On 02/20/2012 07:30 AM, Itagaki Takahiro wrote:
If we pass an ARRAY of json type to array_to_json() function, the
function seems to
re-encode the JSON text. But should the following examples be the same result?
I'm not sure why we don't have a special case for json type in datum_to_json()
-- do we need to pass-through json types in it?
=# \x
=# SELECT '["A"]'::json,
array_to_json(ARRAY['A']),
array_to_json(ARRAY['"A"'::json]);
-[ RECORD 1 ]-+----------
json | ["A"]
array_to_json | ["A"]
array_to_json | ["\"A\""]
Hmm, maybe. The trouble is that datum_to_json doesn't know what type
it's getting, only the type category. We could probably fudge it by
faking a false one for JSON, say with a lower case 'j', which should be
fairly future-proof, where the category is detected - for efficiency
reasons we do this for the whole array rather than for each element of
the array.
There's another case I have on my list to fix too - some numeric output
such as "NaN" and "Infinity" are not legal JSON numeric values, and need
to be quoted in order to avoid generating illegal JSON.
cheers
andrew
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