use strict;
use warnings;
...

sub test_p { 
    my ( $self, $r ) = @_;
    # $r is an Apache::Request instantiated earlier
    my $q = CGI->new;

    $r->print('<p>Testing Apache::Request param method<p>');
    $r->print('<pre>', 
               Dumper( { 
                 map { $_ => $r->param($_) } $r->param } ), 
              '</pre>' );
    $r->print('<p>Testing CGI param method<p>');
    $r->print('<pre>', 
              Dumper( { 
                map { $_ => $q->param($_) }$q->param } ), 
              '</pre>');

    return OK;
}