use Data::Dumper;

sub zip {
  my @list1 = @{shift()};
  my @list2 = @{shift()};
  my @zip;
  while (@list1+@list2) {
    push(@zip, shift(@list1), shift(@list2));
  }
  @zip
}

my @z1 = zip([qw(a b c)], [qw(5 6 7 8 9)]);
print Dumper(\@z1);
my @z2 = zip([qw(5 6 7 8 9)], [qw(d e f)]);
print Dumper(\@z2);