Re: RfD: more powerful "any" types

On Wed, 2009-09-09 at 21:57 +0200, Pavel Stehule wrote:
> 2009/9/9 Alvaro Herrera :
> > Pavel Stehule escribió:
> >> 2009/9/9 Alvaro Herrera :
> >
> >> > I already published a pseudo-sprintf function in the wiki here:
> >> > http://wiki.postgresql.org/wiki/Sprintf  I'm looking for something
> >> > better, not just the same hacks.
> >> >
> >> > I don't see any good reason that the function needs to be far from core.
> >>
> >> what is use case? Why you need sprintf function, when you have ||
> >> operator. This functionality is redundant and out of standard. What I
> >> know, only MySQL has similar function.
> >
> > Extensive use of || turns into horrible messes quickly.  sprintf() makes
> > this kind of thing much cleaner.  You could use strcat/strcpy in C too,
> > but do you?  You could argue that sprintf is redundant in C, yet it
> > turns out to be extremely useful.
> >
> 
> Yes, I agree. But this functionality you will use only in plpgsql
> language. I thing, so there could be some library that should be
> separated from standard functions. It would be nice, when people
> clearly understand if use some enhancing functionality or some base
> sql functionality.

There is lots of stuff in postgreSQL, especially functions, that is not
"some base sql functionality", yet is in core.

> 
> we could to have schema plpgsql. And there could be function subst,
> 
> then in your plpgsql proc you can call
> 
> if (...) then
>   message := plpgsql.subst('some message:% ...', some value, ...);
>   ....
> 
> if you would, then you can add plpgsql schema to search path.
> 
> I dislike to use name sprintf, because this or similar function isn't
> real sprintf function - it doesn't use compatible format string with
> sprintf function.

call it format(txt, variadic "any") - that's what it does

> regards
> Pavel Stehule
> 
> > One use case is using it for error messages in RAISE/USING.  Yes, I am
> > aware you can use concatenation there.
> >
> > --
> > Alvaro Herrera                                http://www.CommandPrompt.com/
> > PostgreSQL Replication, Consulting, Custom Development, 24x7 support
> >
>