Convert Oracle function to PostgreSQL

Hi,
I use this Oracle function(from AskTom - http://asktom.oracle.com/pls/asktom/f?p=100:11:0::::P11_QUESTION_ID:210612357425)

SQL> create or replace type myTableType as table
of varchar2 (255);
2 /

Type created.

ops$tkyte(at)dev8i> create or replace
function in_list( p_string in varchar2 ) return myTableType
2 as
3 l_string long default p_string || ',';
4 l_data myTableType := myTableType();
5 n number;
6 begin
7 loop
8 exit when l_string is null;
9 n := instr( l_string, ',' );
10 l_data.extend;
11 l_data(l_data.count) :=
ltrim( rtrim( substr( l_string, 1, n-1 ) ) );
12 l_string := substr( l_string, n+1 );
13 end loop;
14
15 return l_data;
16 end;
17 /

Function created.

ops$tkyte(at)dev8i> select *
2 from THE
( select cast( in_list('abc, xyz, 012') as
mytableType ) from dual ) a
3 /

COLUMN_VALUE
------------------------
abc
xyz
012

How can I convert this function into PostgreSQL ? Any thoughts?
Thanks