create or replace function f (tab dbms_tf.table_t) return varchar2 sql_macro as 
begin 
    return 'select * from tab  
    join ( select level rn from dual connect by level <= 2 ) on c1 = rn'; 
end f; 

create table t1 (c1 int)

create table t2 (c1 int)

insert into t1 values ( 1 )

insert into t2 values ( 2 )

select * from f (t1)

select * from f (t2)