#! perl -slw
use strict;
use Benchmark::Timer;
use List::Util qw[ reduce ];
use Math::BigFloat;

$a=$b;

sub product{ reduce{ $a *= $b } 1, @_ }
sub sum{ reduce{ $a += $b } 0, @_ }

sub FishersExactTest {
    my @data = map{ Math::BigFloat->new( $_ ) } @_;
    return unless @data == 4;
    my @C = ( sum( @data[ 0, 2 ] ), sum( @data[ 1, 3 ] ) );
    my @R = ( sum( @data[ 0, 1 ] ), sum( @data[ 2, 3 ] ) );
    my $N =  sum @C;
    my $dividend = product map{ $_->bfac } grep $_, @R, @C;
    my $divisor  = product map{ $_->bfac } grep $_, $N, @data;
    return $dividend / $divisor;
}

my $T = new Benchmark::Timer;

$T->start( '' );
print FishersExactTest 989, 9400, 43300, 2400;;
$T->stop( '' );

$T->report;