+ /**
+ * The following part computes the list of part changes between two
+ * parse_url arrays.
+ *
+ * As array_diff_assoc only computes changes to go from the left array
+ * to the right one, we make two differents arrays to have both
+ * directions. We merge these two arrays and sort keys before passing
+ * the result to the switch.
+ *
+ * The resulting array gives us all changing parts between the two
+ * urls: scheme, host, path, query and/or fragment.
+ */