Horton

Re: Built-in CTYPE provider

Peter Eisentraut <peter@eisentraut.org>

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From: Peter Eisentraut <peter@eisentraut.org>
To: Jeff Davis <pgsql@j-davis.com>, Daniel Verite <daniel@manitou-mail.org>
Cc: Robert Haas <robertmhaas@gmail.com>, Jeremy Schneider <schneider@ardentperf.com>, pgsql-hackers@postgresql.org
Date: 2024-02-13T06:24:32Z
Lists: pgsql-hackers 
On 13.02.24 03:01, Jeff Davis wrote:
> 1. The SQL spec mentions the capitalization of "ß" as "SS"
> specifically. Should UCS_BASIC use the unconditional mappings in
> SpecialCasing.txt? I already have some code to do that (not posted
> yet).

It is my understanding that "correct" Unicode case conversion needs to 
use at least some parts of SpecialCasing.txt.  The header of the file says

"For compatibility, the UnicodeData.txt file only contains simple case 
mappings for characters where they are one-to-one and independent of 
context and language. The data in this file, combined with the simple 
case mappings in UnicodeData.txt, defines the full case mappings [...]"

I read this as, just using UnicodeData.txt by itself is incomplete.

I think we need to use the "Unconditional" mappings and the "Conditional 
Language-Insensitive" mappings (which is just Greek sigma).  Obviously, 
skip the "Language-Sensitive" mappings.

Commits

  1. Support PG_UNICODE_FAST locale in the builtin collation provider.

  2. Support Unicode full case mapping and conversion.

  3. Fix test failures when language environment is not UTF-8.

  4. Add unicode_strtitle() for Unicode Default Case Conversion.

  5. Use version for builtin collations.

  6. Fix convert_case(), introduced in 5c40364dd6.

  7. Inline basic UTF-8 functions.

  8. Support C.UTF-8 locale in the new builtin collation provider.

  9. Fix another warning, introduced by 846311051e.

  10. Address more review comments on commit 2d819a08a1.

  11. Fix unreachable code warning from commit 2d819a08a1.

  12. Introduce "builtin" collation provider.

  13. Catalog changes preparing for builtin collation provider.

  14. Unicode case mapping tables and functions.

  15. Add Unicode property tables.

  16. Documentation update for Standard Collations.

  17. Cleanup for unicode-update build target and test.

  18. Shrink Unicode category table.

  19. Make some error strings more generic

  20. pg_upgrade: copy locale and encoding information to new cluster.

  21. Update Unicode data to Unicode 15.0.0

  22. Create a new type category for "internal use" types.