for my $id (@selected) {
    $list{$id}{selected} = 1;
}

for my $key (keys %list) {
    print qq(<li name="$key");
    print ' class="selected"' if $list{$key}{selected};
    print ">$list{$key}\n";
}

##</code><code>##

#!/usr/bin/perl
# Script part 1.
use warnings;
use strict;


my $code = << '__CODE__';
    %list = ( scalar => 'Plain',
              ref    => 'Overwritten' );
    $list{ref}{selected} = 1;

    for my $key (keys %list) {
        print "$key: $list{$key}";
        print " - Selected" if $list{$key}{selected};
        print "\n";
    }
__CODE__


{   no strict;
    my %list;
    eval $code;
    print "Wow: $Overwritten{selected}\n";
}

##</code><code>##

# Script part 2.
{   package StringRef;
    use overload '""' => sub {
        shift->{STRING};
    };
}


{   package StringRefHash;
    use Tie::Hash;
    our @ISA = 'Tie::StdHash';

    sub STORE {
        my ($self, $key, $value) = @_;
        $self->{$key} = bless {STRING => $value}, 'StringRef';
    }
}


tie my %list, 'StringRefHash';
eval $code;

##</code><code>##

# Script part 3.
{   my %list;
    eval "$code;1" or die $@;
}