SQL> ed
Wrote file afiedt.buf

  1* select line,text from user_source where name='FOO'
SQL> /

      LINE TEXT
---------- --------------------------------------------------------------------------------
         1 function fOO(n number) return varchar2 is
         2 retval varchar2(200);
         3 cursor c1 is select  distinct ENAME from EMP where DEPTNO=n;
         4 begin
         5 for crec in c1 loop
         6 if c1%rowcount=1 then
         7 retval:= crec.ENAME;
         8 else
         9 retval:=retval||','||crec.ENAME;
        10 end if;
        11 end loop;
        12 return retval;
        13 end;

13 rows selected.