$a <=> $b already forces $a and $b to be interpretted as numbers, always.
It doesn't appear to with perl 5.8.2: 
use strict;
use warnings;

my $d1 = '2007030110300020070301133000';
my $d2 = '2007030110300020070301143000';

printf "plain = %d\n", ($d1 <=> $d2);
{
    use bigint;
    printf "bigint = %d\n", ($d1 <=> $d2);
}
{
    use bigint;
    printf "bigint-0 = %d\n", (($d1 -0)<=> ($d2-0));
}

[download]
Output: 
plain = 0
bigint = 0
bigint-0 = -1

[download]

In reply to Re^2: Sorting Puzzle (just sort) by imp
in thread Sorting Puzzle by willfould

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