Re: [HACKERS] [PATCH] Generic type subscripting

> On Tue, Dec 22, 2020 at 11:57:13AM -0500, Tom Lane wrote:
> Dmitry Dolgov <9erthalion6(at)gmail(dot)com> writes:
> > On Tue, Dec 22, 2020 at 12:19:26PM +0100, Pavel Stehule wrote:
> >> I expect behave like
> >>
> >> update x set test[1] = 10; --> "[10]";
> >> update x set test['1'] = 10; --> "{"1": 10}"
>
> > Yes, I also was thinking about this because such behaviour is more
> > natural.
>
> I continue to feel that this is a fundamentally bad idea that will
> lead to much more pain than benefit. People are going to want to
> know why "test[1.0]" doesn't act like "test[1]". They are going
> to complain because "test[$1]" acts so much differently depending
> on whether they assigned a type to the $1 parameter or not. And
> they are going to bitch because dumping and reloading a rule causes
> it to do something different than it did before --- or at least we'd
> be at horrid risk of that; only if we hide the injected cast-to-text
> doesd the dumped rule look the way it needs to. Even then, the whole
> thing is critically dependent on the fact that integer-type constants
> are written and displayed differently from other constants, so it
> won't scale to any other type that someone might want to treat specially.
> So you're just leading datatype designers down a garden path that will be
> a dead end for many of them.
>
> IMO this isn't actually any saner than your previous iterations
> on the idea.

Ok. While I don't have any preferences here, we can disregard the last
posted patch (extended-with-subscript-type) and consider only
v38-0001-Subscripting-for-jsonb version.