I realize that for replace_node, the W3C recommendation suggests that you should return the node that was removed.  However, this presents a problem when you are actually trying to write code with the xml functions.  If you create a new node (or import it from another document, or even clone it) and then you do a replace node somewhere, removing the previous node and putting in your new node, there is no way to access the node you just put in.  For all intents and purposes, you have lost your place in the document.  I don't think the function should change per say, but rather this following distinction.

1. Create a new node and return it to a variable $foo
2. Select a node that will be replaced $bar
3. Replace $bar with $foo using $bar->replace_node($foo)
4. Now, $foo should be a reference to the node in its new location.  This argument is based on the recommendation sentence which states "if the newChild is already in the tree, it is first removed".  Hence, it would be impossible for the reference $foo to exist anywhere else then in its new location.

Thoughts?