(Ruby) 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>

Downloads for Windows/Linux and Install Instructions

require 'chilkat'

xml = Chilkat::CkXml.new()

#  The sample input XML is available at http://www.chilkatsoft.com/data/searchOrder.xml
success = xml.LoadXmlFile("searchOrder.xml")
if (success != true)
    print xml.lastErrorText() + "\n";
    exit
end

#  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 = nil
# xFound is a CkXml
xFound = xml.SearchAllForContent(xBeginAfter,"*croc*")
while !(xFound == nil )

    print xFound.tag() + "\n";

    # xBeginAfter is a CkXml
    xBeginAfter = xFound
    # xFound is a CkXml
    xFound = xml.SearchAllForContent(xBeginAfter,"*croc*")
end