Re: Some questions about the array.

On Thursday, November 5, 2015, Craig Ringer <craig(at)2ndquadrant(dot)com> wrote:

> On 6 November 2015 at 12:45, Robert Haas <robertmhaas(at)gmail(dot)com
> <javascript:;>> wrote:
> > On Thu, Nov 5, 2015 at 9:57 AM, YUriy Zhuravlev
> > <u(dot)zhuravlev(at)postgrespro(dot)ru <javascript:;>> wrote:
> >> Hello hackers.
> >> There are comments to my patch? Maybe I should create a separate thread?
> >> Thanks.
> >
> > You should add this on commitfest.postgresql.org.
> >
> > I think the first question that needs to be answered is "do we want
> > this?". I'm sure I know your answer, but what do other people think?
>
> Omitted bounds are common in other languages and would be handy. I
> don't think they'd cause any issues with multi-dimensional arrays or
> variable start-pos arrays.
>
> I'd love negative indexes, but the variable-array-start (mis)feature
> means we can't have those. I wouldn't shed a tear if
> variable-start-position arrays were deprecated and removed, but that's
> a multi-year process, and I'm not convinced negative indexes justify
> it even though the moveable array start pos feature seems little-used.
>
> Since the start-pos is recorded in the array, I wonder if it's worth
> supporting negative indexing for arrays with the default 1-indexed
> element numbering, and just ERRORing for others. Does anyone really
> use anything else?
>
>
Does it have to be "negative"?

Would something like array[1:~1] as a syntax be acceptable to denote
backward counting?

David J.