It's PHP 5.3's namespacing functionality, in a nutshell.

Symfony2 and Lithium are two frameworks I can currently think of that use them extensively. On the one hand, Symfony2 has a quite extreme implementation, and on the other, Lithium's is much more concise. The backslashes can be used to represent a hierarchy.

Oh for the love of science, please let this be a bad dream ... is the parent object referred to as C:\ by any chance?

Zend Framework 2.0 is also a big user of PHP namespaces. It's in beta the moment.

Namespaces, as others have mentioned. The first question I had when I first encountered that as the Namespace operator was: "Why not the double colon operator?"

Double colon is already being used for static member referencing, and in a few talks I've heard from Rasmus, they weren't able to find a way to overload it for Namespaces.

Another option that was discussed was a triple colon operator, which most were opposed to b/c of it's length. I personally think the backslash is ugly, and I kind of like the triple colon operator better b/c of it's similarity to the double colon operator. Regardless of which one is prettier, I wish the double colon operator could have been overloaded.

IIRC, the reasoning against double colons was that if you had a class and a namespace with the same name, it's impossible to tell whether SomeThing::Do() is calling a function in the SomeThing namespace, or the static Do function on the SomeThing class. One could argue that they could simple not allow namespaces and classes to share names, but I guess they didn't like that idea, either.

I hope I'm stating this right, I must admit it's from a fuzzy recollection.

> the backslash is ugly

Not only that, it's very unconfortable to type in some international keyboard layouts.

If you're talking about the German layout and AltGr, then so are the []{} keys, which are already used quite a lot in PHP programming.

It's the main reason why, even though my phyiscal keys are in German layout, I still have the USA layout in software. It's just nice to be able to make [] with a single key press :)

Agreed. Although function-¥ does give my hands a stretch now and then, I don't want to be typing it constantly..

They are harder (than many other commonly used characters) to distinguish from regular text as well.

PHP's method for using Namespaces: http://php.net/manual/en/language.namespaces.php

Since this is a PHP 5.3 library it's using PHP namespaces.

Welcome to PHP 5.3 :)

I wonder how many times I will need to see PHP 5.3's backslashes before they look 'correct' :)