2016-02-24 22:18 GMT+01:00 Peter Eisentraut <peter_e@gmx.net>:
On 1/18/16 4:21 PM, Robert Haas wrote: > One idea that occurs to me is: If you can DECLARE BAR FOO%TYPE, but > then you want to make BAR an array of that type rather than a scalar, > why not write that as DECLARE BAR FOO%TYPE[]? That seems quite > natural to me.
Right, and it's arguably dubious that that doesn't already work. Unfortunately, these % things are just random plpgsql parser hacks, not real types. Maybe this should be done in the main PostgreSQL parser with parameter hooks, if we wanted this feature to be available outside plpgsql as well.
I am not fan to propagate this feature outside PLpgSQL - it is possible new dependency between database object, and the cost is higher than benefits.
> I think the part of this patch that makes %TYPE work for more kinds of > types is probably a good idea, although I haven't carefully studied > exactly what it does.
I agree that this should be more general. For instance, this patch would allow you to get the element type of an array-typed variable, but there is no way to get the element type of just another type. If we could do something like
DECLARE var ELEMENT OF point;
isn't it bug? What is sense of this construct? Our other manipulation with a arrays we raise a error, when we try to to take a element from non array value.
Today I did work on this patch and I am able to implement the syntax proposed by you. It is proprietary, but similar to ADA anonymous types.