use strict;
use warnings;

my $state = \&start;
while (my $next = $state->()) {
  $state = $next;
}

sub start {
  ...get input...
  if (/1/) { return \&menu_1 }
  elsif (/2/) { return \&menu_2 }
  ...
}

sub menu_1 {
  ...
}

sub menu_2 {
 ...
}