Subject: [Ltru] rfc4646bis-18 "not suitable" prefix usage

From: "Randy Presuhn" <[email-masked]>
Date: Sun, 2 Nov 2008 02:14:51 -0700

Hi -

As a co-chair and technical contributor...

As part of a close reading of -18 draft of RFC 4646bis...

In section 2.2.5 (page 16/17):
   Variant subtag records in the language subtag registry MAY include
   one or more 'Prefix' fields.  The 'Prefix' indicates a sequence of
   subtags that would make a suitable prefix (with other subtags, as
   appropriate) in forming a language tag with the variant.  That is,
   each of the subtags in the prefix SHOULD appear, in order, before the
   variant.  For example, the subtag 'nedis' has a Prefix of "sl",
   making it suitable for forming language tags such as "sl-nedis" and
   "sl-IT-nedis", but not suitable for use in a tag such as "zh-nedis"
   or "it-IT-nedis".

And on page 26
         nedis" and "sl-IT-nedis" are appropriate, while the tag "is-
         nedis" (Icelandic, Nadiza dialect) is not.

And in section 3.1.8 on page 32
   The 'Prefix' field contains an "extended language range" (see:
   [RFC4647]) whose subtags are appropriate to use with this subtag:
   each of the subtags in one of the subtag's Prefix fields SHOULD
   appear before the variant in a valid tag.  For example, the variant
   subtag '1996' has a 'Prefix' field of "de".  This means that tags
   starting with the sequence "de-" are appropriate with this subtag, so
   "de-Latg-1996" and "de-CH-1996" are both acceptable, while the tag
   "fr-1996" is an inappropriate choice.

Three concerns:
  (1) I am somewhat concerned that the language discouraging
      use of variants with preceding subtags other that those
      enumerated in the Prefix fields is somewhat stronger
      than the sense of WG discussions, where the sentiment
      was repeatedly expressed that Prefix values were not
      intended to be *absolutely* limiting, but merely very
      strong advice, as is already reflected by the SHOULD
      language.  (I think the "pinyin" discussion on ietf-languages
      is also instructive here.)

      I think this concern could be addressed in with
      the following replacement text: replace "not suitable
      for use" in 2.2.5 with -> "not meaningful", replace
      "appropriate" with "meaningful" in the cited passage
      on page 26, and in 3.1.8 replace "is an inappropriate
      choice" with "does not make sense."  Or something like that.

  (2) When we reference extended language range from 4647, do we
      really mean to include the ability to say "-*", and, if so,
      what do we mean by it?

  (3) If we discount the possibility of "-*", then the baroque
      formulation "each of the subtags in one of the subtag's
      Prefix fields SHOULD appear before the variant in a valid
      tag" could be reduced to the slightly simpler "a valid tag
      employing the variant SHOULD begin with a sequence
      of subtags from one of the subtag's Prefix fields."

I don't think any of these is a show-stopper, or should delay
hand-off to the IESG.  They could reasonably be handled as
low-priority IETF last call comments, IMO.

Randy

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From: "Phillips, Addison" <[email-masked]>
Date: Sun, 2 Nov 2008 11:06:51 -0800

Editor hat OFF)
>       choice" with "does not make sense."  Or something like that.

That's a possible way to address it. I believe that the language was intended to be fairly strong advice.

>       really mean to include the ability to say "-*", and, if so,

"something-*" doesn't have any meaning in an extended language range, or, rather, it doesn't affect the meaning. What we mean by extended language range is: if you have a 'Prefix' of "zh-CN" for a subtag "barbaz", that means tags such as "zh-Brai-CN-barbaz" and "zh-cmn-CN-barbaz" are included by the Prefix. Trailing or interstitial "*" wildcards don't mean anything.

But I think your comment probably means the special range "*" (or any range beginning with "*"). We should probably prohibit those ranges: "*" means the same thing as omitting the prefix and the others run counter to existing practice. Although I do note that this would allow variants that modify script or region rather than strictly the primary language.

>       of subtags from one of the subtag's Prefix fields."

But it is NOT just "begin". The point of using extrange was that there can be interstitial subtags.

Addison

---

From: John Cowan <[email-masked]>
Date: Sun, 2 Nov 2008 14:18:55 -0500

Phillips, Addison scripsit:

> But I think your comment probably means the special range "*" (or any
> range beginning with "*"). We should probably prohibit those ranges: "*"
> means the same thing as omitting the prefix and the others run counter
> to existing practice. Although I do note that this would allow variants
> that modify script or region rather than strictly the primary language.

Let's not go there; better to prohibit '*' in all Prefix: fields.

-- 
But the next day there came no dawn,            John Cowan
and the Grey Company passed on into the         [email-masked]
darkness of the Storm of Mordor and were        http://www.ccil.org/~cowan
lost to mortal sight; but the Dead
followed them.          --"The Passing of the Grey Company"
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From: "Phillips, Addison" <[email-masked]>
Date: Sun, 2 Nov 2008 11:31:17 -0800

(editor hat ON)

I have opened a new editor's copy for draft-19.

Addressing the below as well as Doug/Randy's comments about the typo in this section, I added a new bit of MUSTard to the section on Prefix as follows:

--
<t>Prefix's field-body contains a "extended language range" (basically, a collection of subtags, see <xref target="RFC4647"></xref>) which SHOULD be used with this subtag when forming language tag. The subtags in the prefix MUST appear before the subtag in Prefix's record. The Prefix MUST NOT include the wildcard '*'. This field MUST appear only in records whose 'Type' field-body is either 'extlang' or 'variant'. <vspace blankLines="1"/>For example, the variant 'nedis' (Nadiza dialect) has a 'Prefix' of "sl" (Slovenian), meaning that tags such as "sl-nedis" and "sl-IT-nedis" are appropriate, while the tag "is-nedis" (Icelandic, Nadiza dialect) is not.</t>
--

Addison

Addison Phillips
Globalization Architect -- Lab126

Internationalization is not a feature.
It is an architecture.

> -----Original Message-----
> From: John Cowan [mailto:[email-masked]]
> Sent: Sunday, November 02, 2008 11:19 AM
> To: Phillips, Addison
> Cc: Randy Presuhn; LTRU Working Group
> Subject: Re: [Ltru] rfc4646bis-18 "not suitable" prefix usage
>

---

From: "Mark Davis" <[email-masked]>
Date: Tue, 4 Nov 2008 15:09:12 -0800

I didn't find a draft-19 version at
http://www.inter-locale.com/ID/draft-ietf-ltru-4646bis-19.html

There are a number of textual problems with the proposed text:

<t>Prefix's field-body contains a "extended language range" (basically, a
collection of subtags, see <xref target="RFC4647"></xref>) which SHOULD be
used with this subtag when forming language tag. The subtags in the prefix
MUST appear before the subtag in Prefix's record. The Prefix MUST NOT
include the wildcard '*'. This field MUST appear only in records whose
'Type' field-body is either 'extlang' or 'variant'. <vspace
blankLines="1"/>For example, the variant 'nedis' (Nadiza dialect) has a
'Prefix' of "sl" (Slovenian), meaning that tags such as "sl-nedis" and
"sl-IT-nedis" are appropriate, while the tag "is-nedis" (Icelandic, Nadiza
dialect) is not.</t>

Most of these were present before your latest suggestion:

   - The suggested text ("The subtags in the prefix MUST appear...") in the
   second line is not consistent with the SHOULD of the first line. That is, we
   can't say "The subtags in the prefix MUST appear before the subtag in
   Prefix's record." if it is only a SHOULD that the prefix be used with the
   subtag at all!
   - The wording is also awkward, since it suggests that the subtags are
   appearing in order in the Prefix's *record* instead of in a language tag.
   - Also, the gloss "basically a collection of subtags" is a bit funny,
   since it is not a collection: I'd expect something like {abc, def, ghi} if
   that were the case. Since they are linked with "-", they are actually
   ordered.
   - The use of extended language range, surprisingly, does *not* eliminate
   syntactically invalid Prefixes!
   - And now that we are excluding the *, and with the fact that it doesn't
   help with the syntax, just the use of "extended language range" is now
   useless.
   - The wording also requires that *each* prefix SHOULD be used, instead of
   *at least one of* the Prefixes!

My suggested revised text:

Prefix's field-body contains a sequence of subtags separated by '-'. This
field MUST appear only in records whose 'Type' field-body is either
'extlang' or 'variant', and one of the following concatenations MUST be a
well-formed language tag

   1. prefix_field_body + "-" + subtag_field_body, or
      2. "und-" + prefix_field_body + "-" + subtag_field_body

For example, the Prefix "Latn-de" for the variant '1994' MUST NOT be
registered, since neither "Latn-de-1994" nor  "und-Latn-de-1994" are
well-formed language tags. The prefix "Latn" could be registered for the
variant '1994', since "und-Latn-1994" is well-formed.

If a record contains any Prefix field, then any language tag containing the
record's subtag SHOULD also contain the subtag(s) from at least one Prefix
field. Where a language tag contains the prefix's subtag(s) and the record's
subtag, those subtags SHOULD occur in that order in the language tag,
although perhaps with intervening subtags.

For example, the variant 'nedis' (Nadiza dialect) has a 'Prefix' of "sl"
(Slovenian), meaning that tags such as "sl-nedis" and "sl-IT-nedis" are
appropriate, while the tag "is-nedis" (Icelandic, Nadiza dialect) is
not appropriate and SHOULD NOT be used.

The variant '1994' has multiple prefix fields, where each prefix field has
multiple subtags: "sl-rozaj", "sl-rozaj-biske", "sl-rozaj-njiva",... A
language tag containing '1994' SHOULD have all the subtags from at least one
of these prefix fields, such as "sl-fonipa-rozaj-1994" or "sl-rozaj-biske-
fonipa-1994" (the 'fonipa' subtag is added to show the use of optional
intervening subtags). A language tag could contain subtags from multiple
prefix fields, such as "sl-rozaj-biske-njiva-1994", although that should be
avoided where the subtags are mutually exclusive.

Mark

On Sun, Nov 2, 2008 at 11:31 AM, Phillips, Addison <[email-masked]>wrote:

> Addressing the below as well as Doug/Randy's comments about the typo in
> this section, I added a new bit of MUSTard to the section on Prefix as
> follows:
>
> --
> <t>Prefix's field-body contains a "extended language range" (basically, a
> collection of subtags, see <xref target="RFC4647"></xref>) which SHOULD be
> used with this subtag when forming language tag. The subtags in the prefix
> MUST appear before the subtag in Prefix's record. The Prefix MUST NOT
> include the wildcard '*'. This field MUST appear only in records whose
> 'Type' field-body is either 'extlang' or 'variant'. <vspace
> blankLines="1"/>For example, the variant 'nedis' (Nadiza dialect) has a
> 'Prefix' of "sl" (Slovenian), meaning that tags such as "sl-nedis" and
> "sl-IT-nedis" are appropriate, while the tag "is-nedis" (Icelandic, Nadiza
> dialect) is not.</t>
> --
>
> Addison
>
> Addison Phillips