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Date: Thu, 6 Sep 2012 20:15:26 -0400
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To: Mark <markg85@gmail.com>
Cc: internals@lists.php.net
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Subject: Re: [PHP-DEV] Why are the PHP namespaces different compared to C++?
From: theanomaly.is@gmail.com (Sherif Ramadan)

On Thu, Sep 6, 2012 at 5:30 PM, Mark <markg85@gmail.com> wrote:
> Hi,
>
> I was just using the PHP namespaces for the first time and noticed a
> difference that i really didn't expect. (No, i won't start complaining
> about the slash based namespace).
>
> In C++ when you type:
> using std;
>
> Then you can use all methods/classes/whatever is defined in std
> without typing std.
> so: std::cout becomes just cout.
>
> In PHP that's a bit different. Lets take this as an example:
> =================================
> namespacetst.php
>
> <?php
> namespace Some\Long\Namespace;
>
> Class SomeClass
> {
> }
>
>
> Now the one using that "SomeClass" has to do something like this:
> index.php
> use Some\Long\Namespace;
>
> $oClass = new Namespace\SomeClass();
> =================================
>
> Yes, you can also do:
>
> index.php
> use Some\Long\Namespace\SomeClass;
> $oClass = new SomeClass();
>
> But i'm wondering why the "use Some\Long\Namespace" doesn't work like
> the C++ one. Since i would have guessed that adding that use will give
> me access to all the methods/classes/whatever that live within that
> namespace _without_ having to prefix it with the last part of the
> namespace.
>
> I hope someone can shed some light over this.
>
> Regards,
> Mark
>
> --
> PHP Internals - PHP Runtime Development Mailing List
> To unsubscribe, visit: http://www.php.net/unsub.php
>


Yes, PHP namespaces are completely different from what you'd be used
to in C++. In all honesty namespaces were never well designed in PHP
and were implemented in a haphazard way, which is why I generally
don't bother using them.

To clarify, importing namespaces in PHP isn't like importing
namespaces in C++ at all, really. You are merely aliasing namespaces
in PHP when you use the "use" keyword. Meaning that what's actually
happening is PHP expects you to alias one namespace to another (and
thus you can never import one namespace directly into the existing
namespace since this creates a name conflict). It's messy...

NameSpacedFile.php
namespace My\Name\Space;
class MyClass { }


Index.php
use My\Name\Space; // This doesn't actually import anything
// What happened here is we created an alias
// It's the same thing as saying "use My\Name\Space as \Space
// So now My\Name\Space is aliased to \Space

$obj = new \Space\MyClass; // great
$obj = new MyClass; // this won't do what you want


Here's the full example:

http://viperpad.com/qcAUNM

It simply doesn't work like that because PHP's namespaces are
implemented in such a way that they don't really resemble namespaces.
Just some fancy magic going on in the engine that allow it to mimic
namespaces.