m:= apex_util.string_to_table('1,2,3',',');
...
function f (m in apex_application_global.vc_arr2 ) return clob is

.....
for s in (
                select distinct a, b, c
                      from table
                      where id in (select * from table(pkg.pipe_id_list(m)));  
           )
     loop
     ....
     end loop;
.....
end;

....
type rows_m is table of number;
....

function pipe_id_list(m in apex_application_global.vc_arr2) return rows_m pipelined is
   begin
      for i in m.first..m.last loop
         pipe row(m(i)); 
      end loop;
      return;
   end;