Horton

Re: Built-in CTYPE provider

Jeff Davis <pgsql@j-davis.com>

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From: Jeff Davis <pgsql@j-davis.com>
To: Daniel Verite <daniel@manitou-mail.org>
Cc: Robert Haas <robertmhaas@gmail.com>, Jeremy Schneider <schneider@ardentperf.com>, pgsql-hackers@postgresql.org
Date: 2024-01-12T02:02:30Z
Lists: pgsql-hackers

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On Wed, 2024-01-10 at 23:56 +0100, Daniel Verite wrote:
> A related comment is about naming the builtin locale C.UTF-8, the
> same
> name as in libc. On one hand this is semantically sound, but on the
> other hand, it's likely to confuse people. What about using
> completely
> different names, like "pg_unicode" or something else prefixed by
> "pg_"
> both for the locale name and the collation name (currently
> C.UTF-8/c_utf8)?

New version attached. Changes:

 * Named collation object PG_C_UTF8, which seems like a good idea to
prevent name conflicts with existing collations. The locale name is
still C.UTF-8, which still makes sense to me because it matches the
behavior of the libc locale of the same name so closely.

 * Added missing documentation for initdb --builtin-locale

 * Refactored the upper/lower/initcap implementations

 * Improved tests for case conversions where the byte length of the
UTF8-encoded string changes (the string length doesn't change because
we don't do full case mapping).

 * No longer uses titlecase mappings -- libc doesn't do that, so it was
an unnecessary difference in case mapping behavior.

 * Improved test report per Jeremy's suggestion: now it reports the
number of codepoints tested.


Jeremy also raised a problem with old versions of psql connecting to a
new server: the \l and \dO won't work. Not sure exactly what to do
there, but I could work around it by adding a new field rather than
renaming (though that's not ideal).

Regards,
	Jeff Davis

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.