--
-- CREATE_CAST
--
-- Create some types to test with
CREATE TYPE casttesttype;
CREATE FUNCTION casttesttype_in(cstring)
   RETURNS casttesttype
   AS 'textin'
   LANGUAGE internal STRICT IMMUTABLE;
NOTICE:  return type casttesttype is only a shell
CREATE FUNCTION casttesttype_out(casttesttype)
   RETURNS cstring
   AS 'textout'
   LANGUAGE internal STRICT IMMUTABLE;
NOTICE:  argument type casttesttype is only a shell
CREATE TYPE casttesttype (
   internallength = variable,
   input = casttesttype_in,
   output = casttesttype_out,
   alignment = int4
);
-- a dummy function to test with
CREATE FUNCTION casttestfunc(casttesttype) RETURNS int4 LANGUAGE SQL AS
$$ SELECT 1; $$;
SELECT casttestfunc('foo'::text); -- fails, as there's no cast
ERROR:  function casttestfunc(text) does not exist
LINE 1: SELECT casttestfunc('foo'::text);
               ^
HINT:  No function matches the given name and argument types. You might need to add explicit type casts.
-- Try binary coercion cast
CREATE CAST (text AS casttesttype) WITHOUT FUNCTION;
SELECT casttestfunc('foo'::text); -- doesn't work, as the cast is explicit
ERROR:  function casttestfunc(text) does not exist
LINE 1: SELECT casttestfunc('foo'::text);
               ^
HINT:  No function matches the given name and argument types. You might need to add explicit type casts.
SELECT casttestfunc('foo'::text::casttesttype); -- should work
 casttestfunc 
--------------
            1
(1 row)

DROP CAST (text AS casttesttype); -- cleanup
-- Try IMPLICIT binary coercion cast
CREATE CAST (text AS casttesttype) WITHOUT FUNCTION AS IMPLICIT;
SELECT casttestfunc('foo'::text); -- Should work now
 casttestfunc 
--------------
            1
(1 row)

-- Try I/O conversion cast.
SELECT 1234::int4::casttesttype; -- No cast yet, should fail
ERROR:  cannot cast type integer to casttesttype
LINE 1: SELECT 1234::int4::casttesttype;
                         ^
CREATE CAST (int4 AS casttesttype) WITH INOUT;
SELECT 1234::int4::casttesttype; -- Should work now
 casttesttype 
--------------
 1234
(1 row)

DROP CAST (int4 AS casttesttype);
-- Try cast with a function
CREATE FUNCTION int4_casttesttype(int4) RETURNS casttesttype LANGUAGE SQL AS
$$ SELECT ('foo'::text || $1::text)::casttesttype; $$;
CREATE CAST (int4 AS casttesttype) WITH FUNCTION int4_casttesttype(int4) AS IMPLICIT;
SELECT 1234::int4::casttesttype; -- Should work now
 casttesttype 
--------------
 foo1234
(1 row)

DROP FUNCTION int4_casttesttype(int4) CASCADE;
NOTICE:  drop cascades to cast from integer to casttesttype
-- Try it with a function that requires an implicit cast
CREATE FUNCTION bar_int4_text(int4) RETURNS text LANGUAGE SQL AS
$$ SELECT ('bar'::text || $1::text); $$;
CREATE CAST (int4 AS casttesttype) WITH FUNCTION bar_int4_text(int4) AS IMPLICIT;
SELECT 1234::int4::casttesttype; -- Should work now
 casttesttype 
--------------
 bar1234
(1 row)

-- check dependencies generated for that
SELECT pg_describe_object(classid, objid, objsubid) as obj,
       pg_describe_object(refclassid, refobjid, refobjsubid) as objref,
       deptype
FROM pg_depend
WHERE classid = 'pg_cast'::regclass AND
      objid = (SELECT oid FROM pg_cast
               WHERE castsource = 'int4'::regtype
                 AND casttarget = 'casttesttype'::regtype)
ORDER BY refclassid;
                obj                |             objref              | deptype 
-----------------------------------+---------------------------------+---------
 cast from integer to casttesttype | type casttesttype               | n
 cast from integer to casttesttype | function bar_int4_text(integer) | n
 cast from integer to casttesttype | cast from text to casttesttype  | n
(3 rows)