Subject: [Ltru] Errata in RFC 4646 and 4646bis

From: "Doug Ewell" <[email-masked]>
Date: Fri, 15 Dec 2006 22:20:13 -0800

In the process of double-checking my recollection that the Prefix field 
can contain only one tag value, and not a comma-separated series of them 
(see discussion on ietf-languages), I stumbled across an inconsistency 
in RFC 4646 that is perpetuated in the latest draft of RFC 4646bis.

Section 3.1 of 4646, third paragraph from the end (Section 3.1.7 of 
4646bis) says of the Prefix field:

"The field-body for this type of field MUST NOT be modified."

Section 3.4 of 4646 (and 4646bis), list item 4, says:

"Values in the field 'Prefix' in records of type 'variant' MAY be 
modified, so long as the modifications broaden the set of prefixes."

Obviously both of these cannot be correct.  This is actually fairly 
important since with the current interest in variants, it is a virtual 
certainty that someone will want to modify the Prefix field of a variant 
at some point.

On a much smaller editorial note, Section 2.2.9 (bullet point 2) of the 
latest draft, dealing with the new repeating-extensions issue, has the 
spelling "singletone."

--
Doug Ewell  *  Fullerton, California, USA  *  RFC 4645  *  UTN #14
http://users.adelphia.net/~dewell/
http://www1.ietf.org/html.charters/ltru-charter.html
http://www.alvestrand.no/mailman/listinfo/ietf-languages

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---

From: John Cowan <[email-masked]>
Date: Sat, 16 Dec 2006 02:18:20 -0500

> "The field-body for this type of field MUST NOT be modified."

In 4646 it actually says:

   The field of type 'Prefix' MUST NOT be removed from any record.  The
   field-value for this type of field MUST NOT be modified.

The term "The field" rather than "A field", plus the previous-but-one
paragraph, strongly suggests that this was intended to apply to records
of type extlang only.  4646bis-02 says:

   The field of type 'Prefix' MUST NOT be removed from any record. The
   field-body for this type of field MUST NOT be modified.

I think this should be reworded as "Fields of type 'Prefix'" etc.  In
that way, we can add prefixes to variant records, but can't remove
prefixes.  If we remove the second sentence, then item 4 in Section 3.4
comes into play, specifying that prefixes can be shortened but not
lengthened.

-- 
"But I am the real Strider, fortunately,"       John Cowan
he said, looking down at them with his face     [email-masked]
softened by a sudden smile.  "I am Aragorn son  http://www.ccil.org/~cowan
of Arathorn, and if by life or death I can
save you, I will."  --LotR Book I Chapter 10

---

From: "Doug Ewell" <[email-masked]>
Date: Fri, 15 Dec 2006 23:39:05 -0800

John Cowan <cowan at ccil dot org> wrote:

> prefixes.  If we remove the second sentence, then item 4 in Section 
> 3.4 comes into play, specifying that prefixes can be shortened but not 
> lengthened.

I predict that in the future, someone will demand that an "incorrect" or 
"inappropriate" Prefix for a variant subtag be removed.

---

From: Addison Phillips <[email-masked]>
Date: Sat, 16 Dec 2006 10:48:12 -0800

> "inappropriate" Prefix for a variant subtag be removed.

And that someone's request will be rejected.

Removing a prefix would break validating processors (those based on an 
older registry date). That's why the rule is there. Besides, a wrong 
prefix doesn't hurt anything: you are not required to use a variant with 
a particular prefix, given that it has more than one. If a variant has 
the wrong prefix, add the correct one, plus a note saying that the old 
prefix is ill-advised.

Addison

-- 
Addison Phillips
Globalization Architect -- Yahoo! Inc.

Internationalization is an architecture.
It is not a feature.

---

From: "Mark Davis" <[email-masked]>
Date: Sat, 16 Dec 2006 11:11:11 -0800

A minor clarification. One can remove "all" prefixes, since that broadens
the scope. What we can't do is change a prefix in a way that would narrow
the scope.

Mark

---

From: Addison Phillips <[email-masked]>
Date: Sat, 16 Dec 2006 14:25:47 -0800

No. Prefix fields may not be removed altogether. See the "Stability" 
section, rules 4-6. The "widening" rule is restricted to prefixes of the 
current prefix, but doesn't extend to replacing a concrete range with 
the "*" range.

This was done deliberately, if I recall correctly. It effectively 
prevents variants from becoming generic in the future, hence all the 
discussion of generic vs. non-generic variants in recent months.

Addison

Mark Davis wrote:
> A minor clarification. One can remove "all" prefixes, since that 
> broadens the scope. What we can't do is change a prefix in a way that 
> would narrow the scope.
> 
> Mark
> 
> On 12/16/06, *Addison Phillips* <[email-masked] 
> <mailto:[email-masked]>> wrote:
> 
> 
> 
>     Doug Ewell wrote:
>     [email-masked] <mailto:[email-masked]>