Re: format() with embedded to_char() formatter

Hello

There is little bit complication. There are no one "to_char" function
- so you cannot to use DirectFunctionCall API.

but I am not against to this proposal.

regards

Pavel

2010/11/22 Itagaki Takahiro <itagaki(dot)takahiro(at)gmail(dot)com>:
> format() function is very useful to construct formatted text,
> but it doesn't support embedded formatter unlike sprintf() in C.
> Of course, we can use to_char() functions for each argument value,
> but embedded formatter would be more readable.
>
> I'd like to propose %{...}s syntax, where format('%{xxx}s', arg)
> is equivalent to format('%s', to_char(arg, 'xxx')). I think the
> approach is better than implement C-like formatter because we
> can reuse existing to_char() functions for the purpose.
>
> Here are examples for the usage:
>
> =# SELECT format('%{FM0000}s : %{YYYY-MM-DD}L', 123, current_timestamp);
>       format
> ---------------------
>  0123 : '2010-11-22'
>
> =# SELECT format('CREATE TABLE partition_%{YYYYMMDD}s () INHERITS
> parent',  current_date);
>                       format
> ----------------------------------------------------
>  CREATE TABLE partition_20101122 () INHERITS parent
>
> Is it interesting? Comments welcome.
>
> --
> Itagaki Takahiro
>
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