Peter Eisentraut wrote: > On 5/8/18 09:19, Chapman Flack wrote: > > On 05/08/2018 08:57 AM, Ildar Musin wrote: > >> > >> select map (pow(2, x) - 1 for x in array[1,2,3,4,5]); > > > > I wonder how efficient an implementation would be possible strictly > > as a function, without grammar changes? > > Yeah, you can pass a function to another function (using regprocedure or > just oid), so this should be possible entirely in user space.
How would you invoke it? It seems you'd be forced to use EXECUTE in a plpgsql function, or a C function. -- Álvaro Herrera https://www.2ndQuadrant.com/ PostgreSQL Development, 24x7 Support, Remote DBA, Training & Services
