Some functions to convert arrays/hstore to json :)

to_json.sql

CREATE OR REPLACE FUNCTION escape_json (text) RETURNS text AS $$
SELECT replace($1, '''', '\'''); $$ LANGUAGE SQL IMMUTABLE;


CREATE OR REPLACE FUNCTION to_json(text) RETURNS text AS $$
SELECT escape_json($1) $$ LANGUAGE SQL IMMUTABLE;


CREATE OR REPLACE FUNCTION to_json(KEY text, value text) RETURNS text AS $$
SELECT '''' || to_json($1) || ''': ''' || to_json($2) || ''''; $$ LANGUAGE SQL IMMUTABLE;


CREATE OR REPLACE FUNCTION to_json(hstore) RETURNS text AS $$
SELECT '{' || array_to_string(array_agg(to_json(item.KEY, item.value)), ', ') || '}'
FROM each($1) item; $$ LANGUAGE SQL IMMUTABLE;


CREATE OR REPLACE FUNCTION to_json(text[]) RETURNS text AS $$
SELECT to_json(hstore($1)); $$ LANGUAGE SQL IMMUTABLE;

SELECT to_json(hstore(array[array['a', 'b'], array['c', 'd']])) two_dimensional_array_to_hstore_to_json,
       to_json(array[array['a', 'b'], array['c', 'd']]) two_dimensional_array_to_to_json,
       to_json(hstore(array['a', 'b'], array['c', 'd'])) multi_array_to_hstore_to_json,
       to_json(hstore(array['a', 'b', 'c', 'd'])) array_to_hstore_to_json,
       to_json(array['a', 'b', 'c', 'd']) array_to_to_json;

"A value can be a string in double quotes"
via json standard

Thank you for this great example, though!