regex from plperl

Hi,

I've written following function:

create or replace function dewey(text)
returns text
as '
$_=shift;
if (/(\d\d\d)/) {
return "$1";
} else {
return("this is not a valid dewey!");
}' language plperlu;

Then:

libri=# select dewey('432');
dewey
----------------------------
this is not a valid dewey!
(1 row)

It seems that regex doesn't work at all.

But regex are quite important for me.
Is There something that I've forgotten?

Best wishes, \fer
--