Subject: [Ltru] Re: Reference lists; AND ABNF GRAMMARS

From: "Doug Ewell" <[email-masked]>
Date: Thu, 21 Jul 2005 07:35:28 -0700

Kent Karlsson <kentk at cs dot chalmers dot se> wrote

> You mean it should be (putting this restriction in the grammar):
>
> %% For -registry
> extlang         = (2*3ALPHA
>                    1*3("-" 3ALPHA)   ; reserved for future use
>
> %% for -matching
> extlang         = (2*3ALPHA
>                    *2("-" 3ALPHA)
>                    ("-"(3ALPHA / "*")))
>                                      ; reserved for future use
>
> (or with some non-terminal for 2*3ALPHA and maybe also for 3ALPHA)

That's still not right; it combines the concept of a primary language
subtag and an extended language subtag under one ABNF umbrella.

How about we try it first in prose, and then try to convert that into
ABNF:

A primary language subtag can be 2 to 8 alphas long, although the
4-letter ones are reserved for the (comparatively distant) future.
There must be exactly one primary language subtag, unless you have a
wholly private-use tag of the form "x-whatever", in which case the rest
of this message doesn't pertain.

An extended language subtag must be exactly 3 letters long.  There may
be anywhere from 0 to 3 of these.  This whole mechanism is reserved for
the (comparatively near) future.

An "extlang" does not comprise a primary language subtag plus a string
of 3-letter thingies.  Those 3-letter thingies *are* the extlangs
(extended language subtags).  The fact that an extended language subtag
can only appear after a primary language subtag is nothing special; the
primary language subtag is required for all types of regularly formed
RFC 3066bis language tags (non-grandfathered, non-private-use).

--
Doug Ewell
Fullerton, California
http://users.adelphia.net/~dewell/

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---

From: "Doug Ewell" <[email-masked]>
Date: Thu, 21 Jul 2005 07:42:00 -0700

Addison Phillips <addison dot phillips at quest dot com> wrote:

> 1. 2*4ALPHA / 4*8ALPHA isn't really wrong, but the repetition of the
> number 4 is confusing. It should be 2*4ALPHA/5*8ALPHA. (I'm aware that
> the original draft-09 grammar has this mistake in it: it is on my
> correction list for the next edit)

Actually, I think 2*4ALPHA / 4*8ALPHA really is wrong, not just a matter
of confusion.  If 4-letter primary language subtags are supposed to be
reserved for some future standard, then it shouldn't also be possible to
register them.  Otherwise we are setting ourselves up to register a
4-letter subtag that later turns out to belong to the standard as well,
and Chaos Shall Reign.

I've been going by the assumption all this time that registered primary
language subtags were 5 to 8 letters long, and was surprised to see that
the ABNF states otherwise.

---

From: "Mark Davis" <[email-masked]>
Date: Thu, 21 Jul 2005 08:10:58 -0700

ABNF is tricky, and it is not trivial to 'pretty it up' while maintaining
precisely the same meaning. At this stage, we should only be focusing on
substantive issues, not whether the ABNF is pretty or not.

So if the current ABNF has a substantive flaw, we should fix it. Otherwise
leave it alone.

‎Mark

---

From: Martin Duerst <[email-masked]>
Date: Fri, 22 Jul 2005 09:46:28 +0900

[chair hat on]

 >substantive issues, not whether the ABNF is pretty or not.

The last call isn't restricted to major issues. Both major and cosmetic
issues can and should be brought up, and if appropriate, addressed during
last call. So if there is a way to make the ABNF easier to understand
(while making sure that it's still describing the same syntax), then we
(of course with WG (rough) consensus only) should do it.

This of course applies to other parts of the spec. In many WGs I have
seen (maybe not in this one), WG Last Call is on purpose used to clean
up loose editorial ends and work on cosmetics.

Regards,    Martin.

p.s.: [chair hat off] I'll try to have a look at the new ABNF from Kent,
       but that may take a few days, sorry.