sub purse
{
    my $balance = shift;
    my $coderef;
    $coderef = sub {
        my($who, $qty) = @_;
        print "Paying $who $qty\n"
            if ($balance - $qty) >= 0;
        undef $coderef
            if $balance <= 0
    };

    # Return a reference to your code reference.
    \ $coderef;
}

{
    my $$payment = purse(10);
    for ([qw/mom 7/],
         [qw/dad 3/],
         [qw/myself 1/])
    {
        $$payment->(@$_) if $$payment;
    }
}