my @pageorder = ( "welcome", "address", "recipients", "preview", "done" );

# Routines to create the pages
my %pages = (
  "welcome" => \&page_welcome,
  "address" => \&page_address,
  "recipients" => \&page_recipients,
  "preview" => \&page_preview,
  "done" => \&page_done,
);

# Routines to validate user input for every page
my %validators = (
  "welcome" => undef,
  "address" => \&validate_address,
  "recipients" => \&validate_recipients,
  "preview" => undef,
  "done" => undef,
);

##</code><code>##


# First, determine where we are, using a default of "welcome" on error :
my $page;
if ($cgi->param("go_prev") and $cgi->param("prevpage")) {
  $page = $cgi->param("prevpage");
} else {
  $page = $cgi->param("nextpage");
};
if (! exists $pages{$page}) {
  $page = "welcome";
};

# Parameter validation ommitted, as it's simply a walk of the validation chain for every page ...

# Execute the special code for this page, so all this searching had some sense :
&{$pages{$page}};