Re: json api WIP patch

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']

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
>
>