[precis] shepherd review of draft-ietf-precis-mappings

[Peter Saint-Andre - &yet <[e-mail]>]

With my document shepherd hat on, I just reviewed 
draft-ietf-precis-mappings. I have sent some editorial comments to the 
authors. I also found two more substantive issues...

1. The "local case mapping" method specified in Section 2.3 talks about 
locale and context. However, the example in the second paragraph is a 
matter of language, not locale:

    As an example of locale and context-dependent mapping, LATIN CAPITAL
    LETTER I ("I", U+0049) is normally mapped to LATIN SMALL LETTER I
    ("i", U+0069); however, if the case of Turkish (or one of several
    other languages), unless an I is before a dot_above, the character
    should be mapped to LATIN SMALL LETTER DOTLESS I (U+0131).

As I understand it, locale (see Section 8 of RFC 6365) would refer to a 
particular region within a language-speaking community, such as 
Switzerland within the German-speaking areas.

The SpecialCasing.txt file in the Unicode standard talks about 
language-sensitive mappings for the Lithuanian, Turkish, and Azeri 
languages. (It also talks about a language-insensitive mapping, i.e., 
context-dependent mapping, for Greek final sigma.) It does not talk 
about locale-dependent mappings for particular regions within any 
language-speaking communities.

Therefore, I wonder if all mentions of locale in 
draft-ietf-precis-mappings really ought to be mentions of language. On 
reading the text in the document right now, I provisionally concluded 
that this switch would make sense, but I haven't thought carefully about 
every instance. And I would be curious to hear from the authors and 
working group about this issue.

2. Appendix B purports to describe why local case mapping needs to be an 
alternative to Unicode Default Case Mapping instead of being applied 
sequentially (the text mentions the possibility of applying local case 
mapping before Unicode Default Case Mapping - is that the only option, 
or should we say something about applying it after?).

However, Appendix B only mentions eszett (U+00DF) and to my mind does 
not provide a complete argument for why local case mapping needs to be 
an alternative to Unicode Default Case Mapping. At the least, it might 
be valuable to mention the handling of characters other than eszett. I 
suppose the basic argument is already in Section 2.3, but if so then I 
think that Appendix B might have a misleading title.

Other than these two issues, I think the document is in good shape 
(modulo some editorial adjustments).

Peter

-- 
Peter Saint-Andre
https://andyet.com/