This should do: 

my $old_parent = $root;
my $new_parent;
my %modules;

for my $node ($old_parent->childNodes()) {
    next if $node->nodeName() ne 'module';
    my $mod_name = $node->getAttribute('name');
    if ($mod_name eq 'all') {
        $new_parent = $node;
    } else {
        $old_parent->removeChild($node);
        $modules{$name} = $node;
    }
}

my %refcount;
for my $node ($new_parent->childNodes()) {
    next if $node->nodeName() ne 'moduleref';
    my $mod_name = $node->getAttribute('name');
    my $referred_node = $modules{$name}
        or next;
    $referred_node = $referred_node->cloneNode(1)
        if $refcount{$mod_name}++;
    $new_parent->replaceChild($referred_node, $node);
}

[download]

A bit or error checking is needed. You didn't specify what you wanted to do with the modules that aren't referenced. The above removes them.

In reply to Re: replace node in xml by ikegami
in thread replace node in xml by joeperl

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.