Feedback from Doug Ewell

[msporny]

Doug Ewell wrote:

1. In the proposal's lone example, the Arabic script is a right-to-left script. How does "ar-d-rtl" indicate right-to-left directionality in a way that "ar-Arab" does not?

2. Given Feedback from Martin J. Dürst #1, and given that the script subtag 'Arab' is a Suppress-Script for the language subtag 'ar' (which means "ar" is equivalent to "ar-Arab" for almost all purposes), how is "ar" not sufficient? I agree with Martin's comment here: what rendering process is likely to display Arabic left-to-right?

3. I also agree with Martin that the definition "automatically detected" for subtag 'auto' is not adequate. How does it differ from leaving off the D extension altogether?

4. Scripts exist in other directionalities besides LTR and RTL. Chinese, Japanese, and Korean can be written top-to-bottom, right-to-left. Mongolian in Mongolian script is properly written top-to-bottom, left-to-right, but is sometimes (although incorrectly) rendered LTR as well. Some languages have been written boustrophedon, either with or without reversing the glyphs when transitioning from LTR to RTL. None of these scenarios are covered in the proposal, but some of them seem much more in need of explicit marking than the Arabic example.

5. Given #4, the lack of a registry for the proposed extension, or even the mention of one, is a significant problem. The set of exactly 3 values associated with this extension ('ltr', 'rtl', and 'auto') would be fixed; adding to it would require updating the RFC, which is much more work than updating a registry.

[msporny]

1. In the proposal's lone example, the Arabic script is a
   right-to-left script. How does "ar-d-rtl" indicate right-to-left
   directionality in a way that "ar-Arab" does not?

It's a bad example. Is this one better?

HTML و CSS: تصميم و إنشاء مواقع الويب

2. Given Feedback from Martin J. Dürst #1, and given that the script subtag 'Arab' is a
   Suppress-Script for the language subtag 'ar' (which means "ar" is
   equivalent to "ar-Arab" for almost all purposes), how is "ar" not
   sufficient? I agree with Martin's comment here: what rendering
   process is likely to display Arabic left-to-right?

What about if we switch to the example above?

3. I also agree with Martin that the definition "automatically
   detected" for subtag 'auto' is not adequate. How does it differ from
   leaving off the D extension altogether?

Folks have argued against auto, happy to remove it if that's what folks in this group thinks we should do.

It was meant to achieve the same thing this achieves:

https://www.w3.org/TR/string-meta/#dom-localizable-dir

4. Scripts exist in other directionalities besides LTR and RTL.
   Chinese, Japanese, and Korean can be written top-to-bottom,
   right-to-left. Mongolian in Mongolian script is properly written
   top-to-bottom, left-to-right, but is sometimes (although incorrectly)
   rendered LTR as well. Some languages have been written boustrophedon,
   either with or without reversing the glyphs when transitioning from
   LTR to RTL. None of these scenarios are covered in the proposal, but
   some of them seem much more in need of explicit marking than the
   Arabic example.

Ok, then which ones should we add?

5. Given #4, the lack of a registry for the proposed extension, or
   even the mention of one, is a significant problem. The set of exactly
   3 values associated with this extension ('ltr', 'rtl', and 'auto')
   would be fixed; adding to it would require updating the RFC, which is
   much more work than updating a registry.

Sure, we can use a registry, I can make that change in the next version once it becomes clear that the proposal has merit and won't be rejected by this or the W3C i18n community.