--
-- Composite / record conversion: composites containing arrays, nested
-- composites (a composite field that is itself a record), arrays of composite,
-- and NULL fields -- in both directions.
--
CREATE TYPE box_t AS (id int, tags text[]);
CREATE TYPE nest_t AS (id int, child box_t);
-- A composite whose fields include an array round-trips through a Ruby Hash.
CREATE FUNCTION c_box() RETURNS box_t LANGUAGE plruby AS $$
    {'id' => 1, 'tags' => ['x', 'y']}
$$;
SELECT * FROM c_box();
 id | tags  
----+-------
  1 | {x,y}
(1 row)

-- Reading a composite argument exposes the array field as a Ruby Array.
CREATE FUNCTION c_box_read(box_t) RETURNS text LANGUAGE plruby AS $$
    "id=#{args[0]['id']} tags=#{args[0]['tags'].inspect}"
$$;
SELECT c_box_read(ROW(7, ARRAY['p', 'q'])::box_t);
      c_box_read      
----------------------
 id=7 tags=["p", "q"]
(1 row)

-- A nested composite: a composite field whose value is itself a Hash.
CREATE FUNCTION c_nested() RETURNS nest_t LANGUAGE plruby AS $$
    {'id' => 1, 'child' => {'id' => 2, 'tags' => ['deep']}}
$$;
SELECT * FROM c_nested();
 id |   child    
----+------------
  1 | (2,{deep})
(1 row)

-- Reading a nested composite argument: the child arrives as a nested Hash.
CREATE FUNCTION c_nested_read(nest_t) RETURNS text LANGUAGE plruby AS $$
    o = args[0]
    "id=#{o['id']} child.id=#{o['child']['id']} " +
        "child.tags=#{o['child']['tags'].inspect}"
$$;
SELECT c_nested_read(ROW(1, ROW(2, ARRAY['deep'])::box_t)::nest_t);
            c_nested_read            
-------------------------------------
 id=1 child.id=2 child.tags=["deep"]
(1 row)

-- An array of composite.
CREATE FUNCTION c_arr() RETURNS box_t[] LANGUAGE plruby AS $$
    [{'id' => 1, 'tags' => ['a']}, {'id' => 2, 'tags' => ['b', 'c']}]
$$;
SELECT c_arr();
            c_arr            
-----------------------------
 {"(1,{a})","(2,\"{b,c}\")"}
(1 row)

-- A missing Hash key and an explicit nil both become SQL NULL.
CREATE FUNCTION c_nulls() RETURNS box_t LANGUAGE plruby AS $$
    {'id' => nil}
$$;
SELECT * FROM c_nulls();
 id | tags 
----+------
    | 
(1 row)

DROP FUNCTION c_box_read(box_t);
DROP FUNCTION c_nested_read(nest_t);
DROP TYPE nest_t CASCADE;
NOTICE:  drop cascades to function c_nested()
DROP TYPE box_t CASCADE;
NOTICE:  drop cascades to 3 other objects
DETAIL:  drop cascades to function c_arr()
drop cascades to function c_box()
drop cascades to function c_nulls()