Subject: IPP> ABNF near finished? [problem with - for range?]

From: Tom Hastings <[email-masked]>
Date: Thu, 17 Apr 1997 10:54:40 PDT

Chris,

I haven't had a chance to study your ABNF documents, so this may be
an inappropriate comment.

Will the decision to use "-" for ranges, instead of "..", have problems where 
"-" is one of the characters used in tokens to give nice readable attribute 
names and value names, such as in ASN.1, and IPP?  Having to resort to using
"_" (underscore) as a separator between words in attribute names 
and attribute value names or having to quote attribute names and value 
names that contain "-" would be a big step backward.

I don't know whether ":" could be used for a range or not?

Thanks for your consideration that "-" (hyphen) be used in tokens
and not for ranges.

I happen to like the ".." for range.  I wonder if there is someway
to preserve that usage for ranges and fix you ambiguity problem some
other way?

Tom

>Return-Path: <[email-masked]>
>X-Sender: [email-masked]
>Date: Wed, 16 Apr 1997 23:50:47 PDT
>To: [email-masked]
>From: Carl-Uno Manros <[email-masked]>
>Subject: IPP> ABNF near finished?
>Sender: [email-masked]
>
>Here are suggested fixes to the current ABNF draft.
>
>Carl-Uno
>
>>Date: Mon, 14 Apr 1997 16:46:30 -0700 (PDT)
>>From: Chris Newman <[email-masked]>
>>Subject: ABNF near finished?
>>To: Detailed Revision/Update of Message Standards <[email-masked]>
>>
>>At the IETF meeting, we spent a fair amount of time discussing some
>>possible problems with ABNF.  The conclusions were as follows (using my
>>own interpretations):
>>
>>(1) It's too hard to get the set notation {} both clear and useful, so
>>we'll punt.
>>
>>(2) Range notation needs to be simplified to avoid confusions like
>>"a".."Z", which is ambiguous since each end is case-insensitive.  Also
>>decided to use "-" instead of "..".
>>
>>(3) The "#" notation is used incompatibly in many specs (e.g. 822 & 2060).
>>Decided to drop it from notation since it's usually #thing or 1#thing both
>>of which are fairly simple to write without that notation.  In addition,
>>current definition implies linear-white-space which is troublesome.
>>
>>(4) Case-sensitive strings can be written with literals, and shouldn't be
>>used often anyway.  No special notation needed.
>>
>>Given these decisions it appears the ABNF document has no remaining
>>substantive open issues.  If you think this is wrong, please speak up now.
>>
>>[As an implementation test, I updated my working copy of the ACAP
>> specification to use the new ABNF plus these decisions.  Removing "#"
>> wasn't bad, and the literal numbers + ranges allowed me to get rid of
>> all <description> rules.]
>>
>>
>>
>>
>
>
>

---

From: Chris Newman <[email-masked]>
Date: Thu, 17 Apr 1997 11:46:20 -0700 (PDT)

> names that contain "-" would be a big step backward.

I will note that ABNF now only permits the range notation in literals
(e.g. %x80-FF) so "-" is still valid in rule names (e.g. foo-bar).  On the
other hand, having "-" used both as part of rule names and as ranges is a
likely source of confusion.  That issue was not raised in the discussion
at the WG IETF meeting.

> to preserve that usage for ranges and fix you ambiguity problem some

There were not many strong feelings between "-" and ".." at the IETF
meeting.  Basically, "-" was slightly favored in discussion, although the
issue you raise was not mentioned and could easily swing the rough
concensus.

You need to post your concerns to the DRUMS mailing list (subscribe at
<[email-masked]>, post at <[email-masked]>) and defend your
preference for .. over - on the mailing list.