- added interop between DOM and SimpleXML example

- added xpath example

ext/simplexml/examples/interop.php

@@ -0,0 +1,27 @@
+<?php
+$dom = new domDocument;
+$dom->load("book.xml");
+if(!$dom) {
+  echo "Error while parsing the document\n";
+  exit;
+}
+print "As SimpleXML\n";
+
+$s = simplexml_import_dom($dom);
+$books = $s->book;
+foreach ($books as $book) {
+	echo "{$book->title} was written by {$book->author}\n";
+}
+
+print "As DOM \n";
+
+$dom = dom_import_simplexml($s);
+$books = $dom->getElementsByTagName("book");
+foreach ($books as $book) {
+       $title = $book->getElementsByTagName("title");
+       $author = $book->getElementsByTagName("author");
+       echo $title[0]->firstChild->data . " was written by ". $author[0]->firstChild->data . "\n";
+}
+
+
+?>

ext/simplexml/examples/xpath.php

@@ -0,0 +1,9 @@
+<?php
+$books = simplexml_load_file('book.xml');
+
+$xpath_result = $books->xsearch("/books/book/title");
+foreach($xpath_result as $entry ) {
+    print "$entry \n";
+}
+
+?>