use warnings;
use Date::Manip 6.30; 
my $today = Date::Manip::Date->new(q(today)); 
my $sunday = $today->new($today->calc($today->new_delta("+1day"))
->printf("%G-W%W-1"))->calc($today->new_delta("-1day")); 
say $today->printf("today: %Y-%m-%d %A\n"), $sunday->printf("Sunday: %Y-%m-%d %A");"