Re: HEAD \df doesn't show functions with no arguments

Tom Lane wrote:
> Bruce Momjian <pgman(at)candle(dot)pha(dot)pa(dot)us> writes:
> > Tom Lane wrote:
> >> What makes you think you can't call 'em from SQL?
>
> > Yes, I guess I mean does it make sense to call them from SQL? Their
> > purpose is for internal use, no?
>
> People have actually used them for purposes of cross-type conversion
> where there's I/O compatibility but no built-in cast. For instance
> you can't
> regression=# select '(1,2)'::point::text;
> ERROR: cannot cast type point to text
> but you can
> regression=# select textin(point_out('(1,2)'::point));
> textin
> --------
> (1,2)
> (1 row)
> Before you look down your nose at that, consider it's *exactly* what
> plpgsql does whenever it needs to do a type conversion.
>
> I think this decision was taken many years ago when indeed you couldn't
> use the things from SQL, but it's an obsolete point of view. It's not
> like the functions are typically named in a way that conflicts with
> other functions. If I do "\df int4in", what exactly do you think I'm
> looking for, and why should psql not show it to me?

Interesting. I do remember them not working in SQL in the past. So it
seems they do now, and I guess we should display them.

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