BUG #5277: plperl can't get args properly

The following bug has been logged online:

Bug reference:      5277
Logged by:          louis
Email address:      louis01010100@gmail.com
PostgreSQL version: 8.4.2
Operating system:   PostgreSQL 8.4.2 on x86_64-pc-linux-gnu, compiled by GCC
gcc-4.4.real (Ubuntu 4.4.1-4ubuntu8) 4.4.1, 64-bit
Description:        plperl can't get args properly
Details:

Arguments can't be passed to a plperl function

function definition:
====================
create or replace function foo(text) returns text as $$
   return $_[0];
$$ language plperl;


test:
=====
select foo('a');

result:
=======
INFO:
 foo
-----
(1 row)