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

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.
Thanks,
    Stephen