From: Tom Lane <tgl@sss.pgh.pa.us>
To: "Daniel Verite" <daniel@manitou-mail.org>
cc: hugh@whtc.ca, pgsql-bugs@lists.postgresql.org
Subject: Re: BUG #15548: Unaccent does not remove combining diacritical
 characters
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References: <769f5b7c-42c6-435a-a062-a728891b7d81@manitou-mail.org>
Comments: In-reply-to "Daniel Verite" <daniel@manitou-mail.org>
	message dated "Thu, 13 Dec 2018 14:19:51 +0100"
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Date: Thu, 13 Dec 2018 10:05:42 -0500
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"Daniel Verite" <daniel@manitou-mail.org> writes:
> 	PG Bug reporting form wrote:
>> ... For example, A
>> followed by U+0300 displays À. However, unaccent is not removing
>> these accents.

> Short of having the input normalized by the application, ISTM that the
> best solution would be to provide functions to do it in Postgres, so
> you'd just write for example:
>     unaccent(unicode_NFC(string))

That might be worthwhile, but it seems independent of this issue.

> Otherwise unaccent.rules can be customized. You may add replacements
> for letter+diacritical sequences that are missing for the languages
> you have to deal with. But doing it in general for all diacriticals
> multiplied by all base characters seems unrealistic.

Hm, I thought the OP's proposal was just to make unaccent drop 
combining diacriticals independently of context, which'd avoid the
combinatorial-growth problem.

			regards, tom lane