You could just refer to the same sub more than once: 
my %dispatch = (
   home   => \&default,
   donate => \&default,
   news   => \&default,
   samp   => sub { \&samples($dbh) },
   ...
);

$action = $apr->param('a');
$action = 'home' if !exists $dispatch{$action};
$dispatch{$action}->($action);

sub default {
   my ($action, $params) = @_;
   return render_template($action, $params);
}

sub samples {
   my ($action, $dbh) = shift;
   ...
}

[download]

Shortcut: 

my %dispatch = (
   (map { $_ => \&default } qw(
      home donate news
   )),
   samp => sub { \&samples($dbh) },
   ...
);

[download]

In reply to Re: Reducing the complexity of dispatch tables by ikegami
in thread Reducing the complexity of dispatch tables by hacker

Title:
Use:  <p> text here (a paragraph) </p>
and:  <code> code here </code>
to format your post, it's "PerlMonks-approved HTML":


  • Posts are HTML formatted. Put <p> </p> tags around your paragraphs. Put <code> </code> tags around your code and data!
  • Titles consisting of a single word are discouraged, and in most cases are disallowed outright.
  • Read Where should I post X? if you're not absolutely sure you're posting in the right place.
  • Please read these before you post! —
  • Posts may use any of the Perl Monks Approved HTML tags:
    a, abbr, b, big, blockquote, br, caption, center, col, colgroup, dd, del, details, div, dl, dt, em, font, h1, h2, h3, h4, h5, h6, hr, i, ins, li, ol, p, pre, readmore, small, span, spoiler, strike, strong, sub, summary, sup, table, tbody, td, tfoot, th, thead, tr, tt, u, ul, wbr
  • You may need to use entities for some characters, as follows. (Exception: Within code tags, you can put the characters literally.)
            For:     Use:
    & &amp;
    < &lt;
    > &gt;
    [ &#91;
    ] &#93;
  • Link using PerlMonks shortcuts! What shortcuts can I use for linking?
  • See Writeup Formatting Tips and other pages linked from there for more info.