(Perl) XML Tree Traversal Order for Search* Methods

The Chilkat XML API provides a number of Search* methods for locating XML nodes based on criteria. These methods traverse an XML document in a breadth-first order. (See Breadth-First Search).

The XML document used in this example has the following tree structure:

The nodes are traversed in the order: A, B, C, D, E, F, G, H, I, J, K.

The input XML, available at http://www.chilkatsoft.com/data/searchOrder.xml, is this:

<a>crocodileA
    <b>crocodileB
        <d>crocodileD</d>
        <e>crocodileE
            <h>crocodileH</h>
            <i>crocodileI</i>
        </e>
    </b>
    <c>crocodileC
        <f>crocodileF</f>
        <g>crocodileG
            <j>crocodileJ</j>
            <k>crocodileK</k>
        </g>
    </c>
</a>

 Chilkat Perl Module Downloads for Windows, Linux, and MAC OS X

use chilkat();

$xml = new chilkat::CkXml();

#  The sample input XML is available at http://www.chilkatsoft.com/data/searchOrder.xml
$success = $xml->LoadXmlFile("searchOrder.xml");
if ($success != 1) {
    print $xml->lastErrorText() . "\r\n";
    exit;
}

#  IMPORTANT:  The following loop for iterating over all
#  matching nodes performs reasonably well for small to
#  mid-size XML documents or sub-trees.  Performance
#  can be poor when the sub-tree contains many thousands
#  of nodes (or more).

#  NOTE:  The search is always rooted at the calling node.
#  In this example, it happens to also be the root node of the entire
#  XML document.  Searches can be performed on sub-trees
#  within the document by calling the Search* method from
#  the root node of a sub-tree.

#  Demonstrate the breadth-first traversal:
# xBeginAfter is a CkXml
$xBeginAfter = null;
# xFound is a CkXml
$xFound = $xml->SearchAllForContent($xBeginAfter,"*croc*");
while (!($xFound eq null )) {

    print $xFound->tag() . "\r\n";

    # xBeginAfter is a CkXml
    $xBeginAfter = $xFound;
    # xFound is a CkXml
    $xFound = $xml->SearchAllForContent($xBeginAfter,"*croc*");
}