-wsp ")"

         option         =  "[" *c-wsp alternation *c-wsp "]"

to:

         group          =  order "(" *c-wsp alternation *c-wsp ")"

         option         =  order "[" *c-wsp alternation *c-wsp "]"

         order           = "SET" / "SEQ"
				; unordered vs. ordered, default SEQ

It would be interpreted somewhat like <repeat> construct, in that it only 
affects the specification rule it is defined in.

OK?

Start shooting...

d/


         group          =  "(" *c-wsp alternation *c-wsp ")"

         option         =  "[" *c-wsp alternation *c-wsp "]"

=-=-=-=-=
Dave Crocker  <dcrocker@brandenburg.com>
Brandenburg Consulting  <www.brandenburg.com>
Tel: +1.408.246.8253,  Fax: +1.408.273.6464
675 Spruce Drive,  Sunnyvale, CA 94086 USA