Re: patch (for 9.1) string functions

I merged and enhanced some part of your patch:
 - contrib/stringfunc are merged in the core patch
 - Old format() is replaced with sprintf(), but the function name is
still format().
 - Support %q as alias for %iq.

2010/7/25 Pavel Stehule <pavel.stehule@gmail.com>:
> fixed - it depends on INT64_FORMAT now.
I modified the code a bit not to expect 'll' or 'l'.

> %lq ... literal quoted
> %iq ... ident quoted
I also modified 'q' without specifier, i.e, %q is handled as same as %lq.

>> But I found there is a design issue in format() :
> I prefer a current behave - RAISE statement uses same and it is not
> reported as bug for ten years

I think RAISE is badly designed. Using % as a placeholder has a limitation
to format strings. For example, format() cannot work as concat():
  SELECT format('%%', 123, 456) => ERROR

So, my proposal is renaming stringfunc//sprintf() to format(),
and moving it into the core. I think sprintf() is superior to format()
in every aspect; '%s%s' works as concat(), and '%s%%' can append
% without blanks.

Then, concat_ws() will be moved into core because contrib/stringfunc
only has the function now. In addition, I'd like to include the function for
the compatibility to MySQL. Also, concat() and concat_ws() can share
the implementation.

Comments?

--
Itagaki Takahiro