Re: json api WIP patch

2013/2/5 Hannu Krosing <hannu(at)krosing(dot)net>:
> On 01/31/2013 11:20 PM, Andrew Dunstan wrote:
>>
>>
>> I'm happy to take opinions about this, and I expected
>> some bikeshedding, but your reaction is contrary to
>> everything others have told me. Mostly they love the operators.
>
> What I would really like is if we extended postgresql core and made
> a few more constructs definable as overloadable operator:
>
> 1) array / dictionary element lookup
> a[b]
> CREATE OPERATOR [] (...)
>
> 2) attribute lookup
> a.b
> CREATE OPERATOR . (...)
>
> then you could make json lookups either step-by-step using
>
> CREATE OPERATOR [] (
> PROCEDURE = json_array_lookup, LEFTARG = json, RIGHTARG = int)
>
> and
>
> CREATE OPERATOR [] (
> PROCEDURE = json_dict_lookup, LEFTARG = json, RIGHTARG = text)
>
> fourthname = myjson[4]['name']
>
>
> or perhaps a single
>
>
> CREATE OPERATOR [] (
> PROCEDURE = json_deep_lookup, LEFTARG = json, RIGHTARG = VARIADIC "any")
>
> fourthname = myjson[4, 'name']
>

it is near to full collection implementation - and can be nice to have
it. For this moment we should to return to this topic.

My preference is using well named functions (prefer it against
operator) and operator that are not in collision with current ANSI SQL

I don't see any nice on design select
myjson->>'{"authors",0,"name"}'::text[]; - more it is ugly as
dinosaurs

better and more usual

myjson['authors']['0']['name']

or

myjson['authors/0/name']

Regards

Pavel

>
> though I suspect that we do not support type VARIADIC "any" in operator
> definitions
>
> ---------
> Hannu
>
>
>
>> I guess that '~>' and '~>>' would work as well as '->' and '->>'.
>>
>>
>> cheers
>>
>> andrew
>>
>>
>
>
>
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