gistfile1.pl

#!/usr/bin/env perl

use strict;
use warnings;

package Foo;

sub new {
    my( $class, $hash ) = @_;
    return bless $hash, $class;
}

sub p {
    my ($self) = @_;
    print "$self->{test}\n";
}

package main;

my $foo = Foo->new( { test => 'foo' } );
$foo->p;
local $foo->{test} = 'bar';
$foo->p;