Re: proposal: a width specification for s specifier (format function), fix behave when positional and ordered placeholders are used

Hello

2012/12/29 Stephen Frost <sfrost@snowman.net>:
> Pavel,
>
> * Pavel Stehule (pavel.stehule@gmail.com) wrote:
>> I found so we doesn't have functionality for simply text aligning - so
>> I propose support width for %s like printf's behave. glibc
>> implementation knows a rule for precision, that I don't would to
>> implement, because it is oriented to bytes and not to chars - and it
>> can be confusing. Still I would to have implementation and design of
>> "format" function maximally simple - and a rule for "s" specifier and
>> width is clean and simple.
>
> I started looking at this patch to get a head-start on the next
> commitfest.  There's no documentation, which certainly needs to be
> fixed, but worse, this doesn't appear to match glibc printf and it's not
> entirely clear to me why it doesn't.
>
>> -- our current behave
>> postgres=# select format('%s %2$s %s', 'Hello', 'World');
>> ERROR:  too few arguments for format
>> postgres=#
>
> This is correct, if we're matching glibc (and SUS, I believe), isn't it?
> You're not allowed to mix '%2$s' type parameters and '%s' in a single
> format.

I am not sure, please recheck

pavel ~ $ cat test.c
#include <stdio.h>

void main()
{ printf("%s %2$s %s\n", "AHOJ", "Svete");
}

pavel ~ $ gcc test.c # no warning here
pavel ~ $ gcc --version
gcc (GCC) 4.7.2 20120921 (Red Hat 4.7.2-2)
Copyright (C) 2012 Free Software Foundation, Inc.
This is free software; see the source for copying conditions.  There is NO
warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.

pavel ~ $ ./a.out
AHOJ Svete Svete
pavel ~ $

Regards

Pavel Stehule



>
>         Thanks,
>
>                 Stephen