sub BAR
{
   my $arrayref = shift; #This will receive the array *reference* from FOO

   ### Then, I can refer to specific elements of the
   ### array using the arrayref:
   my $first_element = $arrayref->[0];

   ### or by turning the arrayref back into an array:
   my @bar_array = @{$arrayref};
   my $1st_element = $bar_array[0];

   #code here
}