use strict;
use warnings;
use Foo;
use CGI qw/:standard/;

my $q   = CGI->new( { foo => 'bar', baz => 'Ovid' } );
my $foo = Foo->new;

print $foo->list_params( 1 );
print $foo->list_params( $q );

##</code><code>##

test.pl one=two red=blue red=herring bob= marley=bob

##</code><code>##

$VAR1 = {
          'one' => 'two',
          'red' => [
                     'blue',
                     'herring'
                   ],
          'marley' => 'bob',
          'bob' => ''
        };
$VAR1 = {
          'foo' => 'bar',
          'baz' => 'Ovid'
        };

##</code><code>##

package Foo;
use strict;
use Data::Dumper;

sub new {
    my $class  = shift;
    my ( $package ) = caller;
    my $objref = { _package  => $package };
    bless $objref, $class;
}

sub list_params {
    my ( $self, $cgi ) = @_;
    my %formdata;

    # Use this if OO CGI
    if ( ref $cgi eq 'CGI' ) {
        foreach my $key ( $cgi->param ) {
            my @vals = $cgi->param( $key );
            $formdata{ $key } = _format_vals( \@vals );
        }
        
    # Function-oriented CGI
    } elsif ( $cgi ) {
        {
            # Don't try this at home, kids
            no strict qw/ refs subs /;
            my $_param = $self->{ '_package' }.'::param';
            my $package = \%{$self->{ '_package' } . '::'};

            # Looks like a function oriented call but 'param' was not exported
            if ( ! exists $package->{ 'param' } ) {
                return 0;
            }

            foreach my $key ( eval $_param ) {
                my $_param_call = $_param . "($key)";
                my @vals = eval $_param_call;
                $formdata{ $key } = _format_vals( \@vals );
            }
        }
    } else {
        return 0;
    }
    Dumper( \%formdata );
}

sub _format_vals {
    my $vals = shift;
    @$vals == 1 ? @$vals[ 0 ] :
    ! @$vals    ? undef       :
                  $vals;
}
"Ovid";