Lua

XML Tree Traversal Order for Search* Methods

See more XML Examples

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>

Lua

local chilkat = require("chilkat")

local xml = chilkat.Xml.new()

-- The sample input XML is available at http://www.chilkatsoft.com/data/searchOrder.xml
local success = xml:load_xml_file("searchOrder.xml")
if not success then
    print(xml.last_error_text)
    return
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:
local xBeginAfter = xml:get_self()
local xFound = xml:search_all_for_content(xBeginAfter, "*croc*")
while xml.last_method_success do
    print(xFound.tag)

    xBeginAfter = xFound
    xFound = xml:search_all_for_content(xBeginAfter, "*croc*")
end