PostgreSQLでストアドプロシージャを一括ドロップする方法

-- PostgreSQL 9.2で動作確認しました
-- 前提:sp_drop_function_allという名前のストアドプロシージャはないと仮定
CREATE OR REPLACE FUNCTION sp_drop_function_all(
) RETURNS int AS $$
DECLARE
  cur refcursor;
  sql_text text;
BEGIN
  OPEN cur FOR
    SELECT
      'DROP FUNCTION IF EXISTS ' || p.proname || '(' || pg_catalog.oidvectortypes(p.proargtypes) || ');'
    FROM
      pg_catalog.pg_proc AS p
    LEFT JOIN
      pg_catalog.pg_namespace AS n
    ON
      n.oid = p.pronamespace
    WHERE
        p.prorettype <> 'pg_catalog.cstring'::pg_catalog.regtype
      AND
        (
          p.proargtypes[0] IS NULL
        OR
          p.proargtypes[0] <> 'pg_catalog.cstring'::pg_catalog.regtype
        )
      AND
        NOT p.proisagg
      AND
        n.nspname = 'public'
      AND
        pg_catalog.pg_function_is_visible(p.oid)
      AND
        p.proname != 'sp_drop_function_all'
  ;
  LOOP
    FETCH NEXT FROM
      cur
    INTO
      sql_text
    ;
    IF NOT FOUND THEN
      EXIT;
    END IF;
    --RAISE NOTICE '%', sql_text;
    EXECUTE sql_text;
  END LOOP;
  CLOSE cur;
  RETURN 0;
END;
$$ LANGUAGE plpgsql;

SELECT * FROM sp_drop_function_all();

DROP FUNCTION IF EXISTS sp_drop_function_all();