--
-- Test returning SETOF
--
CREATE FUNCTION test_setof_error() RETURNS SETOF text AS $$
return 37
$$ LANGUAGE plpython3u;
SELECT test_setof_error();
ERROR:  returned object cannot be iterated
DETAIL:  PL/Python set-returning functions must return an iterable object.
CONTEXT:  PL/Python function "test_setof_error"
CREATE FUNCTION test_setof_as_list(count integer, content text) RETURNS SETOF text AS $$
return [ content ]*count
$$ LANGUAGE plpython3u;
CREATE FUNCTION test_setof_as_tuple(count integer, content text) RETURNS SETOF text AS $$
t = ()
for i in range(count):
	t += ( content, )
return t
$$ LANGUAGE plpython3u;
CREATE FUNCTION test_setof_as_iterator(count integer, content text) RETURNS SETOF text AS $$
class producer:
	def __init__ (self, icount, icontent):
		self.icontent = icontent
		self.icount = icount
	def __iter__ (self):
		return self
	def __next__ (self):
		if self.icount == 0:
			raise StopIteration
		self.icount -= 1
		return self.icontent
return producer(count, content)
$$ LANGUAGE plpython3u;
CREATE FUNCTION test_setof_spi_in_iterator() RETURNS SETOF text AS
$$
    for s in ('Hello', 'Brave', 'New', 'World'):
        plpy.execute('select 1')
        yield s
        plpy.execute('select 2')
$$
LANGUAGE plpython3u;
-- Test set returning functions
SELECT test_setof_as_list(0, 'list');
 test_setof_as_list 
--------------------
(0 rows)

SELECT test_setof_as_list(1, 'list');
 test_setof_as_list 
--------------------
 list
(1 row)

SELECT test_setof_as_list(2, 'list');
 test_setof_as_list 
--------------------
 list
 list
(2 rows)

SELECT test_setof_as_list(2, null);
 test_setof_as_list 
--------------------
 
 
(2 rows)

SELECT test_setof_as_tuple(0, 'tuple');
 test_setof_as_tuple 
---------------------
(0 rows)

SELECT test_setof_as_tuple(1, 'tuple');
 test_setof_as_tuple 
---------------------
 tuple
(1 row)

SELECT test_setof_as_tuple(2, 'tuple');
 test_setof_as_tuple 
---------------------
 tuple
 tuple
(2 rows)

SELECT test_setof_as_tuple(2, null);
 test_setof_as_tuple 
---------------------
 
 
(2 rows)

SELECT test_setof_as_iterator(0, 'list');
 test_setof_as_iterator 
------------------------
(0 rows)

SELECT test_setof_as_iterator(1, 'list');
 test_setof_as_iterator 
------------------------
 list
(1 row)

SELECT test_setof_as_iterator(2, 'list');
 test_setof_as_iterator 
------------------------
 list
 list
(2 rows)

SELECT test_setof_as_iterator(2, null);
 test_setof_as_iterator 
------------------------
 
 
(2 rows)

SELECT test_setof_spi_in_iterator();
 test_setof_spi_in_iterator 
----------------------------
 Hello
 Brave
 New
 World
(4 rows)

-- set-returning function that modifies its parameters
CREATE OR REPLACE FUNCTION ugly(x int, lim int) RETURNS SETOF int AS $$
global x
while x <= lim:
    yield x
    x = x + 1
$$ LANGUAGE plpython3u;
SELECT ugly(1, 5);
 ugly 
------
    1
    2
    3
    4
    5
(5 rows)

-- interleaved execution of such a function
SELECT ugly(1,3), ugly(7,8);
 ugly | ugly 
------+------
    1 |    7
    2 |    8
    3 |     
(3 rows)

-- returns set of named-composite-type tuples
CREATE OR REPLACE FUNCTION get_user_records()
RETURNS SETOF users
AS $$
    return plpy.execute("SELECT * FROM users ORDER BY username")
$$ LANGUAGE plpython3u;
SELECT get_user_records();
   get_user_records   
----------------------
 (jane,doe,j_doe,1)
 (john,doe,johnd,2)
 (rick,smith,slash,4)
 (willem,doe,w_doe,3)
(4 rows)

SELECT * FROM get_user_records();
 fname  | lname | username | userid 
--------+-------+----------+--------
 jane   | doe   | j_doe    |      1
 john   | doe   | johnd    |      2
 rick   | smith | slash    |      4
 willem | doe   | w_doe    |      3
(4 rows)

-- same, but returning set of RECORD
CREATE OR REPLACE FUNCTION get_user_records2()
RETURNS TABLE(fname text, lname text, username text, userid int)
AS $$
    return plpy.execute("SELECT * FROM users ORDER BY username")
$$ LANGUAGE plpython3u;
SELECT get_user_records2();
  get_user_records2   
----------------------
 (jane,doe,j_doe,1)
 (john,doe,johnd,2)
 (rick,smith,slash,4)
 (willem,doe,w_doe,3)
(4 rows)

SELECT * FROM get_user_records2();
 fname  | lname | username | userid 
--------+-------+----------+--------
 jane   | doe   | j_doe    |      1
 john   | doe   | johnd    |      2
 rick   | smith | slash    |      4
 willem | doe   | w_doe    |      3
(4 rows)