Why are PHP namespaces defined using a backslash? It looks ugly. Unless of course, there is a good reason for the "\"? Does this namespaced code run more efficiently on Windows?

Since namespaces are new in PHP5 why not take the opportunity to use them when requiring a file?

namespace('my_library_dir', 'lib'); // import my_library_dir as lib
$myClass = new lib::MyClass;      // use the class w/ namespace

Seems a lot simpler and not as ugly. You could namespace old PHP code this way as well. Please enlighten me if I'm off the mark and the implementation of namespaces in PHP5 is a better design than I have suggested!