>perl -wMstrict -le
"use List::MoreUtils qw(natatime);
 ;;
 my @menuStruct = (
   o1 => [
     o1_i1 => 0x11,
     o1_i2 => 0x12,
     o1_i3 => 0x13,
     o1_i4 => 0x14,
     ],
   o2 => [ o2_i1 => 0x21 ],
   o3 => [ o3_i1 => 0x31 ],
   o4 => [
     o4_i1 => 0x41,
     o4_i2 => 0x42,
     o4_i3 => 0x43,
     ],
   o5 => [ o5_i1 => 0x51 ],
   );
 ;;
 my $o_iter = natatime 2, @menuStruct;
 while (my ($ok, $ov) = $o_iter->()) {
   print qq{$ok};
   my $i_iter = natatime 2, @$ov;
   while (my ($ik, $iv) = $i_iter->()) {
     printf qq{  $ik = %x \n}, $iv;
     }
   }
"
o1
  o1_i1 = 11
  o1_i2 = 12
  o1_i3 = 13
  o1_i4 = 14
o2
  o2_i1 = 21
o3
  o3_i1 = 31
o4
  o4_i1 = 41
  o4_i2 = 42
  o4_i3 = 43
o5
  o5_i1 = 51