Subject: Re: [Ltru] rfc4646bis-18 example in 2.2.7

From: "Doug Ewell" <[email-masked]>
Date: Wed, 5 Nov 2008 07:32:27 -0700

Randy Presuhn <randy underscore presuhn at mindspring dot com> wrote:

> As a technical contributor, I think we should be extremely wary of 
> doing anything that might be perceived as encouraging the use of 
> private-use subtags in the slightest, due to their dire consequences 
> for interoperability.

I can think of something much worse for interoperability than 
"encouraging" private-use subtags.  By strongly discouraging them and 
trying to avoid mention of them, we leave users to figure out on their 
own how to solve their (real or perceived) private-use tagging needs. 
More often than not, without guidance, they will do this by grabbing 
"unused" 2- and 3-letter codes not found in the ISO lists or Registry, 
and giving their own meaning to them, or even "repurposing" codes that 
are already assigned.  This is not hypothetical; it was done in Internet 
Explorer 6, and the practice continues in Wikimedia ("bat-smg").

A valid private-use tag is MUCH better than an invalid one, and if we 
deny the valid ones, that is the alternative many people will choose.

--
Doug Ewell  *  Thornton, Colorado, USA  *  RFC 4645  *  UTN #14
http://www.ewellic.org
http://www1.ietf.org/html.charters/ltru-charter.html
http://www.alvestrand.no/mailman/listinfo/ietf-languages  ˆ 

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From: "Mark Davis" <[email-masked]>
Date: Wed, 5 Nov 2008 06:38:04 -0800

I agree. There is clearly a place for private use codes, and we want to
provide examples of 'good' usage.
Mark

On Wed, Nov 5, 2008 at 6:32 AM, Doug Ewell <[email-masked]> wrote:

>  As a technical contributor, I think we should be extremely wary of doing
>> anything that might be perceived as encouraging the use of private-use
>> subtags in the slightest, due to their dire consequences for
>> interoperability.
>>
>
> I can think of something much worse for interoperability than "encouraging"
> private-use subtags.  By strongly discouraging them and trying to avoid
> mention of them, we leave users to figure out on their own how to solve
> their (real or perceived) private-use tagging needs. More often than not,
> without guidance, they will do this by grabbing "unused" 2- and 3-letter
> codes not found in the ISO lists or Registry, and giving their own meaning
> to them, or even "repurposing" codes that are already assigned.  This is not
> hypothetical; it was done in Internet Explorer 6, and the practice continues
> in Wikimedia ("bat-smg").
>
> A valid private-use tag is MUCH better than an invalid one, and if we deny
> the valid ones, that is the alternative many people will choose.
>
> --

---

From: "Randy Presuhn" <[email-masked]>
Date: Wed, 5 Nov 2008 09:50:38 -0800

Hi -

> From: "Mark Davis" <[email-masked]>
> To: "Doug Ewell" <[email-masked]>
> Cc: "LTRU Working Group" <[email-masked]>
> Sent: Wednesday, November 05, 2008 6:38 AM
> Subject: Re: [Ltru] rfc4646bis-18 example in 2.2.7
>

> provide examples of 'good' usage.
...

As a technical contributor...

An example of "good" usage would be fine, but this is not one of them.
When published in a specification like that, they are almost certain
to show up on the wire and to "leak" into environments which are not
party to the private use agreement.  This use case is a prime example
of what should have been handled using an extension registry.

Randy

---

From: "Mark Davis" <[email-masked]>
Date: Wed, 5 Nov 2008 10:05:00 -0800

I think that's orthogonal. Any case that could be handled via extension is a
perfectly good example of what can be done with private use codes *until*
such an extension would be accepted.
Mark

---

From: "Randy Presuhn" <[email-masked]>
Date: Wed, 5 Nov 2008 11:06:25 -0800

Hi -

> To: "Randy Presuhn" <[email-masked]>
> Sent: Wednesday, November 05, 2008 10:05 AM

No, that's just not so.
RFC 4646 says:
    "Private use subtags are NOT RECOMMENDED where alternatives exist
     or for general interchange."
    "They SHOULD NOT be used where alternatives exist and SHOULD NOT
     be used in content or protocols intended for general use."
    "Private use subtags are simply useless for information exchange
     without prior arrangement."

So, if the LDML  example is intended for use in "general interchange" or
in "content or protocols intended for general use", then I see it as a
clearly inapproriate application of private use subtags.  An *appropriate*
use might be within a personnel database which cannot be published due
to privacy regulations, or as an internal markup (not stored in persistent
files) used by a word processor.  As soon as these things leak out, the
possibility of collisions arises.

Randy

---

From: John Cowan <[email-masked]>
Date: Wed, 5 Nov 2008 14:20:59 -0500

>      without prior arrangement."

I think this is a case where a user would want to override a SHOULD NOT.
As RFC 2119 says:

   This phrase, or the phrase "NOT RECOMMENDED" mean that
   there may exist valid reasons in particular circumstances when the
   particular behavior is acceptable or even useful, but the full
   implications should be understood and the case carefully weighed
   before implementing any behavior described with this label.

There does exist a valid reason in the particular circumstances of the
CLDR, namely the lack of an extension registry for collations, and the
fact that there's no serious prospect of getting one in future.

What is more, there does exist prior arrangement in this case: this tag
is used as a unique label for one member of a large collection.
It is not being used to label an arbitrary document fed into a
document-consuming service from who-knows-where.

-- 
Where the wombat has walked,            John Cowan <[email-masked]>
it will inevitably walk again.          http://www.ccil.org/~cowan
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From: "Randy Presuhn" <[email-masked]>
Date: Wed, 5 Nov 2008 11:33:14 -0800

Hi -

> From: "John Cowan" <[email-masked]>
> Sent: Wednesday, November 05, 2008 11:20 AM

That's circular reasoning.  The correct (IMO) course of action would have
been for the CLDR people to define an extension registry for this purpose.

> document-consuming service from who-knows-where.

If these things are guaranteed to never show up on the wire or in 
general use protocols like HTTP, or leak into contexts where language
tags would be expected, I won't worry about them.  But I'm not yet
persuaded that there are sufficient safeguards to prevent leakage.

Randy

---

From: John Cowan <[email-masked]>
Date: Wed, 5 Nov 2008 15:11:10 -0500

> been for the CLDR people to define an extension registry for this purpose.

Which would have taken them just how long, especially in the teeth of
proven anti-extension obstructionists such as John Cowan?

-- 
I don't know half of you half as well           John Cowan
as I should like, and I like less than half     [email-masked]
of you half as well as you deserve.             http://www.ccil.org/~cowan
        --Bilbo
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From: "Phillips, Addison" <[email-masked]>
Date: Wed, 5 Nov 2008 12:49:08 -0800

Perhaps we should just create a hypothetical, then. The current text says:

--
For example: The Unicode Consortium defines a set of private use extensions in LDML ([UTS35] (Davis, M., “Unicode Technical Standard #35: Locale Data Markup Language (LDML),” December 2007.), Locale Data Markup Language, the Unicode standard for defining locale data) such as in the tag "es-419-x-ldml-collatio-traditio", which indicates Latin American Spanish with traditional order for sorted lists.
--

We could replace it with something like:

--
For example, suppose a group of scholars are studying a group of texts in medieval Greek. They might agree to use private-use subtags to identify different styles of writing in the texts. For example, they might use 'el-x-koine' for documents in the "common" style while using 'el-x-attic' for other documents that mimic the Attic style. These subtags would not be recognized by outsider processes or systems, but might be useful in categorizing various texts for study by others in the group.
--

Addison

Addison Phillips
Globalization Architect -- Lab126

Internationalization is not a feature.
It is an architecture.

> -----Original Message-----
> From: [email-masked] [mailto:[email-masked]] On
> Behalf Of John Cowan
> Sent: Wednesday, November 05, 2008 12:11 PM
> To: Randy Presuhn
> Cc: LTRU Working Group

---

From: "Randy Presuhn" <[email-masked]>
Date: Wed, 5 Nov 2008 13:04:59 -0800

Hi -

> From: "Phillips, Addison" <[email-masked]>
> To: "John Cowan" <[email-masked]>; "Randy Presuhn" <[email-masked]>
> Sent: Wednesday, November 05, 2008 12:49 PM
> Subject: RE: [Ltru] rfc4646bis-18 example in 2.2.7
>
> For example: The Unicode Consortium defines a set of private use extensions in LDML ([UTS35] (Davis, M., “Unicode Technical
Standard #35: Locale Data Markup Language (LDML),” December 2007.), Locale Data Markup Language, the Unicode standard for defining
locale data) such as in the tag "es-419-x-ldml-collatio-traditio", which indicates Latin American Spanish with traditional order for
sorted lists.
> For example, suppose a group of scholars are studying a group of texts in medieval Greek. They might agree to use private-use
subtags to identify different styles of writing in the texts. For example, they might use 'el-x-koine' for documents in the "common"
style while using 'el-x-attic' for other documents that mimic the Attic style. These subtags would not be recognized by outsider
processes or systems, but might be useful in categorizing various texts for study by others in the group.

As a technical contributor, I like this proposal very much.
It addresses my concerns nicely.

As co-chair, *if* the WG decides that something should be
done here, we'll probably end up handling it in the same way
as an IETF last call comment, since the current i-d is what I
believe we'll be handing off to our AD.

Randy

---

From: John Cowan <[email-masked]>
Date: Wed, 5 Nov 2008 16:07:08 -0500

Phillips, Addison scripsit:

> For example, suppose a group of scholars are studying a group of texts
> in medieval Greek. They might agree to use private-use subtags to
> identify different styles of writing in the texts. For example, they
> might use 'el-x-koine' for documents in the "common" style while using
> 'el-x-attic' for other documents that mimic the Attic style. These
> subtags would not be recognized by outsider processes or systems, but
> might be useful in categorizing various texts for study by others in
> the group.

+1

-- 
John Cowan    <[email-masked]>     http://www.ccil.org/~cowan
But no living man am I!  You look upon a woman.  Eowyn I am, Eomund's daughter.
You stand between me and my lord and kin.  Begone, if you be not deathless.
For living or dark undead, I will smite you if you touch him.
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