Message-ID: <20d80bfbbec3874d430691fec37465fb7c4cb277.camel@j-davis.com>
Subject: Re: Explanations not clear
From: Jeff Davis <pgsql@j-davis.com>
To: Peter Eisentraut <peter@eisentraut.org>, florian.murat.koch@gmail.com,
	pgsql-docs@lists.postgresql.org
Date: Mon, 13 May 2024 12:10:25 -0700
In-Reply-To: <dbdfcb5f-282c-4426-b67e-56f4d1588a36@eisentraut.org>
References: <171501838010.704.2474442958031349608@wrigleys.postgresql.org>
	 <dbdfcb5f-282c-4426-b67e-56f4d1588a36@eisentraut.org>
Content-Type: text/plain; charset="UTF-8"
Content-Transfer-Encoding: quoted-printable
User-Agent: Evolution 3.44.4-0ubuntu2 
MIME-Version: 1.0
Archived-At: 
 <https://www.postgresql.org/message-id/20d80bfbbec3874d430691fec37465fb7c4cb277.camel%40j-davis.com>
Precedence: bulk

On Wed, 2024-05-08 at 08:52 +0200, Peter Eisentraut wrote:
> > I created a collation specifying the ks-level3 setting and with
> > deterministic set to false. But when I compare "a_b" to "a-b" with
> > this
> > collation I get false. According to the table 24.1 it should yield
> > true.
> > Only after adding ka-shifted this comparison becomes true. The
> > interactions
> > of the different options are not very clear.
>=20
> I think table 24.1 is somewhat incorrect in the sense that
> punctuation=20
> is only level 4 if you use ka-shifted, otherwise it's level 1.=C2=A0 This=
=20
> should perhaps be clarified.

One option is to just include 3 levels (plus "identic") in the table,
and then later document that ka-shifted creates a fourth level and
moves punctuation character differences into that level. That explains
the mechanism but detracts from the examples.

Another option is to say that all the examples in the table are using
ka-shifted for illustration purposes. I like this option, but it's a
bit awkward because it refers to something that hasn't been explained
yet. It's also only relevant for the 'x-y' =3D 'x_y' example, which might
be slightly confusing.

Thoughts?

Regards,
	Jeff Davis