Re: MAP syntax for arrays

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.

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Álvaro Herrera                https://www.2ndQuadrant.com/
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