#### HAND EDITED, NOT TESTED
<a>
<b name="funny words">
  <c name="foo"/>
  <c name="baz"/>
</b>
<b name="foods"/>
  <c name="apple"/>
  <c name="pear"/>
  <c name="cheese"/>
</b>
</a>

##</code><code>##

#### HAND EDITED, NOT TESTED
<a>
<b name="foo">
 <c name="foo"/>
</b>
<b name="baz">
 <c name="baz"/>
</b>
<b name="apple">
 <c name="apple"/>
</b>
<b name="pear">
 <c name="pear"/>
</b>
<b name="cheese">
 <c name="cheese"/>
</b>
</a>

##</code><code>##

#### HAND EDITED
my $t = XML::Twig->new(
    twig_handlers => {
        b => \&b,
    },
    pretty_print => 'indented',
);
$t->parsefile($xml_file);
$t->flush;

sub b {
    my ( $t, $x ) = @_;
         my @c = $x->children('c');
        my %bs;
        foreach my $c (@c) {
            my $text = $c->att('name');
            $c->cut;
            push ( @{ $bs{$text} }, $c );
        }
        foreach my $text ( keys %bs ) {
            my $b =
              $x->insert_new_elt( 'after', 'b', { %{ $x->atts } } );
            $b->set_att( 'name' => $text );
            foreach ( @{ $bs{$text} } ) {
                $adg->insert_new_elt( 'first_child', 'c',
                    { %{ $_->atts } } );
            }
        }
        $x->delete;
    }
}