Message-ID: <36a6e89689716c2ca1fae8adc8e84601a041121c.camel@j-davis.com>
Subject: Re: pgsql: Allow tailoring of ICU locales with custom rules
From: Jeff Davis <pgsql@j-davis.com>
To: Peter Eisentraut <peter@eisentraut.org>, 
	pgsql-committers@lists.postgresql.org
Date: Wed, 08 Mar 2023 12:57:29 -0800
In-Reply-To: <E1pZwGA-002X1G-4w@gemulon.postgresql.org>
References: <E1pZwGA-002X1G-4w@gemulon.postgresql.org>
Content-Type: text/plain; charset="UTF-8"
Content-Transfer-Encoding: quoted-printable
User-Agent: Evolution 3.44.4-0ubuntu1 
MIME-Version: 1.0
Archived-At: <https://www.postgresql.org/message-id/36a6e89689716c2ca1fae8adc8e84601a041121c.camel%40j-davis.com>
Precedence: bulk

On Wed, 2023-03-08 at 16:03 +0000, Peter Eisentraut wrote:
> Allow tailoring of ICU locales with custom rules

Late review:

* Should throw error when provider !=3D icu and rules !=3D NULL

* Explain what the example means. By itself, users might get confused
wondering why someone would want to do that.

* Also consider a more practical example?

* It appears rules IS NULL behaves differently from rules=3D''. Is that
desired? For instance:
  create collation c1(provider=3Dicu,
    locale=3D'und-u-ka-shifted-ks-level1',
    deterministic=3Dfalse);
  create collation c2(provider=3Dicu,
    locale=3D'und-u-ka-shifted-ks-level1',
    rules=3D'',
    deterministic=3Dfalse);
  select 'a b' collate c1 =3D 'ab' collate c1; -- true
  select 'a b' collate c2 =3D 'ab' collate c2; -- false

* Can you document the interaction between locale keywords
("@colStrength=3Dprimary") and a rule like '[strength 2]'?

Regards,
	Jeff Davis