Cool idea. I wouldn't recommend that implementation as an example of good Perl style, though:

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my $date_1 = new DateTime (year => 2014, month => 7, day => 5);
my $date_2 = new DateTime (year => 2014, month => 7, day =>15);

# Calculate Δ
#    delta_tays() returns a DateTime::Duration object
printf "date_2 (%s) is %d days away from date_1 (%s)\n", $date_2 -> dmy, $date_1->delta_days($date_2)->delta_days, $date_1 -> dmy;

my $today = today DateTime;

printf "Tdoay is %s\n", $today->dmy;

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( sic: https://github.com/ReneNyffenegger/PerlModules/blob/master/DateTime/script.pl )