This actually looks to mostly be a parser limitation:
foreach_slice :
{
$$ = 0;
}
| K_SLICE ICONST
{
$$ = $2;
}
;
Everything after that just treats the slice number as a variable. Is
there any underlying grammar ambiguity that prevents it from being an
expression?
Zev
On 12/02/2013 01:24 PM, Pavel Stehule wrote:
2013/12/2 Zev Benjamin <zev-pgsql@xxxxxxxxxxxxxxxxx
<mailto:zev-pgsql@xxxxxxxxxxxxxxxxx>>
Hrm. Conceptually, I think you actually want something like:
CREATE OR REPLACE FUNCTION public.reduce_dim(anyarray)
RETURNS SETOF anyarray
LANGUAGE plpgsql
AS $function$
DECLARE
s $1%type;
d int;
BEGIN
d := array_ndims($1) - 1;
FOREACH s SLICE d IN ARRAY $1 LOOP
RETURN NEXT s;
END LOOP;
RETURN;
END;
$function$;
Otherwise,
select * from reduce_dim(ARRAY[[1], [2], [3]])
and
select * from reduce_dim(ARRAY[[[1], [2], [3]]);
produce the same results. Unfortunately, it looks like the SLICE
keyword only accepts a constant.
yes, it accept only constant - it is unpleasant, but it is necessary due
plpgsql internals :(
Regards
Pavel Stěhule
Zev
On 11/28/2013 02:28 AM, Pavel Stehule wrote:
Hello
postgres=# CREATE OR REPLACE FUNCTION public.reduce_dim(anyarray)
RETURNS SETOF anyarray
LANGUAGE plpgsql
AS $function$
DECLARE s $1%type;
BEGIN
FOREACH s SLICE 1 IN ARRAY $1 LOOP
RETURN NEXT s;
END LOOP;
RETURN;
END;
$function$;
CREATE FUNCTION
postgres=# select reduce_dim(array[array[1, 2], array[2, 3]]);
reduce_dim
------------
{1,2}
{2,3}
(2 rows)
Regards
Pavel Stehule
2013/11/28 Zev Benjamin <zev-pgsql@xxxxxxxxxxxxxxxxx
<mailto:zev-pgsql@xxxxxxxxxxxxxxxxx>
<mailto:zev-pgsql@__strangersgate.com
<mailto:zev-pgsql@xxxxxxxxxxxxxxxxx>>>
It appears that unnest, when called on a multi-dimensional
array,
effectively flattens the array first. For example:
=> select * from unnest(array[array[1, 2], array[2, 3]]);
unnest
--------
1
2
2
3
(4 rows)
while I would have expect something like the following:
=> select * from unnest(array[array[1, 2], array[2, 3]]);
unnest
--------
{1, 2}
{2, 3}
(2 rows)
Is there any way to get the latter behavior?
Zev
--
Sent via pgsql-general mailing list
(pgsql-general@xxxxxxxxxxxxxx <mailto:pgsql-general@xxxxxxxxxxxxxx>
<mailto:pgsql-general@__postgresql.org
<mailto:pgsql-general@xxxxxxxxxxxxxx>>)
To make changes to your subscription:
http://www.postgresql.org/____mailpref/pgsql-general
<http://www.postgresql.org/__mailpref/pgsql-general>
<http://www.postgresql.org/__mailpref/pgsql-general
<http://www.postgresql.org/mailpref/pgsql-general>>
--
Sent via pgsql-general mailing list (pgsql-general@xxxxxxxxxxxxxx
<mailto:pgsql-general@xxxxxxxxxxxxxx>)
To make changes to your subscription:
http://www.postgresql.org/__mailpref/pgsql-general
<http://www.postgresql.org/mailpref/pgsql-general>
--
Sent via pgsql-general mailing list (pgsql-general@xxxxxxxxxxxxxx)
To make changes to your subscription:
http://www.postgresql.org/mailpref/pgsql-general
