Re: Transform for pl/perl

Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> writes:

> ilmari(at)ilmari(dot)org (Dagfinn Ilmari =?utf-8?Q?Manns=C3=A5ker?=) writes:
>> While playing around some more with the extension, I discoverered a few
>> more issues:
>> ...
>> 4) SV_to_JsonbValue() throws an error for infinite NVs, but not NaNs
>
> The others sound like bugs, but that one's intentional, since type
> numeric does have a concept of NaN. If you're arguing that we should
> disallow that value in the context of jsonb, maybe so, but it'd likely
> take changes in quite a few more places than here.

The numeric type that's used internally to represent numbers in jsonb
might have the concept of NaN, but JSON itself does not:

Numeric values that cannot be represented in the grammar below (such
as Infinity and NaN) are not permitted.

- https://tools.ietf.org/html/rfc7159#section-6

And it cannot be cast to json:

=# create or replace function jsonbnan() returns jsonb immutable language plperlu transform for type jsonb as '0+"NaN"';
CREATE FUNCTION
=# select jsonbnan();
┌──────────┐
│ jsonbnan │
├──────────┤
│ NaN │
└──────────┘

=# select jsonb_typeof(jsonbnan());
┌──────────────┐
│ jsonb_typeof │
├──────────────┤
│ number │
└──────────────┘

=# select jsonbnan()::json;
ERROR: invalid input syntax for type json
DETAIL: Token "NaN" is invalid.
CONTEXT: JSON data, line 1: NaN

- ilmari
--
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