Re: Proposal: casts row to array and array to row

On Tue, Oct 11, 2011 at 3:40 AM, Pavel Stehule <pavel.stehule@gmail.com> wrote:
> Hello
>
> A current limits of dynamic work with row types in PL/pgSQL can be
> decreased with a possible casts between rows and arrays. Now we have a
> lot of tools for arrays, and these tools should be used for rows too.
>
> postgres=# \d mypoint
> Composite type "public.mypoint"
>  Column │  Type   │ Modifiers
> ────────┼─────────┼───────────
>  a      │ integer │
>  b      │ integer │
>
> postgres=# select cast(rmypoint '(10,20) as int[]);
>   array
> ────────────
>  {10,20}
> (1 row)
>
> postgres=# select cast(ARRAY[10,20] AS mypoint);
>  mypoint
> ─────────
>  (10,20)
> (1 row)
>
> What do you think about this idea?

Not sure what it buys you over the syntax we already have:

select row(foo[1], bar[2]);
select array[(bar).a, (bar).b];

Also, in my coding of composite types, homogeneously typed rows don't
really come up that often...

merlin