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Date: Thu, 9 Jul 2026 09:20:29 +0200
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Subject: Re: implement CAST(expr AS type FORMAT 'template')
To: Haibo Yan <tristan.yim@gmail.com>
Cc: Robert Haas <robertmhaas@gmail.com>,
 Corey Huinker <corey.huinker@gmail.com>,
 jian he <jian.universality@gmail.com>,
 Zsolt Parragi <zsolt.parragi@percona.com>,
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 "David G. Johnston" <david.g.johnston@gmail.com>,
 PostgreSQL-development <pgsql-hackers@postgresql.org>
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On 06.07.26 19:14, Haibo Yan wrote:
> The cases where I think a generic mechanism could be useful are
> broader than that.  For example:
> 
>      text <-> date/time        using datetime templates
>      text <-> numeric          using number templates
>      text <-> bytea            using hex/base64/escape
>      text/bytea <-> extension types
>                            using external representations such as
>                            WKT/WKB/GeoJSON for geometry types
One problem I see is that this would dictate that there is only one 
possible format language for each of these conversions.