sub get_big_arrayref {
   # blah blah blah

   return \@big_array;
}

{
   ...
   my $big_arrayref = get_big_arrayref();

   foreach my $value (@$big_arrayref) {
       # whatever
   }
}

##</code><code>##

   for my $i (0 .. $#$big_arrayref) {

##</code><code>##

   while ( my($key, $value) = each %$big_hashrerf ) {