<informalexample> to contain one or more <programlisting> element(s) for amulti-line source code section?

Hi,

http://www.docbook.org/tdg/en/html/informalexample.html

cites an example of <informalexample><programlisting>
block that contains 

several lines of source code block
in a single <programlisting> element:

<informalexample>

<programlisting>

sub print_content_model {

    my($self) = shift;

    local($_) = shift;

    local(*FILE) = shift;

    my(@cm) = $self->format_content_model2($_);

    foreach $_ (@cm) {

        print FILE $self->make_links($_, 1, 1),
"\n";

    }

}

</programlisting>

</informalexample>

My limited understanding of XML is
that it does not pay attention to 

the white spaces or new lines within
CDATA sections. The CYGWIN 

distribution of Tidy, for example,
does not not preserve 

the new lines within CDATA. 

Am I better off to use something like
the following?

<informalexample>

  <programlisting>sub print_content_model
{</programlisting>

  <programlisting>&nbsp;&nbsp;my($self)
= shift;</programlisting>

  <programlisting>&nbsp;&nbsp;local($_)
= shift;</programlisting>

  <programlisting>&nbsp;&nbsp;local(*FILE)
= shift;</programlisting>

  <programlisting>&nbsp;&nbsp;
my(@cm) = $self->format_content_model2($_);</programlisting>

  <programlisting/>

  <programlisting>&nbsp;&nbsp;foreach
$_ (@cm) {</programlisting>

  <programlisting>&nbsp;&nbsp;
   print FILE $self->make_links($_, 1, 1), "\n";</programlisting>

  <programlisting>&nbsp;&nbsp;}</programlisting>

  <programlisting>}</programlisting>

</informalexample>

Taro Ikai