Returning on a recursive function in php - php

Question

I'm developing a function to parse 2 xml files. It compares them node by node and then if the nodes are different, the function should return one of them. But it isn't returning anything.
$xml = simplexml_load_file("file1.xml");
$xml2 = simplexml_load_file("file2.xml");
$result = parseNode($xml, $xml2);
print_r($result);
echo $result;
function parseNode($node1, $node2) {
for ($i = 0; $i < count($node1->children()); $i++) {
$child1 = $node1->children();
$child2 = $node2->children();
if ($child1[$i]->getName() != $child2[$i]->getName()) {
return $child1[$i];
} else {
parseNode($child1[$i], $child2[$i]);
}
}
}

Answer 1

return parseNode($child1[$i], $child2[$i]);

Answer 2

Well, you can do it with a simple conditional statement...
$xml = simplexml_load_file("file1.xml");
$xml2 = simplexml_load_file("file2.xml");
$result = parseNode($xml, $xml2);
print_r($result);
echo $result;
function parseNode($node1, $node2) {
$child1 = $node1->children();
$child2 = $node2->children();
$numChildren = count($child1);
for ($i = 0; $i < $numChildren; $i++) {
if ($child1[$i]->getName() != $child2[$i]->getName()) {
return $child1[$i];
} else {
$test = parseNode($child1[$i], $child2[$i]);
if ($test) return $test;
}
}
return false;
}

Answer 3

You could also loop over the XML structures using recursive iterators to simplify your parseNodes() function.
$xml = simplexml_load_string("<root><foo/><bar><baz/></bar></root>", "SimpleXMLIterator");
$xml2 = simplexml_load_string("<root><foo/><bar><baz/></bar><bat/></root>", "SimpleXMLIterator");
$result = parseNode($xml, $xml2);
echo $result;
function parseNode($a, $b) {
$mit = new MultipleIterator(MultipleIterator::MIT_NEED_ANY|MultipleIterator::MIT_KEYS_NUMERIC);
$mit->attachIterator(new RecursiveIteratorIterator($a, RecursiveIteratorIterator::SELF_FIRST));
$mit->attachIterator(new RecursiveIteratorIterator($b, RecursiveIteratorIterator::SELF_FIRST));
foreach ($mit as $node) {
// One has more nodes than another!
if ( ! isset($node[0], $node[1])) {
return 'Curse your sudden but inevitable betrayal!';
}
// Nodes have different names
if ($node[0]->getName() !== $node[1]->getName()) {
return $node[0];
}
}
// No differences in names and order
return FALSE;
}
Setting up the MultipleIterator is pretty verbose (mostly due to the über-long class names) but the logic is darned simple.

Answer 4

There's no return in the recursive call. Hence, no result.
EDIT Do not up-vote this. ircmaxell is right. I have removed the exception part of my answer.