Bob Faist’s Blog

Trying to rush and write a quick script to update some XML files, I forgot how XML parsers deal with mixed content.

Example XML:

 	<para>Some TEXT to display with a <link xlink:href="DOC1">link to DOC1</link>, followed by some more TEXT.</para>

Say I wanted to update the string “TEXT” to “text” so the sentence reads better. Originally, I thought the code would look like this.

foreach my $xPara ($xRoot->get_xpath(’.//para’)) {

my $text_content = $xPara->text();

$text_content =~ s/TEXT/text/s;

$xPara->set_text($text_content);

}

It turns out this is incorrect because it blows away the <link> tag but leaves it’s PCDATA content.The thing to remember here is that there are 3 children to the <para> tag. they are the first PCDATA node (the text before the link node), the <link> node, and the second PCDATA node (after the link node).

Here is some code that updates the XML correctly.

foreach my $xPara ($xRoot->get_xpath(’.//para’)) {

foreach my $xChild ($xPara->children()) {

if($xChild->is_text()) {

my $text_content = $xChild->text();

$text_content =~ s/TEXT/text/s;

$xChild->set_text($text_content);

}

}

}