create or replace FUNCTION source_at_line 
	(name_in IN VARCHAR2, 
         line_in IN INTEGER := 1, 
         type_in IN VARCHAR2 := NULL)
RETURN VARCHAR2
IS
   CURSOR source_cur IS
      SELECT text
        FROM user_source
       WHERE name = UPPER (name_in)
         AND (type =  UPPER (type_in) OR type_in IS NULL)
         AND line = line_in;
   source_rec source_cur%ROWTYPE;
BEGIN
   OPEN source_cur;
   FETCH source_cur INTO source_rec;
   IF source_cur%NOTFOUND
   THEN
       CLOSE source_cur;
       RETURN NULL;
   ELSE
       CLOSE source_cur;
       RETURN source_rec.text;
   END IF;
END;
/