From 51609351f2c4b5082b7e6f0744cd3811c325303f Mon Sep 17 00:00:00 2001
From: emkael <emkael@tlen.pl>
Date: Tue, 11 Oct 2016 14:01:29 +0200
Subject:  * initial template

---
 lib/querypath/QueryPath.php | 4543 +++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 4543 insertions(+)
 create mode 100644 lib/querypath/QueryPath.php

(limited to 'lib/querypath/QueryPath.php')

diff --git a/lib/querypath/QueryPath.php b/lib/querypath/QueryPath.php
new file mode 100644
index 0000000..2585ba6
--- /dev/null
+++ b/lib/querypath/QueryPath.php
@@ -0,0 +1,4543 @@
+<?php
+/** @file
+ * The Query Path package provides tools for manipulating a Document Object Model.
+ * The two major DOMs are the XML DOM and the HTML DOM. Using Query Path, you can 
+ * build, parse, search, and modify DOM documents.
+ *
+ * To use Query Path, this is the only file you should need to import.
+ *
+ * Standard usage:
+ * @code
+ * <?php
+ * require 'QueryPath/QueryPath.php';
+ * $qp = qp('#myID', '<?xml version="1.0"?><test><foo id="myID"/></test>');
+ * $qp->append('<new><elements/></new>')->writeHTML();
+ * ?>
+ * @endcode
+ *
+ * The above would print (formatted for readability):
+ * @code
+ * <?xml version="1.0"?>
+ * <test>
+ *  <foo id="myID">
+ *    <new>
+ *      <element/>
+ *    </new>
+ *  </foo>
+ * </test>
+ * @endcode
+ *
+ * To learn about the functions available to a Query Path object, 
+ * see {@link QueryPath}. The {@link qp()} function is used to build
+ * new QueryPath objects. The documentation for that function explains the
+ * wealth of arguments that the function can take.
+ *
+ * Included with the source code for QueryPath is a complete set of unit tests
+ * as well as some example files. Those are good resources for learning about
+ * how to apply QueryPath's tools. The full API documentation can be generated
+ * from these files using PHPDocumentor.
+ *
+ * If you are interested in building extensions for QueryParser, see the 
+ * {@link QueryPathExtender} class. There, you will find information on adding
+ * your own tools to QueryPath.
+ *
+ * QueryPath also comes with a full CSS 3 selector parser implementation. If
+ * you are interested in reusing that in other code, you will want to start
+ * with {@link CssEventHandler.php}, which is the event interface for the parser.
+ *
+ * All of the code in QueryPath is licensed under either the LGPL or an MIT-like
+ * license (you may choose which you prefer). All of the code is Copyright, 2009
+ * by Matt Butcher.
+ *
+ * @author M Butcher <matt @aleph-null.tv>
+ * @license http://opensource.org/licenses/lgpl-2.1.php The GNU Lesser GPL (LGPL) or an MIT-like license.
+ * @see QueryPath
+ * @see qp()
+ * @see http://querypath.org The QueryPath home page.
+ * @see http://api.querypath.org An online version of the API docs.
+ * @see http://technosophos.com For how-tos and examples.
+ * @copyright Copyright (c) 2009, Matt Butcher.
+ * @version 2.1.2
+ *
+ */
+
+/** @addtogroup querypath_core Core API
+ * Core classes and functions for QueryPath.
+ *
+ * These are the classes, objects, and functions that developers who use QueryPath
+ * are likely to use. The qp() and htmlqp() functions are the best place to start,
+ * while most of the frequently used methods are part of the QueryPath object.
+ */
+
+/** @addtogroup querypath_util Utilities
+ * Utility classes for QueryPath.
+ *
+ * These classes add important, but less-often used features to QueryPath. Some of
+ * these are used transparently (QueryPathIterator). Others you can use directly in your 
+ * code (QueryPathEntities).
+ */
+
+/*   * @namespace QueryPath
+ * The core classes that compose QueryPath.
+ *
+ * The QueryPath classes contain the brunt of the QueryPath code. If you are 
+ * interested in working with just the CSS engine, you may want to look at CssEventHandler,
+ * which can be used without the rest of QueryPath. If you are interested in looking 
+ * carefully at QueryPath's implementation details, then the QueryPath class is where you 
+ * should begin. If you are interested in writing extensions, than you may want to look at
+ * QueryPathExtension, and also at some of the simple extensions, such as QPXML.
+ */
+ 
+/**
+ * Regular expression for checking whether a string looks like XML.
+ * @deprecated This is no longer used in QueryPath.
+ */
+define('ML_EXP','/^[^<]*(<(.|\s)+>)[^>]*$/');
+
+/**
+ * The CssEventHandler interfaces with the CSS parser.
+ */
+require_once 'CssEventHandler.php';
+/**
+ * The extender is used to provide support for extensions.
+ */
+require_once 'QueryPathExtension.php';
+
+/**
+ * Build a new Query Path.
+ * This builds a new Query Path object. The new object can be used for 
+ * reading, search, and modifying a document.
+ *
+ * While it is permissible to directly create new instances of a QueryPath
+ * implementation, it is not advised. Instead, you should use this function
+ * as a factory.
+ *
+ * Example:
+ * @code
+ * <?php
+ * qp(); // New empty QueryPath
+ * qp('path/to/file.xml'); // From a file
+ * qp('<html><head></head><body></body></html>'); // From HTML or XML
+ * qp(QueryPath::XHTML_STUB); // From a basic HTML document.
+ * qp(QueryPath::XHTML_STUB, 'title'); // Create one from a basic HTML doc and position it at the title element.
+ *
+ * // Most of the time, methods are chained directly off of this call.
+ * qp(QueryPath::XHTML_STUB, 'body')->append('<h1>Title</h1>')->addClass('body-class');
+ * ?>
+ * @endcode
+ *
+ * This function is used internally by QueryPath. Anything that modifies the
+ * behavior of this function may also modify the behavior of common QueryPath
+ * methods.
+ *
+ * <b>Types of documents that QueryPath can support</b>
+ *
+ *  qp() can take any of these as its first argument:
+ *
+ *  - A string of XML or HTML (See {@link XHTML_STUB})
+ *  - A path on the file system or a URL
+ *  - A {@link DOMDocument} object
+ *  - A {@link SimpleXMLElement} object.
+ *  - A {@link DOMNode} object.
+ *  - An array of {@link DOMNode} objects (generally {@link DOMElement} nodes).
+ *  - Another {@link QueryPath} object.
+ *
+ * Keep in mind that most features of QueryPath operate on elements. Other 
+ * sorts of DOMNodes might not work with all features.
+ *
+ * <b>Supported Options</b>
+ *  - context: A stream context object. This is used to pass context info
+ *    to the underlying file IO subsystem.
+ *  - encoding: A valid character encoding, such as 'utf-8' or 'ISO-8859-1'.
+ *    The default is system-dependant, typically UTF-8. Note that this is 
+ *    only used when creating new documents, not when reading existing content.
+ *    (See convert_to_encoding below.)
+ *  - parser_flags: An OR-combined set of parser flags. The flags supported
+ *    by the DOMDocument PHP class are all supported here.
+ *  - omit_xml_declaration: Boolean. If this is TRUE, then certain output
+ *    methods (like {@link QueryPath::xml()}) will omit the XML declaration
+ *    from the beginning of a document.
+ *  - replace_entities: Boolean. If this is TRUE, then any of the insertion
+ *    functions (before(), append(), etc.) will replace named entities with
+ *    their decimal equivalent, and will replace un-escaped ampersands with 
+ *    a numeric entity equivalent.
+ *  - ignore_parser_warnings: Boolean. If this is TRUE, then E_WARNING messages
+ *    generated by the XML parser will not cause QueryPath to throw an exception.
+ *    This is useful when parsing
+ *    badly mangled HTML, or when failure to find files should not result in 
+ *    an exception. By default, this is FALSE -- that is, parsing warnings and 
+ *    IO warnings throw exceptions.
+ *  - convert_to_encoding: Use the MB library to convert the document to the 
+ *    named encoding before parsing. This is useful for old HTML (set it to
+ *    iso-8859-1 for best results). If this is not supplied, no character set 
+ *    conversion will be performed. See {@link mb_convert_encoding()}.
+ *    (QueryPath 1.3 and later)
+ *  - convert_from_encoding: If 'convert_to_encoding' is set, this option can be
+ *    used to explicitly define what character set the source document is using.
+ *    By default, QueryPath will allow the MB library to guess the encoding.
+ *    (QueryPath 1.3 and later)
+ *  - strip_low_ascii: If this is set to TRUE then markup will have all low ASCII
+ *    characters (<32) stripped out before parsing. This is good in cases where 
+ *    icky HTML has (illegal) low characters in the document.
+ *  - use_parser: If 'xml', Parse the document as XML. If 'html', parse the 
+ *    document as HTML. Note that the XML parser is very strict, while the 
+ *    HTML parser is more lenient, but does enforce some of the DTD/Schema.
+ *    <i>By default, QueryPath autodetects the type.</i>
+ *  - escape_xhtml_js_css_sections: XHTML needs script and css sections to be
+ *    escaped. Yet older readers do not handle CDATA sections, and comments do not
+ *    work properly (for numerous reasons). By default, QueryPath's *XHTML methods
+ *    will wrap a script body with a CDATA declaration inside of C-style comments.
+ *    If you want to change this, you can set this option with one of the 
+ *    JS_CSS_ESCAPE_* constants, or you can write your own.
+ *  - QueryPath_class: (ADVANCED) Use this to set the actual classname that
+ *    {@link qp()} loads as a QueryPath instance. It is assumed that the 
+ *    class is either {@link QueryPath} or a subclass thereof. See the test 
+ *    cases for an example.
+ *
+ * @ingroup querypath_core
+ * @param mixed $document
+ *  A document in one of the forms listed above.
+ * @param string $string 
+ *  A CSS 3 selector.
+ * @param array $options
+ *  An associative array of options. Currently supported options are listed above.
+ * @return QueryPath
+ */
+function qp($document = NULL, $string = NULL, $options = array()) {
+  
+  $qpClass = isset($options['QueryPath_class']) ? $options['QueryPath_class'] : 'QueryPath';
+  
+  $qp = new $qpClass($document, $string, $options);
+  return $qp;
+}
+
+/**
+ * A special-purpose version of {@link qp()} designed specifically for HTML.
+ *
+ * XHTML (if valid) can be easily parsed by {@link qp()} with no problems. However,
+ * because of the way that libxml handles HTML, there are several common steps that
+ * need to be taken to reliably parse non-XML HTML documents. This function is
+ * a convenience tool for configuring QueryPath to parse HTML.
+ *
+ * The following options are automatically set unless overridden:
+ *  - ignore_parser_warnings: TRUE
+ *  - convert_to_encoding: ISO-8859-1 (the best for the HTML parser).
+ *  - convert_from_encoding: auto (autodetect encoding)
+ *  - use_parser: html
+ *
+ * Parser warning messages are also suppressed, so if the parser emits a warning,
+ * the application will not be notified. This is equivalent to 
+ * calling @code@qp()@endcode.
+ *
+ * Warning: Character set conversions will only work if the Multi-Byte (mb) library
+ * is installed and enabled. This is usually enabled, but not always.
+ *
+ * @ingroup querypath_core
+ * @see qp()
+ */
+function htmlqp($document = NULL, $selector = NULL, $options = array()) {
+
+  // Need a way to force an HTML parse instead of an XML parse when the 
+  // doctype is XHTML, since many XHTML documents are not valid XML
+  // (because of coding errors, not by design).
+  
+  $options += array(
+    'ignore_parser_warnings' => TRUE,
+    'convert_to_encoding' => 'ISO-8859-1',
+    'convert_from_encoding' => 'auto',
+    //'replace_entities' => TRUE,
+    'use_parser' => 'html',
+    // This is stripping actually necessary low ASCII.
+    //'strip_low_ascii' => TRUE,
+  );
+  return @qp($document, $selector, $options);
+}
+
+/**
+ * The Query Path object is the primary tool in this library.
+ *
+ * To create a new Query Path, use the {@link qp()} function.
+ *
+ * If you are new to these documents, start at the {@link QueryPath.php} page.
+ * There you will find a quick guide to the tools contained in this project.
+ *
+ * A note on serialization: QueryPath uses DOM classes internally, and those
+ * do not serialize well at all. In addition, QueryPath may contain many
+ * extensions, and there is no guarantee that extensions can serialize. The
+ * moral of the story: Don't serialize QueryPath.
+ *
+ * @see qp()
+ * @see QueryPath.php
+ * @ingroup querypath_core
+ */
+class QueryPath implements IteratorAggregate, Countable {
+  
+  /**
+   * The version string for this version of QueryPath.
+   *
+   * Standard releases will be of the following form: <MAJOR>.<MINOR>[.<PATCH>][-STABILITY].
+   *
+   * Examples:
+   * - 2.0
+   * - 2.1.1
+   * - 2.0-alpha1
+   *
+   * Developer releases will always be of the form dev-<DATE>.
+   *
+   * @since 2.0
+   */
+  const VERSION = '2.1.2';
+  
+  /**
+   * This is a stub HTML 4.01 document.
+   *
+   * <b>Using {@link QueryPath::XHTML_STUB} is preferred.</b>
+   *
+   * This is primarily for generating legacy HTML content. Modern web applications
+   * should use {@link QueryPath::XHTML_STUB}.
+   *
+   * Use this stub with the HTML familiy of methods ({@link html()}, 
+   * {@link writeHTML()}, {@link innerHTML()}).
+   */
+  const HTML_STUB = '<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
+  <html lang="en">
+  <head>
+  <meta http-equiv="Content-Type" content="text/html; charset=utf-8">
+  <title>Untitled</title>
+  </head>
+  <body></body>
+  </html>';
+  
+  /**
+   * This is a stub XHTML document.
+   * 
+   * Since XHTML is an XML format, you should use XML functions with this document
+   * fragment. For example, you should use {@link xml()}, {@link innerXML()}, and 
+   * {@link writeXML()}.
+   * 
+   * This can be passed into {@link qp()} to begin a new basic HTML document.
+   *
+   * Example:
+   * @code
+   * $qp = qp(QueryPath::XHTML_STUB); // Creates a new XHTML document
+   * $qp->writeXML(); // Writes the document as well-formed XHTML.
+   * @endcode
+   * @since 2.0
+   */
+  const XHTML_STUB = '<?xml version="1.0"?>
+  <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
+  <html xmlns="http://www.w3.org/1999/xhtml">
+  <head>
+  <meta http-equiv="Content-Type" content="text/html; charset=utf-8"/>
+  <title>Untitled</title>
+  </head>
+  <body></body>
+  </html>';
+  
+  /**
+   * Default parser flags.
+   *
+   * These are flags that will be used if no global or local flags override them.
+   * @since 2.0
+   */
+  const DEFAULT_PARSER_FLAGS = NULL;
+  
+  const JS_CSS_ESCAPE_CDATA = '\\1';
+  const JS_CSS_ESCAPE_CDATA_CCOMMENT = '/* \\1 */';
+  const JS_CSS_ESCAPE_CDATA_DOUBLESLASH = '// \\1';
+  const JS_CSS_ESCAPE_NONE = '';
+  
+  //const IGNORE_ERRORS = 1544; //E_NOTICE | E_USER_WARNING | E_USER_NOTICE;
+  private $errTypes = 771; //E_ERROR; | E_USER_ERROR;
+  
+  /**
+   * The base DOMDocument.
+   */
+  protected $document = NULL;
+  private $options = array(
+    'parser_flags' => NULL,
+    'omit_xml_declaration' => FALSE,
+    'replace_entities' => FALSE,
+    'exception_level' => 771, // E_ERROR | E_USER_ERROR | E_USER_WARNING | E_WARNING
+    'ignore_parser_warnings' => FALSE,
+    'escape_xhtml_js_css_sections' => self::JS_CSS_ESCAPE_CDATA_CCOMMENT,
+  );
+  /**
+   * The array of matches.
+   */
+  protected $matches = array();
+  /**
+   * The last array of matches.
+   */
+  protected $last = array(); // Last set of matches.
+  private $ext = array(); // Extensions array.
+  
+  /**
+   * The number of current matches.
+   *
+   * @see count()
+   */
+  public $length = 0;
+  
+  /**
+   * Constructor.
+   *
+   * This should not be called directly. Use the {@link qp()} factory function
+   * instead.
+   *
+   * @param mixed $document 
+   *   A document-like object.
+   * @param string $string
+   *   A CSS 3 Selector
+   * @param array $options
+   *   An associative array of options.
+   * @see qp()
+   */
+  public function __construct($document = NULL, $string = NULL, $options = array()) {
+    $string = trim($string);
+    $this->options = $options + QueryPathOptions::get() + $this->options;
+    
+    $parser_flags = isset($options['parser_flags']) ? $options['parser_flags'] : self::DEFAULT_PARSER_FLAGS;
+    if (!empty($this->options['ignore_parser_warnings'])) {
+      // Don't convert parser warnings into exceptions.
+      $this->errTypes = 257; //E_ERROR | E_USER_ERROR;
+    }
+    elseif (isset($this->options['exception_level'])) {
+      // Set the error level at which exceptions will be thrown. By default, 
+      // QueryPath will throw exceptions for 
+      // E_ERROR | E_USER_ERROR | E_WARNING | E_USER_WARNING.
+      $this->errTypes = $this->options['exception_level'];
+    }
+    
+    // Empty: Just create an empty QP.
+    if (empty($document)) {
+      $this->document = isset($this->options['encoding']) ? new DOMDocument('1.0', $this->options['encoding']) : new DOMDocument();
+      $this->setMatches(new SplObjectStorage());
+    }
+    // Figure out if document is DOM, HTML/XML, or a filename
+    elseif (is_object($document)) {
+      
+      if ($document instanceof QueryPath) {
+        $this->matches = $document->get(NULL, TRUE);
+        if ($this->matches->count() > 0)
+          $this->document = $this->getFirstMatch()->ownerDocument;
+      }
+      elseif ($document instanceof DOMDocument) {
+        $this->document = $document;
+        //$this->matches = $this->matches($document->documentElement);
+        $this->setMatches($document->documentElement);
+      }
+      elseif ($document instanceof DOMNode) {
+        $this->document = $document->ownerDocument;
+        //$this->matches = array($document);
+        $this->setMatches($document);
+      }
+      elseif ($document instanceof SimpleXMLElement) {
+        $import = dom_import_simplexml($document);
+        $this->document = $import->ownerDocument;
+        //$this->matches = array($import);
+        $this->setMatches($import);
+      }
+      elseif ($document instanceof SplObjectStorage) {
+        if ($document->count() == 0) {
+          throw new QueryPathException('Cannot initialize QueryPath from an empty SplObjectStore');
+        }
+        $this->matches = $document;
+        $this->document = $this->getFirstMatch()->ownerDocument;
+      }
+      else {
+        throw new QueryPathException('Unsupported class type: ' . get_class($document));
+      }
+    }
+    elseif (is_array($document)) {
+      //trigger_error('Detected deprecated array support', E_USER_NOTICE);
+      if (!empty($document) && $document[0] instanceof DOMNode) {
+        $found = new SplObjectStorage();
+        foreach ($document as $item) $found->attach($item);
+        //$this->matches = $found;
+        $this->setMatches($found);
+        $this->document = $this->getFirstMatch()->ownerDocument;
+      }
+    }
+    elseif ($this->isXMLish($document)) {
+      // $document is a string with XML
+      $this->document = $this->parseXMLString($document);
+      $this->setMatches($this->document->documentElement);
+    }
+    else {
+      
+      // $document is a filename
+      $context = empty($options['context']) ? NULL : $options['context'];
+      $this->document = $this->parseXMLFile($document, $parser_flags, $context);
+      $this->setMatches($this->document->documentElement);
+    }
+    
+    // Do a find if the second param was set.
+    if (isset($string) && strlen($string) > 0) {
+      $this->find($string);
+    }
+  }
+  
+  /**
+   * A static function for transforming data into a Data URL.
+   *
+   * This can be used to create Data URLs for injection into CSS, JavaScript, or other 
+   * non-XML/HTML content. If you are working with QP objects, you may want to use
+   * {@link dataURL()} instead.
+   *
+   * @param mixed $data
+   *  The contents to inject as the data. The value can be any one of the following:
+   *  - A URL: If this is given, then the subsystem will read the content from that URL. THIS 
+   *    MUST BE A FULL URL, not a relative path.
+   *  - A string of data: If this is given, then the subsystem will encode the string.
+   *  - A stream or file handle: If this is given, the stream's contents will be encoded
+   *    and inserted as data.
+   *  (Note that we make the assumption here that you would never want to set data to be
+   *  a URL. If this is an incorrect assumption, file a bug.)
+   * @param string $mime
+   *  The MIME type of the document.
+   * @param resource $context
+   *  A valid context. Use this only if you need to pass a stream context. This is only necessary
+   *  if $data is a URL. (See {@link stream_context_create()}).
+   * @return 
+   *  An encoded data URL.
+   */
+  public static function encodeDataURL($data, $mime = 'application/octet-stream', $context = NULL) {
+    if (is_resource($data)) {
+      $data = stream_get_contents($data);
+    }
+    elseif (filter_var($data, FILTER_VALIDATE_URL)) {
+      $data = file_get_contents($data, FALSE, $context);
+    }
+    
+    $encoded = base64_encode($data);
+    
+    return 'data:' . $mime . ';base64,' . $encoded;
+  }
+  
+  /**
+   * Get the effective options for the current QueryPath object.
+   *
+   * This returns an associative array of all of the options as set
+   * for the current QueryPath object. This includes default options,
+   * options directly passed in via {@link qp()} or the constructor,
+   * an options set in the {@link QueryPathOptions} object.
+   *
+   * The order of merging options is this:
+   *  - Options passed in using {@link qp()} are highest priority, and will
+   *    override other options.
+   *  - Options set with {@link QueryPathOptions} will override default options,
+   *    but can be overridden by options passed into {@link qp()}.
+   *  - Default options will be used when no overrides are present.
+   *
+   * This function will return the options currently used, with the above option
+   * overriding having been calculated already.
+   *
+   * @return array
+   *  An associative array of options, calculated from defaults and overridden 
+   *  options. 
+   * @see qp()
+   * @see QueryPathOptions::set()
+   * @see QueryPathOptions::merge()
+   * @since 2.0
+   */
+  public function getOptions() {
+    return $this->options;
+  }
+  
+  /**
+   * Select the root element of the document.
+   *
+   * This sets the current match to the document's root element. For 
+   * practical purposes, this is the same as:
+   * @code
+   * qp($someDoc)->find(':root');
+   * @endcode
+   * However, since it doesn't invoke a parser, it has less overhead. It also 
+   * works in cases where the QueryPath has been reduced to zero elements (a
+   * case that is not handled by find(':root') because there is no element
+   * whose root can be found).
+   *
+   * @param string $selector
+   *  A selector. If this is supplied, QueryPath will navigate to the 
+   *  document root and then run the query. (Added in QueryPath 2.0 Beta 2) 
+   * @return QueryPath
+   *  The QueryPath object, wrapping the root element (document element)
+   *  for the current document.
+   */
+  public function top($selector = NULL) {
+    $this->setMatches($this->document->documentElement);
+    // print '=====================' . PHP_EOL;
+    // var_dump($this->document);
+    // print '=====================' . PHP_EOL;
+    return !empty($selector) ? $this->find($selector) : $this;
+  }
+  
+  /**
+   * Given a CSS Selector, find matching items.
+   *
+   * @param string $selector
+   *   CSS 3 Selector
+   * @return QueryPath
+   * @see filter()
+   * @see is()
+   * @todo If a find() returns zero matches, then a subsequent find() will
+   *  also return zero matches, even if that find has a selector like :root.
+   *  The reason for this is that the {@link QueryPathCssEventHandler} does
+   *  not set the root of the document tree if it cannot find any elements
+   *  from which to determine what the root is. The workaround is to use 
+   *  {@link top()} to select the root element again.
+   */
+  public function find($selector) {
+    
+    // Optimize for ID/Class searches. These two take a long time
+    // when a rdp is used. Using an XPath pushes work to C code.
+    $ids = array();
+    
+    $regex = '/^#([\w-]+)$|^\.([\w-]+)$/'; // $1 is ID, $2 is class.
+    //$regex = '/^#([\w-]+)$/';
+    if (preg_match($regex, $selector, $ids) === 1) {
+      // If $1 is a match, we have an ID.
+      if (!empty($ids[1])) {
+        $xpath = new DOMXPath($this->document);
+        foreach ($this->matches as $item) {
+          
+          // For whatever reasons, the .// does not work correctly
+          // if the selected element is the root element. So we have
+          // an awful hack.
+          if ($item->isSameNode($this->document->documentElement) ) {
+            $xpathQuery = "//*[@id='{$ids[1]}']";
+          }
+          // This is the correct XPath query.
+          else {
+            $xpathQuery = ".//*[@id='{$ids[1]}']";
+          }
+          //$nl = $xpath->query("//*[@id='{$ids[1]}']", $item);
+          //$nl = $xpath->query(".//*[@id='{$ids[1]}']", $item);
+          $nl = $xpath->query($xpathQuery, $item);
+          if ($nl->length > 0) {
+            $this->setMatches($nl->item(0));
+            break;
+          }
+          else {
+            // If no match is found, we set an empty.
+            $this->noMatches();
+          }
+        }
+      }
+      // Quick search for class values. While the XPath can't do it
+      // all, it is faster than doing a recusive node search.
+      else {
+        $xpath = new DOMXPath($this->document);
+        $found = new SplObjectStorage();
+        foreach ($this->matches as $item) {
+          // See comments on this in the #id code above.
+          if ($item->isSameNode($this->document->documentElement) ) {
+            $xpathQuery = "//*[@class]";
+          }
+          // This is the correct XPath query.
+          else {
+            $xpathQuery = ".//*[@class]";
+          }
+          $nl = $xpath->query($xpathQuery, $item);
+          for ($i = 0; $i < $nl->length; ++$i) {
+            $vals = explode(' ', $nl->item($i)->getAttribute('class'));
+            if (in_array($ids[2], $vals)) $found->attach($nl->item($i));
+          }
+        }
+        $this->setMatches($found);
+      }
+      
+      return $this;
+    }
+    
+    
+    $query = new QueryPathCssEventHandler($this->matches);
+    $query->find($selector);
+    //$this->matches = $query->getMatches();
+    $this->setMatches($query->getMatches());
+    return $this;
+  }
+  
+  /**
+   * Execute an XPath query and store the results in the QueryPath.
+   *
+   * Most methods in this class support CSS 3 Selectors. Sometimes, though,
+   * XPath provides a finer-grained query language. Use this to execute
+   * XPath queries.
+   *
+   * Beware, though. QueryPath works best on DOM Elements, but an XPath 
+   * query can return other nodes, strings, and values. These may not work with
+   * other QueryPath functions (though you will be able to access the
+   * values with {@link get()}).
+   *
+   * @param string $query
+   *  An XPath query.
+   * @param array $options
+   *  Currently supported options are:
+   *   - 'namespace_prefix': And XML namespace prefix to be used as the default. Used 
+   *      in conjunction with 'namespace_uri'
+   *   - 'namespace_uri': The URI to be used as the default namespace URI. Used 
+   *      with 'namespace_prefix'
+   * @return QueryPath 
+   *  A QueryPath object wrapping the results of the query.
+   * @see find()
+   * @author M Butcher
+   * @author Xavier Prud'homme
+   */
+  public function xpath($query, $options = array()) {
+    $xpath = new DOMXPath($this->document);
+    
+    // Register a default namespace.
+    if (!empty($options['namespace_prefix']) && !empty($options['namespace_uri'])) {
+      $xpath->registerNamespace($options['namespace_prefix'], $options['namespace_uri']);
+    }
+    
+    $found = new SplObjectStorage();
+    foreach ($this->matches as $item) {
+      $nl = $xpath->query($query, $item);
+      if ($nl->length > 0) {
+        for ($i = 0; $i < $nl->length; ++$i) $found->attach($nl->item($i));
+      }
+    }
+    $this->setMatches($found);
+    return $this;
+  }
+  
+  /**
+   * Get the number of elements currently wrapped by this object.
+   *
+   * Note that there is no length property on this object.
+   *
+   * @return int
+   *  Number of items in the object.
+   * @deprecated QueryPath now implements Countable, so use count().
+   */
+  public function size() {
+    return $this->matches->count();
+  }
+  
+  /**
+   * Get the number of elements currently wrapped by this object.
+   *
+   * Since QueryPath is Countable, the PHP count() function can also
+   * be used on a QueryPath.
+   *
+   * @code
+   * <?php
+   *  count(qp($xml, 'div'));
+   * ?>
+   * @endcode
+   *
+   * @return int
+   *  The number of matches in the QueryPath.
+   */
+  public function count() {
+    return $this->matches->count();
+  }
+  
+  /**
+   * Get one or all elements from this object.
+   *
+   * When called with no paramaters, this returns all objects wrapped by 
+   * the QueryPath. Typically, these are DOMElement objects (unless you have
+   * used {@link map()}, {@link xpath()}, or other methods that can select
+   * non-elements).
+   *
+   * When called with an index, it will return the item in the QueryPath with 
+   * that index number.
+   *
+   * Calling this method does not change the QueryPath (e.g. it is 
+   * non-destructive).
+   *
+   * You can use qp()->get() to iterate over all elements matched. You can
+   * also iterate over qp() itself (QueryPath implementations must be Traversable). 
+   * In the later case, though, each item 
+   * will be wrapped in a QueryPath object. To learn more about iterating
+   * in QueryPath, see {@link examples/techniques.php}.
+   *
+   * @param int $index
+   *   If specified, then only this index value will be returned. If this 
+   *   index is out of bounds, a NULL will be returned.
+   * @param boolean $asObject
+   *   If this is TRUE, an {@link SplObjectStorage} object will be returned 
+   *   instead of an array. This is the preferred method for extensions to use.
+   * @return mixed
+   *   If an index is passed, one element will be returned. If no index is
+   *   present, an array of all matches will be returned.
+   * @see eq()
+   * @see SplObjectStorage
+   */
+  public function get($index = NULL, $asObject = FALSE) {
+    if (isset($index)) {
+      return ($this->size() > $index) ? $this->getNthMatch($index) : NULL;
+    }
+    // Retain support for legacy.
+    if (!$asObject) {
+      $matches = array();
+      foreach ($this->matches as $m) $matches[] = $m;
+      return $matches;
+    }
+    return $this->matches;
+  }
+  
+  /**
+   * Get the DOMDocument that we currently work with.
+   *
+   * This returns the current DOMDocument. Any changes made to this document will be
+   * accessible to QueryPath, as both will share access to the same object.
+   * 
+   * @return DOMDocument
+   */
+  public function document() {
+    return $this->document;
+  }
+  
+  /**
+   * On an XML document, load all XIncludes.
+   *
+   * @return QueryPath
+   */
+  public function xinclude() {
+    $this->document->xinclude();
+    return $this;
+  }
+  
+  /**
+   * Get all current elements wrapped in an array.
+   * Compatibility function for jQuery 1.4, but identical to calling {@link get()}
+   * with no parameters.
+   *
+   * @return array
+   *  An array of DOMNodes (typically DOMElements).
+   */
+  public function toArray() {
+    return $this->get();
+  }
+  /**
+   * Get/set an attribute.
+   * - If no parameters are specified, this returns an associative array of all 
+   *   name/value pairs.
+   * - If both $name and $value are set, then this will set the attribute name/value
+   *   pair for all items in this object. 
+   * - If $name is set, and is an array, then
+   *   all attributes in the array will be set for all items in this object.
+   * - If $name is a string and is set, then the attribute value will be returned.
+   *
+   * When an attribute value is retrieved, only the attribute value of the FIRST
+   * match is returned.
+   *
+   * @param mixed $name
+   *   The name of the attribute or an associative array of name/value pairs.
+   * @param string $value
+   *   A value (used only when setting an individual property).
+   * @return mixed
+   *   If this was a setter request, return the QueryPath object. If this was
+   *   an access request (getter), return the string value.
+   * @see removeAttr()
+   * @see tag()
+   * @see hasAttr()
+   * @see hasClass()
+   */
+  public function attr($name = NULL, $value = NULL) {
+    
+    // Default case: Return all attributes as an assoc array.
+    if (is_null($name)) {
+      if ($this->matches->count() == 0) return NULL;
+      $ele = $this->getFirstMatch();
+      $buffer = array();
+      
+      // This does not appear to be part of the DOM
+      // spec. Nor is it documented. But it works.
+      foreach ($ele->attributes as $name => $attrNode) {
+        $buffer[$name] = $attrNode->value;
+      }
+      return $buffer;
+    }
+    
+    // multi-setter
+    if (is_array($name)) {
+      foreach ($name as $k => $v) {
+        foreach ($this->matches as $m) $m->setAttribute($k, $v);
+      }
+      return $this;
+    }
+    // setter
+    if (isset($value)) {
+      foreach ($this->matches as $m) $m->setAttribute($name, $value);
+      return $this;
+    }
+    
+    //getter
+    if ($this->matches->count() == 0) return NULL;
+    
+    // Special node type handler:
+    if ($name == 'nodeType') {
+      return $this->getFirstMatch()->nodeType;
+    }
+    
+    // Always return first match's attr.
+    return $this->getFirstMatch()->getAttribute($name);
+  }
+  /**
+   * Check to see if the given attribute is present.
+   *
+   * This returns TRUE if <em>all</em> selected items have the attribute, or 
+   * FALSE if at least one item does not have the attribute.
+   *
+   * @param string $attrName
+   *  The attribute name.
+   * @return boolean
+   *  TRUE if all matches have the attribute, FALSE otherwise.
+   * @since 2.0
+   * @see attr()
+   * @see hasClass()
+   */
+  public function hasAttr($attrName) {
+    foreach ($this->matches as $match) {
+      if (!$match->hasAttribute($attrName)) return FALSE;
+    }
+    return TRUE;
+  }
+  
+  /**
+   * Set/get a CSS value for the current element(s).
+   * This sets the CSS value for each element in the QueryPath object.
+   * It does this by setting (or getting) the style attribute (without a namespace).
+   *
+   * For example, consider this code:
+   * @code
+   * <?php
+   * qp(HTML_STUB, 'body')->css('background-color','red')->html();
+   * ?>
+   * @endcode
+   * This will return the following HTML:
+   * @code
+   * <body style="background-color: red"/>
+   * @endcode
+   *
+   * If no parameters are passed into this function, then the current style
+   * element will be returned unparsed. Example:
+   * @code
+   * <?php
+   * qp(HTML_STUB, 'body')->css('background-color','red')->css();
+   * ?>
+   * @endcode
+   * This will return the following:
+   * @code
+   * background-color: red
+   * @endcode
+   *
+   * As of QueryPath 2.1, existing style attributes will be merged with new attributes.
+   * (In previous versions of QueryPath, a call to css() overwrite the existing style
+   * values).
+   *
+   * @param mixed $name
+   *  If this is a string, it will be used as a CSS name. If it is an array,
+   *  this will assume it is an array of name/value pairs of CSS rules. It will
+   *  apply all rules to all elements in the set.
+   * @param string $value
+   *  The value to set. This is only set if $name is a string.
+   * @return QueryPath
+   */
+  public function css($name = NULL, $value = '') {
+    if (empty($name)) {
+      return $this->attr('style');
+    }
+    
+    // Get any existing CSS.
+    $css = array();
+    foreach ($this->matches as $match) {
+      $style = $match->getAttribute('style');
+      if (!empty($style)) {
+        // XXX: Is this sufficient?
+        $style_array = explode(';', $style);
+        foreach ($style_array as $item) {
+          $item = trim($item);
+          
+          // Skip empty attributes.
+          if (strlen($item) == 0) continue;
+          
+          list($css_att, $css_val) = explode(':',$item, 2);
+          $css[$css_att] = trim($css_val);
+        }
+      }
+    }
+    
+    if (is_array($name)) {
+      // Use array_merge instead of + to preserve order.
+      $css = array_merge($css, $name);
+    }
+    else {
+      $css[$name] = $value;
+    }
+    
+    // Collapse CSS into a string.
+    $format = '%s: %s;';
+    $css_string = '';
+    foreach ($css as $n => $v) {
+      $css_string .= sprintf($format, $n, trim($v));
+    }
+    
+    $this->attr('style', $css_string);
+    return $this;
+  }
+  
+  /**
+   * Insert or retrieve a Data URL.
+   *
+   * When called with just $attr, it will fetch the result, attempt to decode it, and
+   * return an array with the MIME type and the application data.
+   *
+   * When called with both $attr and $data, it will inject the data into all selected elements
+   * So @code$qp->dataURL('src', file_get_contents('my.png'), 'image/png')@endcode will inject 
+   * the given PNG image into the selected elements.
+   *
+   * The current implementation only knows how to encode and decode Base 64 data.
+   *
+   * Note that this is known *not* to work on IE 6, but should render fine in other browsers.
+   *
+   * @param string $attr
+   *  The name of the attribute.
+   * @param mixed $data
+   *  The contents to inject as the data. The value can be any one of the following:
+   *  - A URL: If this is given, then the subsystem will read the content from that URL. THIS 
+   *    MUST BE A FULL URL, not a relative path.
+   *  - A string of data: If this is given, then the subsystem will encode the string.
+   *  - A stream or file handle: If this is given, the stream's contents will be encoded
+   *    and inserted as data.
+   *  (Note that we make the assumption here that you would never want to set data to be
+   *  a URL. If this is an incorrect assumption, file a bug.)
+   * @param string $mime
+   *  The MIME type of the document.
+   * @param resource $context
+   *  A valid context. Use this only if you need to pass a stream context. This is only necessary
+   *  if $data is a URL. (See {@link stream_context_create()}).
+   * @return
+   *  If this is called as a setter, this will return a QueryPath object. Otherwise, it
+   *  will attempt to fetch data out of the attribute and return that.
+   * @see http://en.wikipedia.org/wiki/Data:_URL
+   * @see attr()
+   * @since 2.1
+   */
+  public function dataURL($attr, $data = NULL, $mime = 'application/octet-stream', $context = NULL) {
+    if (is_null($data)) {
+      // Attempt to fetch the data
+      $data = $this->attr($attr);
+      if (empty($data) || is_array($data) || strpos($data, 'data:') !== 0) {
+        return;
+      }
+      
+      // So 1 and 2 should be MIME types, and 3 should be the base64-encoded data.
+      $regex = '/^data:([a-zA-Z0-9]+)\/([a-zA-Z0-9]+);base64,(.*)$/';
+      $matches = array();
+      preg_match($regex, $data, $matches);
+      
+      if (!empty($matches)) {
+        $result = array(
+          'mime' => $matches[1] . '/' . $matches[2],
+          'data' => base64_decode($matches[3]),
+        );
+        return $result;
+      }
+    }
+    else {
+      
+      $attVal = self::encodeDataURL($data, $mime, $context);
+      
+      return $this->attr($attr, $attVal);
+      
+    }
+  }
+  
+
+  
+  /**
+   * Remove the named attribute from all elements in the current QueryPath.
+   *
+   * This will remove any attribute with the given name. It will do this on each
+   * item currently wrapped by QueryPath.
+   *
+   * As is the case in jQuery, this operation is not considered destructive.
+   *
+   * @param string $name
+   *  Name of the parameter to remove.
+   * @return QueryPath
+   *  The QueryPath object with the same elements.
+   * @see attr()
+   */
+  public function removeAttr($name) {
+    foreach ($this->matches as $m) {
+      //if ($m->hasAttribute($name))
+        $m->removeAttribute($name);
+    }
+    return $this;
+  }
+  /**
+   * Reduce the matched set to just one.
+   *
+   * This will take a matched set and reduce it to just one item -- the item 
+   * at the index specified. This is a destructive operation, and can be undone
+   * with {@link end()}.
+   *
+   * @param $index
+   *  The index of the element to keep. The rest will be 
+   *  discarded.
+   * @return QueryPath
+   * @see get()
+   * @see is()
+   * @see end()
+   */
+  public function eq($index) {
+    // XXX: Might there be a more efficient way of doing this?
+    $this->setMatches($this->getNthMatch($index));
+    return $this;
+  }
+  /**
+   * Given a selector, this checks to see if the current set has one or more matches.
+   *
+   * Unlike jQuery's version, this supports full selectors (not just simple ones).
+   *
+   * @param string $selector
+   *   The selector to search for. As of QueryPath 2.1.1, this also supports passing a
+   *   DOMNode object.
+   * @return boolean
+   *   TRUE if one or more elements match. FALSE if no match is found.
+   * @see get()
+   * @see eq()
+   */
+  public function is($selector) {
+    
+    if (is_object($selector)) {
+      if ($selector instanceof DOMNode) {
+        return count($this->matches) == 1 && $selector->isSameNode($this->get(0));
+      }
+      elseif ($selector instanceof Traversable) {
+        if (count($selector) != count($this->matches)) {
+          return FALSE;
+        }
+        // Without $seen, there is an edge case here if $selector contains the same object
+        // more than once, but the counts are equal. For example, [a, a, a, a] will
+        // pass an is() on [a, b, c, d]. We use the $seen SPLOS to prevent this.
+        $seen = new SplObjectStorage();
+        foreach ($selector as $item) {
+          if (!$this->matches->contains($item) || $seen->contains($item)) {
+            return FALSE;
+          }
+          $seen->attach($item);
+        }
+        return TRUE;
+      }
+      throw new Exception('Cannot compare an object to a QueryPath.');
+      return FALSE;
+    }
+    
+    foreach ($this->matches as $m) {
+      $q = new QueryPathCssEventHandler($m);
+      if ($q->find($selector)->getMatches()->count()) {
+        return TRUE;
+      }
+    }
+    return FALSE;
+  }
+  /**
+   * Filter a list down to only elements that match the selector.
+   * Use this, for example, to find all elements with a class, or with 
+   * certain children.
+   *
+   * @param string $selector
+   *   The selector to use as a filter.
+   * @return QueryPath
+   *   The QueryPath with non-matching items filtered out.
+   * @see filterLambda()
+   * @see filterCallback()
+   * @see map()
+   * @see find()
+   * @see is()
+   */
+  public function filter($selector) {
+    $found = new SplObjectStorage();
+    foreach ($this->matches as $m) if (qp($m, NULL, $this->options)->is($selector)) $found->attach($m);
+    $this->setMatches($found);
+    return $this;
+  }
+  /**
+   * Filter based on a lambda function.
+   *
+   * The function string will be executed as if it were the body of a 
+   * function. It is passed two arguments:
+   * - $index: The index of the item.
+   * - $item: The current Element.
+   * If the function returns boolean FALSE, the item will be removed from
+   * the list of elements. Otherwise it will be kept.
+   *
+   * Example:
+   * @code
+   * qp('li')->filterLambda('qp($item)->attr("id") == "test"');
+   * @endcode
+   *
+   * The above would filter down the list to only an item whose ID is
+   * 'text'.
+   *
+   * @param string $fn
+   *  Inline lambda function in a string.
+   * @return QueryPath
+   * @see filter()
+   * @see map()
+   * @see mapLambda()
+   * @see filterCallback()
+   */
+  public function filterLambda($fn) {
+    $function = create_function('$index, $item', $fn);
+    $found = new SplObjectStorage();
+    $i = 0;
+    foreach ($this->matches as $item)
+      if ($function($i++, $item) !== FALSE) $found->attach($item);
+    
+    $this->setMatches($found);
+    return $this;
+  }
+  
+  /**
+   * Use regular expressions to filter based on the text content of matched elements.
+   *
+   * Only items that match the given regular expression will be kept. All others will
+   * be removed.
+   *
+   * The regular expression is run against the <i>text content</i> (the PCDATA) of the 
+   * elements. This is a way of filtering elements based on their content. 
+   *
+   * Example:
+   * @code
+   *  <?xml version="1.0"?>
+   *  <div>Hello <i>World</i></div>
+   * @endcode
+   *
+   * @code
+   *  <?php
+   *    // This will be 1.
+   *    qp($xml, 'div')->filterPreg('/World/')->size();
+   *  ?>
+   * @endcode
+   *
+   * The return value above will be 1 because the text content of @codeqp($xml, 'div')@endcode is
+   * @codeHello World@endcode.
+   *
+   * Compare this to the behavior of the <em>:contains()</em> CSS3 pseudo-class.
+   * 
+   * @param string $regex
+   *  A regular expression.
+   * @return QueryPath
+   * @see filter()
+   * @see filterCallback()
+   * @see preg_match()
+   */
+  public function filterPreg($regex) {
+    
+    $found = new SplObjectStorage();
+    
+    foreach ($this->matches as $item) {
+      if (preg_match($regex, $item->textContent) > 0) {
+        $found->attach($item);
+      }
+    }
+    $this->setMatches($found);
+    
+    return $this;
+  }
+  /**
+   * Filter based on a callback function.
+   *
+   * A callback may be any of the following:
+   *  - a function: 'my_func'.
+   *  - an object/method combo: $obj, 'myMethod'
+   *  - a class/method combo: 'MyClass', 'myMethod'
+   * Note that classes are passed in strings. Objects are not.
+   *
+   * Each callback is passed to arguments:
+   *  - $index: The index position of the object in the array.
+   *  - $item: The item to be operated upon.
+   *
+   * If the callback function returns FALSE, the item will be removed from the 
+   * set of matches. Otherwise the item will be considered a match and left alone.
+   *
+   * @param callback $callback.
+   *   A callback either as a string (function) or an array (object, method OR 
+   *   classname, method).
+   * @return QueryPath
+   *   Query path object augmented according to the function.
+   * @see filter()
+   * @see filterLambda()
+   * @see map()
+   * @see is()
+   * @see find()
+   */
+  public function filterCallback($callback) {
+    $found = new SplObjectStorage();
+    $i = 0;
+    if (is_callable($callback)) {
+      foreach($this->matches as $item) 
+        if (call_user_func($callback, $i++, $item) !== FALSE) $found->attach($item);
+    }
+    else {
+      throw new QueryPathException('The specified callback is not callable.');
+    }
+    $this->setMatches($found);
+    return $this;
+  }
+  /**
+   * Filter a list to contain only items that do NOT match.
+   *
+   * @param string $selector
+   *  A selector to use as a negation filter. If the filter is matched, the 
+   *  element will be removed from the list.
+   * @return QueryPath
+   *  The QueryPath object with matching items filtered out.
+   * @see find()
+   */
+  public function not($selector) {
+    $found = new SplObjectStorage();
+    if ($selector instanceof DOMElement) {
+      foreach ($this->matches as $m) if ($m !== $selector) $found->attach($m); 
+    }
+    elseif (is_array($selector)) {
+      foreach ($this->matches as $m) {
+        if (!in_array($m, $selector, TRUE)) $found->attach($m);
+      }
+    }
+    elseif ($selector instanceof SplObjectStorage) {
+      foreach ($this->matches as $m) if ($selector->contains($m)) $found->attach($m); 
+    }
+    else {
+      foreach ($this->matches as $m) if (!qp($m, NULL, $this->options)->is($selector)) $found->attach($m);
+    }
+    $this->setMatches($found);
+    return $this;
+  }
+  /**
+   * Get an item's index.
+   *
+   * Given a DOMElement, get the index from the matches. This is the 
+   * converse of {@link get()}.
+   *
+   * @param DOMElement $subject
+   *  The item to match.
+   * 
+   * @return mixed
+   *  The index as an integer (if found), or boolean FALSE. Since 0 is a 
+   *  valid index, you should use strong equality (===) to test..
+   * @see get()
+   * @see is()
+   */
+  public function index($subject) {
+    
+    $i = 0;
+    foreach ($this->matches as $m) {
+      if ($m === $subject) {
+        return $i;
+      }
+      ++$i;
+    }
+    return FALSE;
+  }
+  /**
+   * Run a function on each item in a set.
+   *
+   * The mapping callback can return anything. Whatever it returns will be
+   * stored as a match in the set, though. This means that afer a map call, 
+   * there is no guarantee that the elements in the set will behave correctly
+   * with other QueryPath functions.
+   *
+   * Callback rules:
+   * - If the callback returns NULL, the item will be removed from the array.
+   * - If the callback returns an array, the entire array will be stored in 
+   *   the results.
+   * - If the callback returns anything else, it will be appended to the array 
+   *   of matches.
+   *
+   * @param callback $callback
+   *  The function or callback to use. The callback will be passed two params:
+   *  - $index: The index position in the list of items wrapped by this object.
+   *  - $item: The current item.
+   *
+   * @return QueryPath
+   *  The QueryPath object wrapping a list of whatever values were returned
+   *  by each run of the callback.
+   *
+   * @see QueryPath::get()
+   * @see filter()
+   * @see find()
+   */
+  public function map($callback) {
+    $found = new SplObjectStorage();
+    
+    if (is_callable($callback)) {
+      $i = 0;
+      foreach ($this->matches as $item) {
+        $c = call_user_func($callback, $i, $item);
+        if (isset($c)) {
+          if (is_array($c) || $c instanceof Iterable) {
+            foreach ($c as $retval) {
+              if (!is_object($retval)) {
+                $tmp = new stdClass();
+                $tmp->textContent = $retval;
+                $retval = $tmp;
+              }
+              $found->attach($retval);
+            }
+          }
+          else {
+            if (!is_object($c)) {
+              $tmp = new stdClass();
+              $tmp->textContent = $c;
+              $c = $tmp;
+            }
+            $found->attach($c);
+          }
+        }
+        ++$i;
+      }
+    }
+    else {
+      throw new QueryPathException('Callback is not callable.');
+    }
+    $this->setMatches($found, FALSE);
+    return $this;
+  }
+  /**
+   * Narrow the items in this object down to only a slice of the starting items.
+   *
+   * @param integer $start
+   *  Where in the list of matches to begin the slice.
+   * @param integer $length
+   *  The number of items to include in the slice. If nothing is specified, the 
+   *  all remaining matches (from $start onward) will be included in the sliced
+   *  list.
+   * @return QueryPath
+   * @see array_slice()
+   */
+  public function slice($start, $length = 0) {
+    $end = $length;
+    $found = new SplObjectStorage();
+    if ($start >= $this->size()) {
+      $this->setMatches($found);
+      return $this;
+    }
+    
+    $i = $j = 0;
+    foreach ($this->matches as $m) {
+      if ($i >= $start) {
+        if ($end > 0 && $j >= $end) {
+          break;
+        }
+        $found->attach($m);
+        ++$j;
+      }
+      ++$i;
+    }
+    
+    $this->setMatches($found);
+    return $this;
+  }
+  /**
+   * Run a callback on each item in the list of items.
+   *
+   * Rules of the callback:
+   * - A callback is passed two variables: $index and $item. (There is no 
+   *   special treatment of $this, as there is in jQuery.)
+   *   - You will want to pass $item by reference if it is not an
+   *     object (DOMNodes are all objects).
+   * - A callback that returns FALSE will stop execution of the each() loop. This
+   *   works like break in a standard loop.
+   * - A TRUE return value from the callback is analogous to a continue statement.
+   * - All other return values are ignored.
+   *
+   * @param callback $callback
+   *  The callback to run.
+   * @return QueryPath
+   *  The QueryPath.
+   * @see eachLambda()
+   * @see filter()
+   * @see map()
+   */
+  public function each($callback) {
+    if (is_callable($callback)) {
+      $i = 0;
+      foreach ($this->matches as $item) {
+        if (call_user_func($callback, $i, $item) === FALSE) return $this;
+        ++$i;
+      }
+    }
+    else {
+      throw new QueryPathException('Callback is not callable.');
+    }
+    return $this;
+  }
+  /**
+   * An each() iterator that takes a lambda function.
+   * 
+   * @param string $lambda
+   *  The lambda function. This will be passed ($index, &$item).
+   * @return QueryPath
+   *  The QueryPath object.
+   * @see each()
+   * @see filterLambda()
+   * @see filterCallback()
+   * @see map()
+   */
+  public function eachLambda($lambda) {
+    $index = 0;
+    foreach ($this->matches as $item) {
+      $fn = create_function('$index, &$item', $lambda);
+      if ($fn($index, $item) === FALSE) return $this;
+      ++$index;
+    }
+    return $this;
+  }
+  /**
+   * Insert the given markup as the last child.
+   *
+   * The markup will be inserted into each match in the set.
+   *
+   * The same element cannot be inserted multiple times into a document. DOM
+   * documents do not allow a single object to be inserted multiple times 
+   * into the DOM. To insert the same XML repeatedly, we must first clone
+   * the object. This has one practical implication: Once you have inserted
+   * an element into the object, you cannot further manipulate the original 
+   * element and expect the changes to be replciated in the appended object.
+   * (They are not the same -- there is no shared reference.) Instead, you
+   * will need to retrieve the appended object and operate on that.
+   *
+   * @param mixed $data
+   *  This can be either a string (the usual case), or a DOM Element.
+   * @return QueryPath
+   *  The QueryPath object.
+   * @see appendTo()
+   * @see prepend()
+   * @throws QueryPathException
+   *  Thrown if $data is an unsupported object type.
+   */
+  public function append($data) {
+    $data = $this->prepareInsert($data);
+    if (isset($data)) {
+      if (empty($this->document->documentElement) && $this->matches->count() == 0) {
+        // Then we assume we are writing to the doc root
+        $this->document->appendChild($data);
+        $found = new SplObjectStorage();
+        $found->attach($this->document->documentElement);
+        $this->setMatches($found);
+      }
+      else {
+        // You can only append in item once. So in cases where we
+        // need to append multiple times, we have to clone the node.
+        foreach ($this->matches as $m) { 
+          // DOMDocumentFragments are even more troublesome, as they don't
+          // always clone correctly. So we have to clone their children.
+          if ($data instanceof DOMDocumentFragment) {
+            foreach ($data->childNodes as $n)
+              $m->appendChild($n->cloneNode(TRUE));
+          }
+          else {
+            // Otherwise a standard clone will do.
+            $m->appendChild($data->cloneNode(TRUE));
+          }
+          
+        }
+      }
+        
+    }
+    return $this;
+  }
+  /**
+   * Append the current elements to the destination passed into the function.
+   *
+   * This cycles through all of the current matches and appends them to 
+   * the context given in $destination. If a selector is provided then the 
+   * $destination is queried (using that selector) prior to the data being
+   * appended. The data is then appended to the found items.
+   *
+   * @param QueryPath $dest
+   *  A QueryPath object that will be appended to.
+   * @return QueryPath
+   *  The original QueryPath, unaltered. Only the destination QueryPath will
+   *  be modified.
+   * @see append()
+   * @see prependTo()
+   * @throws QueryPathException
+   *  Thrown if $data is an unsupported object type.
+   */
+  public function appendTo(QueryPath $dest) {
+    foreach ($this->matches as $m) $dest->append($m);
+    return $this;
+  }
+  /**
+   * Insert the given markup as the first child.
+   *
+   * The markup will be inserted into each match in the set.
+   *
+   * @param mixed $data
+   *  This can be either a string (the usual case), or a DOM Element.
+   * @return QueryPath
+   * @see append()
+   * @see before()
+   * @see after()
+   * @see prependTo()
+   * @throws QueryPathException
+   *  Thrown if $data is an unsupported object type.
+   */
+  public function prepend($data) {
+    $data = $this->prepareInsert($data);
+    if (isset($data)) {
+      foreach ($this->matches as $m) {
+        $ins = $data->cloneNode(TRUE);
+        if ($m->hasChildNodes())
+          $m->insertBefore($ins, $m->childNodes->item(0));
+        else
+          $m->appendChild($ins);
+      }
+    }
+    return $this;
+  }
+  /**
+   * Take all nodes in the current object and prepend them to the children nodes of
+   * each matched node in the passed-in QueryPath object.
+   *
+   * This will iterate through each item in the current QueryPath object and 
+   * add each item to the beginning of the children of each element in the 
+   * passed-in QueryPath object.
+   *
+   * @see insertBefore()
+   * @see insertAfter()
+   * @see prepend()
+   * @see appendTo()
+   * @param QueryPath $dest
+   *  The destination QueryPath object.
+   * @return QueryPath
+   *  The original QueryPath, unmodified. NOT the destination QueryPath.
+   * @throws QueryPathException
+   *  Thrown if $data is an unsupported object type.
+   */
+  public function prependTo(QueryPath $dest) {
+    foreach ($this->matches as $m) $dest->prepend($m);
+    return $this;
+  }
+
+  /**
+   * Insert the given data before each element in the current set of matches.
+   *
+   * This will take the give data (XML or HTML) and put it before each of the items that 
+   * the QueryPath object currently contains. Contrast this with after().
+   * 
+   * @param mixed $data
+   *  The data to be inserted. This can be XML in a string, a DomFragment, a DOMElement,
+   *  or the other usual suspects. (See {@link qp()}).
+   * @return QueryPath
+   *  Returns the QueryPath with the new modifications. The list of elements currently
+   *  selected will remain the same.
+   * @see insertBefore()
+   * @see after()
+   * @see append()
+   * @see prepend()
+   * @throws QueryPathException
+   *  Thrown if $data is an unsupported object type.
+   */
+  public function before($data) {
+    $data = $this->prepareInsert($data);
+    foreach ($this->matches as $m) {
+      $ins = $data->cloneNode(TRUE);
+      $m->parentNode->insertBefore($ins, $m);
+    }
+    
+    return $this;
+  }
+  /**
+   * Insert the current elements into the destination document.
+   * The items are inserted before each element in the given QueryPath document.
+   * That is, they will be siblings with the current elements.
+   *
+   * @param QueryPath $dest
+   *  Destination QueryPath document.
+   * @return QueryPath
+   *  The current QueryPath object, unaltered. Only the destination QueryPath
+   *  object is altered.
+   * @see before()
+   * @see insertAfter()
+   * @see appendTo()
+   * @throws QueryPathException
+   *  Thrown if $data is an unsupported object type.
+   */
+  public function insertBefore(QueryPath $dest) {
+    foreach ($this->matches as $m) $dest->before($m);
+    return $this;
+  }
+  /**
+   * Insert the contents of the current QueryPath after the nodes in the 
+   * destination QueryPath object.
+   *
+   * @param QueryPath $dest
+   *  Destination object where the current elements will be deposited.
+   * @return QueryPath
+   *  The present QueryPath, unaltered. Only the destination object is altered.
+   * @see after()
+   * @see insertBefore()
+   * @see append()
+   * @throws QueryPathException
+   *  Thrown if $data is an unsupported object type.
+   */
+  public function insertAfter(QueryPath $dest) {
+    foreach ($this->matches as $m) $dest->after($m);
+    return $this;
+  }
+  /**
+   * Insert the given data after each element in the current QueryPath object.
+   *
+   * This inserts the element as a peer to the currently matched elements.
+   * Contrast this with {@link append()}, which inserts the data as children
+   * of matched elements.
+   *
+   * @param mixed $data
+   *  The data to be appended.
+   * @return QueryPath
+   *  The QueryPath object (with the items inserted).
+   * @see before()
+   * @see append()
+   * @throws QueryPathException
+   *  Thrown if $data is an unsupported object type.
+   */
+  public function after($data) {
+    $data = $this->prepareInsert($data);
+    foreach ($this->matches as $m) {
+      $ins = $data->cloneNode(TRUE);
+      if (isset($m->nextSibling)) 
+        $m->parentNode->insertBefore($ins, $m->nextSibling);
+      else
+        $m->parentNode->appendChild($ins);
+    }
+    return $this;
+  }
+  /**
+   * Replace the existing element(s) in the list with a new one.
+   *
+   * @param mixed $new
+   *  A DOMElement or XML in a string. This will replace all elements
+   *  currently wrapped in the QueryPath object.
+   * @return QueryPath
+   *  The QueryPath object wrapping <b>the items that were removed</b>.
+   *  This remains consistent with the jQuery API.
+   * @see append()
+   * @see prepend()
+   * @see before()
+   * @see after()
+   * @see remove()
+   * @see replaceAll()
+   */
+  public function replaceWith($new) {
+    $data = $this->prepareInsert($new);
+    $found = new SplObjectStorage();
+    foreach ($this->matches as $m) {
+      $parent = $m->parentNode;
+      $parent->insertBefore($data->cloneNode(TRUE), $m);
+      $found->attach($parent->removeChild($m));
+    }
+    $this->setMatches($found);
+    return $this;
+  }
+  /**
+   * Remove the parent element from the selected node or nodes.
+   *
+   * This takes the given list of nodes and "unwraps" them, moving them out of their parent
+   * node, and then deleting the parent node.
+   *
+   * For example, consider this:
+   *
+   * @code
+   *   <root><wrapper><content/></wrapper></root>
+   * @endcode
+   * 
+   * Now we can run this code:
+   * @code
+   *   qp($xml, 'content')->unwrap();
+   * @endcode
+   *
+   * This will result in:
+   *
+   * @code
+   *   <root><content/></root>
+   * @endcode
+   * This is the opposite of {@link wrap()}.
+   *
+   * <b>The root element cannot be unwrapped.</b> It has no parents.
+   * If you attempt to use unwrap on a root element, this will throw a QueryPathException.
+   * (You can, however, "Unwrap" a child that is a direct descendant of the root element. This
+   * will remove the root element, and replace the child as the root element. Be careful, though.
+   * You cannot set more than one child as a root element.)
+   *
+   * @return QueryPath
+   *  The QueryPath object, with the same element(s) selected.
+   * @throws QueryPathException
+   *  An exception is thrown if one attempts to unwrap a root element.
+   * @see wrap()
+   * @since 2.1
+   * @author mbutcher
+   */
+  public function unwrap() {
+    
+    // We do this in two loops in order to
+    // capture the case where two matches are
+    // under the same parent. Othwerwise we might
+    // remove a match before we can move it.
+    $parents = new SplObjectStorage();
+    foreach ($this->matches as $m) {
+      
+      // Cannot unwrap the root element.
+      if ($m->isSameNode($m->ownerDocument->documentElement)) {
+        throw new QueryPathException('Cannot unwrap the root element.');
+      }
+      
+      // Move children to peer of parent.
+      $parent = $m->parentNode;
+      $old = $parent->removeChild($m);
+      $parent->parentNode->insertBefore($old, $parent);
+      $parents->attach($parent);
+    }
+    
+    // Now that all the children are moved, we 
+    // remove all of the parents.
+    foreach ($parents as $ele) {
+      $ele->parentNode->removeChild($ele);
+    }
+    
+    return $this;
+  }
+  /**
+   * Wrap each element inside of the given markup.
+   *
+   * Markup is usually a string, but it can also be a DOMNode, a document
+   * fragment, a SimpleXMLElement, or another QueryPath object (in which case
+   * the first item in the list will be used.)
+   *
+   * @param mixed $markup 
+   *  Markup that will wrap each element in the current list.
+   * @return QueryPath
+   *  The QueryPath object with the wrapping changes made.
+   * @see wrapAll()
+   * @see wrapInner()
+   */
+  public function wrap($markup) {
+    $data = $this->prepareInsert($markup);
+    
+    // If the markup passed in is empty, we don't do any wrapping.
+    if (empty($data)) {
+      return $this;
+    }
+    
+    foreach ($this->matches as $m) {
+      $copy = $data->firstChild->cloneNode(TRUE);
+      
+      // XXX: Should be able to avoid doing this over and over.
+      if ($copy->hasChildNodes()) {
+        $deepest = $this->deepestNode($copy); 
+        // FIXME: Does this need a different data structure?
+        $bottom = $deepest[0];
+      }
+      else
+        $bottom = $copy;
+
+      $parent = $m->parentNode;
+      $parent->insertBefore($copy, $m);
+      $m = $parent->removeChild($m);
+      $bottom->appendChild($m);
+      //$parent->appendChild($copy);
+    }
+    return $this;  
+  }
+  /**
+   * Wrap all elements inside of the given markup.
+   *
+   * So all elements will be grouped together under this single marked up 
+   * item. This works by first determining the parent element of the first item
+   * in the list. It then moves all of the matching elements under the wrapper
+   * and inserts the wrapper where that first element was found. (This is in 
+   * accordance with the way jQuery works.)
+   *
+   * Markup is usually XML in a string, but it can also be a DOMNode, a document
+   * fragment, a SimpleXMLElement, or another QueryPath object (in which case
+   * the first item in the list will be used.)
+   * 
+   * @param string $markup 
+   *  Markup that will wrap all elements in the current list.
+   * @return QueryPath
+   *  The QueryPath object with the wrapping changes made.
+   * @see wrap()
+   * @see wrapInner()
+   */
+  public function wrapAll($markup) {
+    if ($this->matches->count() == 0) return;
+    
+    $data = $this->prepareInsert($markup);
+    
+    if (empty($data)) {
+      return $this;
+    }
+    
+    if ($data->hasChildNodes()) {
+      $deepest = $this->deepestNode($data); 
+      // FIXME: Does this need fixing?
+      $bottom = $deepest[0];
+    }
+    else
+      $bottom = $data;
+
+    $first = $this->getFirstMatch();
+    $parent = $first->parentNode;
+    $parent->insertBefore($data, $first);
+    foreach ($this->matches as $m) {
+      $bottom->appendChild($m->parentNode->removeChild($m));
+    }
+    return $this;
+  }
+  /**
+   * Wrap the child elements of each item in the list with the given markup.
+   *
+   * Markup is usually a string, but it can also be a DOMNode, a document
+   * fragment, a SimpleXMLElement, or another QueryPath object (in which case
+   * the first item in the list will be used.)
+   *
+   * @param string $markup 
+   *  Markup that will wrap children of each element in the current list.
+   * @return QueryPath
+   *  The QueryPath object with the wrapping changes made.
+   * @see wrap()
+   * @see wrapAll()
+   */
+  public function wrapInner($markup) {
+    $data = $this->prepareInsert($markup);
+    
+    // No data? Short circuit.
+    if (empty($data)) return $this;
+    
+    if ($data->hasChildNodes()) {
+      $deepest = $this->deepestNode($data); 
+      // FIXME: ???
+      $bottom = $deepest[0];
+    }
+    else
+      $bottom = $data;
+      
+    foreach ($this->matches as $m) {
+      if ($m->hasChildNodes()) {
+        while($m->firstChild) {
+          $kid = $m->removeChild($m->firstChild);
+          $bottom->appendChild($kid);
+        }
+      }
+      $m->appendChild($data);
+    }
+    return $this; 
+  }
+  /**
+   * Reduce the set of matches to the deepest child node in the tree.
+   *
+   * This loops through the matches and looks for the deepest child node of all of 
+   * the matches. "Deepest", here, is relative to the nodes in the list. It is 
+   * calculated as the distance from the starting node to the most distant child
+   * node. In other words, it is not necessarily the farthest node from the root
+   * element, but the farthest note from the matched element.
+   *
+   * In the case where there are multiple nodes at the same depth, all of the 
+   * nodes at that depth will be included.
+   *
+   * @return QueryPath
+   *  The QueryPath wrapping the single deepest node.
+   */
+  public function deepest() {
+    $deepest = 0;
+    $winner = new SplObjectStorage();
+    foreach ($this->matches as $m) {
+      $local_deepest = 0;
+      $local_ele = $this->deepestNode($m, 0, NULL, $local_deepest);
+      
+      // Replace with the new deepest.
+      if ($local_deepest > $deepest) {
+        $winner = new SplObjectStorage();
+        foreach ($local_ele as $lele) $winner->attach($lele);
+        $deepest = $local_deepest;
+      }
+      // Augument with other equally deep elements.
+      elseif ($local_deepest == $deepest) {
+        foreach ($local_ele as $lele)
+          $winner->attach($lele);
+      }
+    }
+    $this->setMatches($winner);
+    return $this;
+  }
+  
+  /**
+   * A depth-checking function. Typically, it only needs to be
+   * invoked with the first parameter. The rest are used for recursion.
+   * @see deepest();
+   * @param DOMNode $ele
+   *  The element.
+   * @param int $depth
+   *  The depth guage
+   * @param mixed $current
+   *  The current set.
+   * @param DOMNode $deepest
+   *  A reference to the current deepest node.
+   * @return array
+   *  Returns an array of DOM nodes.
+   */
+  protected function deepestNode(DOMNode $ele, $depth = 0, $current = NULL, &$deepest = NULL) {
+    // FIXME: Should this use SplObjectStorage?
+    if (!isset($current)) $current = array($ele);
+    if (!isset($deepest)) $deepest = $depth;
+    if ($ele->hasChildNodes()) {
+      foreach ($ele->childNodes as $child) {
+        if ($child->nodeType === XML_ELEMENT_NODE) {
+          $current = $this->deepestNode($child, $depth + 1, $current, $deepest);
+        }
+      }
+    }
+    elseif ($depth > $deepest) {
+      $current = array($ele);
+      $deepest = $depth;
+    }
+    elseif ($depth === $deepest) {
+      $current[] = $ele;
+    }
+    return $current;
+  }
+  
+  /**
+   * Prepare an item for insertion into a DOM.
+   *
+   * This handles a variety of boilerplate tasks that need doing before an 
+   * indeterminate object can be inserted into a DOM tree.
+   * - If item is a string, this is converted into a document fragment and returned.
+   * - If item is a QueryPath, then the first item is retrieved and this call function
+   *   is called recursivel.
+   * - If the item is a DOMNode, it is imported into the current DOM if necessary.
+   * - If the item is a SimpleXMLElement, it is converted into a DOM node and then
+   *   imported.
+   *
+   * @param mixed $item
+   *  Item to prepare for insert.
+   * @return mixed
+   *  Returns the prepared item.
+   * @throws QueryPathException
+   *  Thrown if the object passed in is not of a supprted object type.
+   */
+  protected function prepareInsert($item) {
+    if(empty($item)) {
+      return;
+    }
+    elseif (is_string($item)) {
+      // If configured to do so, replace all entities.
+      if ($this->options['replace_entities']) {
+        $item = QueryPathEntities::replaceAllEntities($item);
+      }
+      
+      $frag = $this->document->createDocumentFragment();
+      try {
+        set_error_handler(array('QueryPathParseException', 'initializeFromError'), $this->errTypes);
+        $frag->appendXML($item);
+      }
+      // Simulate a finally block.
+      catch (Exception $e) {
+        restore_error_handler();
+        throw $e;
+      }
+      restore_error_handler();
+      return $frag;
+    }
+    elseif ($item instanceof QueryPath) {
+      if ($item->size() == 0) 
+        return;
+        
+      return $this->prepareInsert($item->get(0));
+    }
+    elseif ($item instanceof DOMNode) {
+      if ($item->ownerDocument !== $this->document) {
+        // Deep clone this and attach it to this document
+        $item = $this->document->importNode($item, TRUE);
+      }
+      return $item;
+    }
+    elseif ($item instanceof SimpleXMLElement) {
+      $element = dom_import_simplexml($item);
+      return $this->document->importNode($element, TRUE);
+    }
+    // What should we do here?
+    //var_dump($item);
+    throw new QueryPathException("Cannot prepare item of unsupported type: " . gettype($item));
+  }
+  /**
+   * The tag name of the first element in the list.
+   *
+   * This returns the tag name of the first element in the list of matches. If
+   * the list is empty, an empty string will be used.
+   *
+   * @see replaceAll()
+   * @see replaceWith()
+   * @return string
+   *  The tag name of the first element in the list.
+   */
+  public function tag() {
+    return ($this->size() > 0) ? $this->getFirstMatch()->tagName : '';
+  }
+  /**
+   * Remove any items from the list if they match the selector.
+   *
+   * In other words, each item that matches the selector will be remove 
+   * from the DOM document. The returned QueryPath wraps the list of 
+   * removed elements.
+   *
+   * If no selector is specified, this will remove all current matches from
+   * the document.
+   *
+   * @param string $selector
+   *  A CSS Selector.
+   * @return QueryPath
+   *  The Query path wrapping a list of removed items.
+   * @see replaceAll()
+   * @see replaceWith()
+   * @see removeChildren()
+   */
+  public function remove($selector = NULL) {
+    if(!empty($selector)) {
+      // Do a non-destructive find.
+      $query = new QueryPathCssEventHandler($this->matches);
+      $query->find($selector);
+      $matches = $query->getMatches();
+    }
+    else {
+      $matches = $this->matches;
+    }
+
+    $found = new SplObjectStorage();
+    foreach ($matches as $item) { 
+      // The item returned is (according to docs) different from 
+      // the one passed in, so we have to re-store it.
+      $found->attach($item->parentNode->removeChild($item));
+    }
+    
+    // Return a clone QueryPath with just the removed items. If
+    // no items are found, this will return an empty QueryPath.
+    return count($found) == 0 ? new QueryPath() : new QueryPath($found);
+  }
+  /**
+   * This replaces everything that matches the selector with the first value
+   * in the current list.
+   *
+   * This is the reverse of replaceWith.
+   *
+   * Unlike jQuery, QueryPath cannot assume a default document. Consequently,
+   * you must specify the intended destination document. If it is omitted, the
+   * present document is assumed to be tthe document. However, that can result
+   * in undefined behavior if the selector and the replacement are not sufficiently
+   * distinct.
+   *
+   * @param string $selector
+   *  The selector.
+   * @param DOMDocument $document
+   *  The destination document.
+   * @return QueryPath
+   *  The QueryPath wrapping the modified document.
+   * @deprecated Due to the fact that this is not a particularly friendly method,
+   *  and that it can be easily replicated using {@see replaceWith()}, it is to be 
+   *  considered deprecated.
+   * @see remove()
+   * @see replaceWith()
+   */
+  public function replaceAll($selector, DOMDocument $document) {
+    $replacement = $this->size() > 0 ? $this->getFirstMatch() : $this->document->createTextNode('');
+    
+    $c = new QueryPathCssEventHandler($document);
+    $c->find($selector);
+    $temp = $c->getMatches();
+    foreach ($temp as $item) {
+      $node = $replacement->cloneNode();
+      $node = $document->importNode($node);
+      $item->parentNode->replaceChild($node, $item);
+    }
+    return qp($document, NULL, $this->options);
+  }
+  /**
+   * Add more elements to the current set of matches.
+   *
+   * This begins the new query at the top of the DOM again. The results found
+   * when running this selector are then merged into the existing results. In
+   * this way, you can add additional elements to the existing set.
+   *
+   * @param string $selector
+   *  A valid selector.
+   * @return QueryPath
+   *  The QueryPath object with the newly added elements.
+   * @see append()
+   * @see after()
+   * @see andSelf()
+   * @see end()
+   */
+  public function add($selector) {
+    
+    // This is destructive, so we need to set $last:
+    $this->last = $this->matches;
+    
+    foreach (qp($this->document, $selector, $this->options)->get() as $item)
+      $this->matches->attach($item);
+    return $this;
+  }
+  /**
+   * Revert to the previous set of matches.
+   *
+   * This will revert back to the last set of matches (before the last 
+   * "destructive" set of operations). This undoes any change made to the set of
+   * matched objects. Functions like find() and filter() change the 
+   * list of matched objects. The end() function will revert back to the last set of
+   * matched items.
+   *
+   * Note that functions that modify the document, but do not change the list of 
+   * matched objects, are not "destructive". Thus, calling append('something')->end()
+   * will not undo the append() call.
+   *
+   * Only one level of changes is stored. Reverting beyond that will result in 
+   * an empty set of matches. Example:
+   *
+   * @code
+   * // The line below returns the same thing as qp(document, 'p');
+   * qp(document, 'p')->find('div')->end();
+   * // This returns an empty array:
+   * qp(document, 'p')->end();
+   * // This returns an empty array:
+   * qp(document, 'p')->find('div')->find('span')->end()->end();
+   * @endcode
+   *
+   * The last one returns an empty array because only one level of changes is stored.
+   *
+   * @return QueryPath
+   *  A QueryPath object reflecting the list of matches prior to the last destructive
+   *  operation.
+   * @see andSelf()
+   * @see add()
+   */
+  public function end() {
+    // Note that this does not use setMatches because it must set the previous
+    // set of matches to empty array.
+    $this->matches = $this->last;
+    $this->last = new SplObjectStorage();
+    return $this;
+  }
+  /**
+   * Combine the current and previous set of matched objects.
+   *
+   * Example:
+   *
+   * @code
+   * qp(document, 'p')->find('div')->andSelf();
+   * @endcode
+   *
+   * The code above will contain a list of all p elements and all div elements that 
+   * are beneath p elements.
+   *
+   * @see end();
+   * @return QueryPath
+   *  A QueryPath object with the results of the last two "destructive" operations.
+   * @see add()
+   * @see end()
+   */
+  public function andSelf() {
+    // This is destructive, so we need to set $last:
+    $last = $this->matches;
+    
+    foreach ($this->last as $item) $this->matches->attach($item);
+    
+    $this->last = $last;
+    return $this;
+  }
+  /**
+   * Remove all child nodes.
+   *
+   * This is equivalent to jQuery's empty() function. (However, empty() is a 
+   * PHP built-in, and cannot be used as a method name.)
+   *
+   * @return QueryPath
+   *  The QueryPath object with the child nodes removed.
+   * @see replaceWith()
+   * @see replaceAll()
+   * @see remove()
+   */
+  public function removeChildren() {
+    foreach ($this->matches as $m) {
+      while($kid = $m->firstChild) {
+        $m->removeChild($kid);
+      }
+    }
+    return $this;
+  }
+  /**
+   * Get the children of the elements in the QueryPath object.
+   *
+   * If a selector is provided, the list of children will be filtered through
+   * the selector.
+   *
+   * @param string $selector
+   *  A valid selector.
+   * @return QueryPath
+   *  A QueryPath wrapping all of the children.
+   * @see removeChildren()
+   * @see parent()
+   * @see parents()
+   * @see next()
+   * @see prev()
+   */
+  public function children($selector = NULL) {
+    $found = new SplObjectStorage();
+    foreach ($this->matches as $m) {
+      foreach($m->childNodes as $c) {
+        if ($c->nodeType == XML_ELEMENT_NODE) $found->attach($c);
+      }
+    }
+    if (empty($selector)) {
+      $this->setMatches($found);
+    }
+    else {
+      $this->matches = $found; // Don't buffer this. It is temporary.
+      $this->filter($selector);
+    }
+    return $this;
+  }
+  /**
+   * Get all child nodes (not just elements) of all items in the matched set.
+   *
+   * It gets only the immediate children, not all nodes in the subtree.
+   *
+   * This does not process iframes. Xinclude processing is dependent on the 
+   * DOM implementation and configuration.
+   *
+   * @return QueryPath
+   *  A QueryPath object wrapping all child nodes for all elements in the 
+   *  QueryPath object.
+   * @see find()
+   * @see text()
+   * @see html()
+   * @see innerHTML()
+   * @see xml()
+   * @see innerXML()
+   */
+  public function contents() {
+    $found = new SplObjectStorage();
+    foreach ($this->matches as $m) {
+      if (empty($m->childNodes)) continue; // Issue #51
+      foreach ($m->childNodes as $c) {
+        $found->attach($c);
+      }
+    }
+    $this->setMatches($found);
+    return $this;
+  }
+  /**
+   * Get a list of siblings for elements currently wrapped by this object.
+   *
+   * This will compile a list of every sibling of every element in the 
+   * current list of elements. 
+   *
+   * Note that if two siblings are present in the QueryPath object to begin with,
+   * then both will be returned in the matched set, since they are siblings of each 
+   * other. In other words,if the matches contain a and b, and a and b are siblings of 
+   * each other, than running siblings will return a set that contains 
+   * both a and b.
+   *
+   * @param string $selector
+   *  If the optional selector is provided, siblings will be filtered through
+   *  this expression.
+   * @return QueryPath
+   *  The QueryPath containing the matched siblings.
+   * @see contents()
+   * @see children()
+   * @see parent()
+   * @see parents()
+   */
+  public function siblings($selector = NULL) {
+    $found = new SplObjectStorage();
+    foreach ($this->matches as $m) {
+      $parent = $m->parentNode;
+      foreach ($parent->childNodes as $n) {
+        if ($n->nodeType == XML_ELEMENT_NODE && $n !== $m) {
+          $found->attach($n);
+        }
+      }
+    }
+    if (empty($selector)) {
+      $this->setMatches($found);
+    }
+    else {
+      $this->matches = $found; // Don't buffer this. It is temporary.
+      $this->filter($selector);
+    }
+    return $this;
+  }
+  /**
+   * Find the closest element matching the selector.
+   *
+   * This finds the closest match in the ancestry chain. It first checks the 
+   * present element. If the present element does not match, this traverses up 
+   * the ancestry chain (e.g. checks each parent) looking for an item that matches.
+   *
+   * It is provided for jQuery 1.3 compatibility.
+   * @param string $selector
+   *  A CSS Selector to match.
+   * @return QueryPath
+   *  The set of matches.
+   * @since 2.0
+   */
+  public function closest($selector) {
+    $found = new SplObjectStorage();
+    foreach ($this->matches as $m) {
+      
+      if (qp($m, NULL, $this->options)->is($selector) > 0) {
+        $found->attach($m);
+      }
+      else {
+        while ($m->parentNode->nodeType !== XML_DOCUMENT_NODE) {
+          $m = $m->parentNode;
+          // Is there any case where parent node is not an element?
+          if ($m->nodeType === XML_ELEMENT_NODE && qp($m, NULL, $this->options)->is($selector) > 0) {
+            $found->attach($m);
+            break;
+          }
+        }
+      }
+      
+    }
+    $this->setMatches($found);
+    return $this;
+  }
+  /**
+   * Get the immediate parent of each element in the QueryPath.
+   *
+   * If a selector is passed, this will return the nearest matching parent for
+   * each element in the QueryPath.
+   *
+   * @param string $selector
+   *  A valid CSS3 selector.
+   * @return QueryPath
+   *  A QueryPath object wrapping the matching parents.
+   * @see children()
+   * @see siblings()
+   * @see parents()
+   */
+  public function parent($selector = NULL) {
+    $found = new SplObjectStorage();
+    foreach ($this->matches as $m) {
+      while ($m->parentNode->nodeType !== XML_DOCUMENT_NODE) {
+        $m = $m->parentNode;
+        // Is there any case where parent node is not an element?
+        if ($m->nodeType === XML_ELEMENT_NODE) {
+          if (!empty($selector)) {
+            if (qp($m, NULL, $this->options)->is($selector) > 0) {
+              $found->attach($m);
+              break;
+            }
+          }
+          else {
+            $found->attach($m);
+            break;
+          }
+        }
+      }
+    }
+    $this->setMatches($found);
+    return $this;
+  }
+  /**
+   * Get all ancestors of each element in the QueryPath.
+   * 
+   * If a selector is present, only matching ancestors will be retrieved.
+   *
+   * @see parent()
+   * @param string $selector
+   *  A valid CSS 3 Selector.
+   * @return QueryPath
+   *  A QueryPath object containing the matching ancestors.
+   * @see siblings()
+   * @see children()
+   */
+  public function parents($selector = NULL) {
+    $found = new SplObjectStorage();
+    foreach ($this->matches as $m) {
+      while ($m->parentNode->nodeType !== XML_DOCUMENT_NODE) {
+        $m = $m->parentNode;
+        // Is there any case where parent node is not an element?
+        if ($m->nodeType === XML_ELEMENT_NODE) {
+          if (!empty($selector)) {
+            if (qp($m, NULL, $this->options)->is($selector) > 0)
+              $found->attach($m);
+          }
+          else 
+            $found->attach($m);
+        }
+      }
+    }
+    $this->setMatches($found);
+    return $this;
+  }
+  /**
+   * Set or get the markup for an element.
+   * 
+   * If $markup is set, then the giving markup will be injected into each
+   * item in the set. All other children of that node will be deleted, and this
+   * new code will be the only child or children. The markup MUST BE WELL FORMED.
+   *
+   * If no markup is given, this will return a string representing the child 
+   * markup of the first node.
+   *
+   * <b>Important:</b> This differs from jQuery's html() function. This function
+   * returns <i>the current node</i> and all of its children. jQuery returns only
+   * the children. This means you do not need to do things like this: 
+   * @code$qp->parent()->html()@endcode.
+   *
+   * By default, this is HTML 4.01, not XHTML. Use {@link xml()} for XHTML.
+   *
+   * @param string $markup
+   *  The text to insert.
+   * @return mixed
+   *  A string if no markup was passed, or a QueryPath if markup was passed.
+   * @see xml()
+   * @see text()
+   * @see contents()
+   */
+  public function html($markup = NULL) {
+    if (isset($markup)) {
+      
+      if ($this->options['replace_entities']) {
+        $markup = QueryPathEntities::replaceAllEntities($markup);
+      }
+      
+      // Parse the HTML and insert it into the DOM
+      //$doc = DOMDocument::loadHTML($markup);
+      $doc = $this->document->createDocumentFragment();
+      $doc->appendXML($markup);
+      $this->removeChildren();
+      $this->append($doc);
+      return $this;
+    }
+    $length = $this->size();
+    if ($length == 0) {
+      return NULL;
+    }
+    // Only return the first item -- that's what JQ does.
+    $first = $this->getFirstMatch();
+
+    // Catch cases where first item is not a legit DOM object.
+    if (!($first instanceof DOMNode)) {
+      return NULL;
+    }
+    
+    // Added by eabrand.
+    if(!$first->ownerDocument->documentElement) {
+      return NULL;
+    }
+    
+    if ($first instanceof DOMDocument || $first->isSameNode($first->ownerDocument->documentElement)) {
+      return $this->document->saveHTML();
+    }
+    // saveHTML cannot take a node and serialize it.
+    return $this->document->saveXML($first);
+  }
+  
+  /**
+   * Fetch the HTML contents INSIDE of the first QueryPath item.
+   *
+   * <b>This behaves the way jQuery's @codehtml()@endcode function behaves.</b>
+   *
+   * This gets all children of the first match in QueryPath. 
+   *
+   * Consider this fragment:
+   * @code
+   * <div>
+   * test <p>foo</p> test
+   * </div>
+   * @endcode
+   *
+   * We can retrieve just the contents of this code by doing something like
+   * this:
+   * @code
+   * qp($xml, 'div')->innerHTML();
+   * @endcode
+   *
+   * This would return the following:
+   * @codetest <p>foo</p> test@endcode
+   *
+   * @return string
+   *  Returns a string representation of the child nodes of the first
+   *  matched element.
+   * @see html()
+   * @see innerXML()
+   * @see innerXHTML()
+   * @since 2.0
+   */
+  public function innerHTML() {
+    return $this->innerXML();
+  } 
+  
+  /**
+   * Fetch child (inner) nodes of the first match.
+   *
+   * This will return the children of the present match. For an example, 
+   * see {@link innerHTML()}.
+   *
+   * @see innerHTML()
+   * @see innerXML()
+   * @return string
+   *  Returns a string of XHTML that represents the children of the present
+   *  node.
+   * @since 2.0
+   */
+  public function innerXHTML() {
+    $length = $this->size();
+    if ($length == 0) {
+      return NULL;
+    }
+    // Only return the first item -- that's what JQ does.
+    $first = $this->getFirstMatch();
+
+    // Catch cases where first item is not a legit DOM object.
+    if (!($first instanceof DOMNode)) {
+      return NULL;
+    }
+    elseif (!$first->hasChildNodes()) {
+      return '';
+    }
+    
+    $buffer = '';
+    foreach ($first->childNodes as $child) {
+      $buffer .= $this->document->saveXML($child, LIBXML_NOEMPTYTAG);
+    }
+    
+    return $buffer;
+  }
+  
+  /**
+   * Fetch child (inner) nodes of the first match.
+   *
+   * This will return the children of the present match. For an example, 
+   * see {@link innerHTML()}.
+   *
+   * @see innerHTML()
+   * @see innerXHTML()
+   * @return string
+   *  Returns a string of XHTML that represents the children of the present
+   *  node.
+   * @since 2.0
+   */
+  public function innerXML() {
+    $length = $this->size();
+    if ($length == 0) {
+      return NULL;
+    }
+    // Only return the first item -- that's what JQ does.
+    $first = $this->getFirstMatch();
+
+    // Catch cases where first item is not a legit DOM object.
+    if (!($first instanceof DOMNode)) {
+      return NULL;
+    }
+    elseif (!$first->hasChildNodes()) {
+      return '';
+    }
+    
+    $buffer = '';
+    foreach ($first->childNodes as $child) {
+      $buffer .= $this->document->saveXML($child);
+    }
+    
+    return $buffer;
+  }
+  
+  /**
+   * Retrieve the text of each match and concatenate them with the given separator.
+   *
+   * This has the effect of looping through all children, retrieving their text
+   * content, and then concatenating the text with a separator.
+   *
+   * @param string $sep
+   *  The string used to separate text items. The default is a comma followed by a
+   *  space.
+   * @param boolean $filterEmpties
+   *  If this is true, empty items will be ignored.
+   * @return string
+   *  The text contents, concatenated together with the given separator between
+   *  every pair of items.
+   * @see implode()
+   * @see text()
+   * @since 2.0
+   */
+  public function textImplode($sep = ', ', $filterEmpties = TRUE) {
+    $tmp = array(); 
+    foreach ($this->matches as $m) {
+      $txt = $m->textContent;
+      $trimmed = trim($txt);
+      // If filter empties out, then we only add items that have content.
+      if ($filterEmpties) {
+        if (strlen($trimmed) > 0) $tmp[] = $txt;
+      }
+      // Else add all content, even if it's empty.
+      else {
+        $tmp[] = $txt;
+      }
+    }
+    return implode($sep, $tmp);
+  }
+  /**
+   * Get the text contents from just child elements.
+   *
+   * This is a specialized variant of textImplode() that implodes text for just the
+   * child elements of the current element.
+   *
+   * @param string $separator
+   *  The separator that will be inserted between found text content.
+   * @return string
+   *  The concatenated values of all children.
+   */
+  function childrenText($separator = ' ') {
+    // Branch makes it non-destructive.
+    return $this->branch()->xpath('descendant::text()')->textImplode($separator);
+  }
+  /**
+   * Get or set the text contents of a node.
+   * @param string $text
+   *  If this is not NULL, this value will be set as the text of the node. It
+   *  will replace any existing content.
+   * @return mixed 
+   *  A QueryPath if $text is set, or the text content if no text
+   *  is passed in as a pram.
+   * @see html()
+   * @see xml()
+   * @see contents()
+   */
+  public function text($text = NULL) {
+    if (isset($text)) {
+      $this->removeChildren();
+      $textNode = $this->document->createTextNode($text);
+      foreach ($this->matches as $m) $m->appendChild($textNode);
+      return $this;
+    }
+    // Returns all text as one string:
+    $buf = '';
+    foreach ($this->matches as $m) $buf .= $m->textContent;
+    return $buf;
+  }
+  /**
+   * Get or set the text before each selected item.
+   *
+   * If $text is passed in, the text is inserted before each currently selected item.
+   *
+   * If no text is given, this will return the concatenated text after each selected element.
+   *
+   * @code
+   * <?php
+   * $xml = '<?xml version="1.0"?><root>Foo<a>Bar</a><b/></root>';
+   * 
+   * // This will return 'Foo'
+   * qp($xml, 'a')->textBefore();
+   *
+   * // This will insert 'Baz' right before <b/>.
+   * qp($xml, 'b')->textBefore('Baz');
+   * ?>
+   * @endcode
+   *
+   * @param string $text
+   *  If this is set, it will be inserted before each node in the current set of
+   *  selected items.
+   * @return mixed
+   *  Returns the QueryPath object if $text was set, and returns a string (possibly empty)
+   *  if no param is passed.
+   */
+  public function textBefore($text = NULL) {
+    if (isset($text)) {
+      $textNode = $this->document->createTextNode($text);
+      return $this->before($textNode);
+    }
+    $buffer = '';
+    foreach ($this->matches as $m) {
+      $p = $m;
+      while (isset($p->previousSibling) && $p->previousSibling->nodeType == XML_TEXT_NODE) {
+        $p = $p->previousSibling;
+        $buffer .= $p->textContent;
+      }
+    }
+    return $buffer;
+  }
+  
+  public function textAfter($text = NULL) {
+    if (isset($text)) {
+      $textNode = $this->document->createTextNode($text);
+      return $this->after($textNode);
+    }
+    $buffer = '';
+    foreach ($this->matches as $m) {
+      $n = $m;
+      while (isset($n->nextSibling) && $n->nextSibling->nodeType == XML_TEXT_NODE) {
+        $n = $n->nextSibling;
+        $buffer .= $n->textContent;
+      }
+    }
+    return $buffer;
+  }
+  
+  /**
+   * Set or get the value of an element's 'value' attribute.
+   *
+   * The 'value' attribute is common in HTML form elements. This is a 
+   * convenience function for accessing the values. Since this is not  common
+   * task on the server side, this method may be removed in future releases. (It 
+   * is currently provided for jQuery compatibility.)
+   *
+   * If a value is provided in the params, then the value will be set for all 
+   * matches. If no params are given, then the value of the first matched element
+   * will be returned. This may be NULL.
+   *
+   * @deprecated Just use attr(). There's no reason to use this on the server.
+   * @see attr()
+   * @param string $value
+   * @return mixed
+   *  Returns a QueryPath if a string was passed in, and a string if no string
+   *  was passed in. In the later case, an error will produce NULL.
+   */
+  public function val($value = NULL) {
+    if (isset($value)) {
+      $this->attr('value', $value);
+      return $this;
+    }
+    return $this->attr('value');
+  }
+  /**
+   * Set or get XHTML markup for an element or elements.
+   * 
+   * This differs from {@link html()} in that it processes (and produces)
+   * strictly XML 1.0 compliant markup.
+   *
+   * Like {@link xml()} and {@link html()}, this functions as both a 
+   * setter and a getter.
+   *
+   * This is a convenience function for fetching HTML in XML format.
+   * It does no processing of the markup (such as schema validation).
+   * @param string $markup
+   *  A string containing XML data.
+   * @return mixed
+   *  If markup is passed in, a QueryPath is returned. If no markup is passed
+   *  in, XML representing the first matched element is returned.
+   * @see html()
+   * @see innerXHTML()
+   */
+  public function xhtml($markup = NULL) {
+    
+    // XXX: This is a minor reworking of the original xml() method.
+    // This should be refactored, probably.
+    // See http://github.com/technosophos/querypath/issues#issue/10
+   
+    $omit_xml_decl = $this->options['omit_xml_declaration'];
+    if ($markup === TRUE) {
+      // Basically, we handle the special case where we don't
+      // want the XML declaration to be displayed.
+      $omit_xml_decl = TRUE;
+    }
+    elseif (isset($markup)) {
+      return $this->xml($markup);
+    }
+    
+    $length = $this->size();
+    if ($length == 0) {
+      return NULL;
+    }
+    
+    // Only return the first item -- that's what JQ does.
+    $first = $this->getFirstMatch();
+    // Catch cases where first item is not a legit DOM object.
+    if (!($first instanceof DOMNode)) {
+      return NULL;
+    }
+    
+    if ($first instanceof DOMDocument || $first->isSameNode($first->ownerDocument->documentElement)) {
+      
+      // Has the unfortunate side-effect of stripping doctype.
+      //$text = ($omit_xml_decl ? $this->document->saveXML($first->ownerDocument->documentElement, LIBXML_NOEMPTYTAG) : $this->document->saveXML(NULL, LIBXML_NOEMPTYTAG));
+      $text = $this->document->saveXML(NULL, LIBXML_NOEMPTYTAG);
+    }
+    else {
+      $text = $this->document->saveXML($first, LIBXML_NOEMPTYTAG);
+    }
+    
+    // Issue #47: Using the old trick for removing the XML tag also removed the 
+    // doctype. So we remove it with a regex:
+    if ($omit_xml_decl) {
+      $text = preg_replace('/<\?xml\s[^>]*\?>/', '', $text);
+    }
+    
+    // This is slightly lenient: It allows for cases where code incorrectly places content
+    // inside of these supposedly unary elements.
+    $unary = '/<(area|base|basefont|br|col|frame|hr|img|input|isindex|link|meta|param)(?(?=\s)([^>\/]+))><\/[^>]*>/i';
+    $text = preg_replace($unary, '<\\1\\2 />', $text);
+    
+    // Experimental: Support for enclosing CDATA sections with comments to be both XML compat
+    // and HTML 4/5 compat
+    $cdata = '/(<!\[CDATA\[|\]\]>)/i';
+    $replace = $this->options['escape_xhtml_js_css_sections'];
+    $text = preg_replace($cdata, $replace, $text);
+    
+    return $text;
+  }
+  /**
+   * Set or get the XML markup for an element or elements.
+   *
+   * Like {@link html()}, this functions in both a setter and a getter mode.
+   * 
+   * In setter mode, the string passed in will be parsed and then appended to the 
+   * elements wrapped by this QueryPath object.When in setter mode, this parses 
+   * the XML using the DOMFragment parser. For that reason, an XML declaration 
+   * is not necessary.
+   *
+   * In getter mode, the first element wrapped by this QueryPath object will be 
+   * converted to an XML string and returned.
+   *
+   * @param string $markup
+   *  A string containing XML data.
+   * @return mixed
+   *  If markup is passed in, a QueryPath is returned. If no markup is passed
+   *  in, XML representing the first matched element is returned.
+   * @see xhtml()
+   * @see html()
+   * @see text()
+   * @see content()
+   * @see innerXML()
+   */
+  public function xml($markup = NULL) {
+    $omit_xml_decl = $this->options['omit_xml_declaration'];
+    if ($markup === TRUE) {
+      // Basically, we handle the special case where we don't
+      // want the XML declaration to be displayed.
+      $omit_xml_decl = TRUE;
+    }
+    elseif (isset($markup)) {
+      if ($this->options['replace_entities']) {
+        $markup = QueryPathEntities::replaceAllEntities($markup);
+      }
+      $doc = $this->document->createDocumentFragment();
+      $doc->appendXML($markup);
+      $this->removeChildren();
+      $this->append($doc);
+      return $this;
+    }
+    $length = $this->size();
+    if ($length == 0) {
+      return NULL;
+    }
+    // Only return the first item -- that's what JQ does.
+    $first = $this->getFirstMatch();
+    
+    // Catch cases where first item is not a legit DOM object.
+    if (!($first instanceof DOMNode)) {
+      return NULL;
+    }
+    
+    if ($first instanceof DOMDocument || $first->isSameNode($first->ownerDocument->documentElement)) {
+      
+      return  ($omit_xml_decl ? $this->document->saveXML($first->ownerDocument->documentElement) : $this->document->saveXML());
+    }
+    return $this->document->saveXML($first);
+  }
+  /**
+   * Send the XML document to the client.
+   * 
+   * Write the document to a file path, if given, or 
+   * to stdout (usually the client).
+   *
+   * This prints the entire document.
+   *
+   * @param string $path
+   *  The path to the file into which the XML should be written. if 
+   *  this is NULL, data will be written to STDOUT, which is usually
+   *  sent to the remote browser.
+   * @param int $options
+   *  (As of QueryPath 2.1) Pass libxml options to the saving mechanism.
+   * @return QueryPath
+   *  The QueryPath object, unmodified.
+   * @see xml()
+   * @see innerXML()
+   * @see writeXHTML()
+   * @throws Exception 
+   *  In the event that a file cannot be written, an Exception will be thrown.
+   */
+  public function writeXML($path = NULL, $options = NULL) {
+    if ($path == NULL) {
+      print $this->document->saveXML(NULL, $options);
+    }
+    else {
+      try {
+        set_error_handler(array('QueryPathIOException', 'initializeFromError'));
+        $this->document->save($path, $options);
+      }
+      catch (Exception $e) {
+        restore_error_handler();
+        throw $e;
+      }
+      restore_error_handler();
+    }
+    return $this;
+  }
+  /**
+   * Writes HTML to output.
+   *
+   * HTML is formatted as HTML 4.01, without strict XML unary tags. This is for
+   * legacy HTML content. Modern XHTML should be written using {@link toXHTML()}.
+   * 
+   * Write the document to stdout (usually the client) or to a file.
+   *
+   * @param string $path
+   *  The path to the file into which the XML should be written. if 
+   *  this is NULL, data will be written to STDOUT, which is usually
+   *  sent to the remote browser.
+   * @return QueryPath
+   *  The QueryPath object, unmodified.
+   * @see html()
+   * @see innerHTML()
+   * @throws Exception 
+   *  In the event that a file cannot be written, an Exception will be thrown.
+   */
+  public function writeHTML($path = NULL) {
+    if ($path == NULL) {
+      print $this->document->saveHTML();
+    }
+    else {
+      try {
+        set_error_handler(array('QueryPathParseException', 'initializeFromError'));
+        $this->document->saveHTMLFile($path);
+      }
+      catch (Exception $e) {
+        restore_error_handler();
+        throw $e;
+      }
+      restore_error_handler();
+    }
+    return $this;
+  }
+  
+  /**
+   * Write an XHTML file to output.
+   *
+   * Typically, you should use this instead of {@link writeHTML()}.
+   *
+   * Currently, this functions identically to {@link toXML()} <i>except that</i>
+   * it always uses closing tags (e.g. always @code<script></script>@endcode, 
+   * never @code<script/>@endcode). It will
+   * write the file as well-formed XML. No XHTML schema validation is done.
+   *
+   * @see writeXML()
+   * @see xml()
+   * @see writeHTML()
+   * @see innerXHTML()
+   * @see xhtml()
+   * @param string $path
+   *  The filename of the file to write to.
+   * @return QueryPath
+   *  Returns the QueryPath, unmodified.
+   * @throws Exception
+   *  In the event that the output file cannot be written, an exception is
+   *  thrown.
+   * @since 2.0
+   */
+  public function writeXHTML($path = NULL) {
+    return $this->writeXML($path, LIBXML_NOEMPTYTAG);
+    /*
+    if ($path == NULL) {
+      print $this->document->saveXML(NULL, LIBXML_NOEMPTYTAG);
+    }
+    else {
+      try {
+        set_error_handler(array('QueryPathIOException', 'initializeFromError'));
+        $this->document->save($path, LIBXML_NOEMPTYTAG);
+      }
+      catch (Exception $e) {
+        restore_error_handler();
+        throw $e;
+      }
+      restore_error_handler();
+    }
+    return $this;
+    */
+  }
+  /**
+   * Get the next sibling of each element in the QueryPath.
+   *
+   * If a selector is provided, the next matching sibling will be returned.
+   *
+   * @param string $selector
+   *  A CSS3 selector.
+   * @return QueryPath
+   *  The QueryPath object.
+   * @see nextAll()
+   * @see prev()
+   * @see children()
+   * @see contents()
+   * @see parent()
+   * @see parents()
+   */
+  public function next($selector = NULL) {
+    $found = new SplObjectStorage();
+    foreach ($this->matches as $m) {
+      while (isset($m->nextSibling)) {
+        $m = $m->nextSibling;
+        if ($m->nodeType === XML_ELEMENT_NODE) {
+          if (!empty($selector)) {
+            if (qp($m, NULL, $this->options)->is($selector) > 0) {
+              $found->attach($m);
+              break;
+            }
+          }
+          else {
+            $found->attach($m);
+            break;
+          }
+        }
+      }
+    }
+    $this->setMatches($found);
+    return $this;
+  }
+  /**
+   * Get all siblings after an element.
+   *
+   * For each element in the QueryPath, get all siblings that appear after
+   * it. If a selector is passed in, then only siblings that match the 
+   * selector will be included.
+   *
+   * @param string $selector 
+   *  A valid CSS 3 selector.
+   * @return QueryPath
+   *  The QueryPath object, now containing the matching siblings.
+   * @see next()
+   * @see prevAll()
+   * @see children()
+   * @see siblings()
+   */
+  public function nextAll($selector = NULL) {
+    $found = new SplObjectStorage();
+    foreach ($this->matches as $m) {
+      while (isset($m->nextSibling)) {
+        $m = $m->nextSibling;
+        if ($m->nodeType === XML_ELEMENT_NODE) {
+          if (!empty($selector)) {
+            if (qp($m, NULL, $this->options)->is($selector) > 0) {
+              $found->attach($m);
+            }
+          }
+          else {
+            $found->attach($m);
+          }
+        }
+      }
+    }
+    $this->setMatches($found);
+    return $this;
+  }
+  /**
+   * Get the next sibling before each element in the QueryPath.
+   *
+   * For each element in the QueryPath, this retrieves the previous sibling
+   * (if any). If a selector is supplied, it retrieves the first matching 
+   * sibling (if any is found).
+   *
+   * @param string $selector
+   *  A valid CSS 3 selector.
+   * @return QueryPath
+   *  A QueryPath object, now containing any previous siblings that have been 
+   *  found.
+   * @see prevAll()
+   * @see next()
+   * @see siblings()
+   * @see children()
+   */
+  public function prev($selector = NULL) {
+    $found = new SplObjectStorage();
+    foreach ($this->matches as $m) {
+      while (isset($m->previousSibling)) {
+        $m = $m->previousSibling;
+        if ($m->nodeType === XML_ELEMENT_NODE) {
+          if (!empty($selector)) {
+            if (qp($m, NULL, $this->options)->is($selector)) {
+              $found->attach($m);
+              break;
+            }
+          }
+          else {
+            $found->attach($m);
+            break;
+          }
+        }
+      }
+    }
+    $this->setMatches($found);
+    return $this;
+  }
+  /**
+   * Get the previous siblings for each element in the QueryPath.
+   *
+   * For each element in the QueryPath, get all previous siblings. If a 
+   * selector is provided, only matching siblings will be retrieved.
+   *
+   * @param string $selector
+   *  A valid CSS 3 selector.
+   * @return QueryPath
+   *  The QueryPath object, now wrapping previous sibling elements.
+   * @see prev()
+   * @see nextAll()
+   * @see siblings()
+   * @see contents()
+   * @see children()
+   */
+  public function prevAll($selector = NULL) {
+    $found = new SplObjectStorage();
+    foreach ($this->matches as $m) {
+      while (isset($m->previousSibling)) {
+        $m = $m->previousSibling;
+        if ($m->nodeType === XML_ELEMENT_NODE) {
+          if (!empty($selector)) {
+            if (qp($m, NULL, $this->options)->is($selector)) {
+              $found->attach($m);
+            }
+          }
+          else {
+            $found->attach($m);
+          }
+        }
+      }
+    }
+    $this->setMatches($found);
+    return $this;
+  }
+  /**
+   * @deprecated Use {@link siblings()}.
+   */
+  public function peers($selector = NULL) {
+    $found = new SplObjectStorage();
+    foreach ($this->matches as $m) {
+      foreach ($m->parentNode->childNodes as $kid) {
+        if ($kid->nodeType == XML_ELEMENT_NODE && $m !== $kid) {
+          if (!empty($selector)) {
+            if (qp($kid, NULL, $this->options)->is($selector)) {
+              $found->attach($kid);
+            }
+          }
+          else {
+            $found->attach($kid);
+          }
+        }
+      }
+    }
+    $this->setMatches($found);
+    return $this;
+  }
+  /**
+   * Add a class to all elements in the current QueryPath.
+   *
+   * This searchers for a class attribute on each item wrapped by the current 
+   * QueryPath object. If no attribute is found, a new one is added and its value
+   * is set to $class. If a class attribute is found, then the value is appended
+   * on to the end.
+   *
+   * @param string $class 
+   *  The name of the class.
+   * @return QueryPath
+   *  Returns the QueryPath object.
+   * @see css()
+   * @see attr()
+   * @see removeClass()
+   * @see hasClass()
+   */
+  public function addClass($class) {
+    foreach ($this->matches as $m) {
+      if ($m->hasAttribute('class')) {
+        $val = $m->getAttribute('class');
+        $m->setAttribute('class', $val . ' ' . $class);
+      }
+      else {
+        $m->setAttribute('class', $class);
+      }
+    }
+    return $this;
+  }
+  /**
+   * Remove the named class from any element in the QueryPath that has it.
+   *
+   * This may result in the entire class attribute being removed. If there
+   * are other items in the class attribute, though, they will not be removed.
+   * 
+   * Example:
+   * Consider this XML:
+   * @code
+   * <element class="first second"/>
+   * @endcode
+   *
+   * Executing this fragment of code will remove only the 'first' class:
+   * @code
+   * qp(document, 'element')->removeClass('first');
+   * @endcode
+   *
+   * The resulting XML will be:
+   * @code
+   * <element class="second"/>
+   * @endcode
+   *
+   * To remove the entire 'class' attribute, you should use {@see removeAttr()}.
+   *
+   * @param string $class
+   *  The class name to remove.
+   * @return QueryPath
+   *  The modified QueryPath object.
+   * @see attr()
+   * @see addClass()
+   * @see hasClass()
+   */
+  public function removeClass($class) {
+    foreach ($this->matches as $m) {
+      if ($m->hasAttribute('class')) {
+        $vals = explode(' ', $m->getAttribute('class'));
+        if (in_array($class, $vals)) {
+          $buf = array();
+          foreach ($vals as $v) {
+            if ($v != $class) $buf[] = $v;
+          }
+          if (count($buf) == 0)
+            $m->removeAttribute('class');
+          else
+            $m->setAttribute('class', implode(' ', $buf));
+        }
+      }
+    }
+    return $this;
+  }
+  /**
+   * Returns TRUE if any of the elements in the QueryPath have the specified class.
+   *
+   * @param string $class
+   *  The name of the class.
+   * @return boolean 
+   *  TRUE if the class exists in one or more of the elements, FALSE otherwise.
+   * @see addClass()
+   * @see removeClass()
+   */
+  public function hasClass($class) {
+    foreach ($this->matches as $m) {
+      if ($m->hasAttribute('class')) {
+        $vals = explode(' ', $m->getAttribute('class'));
+        if (in_array($class, $vals)) return TRUE;
+      }
+    }
+    return FALSE;
+  }
+
+  /**
+   * Branch the base QueryPath into another one with the same matches.
+   *
+   * This function makes a copy of the QueryPath object, but keeps the new copy 
+   * (initially) pointed at the same matches. This object can then be queried without
+   * changing the original QueryPath. However, changes to the elements inside of this
+   * QueryPath will show up in the QueryPath from which it is branched.
+   * 
+   * Compare this operation with {@link cloneAll()}. The cloneAll() call takes
+   * the current QueryPath object and makes a copy of all of its matches. You continue
+   * to operate on the same QueryPath object, but the elements inside of the QueryPath
+   * are copies of those before the call to cloneAll().
+   *
+   * This, on the other hand, copies <i>the QueryPath</i>, but keeps valid 
+   * references to the document and the wrapped elements. A new query branch is 
+   * created, but any changes will be written back to the same document.
+   *
+   * In practice, this comes in handy when you want to do multiple queries on a part
+   * of the document, but then return to a previous set of matches. (see {@link QPTPL}
+   * for examples of this in practice).
+   *
+   * Example:
+   *
+   * @code
+   * <?php
+   * $qp = qp(QueryPath::HTML_STUB);
+   * $branch = $qp->branch();
+   * $branch->find('title')->text('Title');
+   * $qp->find('body')->text('This is the body')->writeHTML;
+   * ?>
+   * @endcode
+   *
+   * Notice that in the code, each of the QueryPath objects is doing its own 
+   * query. However, both are modifying the same document. The result of the above 
+   * would look something like this:
+   *
+   * @code
+   * <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
+   * <html xmlns="http://www.w3.org/1999/xhtml">
+   * <head>
+   *    <meta http-equiv="Content-Type" content="text/html; charset=utf-8"></meta>
+   *    <title>Title</title>
+   * </head>
+   * <body>This is the body</body>
+   * </html>
+   * @endcode
+   *
+   * Notice that while $qp and $banch were performing separate queries, they 
+   * both modified the same document.
+   *
+   * In jQuery or a browser-based solution, you generally do not need a branching
+   * function because there is (implicitly) only one document. In QueryPath, there
+   * is no implicit document. Every document must be explicitly specified (and,
+   * in most cases, parsed -- which is costly). Branching makes it possible to 
+   * work on one document with multiple QueryPath objects.
+   *
+   * @param string $selector
+   *  If a selector is passed in, an additional {@link find()} will be executed
+   *  on the branch before it is returned. (Added in QueryPath 2.0.)
+   * @return QueryPath
+   *  A copy of the QueryPath object that points to the same set of elements that
+   *  the original QueryPath was pointing to.
+   * @since 1.1
+   * @see cloneAll()
+   * @see find()
+   */
+  public function branch($selector = NULL) {
+    $temp = qp($this->matches, NULL, $this->options);
+    if (isset($selector)) $temp->find($selector);
+    return $temp;
+  }
+  /**
+   * Perform a deep clone of each node in the QueryPath.
+   *
+   * This does not clone the QueryPath object, but instead clones the 
+   * list of nodes wrapped by the QueryPath. Every element is deeply 
+   * cloned.
+   *
+   * This method is analogous to jQuery's clone() method.
+   *
+   * This is a destructive operation, which means that end() will revert
+   * the list back to the clone's original.
+   * @see qp()
+   * @return QueryPath
+   */
+  public function cloneAll() {
+    $found = new SplObjectStorage();
+    foreach ($this->matches as $m) $found->attach($m->cloneNode(TRUE));
+    $this->setMatches($found, FALSE);
+    return $this;
+  }
+  
+  /**
+   * Clone the QueryPath.
+   *
+   * This makes a deep clone of the elements inside of the QueryPath.
+   *
+   * This clones only the QueryPathImpl, not all of the decorators. The
+   * clone operator in PHP should handle the cloning of the decorators.
+   */
+  public function __clone() {
+    //XXX: Should we clone the document?
+    
+    // Make sure we clone the kids.
+    $this->cloneAll();
+  }  
+
+  /**
+   * Detach any items from the list if they match the selector.
+   *
+   * In other words, each item that matches the selector will be remove
+   * from the DOM document. The returned QueryPath wraps the list of
+   * removed elements.
+   *
+   * If no selector is specified, this will remove all current matches from
+   * the document.
+   *
+   * @param string $selector
+   *  A CSS Selector.
+   * @return QueryPath
+   *  The Query path wrapping a list of removed items.
+   * @see replaceAll()
+   * @see replaceWith()
+   * @see removeChildren()
+   * @since 2.1
+   * @author eabrand
+   */
+  public function detach($selector = NULL) {
+
+    if(!empty($selector))
+    $this->find($selector);
+
+    $found = new SplObjectStorage();
+    $this->last = $this->matches;
+    foreach ($this->matches as $item) {
+      // The item returned is (according to docs) different from
+      // the one passed in, so we have to re-store it.
+      $found->attach($item->parentNode->removeChild($item));
+    }
+    $this->setMatches($found);
+    return $this;
+  }
+
+  /**
+   * Attach any items from the list if they match the selector.
+   *
+   * If no selector is specified, this will remove all current matches from
+   * the document.
+   *
+   * @param QueryPath $dest
+   *  A QueryPath Selector.
+   * @return QueryPath
+   *  The Query path wrapping a list of removed items.
+   * @see replaceAll()
+   * @see replaceWith()
+   * @see removeChildren()
+   * @since 2.1
+   * @author eabrand
+   */
+  public function attach(QueryPath $dest) {
+    foreach ($this->last as $m) $dest->append($m);
+    return $this;
+  }
+  
+  /**
+   * Reduce the elements matched by QueryPath to only those which contain the given item.
+   *
+   * There are two ways in which this is different from jQuery's implementation:
+   * - We allow ANY DOMNode, not just DOMElements. That means this will work on 
+   *   processor instructions, text nodes, comments, etc.
+   * - Unlike jQuery, this implementation of has() follows QueryPath standard behavior
+   *   and modifies the existing object. It does not create a brand new object.
+   * 
+   * @param mixed $contained
+   *   - If $contained is a CSS selector (e.g. '#foo'), this will test to see
+   *     if the current QueryPath has any elements that contain items that match
+   *     the selector.
+   *   - If $contained is a DOMNode, then this will test to see if THE EXACT DOMNode
+   *     exists in the currently matched elements. (Note that you cannot match across DOM trees, even if it is the same document.)
+   * @since 2.1
+   * @author eabrand
+   * @todo It would be trivially easy to add support for iterating over an array or Iterable of DOMNodes.
+   */
+  public function has($contained) {
+    $found = new SplObjectStorage();
+    
+    // If it's a selector, we just get all of the DOMNodes that match the selector.
+    $nodes = array();
+    if (is_string($contained)) {
+      // Get the list of nodes.
+      $nodes = $this->branch($contained)->get();
+    }
+    elseif ($contained instanceof DOMNode) {
+      // Make a list with one node.
+      $nodes = array($contained);
+    }
+    
+    // Now we go through each of the nodes that we are testing. We want to find
+    // ALL PARENTS that are in our existing QueryPath matches. Those are the
+    // ones we add to our new matches.
+    foreach ($nodes as $original_node) {
+      $node = $original_node;
+      while (!empty($node)/* && $node != $node->ownerDocument*/) {
+        if ($this->matches->contains($node)) {
+          $found->attach($node);
+        }
+        $node = $node->parentNode;
+      }
+    }
+    
+    $this->setMatches($found);
+    return $this;
+  }
+
+  /**
+   * Empty everything within the specified element.
+   *
+   * A convenience function for removeChildren(). This is equivalent to jQuery's 
+   * empty() function. However, `empty` is a built-in in PHP, and cannot be used as a 
+   * function name.
+   *
+   * @return QueryPath
+   *  The QueryPath object with the newly emptied elements.
+   * @see removeChildren()
+   * @since 2.1
+   * @author eabrand
+   * @deprecated The removeChildren() function is the preferred method.
+   */
+  public function emptyElement() {
+    $this->removeChildren();
+    return $this;
+  }
+  
+  /**
+   * Get the even elements, so counter-intuitively 1, 3, 5, etc.
+   *
+   *
+   *
+   * @return QueryPath
+   *  A QueryPath wrapping all of the children.
+   * @see removeChildren()
+   * @see parent()
+   * @see parents()
+   * @see next()
+   * @see prev()
+   * @since 2.1
+   * @author eabrand
+   */
+  public function even() {
+    $found = new SplObjectStorage();
+    $even = false;
+    foreach ($this->matches as $m) {
+      if ($even && $m->nodeType == XML_ELEMENT_NODE) $found->attach($m);
+      $even = ($even) ? false : true;
+    }
+    $this->setMatches($found);
+    $this->matches = $found; // Don't buffer this. It is temporary.
+    return $this;
+  }
+
+  /**
+   * Get the odd elements, so counter-intuitively 0, 2, 4, etc.
+   *
+   *
+   *
+   * @return QueryPath
+   *  A QueryPath wrapping all of the children.
+   * @see removeChildren()
+   * @see parent()
+   * @see parents()
+   * @see next()
+   * @see prev()
+   * @since 2.1
+   * @author eabrand
+   */
+  public function odd() {
+    $found = new SplObjectStorage();
+    $odd = true;
+    foreach ($this->matches as $m) {
+      if ($odd && $m->nodeType == XML_ELEMENT_NODE) $found->attach($m);
+      $odd = ($odd) ? false : true;
+    }
+    $this->setMatches($found);
+    $this->matches = $found; // Don't buffer this. It is temporary.
+    return $this;
+  }
+  
+  /**
+   * Get the first matching element.
+   *
+   *
+   * @return QueryPath
+   *  A QueryPath wrapping all of the children.
+   * @see next()
+   * @see prev()
+   * @since 2.1
+   * @author eabrand
+   */
+  public function first() {
+    $found = new SplObjectStorage();
+    foreach ($this->matches as $m) {
+      if ($m->nodeType == XML_ELEMENT_NODE) {
+        $found->attach($m);
+        break;
+      }
+    }
+    $this->setMatches($found);
+    $this->matches = $found; // Don't buffer this. It is temporary.
+    return $this;
+  }
+
+  /**
+   * Get the first child of the matching element.
+   *
+   *
+   * @return QueryPath
+   *  A QueryPath wrapping all of the children.
+   * @see next()
+   * @see prev()
+   * @since 2.1
+   * @author eabrand
+   */
+  public function firstChild() {
+    // Could possibly use $m->firstChild http://theserverpages.com/php/manual/en/ref.dom.php
+    $found = new SplObjectStorage();
+    $flag = false;
+    foreach ($this->matches as $m) {
+      foreach($m->childNodes as $c) {
+        if ($c->nodeType == XML_ELEMENT_NODE) {
+          $found->attach($c);
+          $flag = true;
+          break;
+        }
+      }
+      if($flag) break;
+    }
+    $this->setMatches($found);
+    $this->matches = $found; // Don't buffer this. It is temporary.
+    return $this;
+  }
+
+  /**
+   * Get the last matching element.
+   *
+   *
+   * @return QueryPath
+   *  A QueryPath wrapping all of the children.
+   * @see next()
+   * @see prev()
+   * @since 2.1
+   * @author eabrand
+   */
+  public function last() {
+    $found = new SplObjectStorage();
+    $item = null;
+    foreach ($this->matches as $m) {
+      if ($m->nodeType == XML_ELEMENT_NODE) {
+        $item = $m;
+      }
+    }
+    if ($item) {
+      $found->attach($item);
+    }
+    $this->setMatches($found);
+    $this->matches = $found; // Don't buffer this. It is temporary.
+    return $this;
+  }
+
+  /**
+   * Get the last child of the matching element.
+   *
+   *
+   * @return QueryPath
+   *  A QueryPath wrapping all of the children.
+   * @see next()
+   * @see prev()
+   * @since 2.1
+   * @author eabrand
+   */
+  public function lastChild() {
+    $found = new SplObjectStorage();
+    $item = null;
+    foreach ($this->matches as $m) {
+      foreach($m->childNodes as $c) {
+        if ($c->nodeType == XML_ELEMENT_NODE) {
+          $item = $c;
+        }
+      }
+      if ($item) {
+        $found->attach($item);
+        $item = null;
+      }
+    }
+    $this->setMatches($found);
+    $this->matches = $found; // Don't buffer this. It is temporary.
+    return $this;
+  }
+
+  /**
+   * Get all siblings after an element until the selector is reached.
+   *
+   * For each element in the QueryPath, get all siblings that appear after
+   * it. If a selector is passed in, then only siblings that match the
+   * selector will be included.
+   *
+   * @param string $selector
+   *  A valid CSS 3 selector.
+   * @return QueryPath
+   *  The QueryPath object, now containing the matching siblings.
+   * @see next()
+   * @see prevAll()
+   * @see children()
+   * @see siblings()
+   * @since 2.1
+   * @author eabrand
+   */
+  public function nextUntil($selector = NULL) {
+    $found = new SplObjectStorage();
+    foreach ($this->matches as $m) {
+      while (isset($m->nextSibling)) {
+        $m = $m->nextSibling;
+        if ($m->nodeType === XML_ELEMENT_NODE) {
+          if (!empty($selector)) {
+            if (qp($m, NULL, $this->options)->is($selector) > 0) {
+              break;
+            }
+            else {
+              $found->attach($m);
+            }
+          }
+          else {
+            $found->attach($m);
+          }
+        }
+      }
+    }
+    $this->setMatches($found);
+    return $this;
+  } 
+
+  /**
+   * Get the previous siblings for each element in the QueryPath
+   * until the selector is reached.
+   *
+   * For each element in the QueryPath, get all previous siblings. If a
+   * selector is provided, only matching siblings will be retrieved.
+   *
+   * @param string $selector
+   *  A valid CSS 3 selector.
+   * @return QueryPath
+   *  The QueryPath object, now wrapping previous sibling elements.
+   * @see prev()
+   * @see nextAll()
+   * @see siblings()
+   * @see contents()
+   * @see children()
+   * @since 2.1
+   * @author eabrand
+   */
+  public function prevUntil($selector = NULL) {
+    $found = new SplObjectStorage();
+    foreach ($this->matches as $m) {
+      while (isset($m->previousSibling)) {
+        $m = $m->previousSibling;
+        if ($m->nodeType === XML_ELEMENT_NODE) {
+          if (!empty($selector) && qp($m, NULL, $this->options)->is($selector))
+          break;
+          else
+          $found->attach($m);
+        }
+      }
+    }
+    $this->setMatches($found);
+    return $this;
+  }
+  
+  /**
+   * Get all ancestors of each element in the QueryPath until the selector is reached.
+   *
+   * If a selector is present, only matching ancestors will be retrieved.
+   *
+   * @see parent()
+   * @param string $selector
+   *  A valid CSS 3 Selector.
+   * @return QueryPath
+   *  A QueryPath object containing the matching ancestors.
+   * @see siblings()
+   * @see children()
+   * @since 2.1
+   * @author eabrand
+   */
+  public function parentsUntil($selector = NULL) {
+    $found = new SplObjectStorage();
+    foreach ($this->matches as $m) {
+      while ($m->parentNode->nodeType !== XML_DOCUMENT_NODE) {
+        $m = $m->parentNode;
+        // Is there any case where parent node is not an element?
+        if ($m->nodeType === XML_ELEMENT_NODE) {
+          if (!empty($selector)) {
+            if (qp($m, NULL, $this->options)->is($selector) > 0)
+            break;
+            else
+            $found->attach($m);
+          }
+          else
+          $found->attach($m);
+        }
+      }
+    }
+    $this->setMatches($found);
+    return $this;
+  }
+  
+  /////// INTERNAL FUNCTIONS ////////
+  
+  
+  /**
+   * Determine whether a given string looks like XML or not.
+   *
+   * Basically, this scans a portion of the supplied string, checking to see
+   * if it has a tag-like structure. It is possible to "confuse" this, which
+   * may subsequently result in parse errors, but in the vast majority of 
+   * cases, this method serves as a valid inicator of whether or not the 
+   * content looks like XML.
+   *
+   * Things that are intentional excluded:
+   * - plain text with no markup.
+   * - strings that look like filesystem paths.
+   * 
+   * Subclasses SHOULD NOT OVERRIDE THIS. Altering it may be altering
+   * core assumptions about how things work. Instead, classes should 
+   * override the constructor and pass in only one of the parsed types
+   * that this class expects.
+   */
+  protected function isXMLish($string) {
+    // Long strings will exhaust the regex engine, so we
+    // grab a representative string.
+    // $test = substr($string, 0, 255);
+    return (strpos($string, '<') !== FALSE && strpos($string, '>') !== FALSE);
+    //return preg_match(ML_EXP, $test) > 0;
+  }
+  
+  private function parseXMLString($string, $flags = NULL) {
+    
+    $document = new DOMDocument('1.0');
+    $lead = strtolower(substr($string, 0, 5)); // <?xml
+    try {
+      set_error_handler(array('QueryPathParseException', 'initializeFromError'), $this->errTypes);
+      
+      if (isset($this->options['convert_to_encoding'])) {
+        // Is there another way to do this?
+        
+        $from_enc = isset($this->options['convert_from_encoding']) ? $this->options['convert_from_encoding'] : 'auto';
+        $to_enc = $this->options['convert_to_encoding'];
+        
+        if (function_exists('mb_convert_encoding')) {
+          $string = mb_convert_encoding($string, $to_enc, $from_enc);
+        }
+        
+      }
+      
+      // This is to avoid cases where low ascii digits have slipped into HTML.
+      // AFAIK, it should not adversly effect UTF-8 documents.
+      if (!empty($this->options['strip_low_ascii'])) {
+        $string = filter_var($string, FILTER_UNSAFE_RAW, FILTER_FLAG_ENCODE_LOW);
+      }
+      
+      // Allow users to override parser settings.
+      if (empty($this->options['use_parser'])) {
+        $useParser = '';
+      }
+      else {
+        $useParser = strtolower($this->options['use_parser']);
+      }
+      
+      // If HTML parser is requested, we use it.
+      if ($useParser == 'html') {
+        $document->loadHTML($string);
+      }
+      // Parse as XML if it looks like XML, or if XML parser is requested.
+      elseif ($lead == '<?xml' || $useParser == 'xml') {
+        if ($this->options['replace_entities']) {
+          $string = QueryPathEntities::replaceAllEntities($string);
+        }
+        $document->loadXML($string, $flags);
+      }
+      // In all other cases, we try the HTML parser.
+      else {
+        $document->loadHTML($string);
+      }
+    }
+    // Emulate 'finally' behavior.
+    catch (Exception $e) {
+      restore_error_handler();
+      throw $e;
+    }
+    restore_error_handler();
+    
+    if (empty($document)) {
+      throw new QueryPathParseException('Unknown parser exception.');
+    }
+    return $document;
+  }
+  
+  /**
+   * EXPERT: Be very, very careful using this.
+   * A utility function for setting the current set of matches.
+   * It makes sure the last matches buffer is set (for end() and andSelf()).
+   * @since 2.0
+   */
+  public function setMatches($matches, $unique = TRUE) {
+    // This causes a lot of overhead....
+    //if ($unique) $matches = self::unique($matches);
+    $this->last = $this->matches;
+    
+    // Just set current matches.
+    if ($matches instanceof SplObjectStorage) {
+      $this->matches = $matches;
+    }
+    // This is likely legacy code that needs conversion.
+    elseif (is_array($matches)) {
+      trigger_error('Legacy array detected.');
+      $tmp = new SplObjectStorage();
+      foreach ($matches as $m) $tmp->attach($m);
+      $this->matches = $tmp;
+    }
+    // For non-arrays, try to create a new match set and 
+    // add this object.
+    else {
+      $found = new SplObjectStorage();
+      if (isset($matches)) $found->attach($matches);
+      $this->matches = $found;
+    }
+    
+    // EXPERIMENTAL: Support for qp()->length.
+    $this->length = $this->matches->count();
+  }
+  
+  /**
+   * Set the match monitor to empty.
+   *
+   * This preserves history.
+   *
+   * @since 2.0
+   */
+  private function noMatches() {
+    $this->setMatches(NULL);
+  }
+    
+  /**
+   * A utility function for retriving a match by index.
+   *
+   * The internal data structure used in QueryPath does not have
+   * strong random access support, so we suppliment it with this method.
+   */
+  private function getNthMatch($index) {
+    if ($index > $this->matches->count() || $index < 0) return;
+    
+    $i = 0;
+    foreach ($this->matches as $m) {
+      if ($i++ == $index) return $m;
+    }
+  }
+  
+  /**
+   * Convenience function for getNthMatch(0).
+   */
+  private function getFirstMatch() {
+    $this->matches->rewind();
+    return $this->matches->current();
+  }
+  
+  /**
+   * Parse just a fragment of XML.
+   * This will automatically prepend an <?xml ?> declaration before parsing.
+   * @param string $string 
+   *   Fragment to parse.
+   * @return DOMDocumentFragment 
+   *   The parsed document fragment.
+   */
+   /*
+  private function parseXMLFragment($string) {
+    $frag = $this->document->createDocumentFragment();
+    $frag->appendXML($string);
+    return $frag;
+  }
+  */
+  
+  /**
+   * Parse an XML or HTML file.
+   *
+   * This attempts to autodetect the type of file, and then parse it.
+   *
+   * @param string $filename
+   *  The file name to parse.
+   * @param int $flags
+   *  The OR-combined flags accepted by the DOM parser. See the PHP documentation
+   *  for DOM or for libxml.
+   * @param resource $context
+   *  The stream context for the file IO. If this is set, then an alternate 
+   *  parsing path is followed: The file is loaded by PHP's stream-aware IO
+   *  facilities, read entirely into memory, and then handed off to 
+   *  {@link parseXMLString()}. On large files, this can have a performance impact.
+   * @throws QueryPathParseException 
+   *  Thrown when a file cannot be loaded or parsed.
+   */
+  private function parseXMLFile($filename, $flags = NULL, $context = NULL) {
+    
+    // If a context is specified, we basically have to do the reading in 
+    // two steps:
+    if (!empty($context)) {
+      try {
+        set_error_handler(array('QueryPathParseException', 'initializeFromError'), $this->errTypes);
+        $contents = file_get_contents($filename, FALSE, $context);
+        
+      }
+      // Apparently there is no 'finally' in PHP, so we have to restore the error
+      // handler this way:
+      catch(Exception $e) {
+        restore_error_handler();
+        throw $e;
+      }
+      restore_error_handler();
+      
+      if ($contents == FALSE) {
+        throw new QueryPathParseException(sprintf('Contents of the file %s could not be retrieved.', $filename));
+      }
+      
+      
+      /* This is basically unneccessary overhead, as it is not more
+       * accurate than the existing method.
+      if (isset($md['wrapper_type']) &&  $md['wrapper_type'] == 'http') {
+        for ($i = 0; $i < count($md['wrapper_data']); ++$i) {
+          if (stripos($md['wrapper_data'][$i], 'content-type:') !== FALSE) {
+            $ct = trim(substr($md['wrapper_data'][$i], 12));
+            if (stripos('text/html') === 0) {
+              $this->parseXMLString($contents, $flags, 'text/html');
+            }
+            else {
+              // We can't account for all of the mime types that have
+              // an XML payload, so we set it to XML.
+              $this->parseXMLString($contents, $flags, 'text/xml');
+            }
+            break;
+          }
+        }
+      }
+      */
+      
+      return $this->parseXMLString($contents, $flags);
+    }
+    
+    $document = new DOMDocument();
+    $lastDot = strrpos($filename, '.');
+    
+    $htmlExtensions = array(
+      '.html' => 1,
+      '.htm' => 1,
+    );
+    
+    // Allow users to override parser settings.
+    if (empty($this->options['use_parser'])) {
+      $useParser = '';
+    }
+    else {
+      $useParser = strtolower($this->options['use_parser']);
+    }
+    
+    $ext = $lastDot !== FALSE ? strtolower(substr($filename, $lastDot)) : '';
+    
+    try {
+      set_error_handler(array('QueryPathParseException', 'initializeFromError'), $this->errTypes);
+      
+      // If the parser is explicitly set to XML, use that parser.
+      if ($useParser == 'xml') {
+        $r = $document->load($filename, $flags);
+      }
+      // Otherwise, see if it looks like HTML.
+      elseif (isset($htmlExtensions[$ext]) || $useParser == 'html') {
+        // Try parsing it as HTML.
+        $r = $document->loadHTMLFile($filename);
+      }
+      // Default to XML.
+      else {
+        $r = $document->load($filename, $flags);
+      }
+      
+    }
+    // Emulate 'finally' behavior.
+    catch (Exception $e) {
+      restore_error_handler();
+      throw $e;
+    }
+    restore_error_handler();
+    
+    
+    
+    /*
+    if ($r == FALSE) {
+      $fmt = 'Failed to load file %s: %s (%s, %s)';
+      $err = error_get_last();
+      if ($err['type'] & self::IGNORE_ERRORS) {
+        // Need to report these somehow...
+        trigger_error($err['message'], E_USER_WARNING);
+      }
+      else {
+        throw new QueryPathParseException(sprintf($fmt, $filename, $err['message'], $err['file'], $err['line']));
+      }
+      
+      //throw new QueryPathParseException(sprintf($fmt, $filename, $err['message'], $err['file'], $err['line']));
+    }
+    */
+    return $document;
+  }
+  
+  /**
+   * Call extension methods.
+   *
+   * This function is used to invoke extension methods. It searches the
+   * registered extenstensions for a matching function name. If one is found,
+   * it is executed with the arguments in the $arguments array.
+   * 
+   * @throws QueryPathException
+   *  An exception is thrown if a non-existent method is called.
+   */
+  public function __call($name, $arguments) {
+    
+    if (!QueryPathExtensionRegistry::$useRegistry) {
+      throw new QueryPathException("No method named $name found (Extensions disabled).");      
+    }
+    
+    // Loading of extensions is deferred until the first time a
+    // non-core method is called. This makes constructing faster, but it
+    // may make the first invocation of __call() slower (if there are 
+    // enough extensions.)
+    //
+    // The main reason for moving this out of the constructor is that most
+    // new QueryPath instances do not use extensions. Charging qp() calls
+    // with the additional hit is not a good idea.
+    //
+    // Also, this will at least limit the number of circular references.
+    if (empty($this->ext)) {
+      // Load the registry
+      $this->ext = QueryPathExtensionRegistry::getExtensions($this);
+    }
+    
+    // Note that an empty ext registry indicates that extensions are disabled.
+    if (!empty($this->ext) && QueryPathExtensionRegistry::hasMethod($name)) {
+      $owner = QueryPathExtensionRegistry::getMethodClass($name);
+      $method = new ReflectionMethod($owner, $name);
+      return $method->invokeArgs($this->ext[$owner], $arguments);
+    }
+    throw new QueryPathException("No method named $name found. Possibly missing an extension.");
+  }
+  
+  /**
+   * Dynamically generate certain properties.
+   *
+   * This is used primarily to increase jQuery compatibility by providing property-like
+   * behaviors.
+   *
+   * Currently defined properties:
+   *   - length: Alias of {@link size()}.
+   */
+   /*
+  public function __get($name) {
+    switch ($name) {
+      case 'length':
+        return $this->size();
+      default:
+        throw new QueryPathException('Unknown or inaccessible property "' . $name . '" (via __get())');
+    }
+  }
+  */
+  
+  /**
+   * Get an iterator for the matches in this object.
+   * @return Iterable
+   *  Returns an iterator.
+   */
+  public function getIterator() {
+    $i = new QueryPathIterator($this->matches);
+    $i->options = $this->options;
+    return $i;
+  }
+}
+
+/**
+ * Perform various tasks on HTML/XML entities.
+ *
+ * @ingroup querypath_util
+ */
+class QueryPathEntities {
+  
+  /**
+   * This is three regexes wrapped into 1. The | divides them.
+   * 1: Match any char-based entity. This will go in $matches[1]
+   * 2: Match any num-based entity. This will go in $matches[2]
+   * 3: Match any hex-based entry. This will go in $matches[3]
+   * 4: Match any ampersand that is not an entity. This goes in $matches[4]
+   *    This last rule will only match if one of the previous two has not already
+   *    matched.
+   * XXX: Are octal encodings for entities acceptable?
+   */
+  //protected static $regex = '/&([\w]+);|&#([\d]+);|&([\w]*[\s$]+)/m';
+  protected static $regex = '/&([\w]+);|&#([\d]+);|&#(x[0-9a-fA-F]+);|(&)/m';
+  
+  /**
+   * Replace all entities.
+   * This will scan a string and will attempt to replace all
+   * entities with their numeric equivalent. This will not work
+   * with specialized entities.
+   *
+   * @param string $string
+   *  The string to perform replacements on.
+   * @return string
+   *  Returns a string that is similar to the original one, but with 
+   *  all entity replacements made.
+   */
+  public static function replaceAllEntities($string) {
+    return preg_replace_callback(self::$regex, 'QueryPathEntities::doReplacement', $string);
+  }
+  
+  /**
+   * Callback for processing replacements.
+   *
+   * @param array $matches
+   *  The regular expression replacement array.
+   */
+  protected static function doReplacement($matches) {
+    // See how the regex above works out.
+    //print_r($matches);
+
+    // From count, we can tell whether we got a 
+    // char, num, or bare ampersand.
+    $count = count($matches);
+    switch ($count) {
+      case 2:
+        // We have a character entity
+        return '&#' . self::replaceEntity($matches[1]) . ';';
+      case 3:
+      case 4:
+        // we have a numeric entity
+        return '&#' . $matches[$count-1] . ';'; 
+      case 5:
+        // We have an unescaped ampersand.
+        return '&#38;';
+    }
+  }
+  
+  /**
+   * Lookup an entity string's numeric equivalent.
+   *
+   * @param string $entity
+   *  The entity whose numeric value is needed.
+   * @return int
+   *  The integer value corresponding to the entity.
+   * @author Matt Butcher
+   * @author Ryan Mahoney
+   */
+  public static function replaceEntity($entity) {
+    return self::$entity_array[$entity];
+  }
+  
+  /**
+   * Conversion mapper for entities in HTML.
+   * Large entity conversion table. This is 
+   * significantly broader in range than 
+   * get_html_translation_table(HTML_ENTITIES).
+   *
+   * This code comes from Rhizome ({@link http://code.google.com/p/sinciput})
+   *
+   * @see get_html_translation_table()
+   */
+  private static $entity_array = array(
+	  'nbsp' => 160, 'iexcl' => 161, 'cent' => 162, 'pound' => 163, 
+	  'curren' => 164, 'yen' => 165, 'brvbar' => 166, 'sect' => 167, 
+	  'uml' => 168, 'copy' => 169, 'ordf' => 170, 'laquo' => 171, 
+	  'not' => 172, 'shy' => 173, 'reg' => 174, 'macr' => 175, 'deg' => 176, 
+	  'plusmn' => 177, 'sup2' => 178, 'sup3' => 179, 'acute' => 180, 
+	  'micro' => 181, 'para' => 182, 'middot' => 183, 'cedil' => 184, 
+	  'sup1' => 185, 'ordm' => 186, 'raquo' => 187, 'frac14' => 188, 
+	  'frac12' => 189, 'frac34' => 190, 'iquest' => 191, 'Agrave' => 192, 
+	  'Aacute' => 193, 'Acirc' => 194, 'Atilde' => 195, 'Auml' => 196, 
+	  'Aring' => 197, 'AElig' => 198, 'Ccedil' => 199, 'Egrave' => 200, 
+	  'Eacute' => 201, 'Ecirc' => 202, 'Euml' => 203, 'Igrave' => 204, 
+	  'Iacute' => 205, 'Icirc' => 206, 'Iuml' => 207, 'ETH' => 208, 
+	  'Ntilde' => 209, 'Ograve' => 210, 'Oacute' => 211, 'Ocirc' => 212, 
+	  'Otilde' => 213, 'Ouml' => 214, 'times' => 215, 'Oslash' => 216, 
+	  'Ugrave' => 217, 'Uacute' => 218, 'Ucirc' => 219, 'Uuml' => 220, 
+	  'Yacute' => 221, 'THORN' => 222, 'szlig' => 223, 'agrave' => 224, 
+	  'aacute' => 225, 'acirc' => 226, 'atilde' => 227, 'auml' => 228, 
+	  'aring' => 229, 'aelig' => 230, 'ccedil' => 231, 'egrave' => 232, 
+	  'eacute' => 233, 'ecirc' => 234, 'euml' => 235, 'igrave' => 236, 
+	  'iacute' => 237, 'icirc' => 238, 'iuml' => 239, 'eth' => 240, 
+	  'ntilde' => 241, 'ograve' => 242, 'oacute' => 243, 'ocirc' => 244, 
+	  'otilde' => 245, 'ouml' => 246, 'divide' => 247, 'oslash' => 248, 
+	  'ugrave' => 249, 'uacute' => 250, 'ucirc' => 251, 'uuml' => 252, 
+	  'yacute' => 253, 'thorn' => 254, 'yuml' => 255, 'quot' => 34, 
+	  'amp' => 38, 'lt' => 60, 'gt' => 62, 'apos' => 39, 'OElig' => 338, 
+	  'oelig' => 339, 'Scaron' => 352, 'scaron' => 353, 'Yuml' => 376, 
+	  'circ' => 710, 'tilde' => 732, 'ensp' => 8194, 'emsp' => 8195, 
+	  'thinsp' => 8201, 'zwnj' => 8204, 'zwj' => 8205, 'lrm' => 8206, 
+	  'rlm' => 8207, 'ndash' => 8211, 'mdash' => 8212, 'lsquo' => 8216, 
+	  'rsquo' => 8217, 'sbquo' => 8218, 'ldquo' => 8220, 'rdquo' => 8221, 
+	  'bdquo' => 8222, 'dagger' => 8224, 'Dagger' => 8225, 'permil' => 8240, 
+	  'lsaquo' => 8249, 'rsaquo' => 8250, 'euro' => 8364, 'fnof' => 402, 
+	  'Alpha' => 913, 'Beta' => 914, 'Gamma' => 915, 'Delta' => 916, 
+	  'Epsilon' => 917, 'Zeta' => 918, 'Eta' => 919, 'Theta' => 920, 
+	  'Iota' => 921, 'Kappa' => 922, 'Lambda' => 923, 'Mu' => 924, 'Nu' => 925, 
+	  'Xi' => 926, 'Omicron' => 927, 'Pi' => 928, 'Rho' => 929, 'Sigma' => 931,
+	  'Tau' => 932, 'Upsilon' => 933, 'Phi' => 934, 'Chi' => 935, 'Psi' => 936,
+	  'Omega' => 937, 'alpha' => 945, 'beta' => 946, 'gamma' => 947, 
+	  'delta' => 948, 'epsilon' => 949, 'zeta' => 950, 'eta' => 951, 
+	  'theta' => 952, 'iota' => 953, 'kappa' => 954, 'lambda' => 955, 
+	  'mu' => 956, 'nu' => 957, 'xi' => 958, 'omicron' => 959, 'pi' => 960, 
+	  'rho' => 961, 'sigmaf' => 962, 'sigma' => 963, 'tau' => 964, 
+	  'upsilon' => 965, 'phi' => 966, 'chi' => 967, 'psi' => 968, 
+	  'omega' => 969, 'thetasym' => 977, 'upsih' => 978, 'piv' => 982, 
+	  'bull' => 8226, 'hellip' => 8230, 'prime' => 8242, 'Prime' => 8243, 
+	  'oline' => 8254, 'frasl' => 8260, 'weierp' => 8472, 'image' => 8465, 
+	  'real' => 8476, 'trade' => 8482, 'alefsym' => 8501, 'larr' => 8592, 
+	  'uarr' => 8593, 'rarr' => 8594, 'darr' => 8595, 'harr' => 8596, 
+	  'crarr' => 8629, 'lArr' => 8656, 'uArr' => 8657, 'rArr' => 8658, 
+	  'dArr' => 8659, 'hArr' => 8660, 'forall' => 8704, 'part' => 8706, 
+	  'exist' => 8707, 'empty' => 8709, 'nabla' => 8711, 'isin' => 8712, 
+	  'notin' => 8713, 'ni' => 8715, 'prod' => 8719, 'sum' => 8721, 
+	  'minus' => 8722, 'lowast' => 8727, 'radic' => 8730, 'prop' => 8733, 
+	  'infin' => 8734, 'ang' => 8736, 'and' => 8743, 'or' => 8744, 'cap' => 8745, 
+	  'cup' => 8746, 'int' => 8747, 'there4' => 8756, 'sim' => 8764, 
+	  'cong' => 8773, 'asymp' => 8776, 'ne' => 8800, 'equiv' => 8801, 
+	  'le' => 8804, 'ge' => 8805, 'sub' => 8834, 'sup' => 8835, 'nsub' => 8836, 
+	  'sube' => 8838, 'supe' => 8839, 'oplus' => 8853, 'otimes' => 8855, 
+	  'perp' => 8869, 'sdot' => 8901, 'lceil' => 8968, 'rceil' => 8969, 
+	  'lfloor' => 8970, 'rfloor' => 8971, 'lang' => 9001, 'rang' => 9002, 
+	  'loz' => 9674, 'spades' => 9824, 'clubs' => 9827, 'hearts' => 9829, 
+	  'diams' => 9830
+	);
+}
+
+/**
+ * An iterator for QueryPath.
+ *
+ * This provides iterator support for QueryPath. You do not need to construct
+ * a QueryPathIterator. QueryPath does this when its {@link QueryPath::getIterator()}
+ * method is called.
+ *
+ * @ingroup querypath_util
+ */
+class QueryPathIterator extends IteratorIterator {
+  public $options = array();
+  private $qp = NULL;
+  
+  public function current() {
+    if (!isset($this->qp)) {
+      $this->qp = qp(parent::current(), NULL, $this->options);
+    }
+    else {
+      $splos = new SplObjectStorage();
+      $splos->attach(parent::current());
+      $this->qp->setMatches($splos);
+    }
+    return $this->qp;
+  }
+}
+
+/**
+ * Manage default options.
+ *
+ * This class stores the default options for QueryPath. When a new 
+ * QueryPath object is constructed, options specified here will be 
+ * used.
+ *
+ * <b>Details</b>
+ * This class defines no options of its own. Instead, it provides a 
+ * central tool for developers to override options set by QueryPath.
+ * When a QueryPath object is created, it will evaluate options in the 
+ * following order:
+ *
+ * - Options passed into {@link qp()} have highest priority.
+ * - Options in {@link QueryPathOptions} (this class) have the next highest priority.
+ * - If the option is not specified elsewhere, QueryPath will use its own defaults.
+ *
+ * @see qp()
+ * @see QueryPathOptions::set()
+ * @ingroup querypath_util
+ */
+class QueryPathOptions {
+  
+  /**
+   * This is the static options array.
+   *
+   * Use the {@link set()}, {@link get()}, and {@link merge()} to
+   * modify this array.
+   */
+  static $options = array();
+  
+  /**
+   * Set the default options.
+   *
+   * The passed-in array will be used as the default options list.
+   *
+   * @param array $array
+   *  An associative array of options.
+   */
+  static function set($array) {
+    self::$options = $array;
+  }
+  
+  /**
+   * Get the default options.
+   *
+   * Get all options currently set as default.
+   *
+   * @return array
+   *  An array of options. Note that only explicitly set options are 
+   *  returned. {@link QueryPath} defines default options which are not
+   *  stored in this object.
+   */
+  static function get() {
+    return self::$options;
+  }
+  
+  /**
+   * Merge the provided array with existing options.
+   *
+   * On duplicate keys, the value in $array will overwrite the 
+   * value stored in the options.
+   *
+   * @param array $array
+   *  Associative array of options to merge into the existing options.
+   */
+  static function merge($array) {
+    self::$options = $array + self::$options;
+  }
+  
+  /**
+   * Returns true of the specified key is already overridden in this object.
+   *
+   * @param string $key
+   *  The key to search for.
+   */
+  static function has($key) {
+    return array_key_exists($key, self::$options);
+  }
+  
+}
+
+/**
+ * Exception indicating that a problem has occured inside of a QueryPath object.
+ *
+ * @ingroup querypath_core
+ */
+class QueryPathException extends Exception {}
+
+/**
+ * Exception indicating that a parser has failed to parse a file.
+ *
+ * This will report parser warnings as well as parser errors. It should only be 
+ * thrown, though, under error conditions.
+ *
+ * @ingroup querypath_core
+ */
+class QueryPathParseException extends QueryPathException {
+  const ERR_MSG_FORMAT = 'Parse error in %s on line %d column %d: %s (%d)';
+  const WARN_MSG_FORMAT = 'Parser warning in %s on line %d column %d: %s (%d)';
+  // trigger_error
+  public function __construct($msg = '', $code = 0, $file = NULL, $line = NULL) {
+
+    $msgs = array();
+    foreach(libxml_get_errors() as $err) {
+      $format = $err->level == LIBXML_ERR_WARNING ? self::WARN_MSG_FORMAT : self::ERR_MSG_FORMAT;
+      $msgs[] = sprintf($format, $err->file, $err->line, $err->column, $err->message, $err->code);
+    }
+    $msg .= implode("\n", $msgs);
+    
+    if (isset($file)) {
+      $msg .= ' (' . $file;
+      if (isset($line)) $msg .= ': ' . $line;
+      $msg .= ')';
+    }
+    
+    parent::__construct($msg, $code);
+  }
+  
+  public static function initializeFromError($code, $str, $file, $line, $cxt) {
+    //printf("\n\nCODE: %s %s\n\n", $code, $str);
+    $class = __CLASS__;
+    throw new $class($str, $code, $file, $line);
+  }
+}
+
+/**
+ * Indicates that an input/output exception has occurred.
+ *
+ * @ingroup querypath_core
+ */
+class QueryPathIOException extends QueryPathParseException {
+  public static function initializeFromError($code, $str, $file, $line, $cxt) {
+    $class = __CLASS__;
+    throw new $class($str, $code, $file, $line);
+  }
+  
+}
\ No newline at end of file
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