Re: Small improvements to pg_list.h's linitial(), lsecond(), lthird() etc macros

On Mon, 28 Sep 2020 at 12:58, Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> wrote:
>
> David Rowley <dgrowleyml(at)gmail(dot)com> writes:
> > I'm a bit unsure about llast()'s new double evaluation of the list.
> > Perhaps I can add a new inline function named list_last_cell() to get
> > around that... Or maybe it doesn't matter. I'm not quite sure what's
> > best there.
>
> Double evaluation bad, especially in a macro that has not had such a
> hazard for the last twenty-plus years.
>
> It might not be worth mucking with llast, as it's not used very heavily
> I believe. But if it is, then let's add another inline function.

Thanks for having a look at this.

I changed things around to make llast() and the int and oid variant
use a new inline function to get the last cell.

I also pushed the resulting code to master.

David