How to use DECODE to create a script for compilation of both packages and package bodies

connect scott/tiger
alter session set nls_language='AMERICAN';
set heading off
set trimspool on
set feedback off
set verify off
set echo off
set pagesize 0
spool recompl.lst
select 'alter '||decode(object_type, 'PACKAGE BODY', 'package', object_type) || ' ' || object_name || ' compile' || decode(object_type, 'PACKAGE BODY', ' body;', ';')
from user_objects
where status = 'INVALID'
order by object_type;
select 'show errors' from dual;
select 'exit' from dual;
spool off
start recompl.lst