package MyApp::Config;
use vars qw($ActionsHRef);
use Readonly $ActionsHRef =>
  {
    default => {
      subroutine => \&ActionDefault,
      template   => 'action_default.tmpl',
    },
    overview => {
      subroutine => \&ActionOverview,
      template  => 'action_overview.tmpl',
      maxEntriesPerPage => 40,
    },
    # ...
  };

package main; # hauptprogramm
use CGI;
my $cgi = CGI->new();
my $action = $cgi->param('action') || 'default'; # action nie 0

my $dbh = DBI->connect($dsn, $user, $pw)
  or die ...;

my $subRef;
if( exists $MyApp::Config::ActionsHRef->{$action} ) {
  $subRef = $MyApp::Config::ActionsHRef->{$action}->{subroutine};
} # if
else {
  $subRef = $MyApp::Config::ActionsHRef->{'action_error'};
} # else

my ($templateFile, $params) = $subRef->( $cgi, $dbh, $action );
print $cgi->header();
my $template = &ReadAndFillTemplate( $templateFile, %DefaultParams, %$params );
$template->output();
# -----------------------------------------
sub ActionDefault {
  my ($cgi, $dbh, $action) = @_;

  # mach was...
  my %params = (p1 => 'v1', p2 => 'v2');

  return ($MyApp::Config::ActionsHRef->{$action}->{template}, \%params);
} # ActionDefault