PHP namespacing benefits

Question

After doing some research about namespacing in PHP I'm trying to figure out what are the real benefits other than having library items grouped together and re-use of the same class name.

What I don't like about namespaces are these extra lines at the top of the file you're calling the classes from 'use core\whatever\class', which you don't have to do with the standard approach.

Also - something I couldn't find information about - what happens in the situation where we need to use two classes with the same name, but in the different folders, which contain the same method name? We would still have to call the namespace, but how would the code figure out which method from which class should be used?

I've just started with namespaces so excuse me if this question seem to sound very basic.

Also - how does it work with the static methods - things like Helper class for instance - do I also have to indicate that I need this namespace 'use core\whatever\Helper' ?

Answer 1

If you have a large project with many classes, you'll eventually run into naming conflicts. You have a db/mysql/adapter.php and a http/curl/adapter.php. To deal with this without namespaces, you have to give your classes unique names like Db_Mysql_Adapter and Http_Curl_Adapter, and any time you refer to these classes you need to use their full name.

Namespaces allow you to name your classes Db\Mysql\Adapter and Http\Curl\Adapter and refer to them simply by Adapter in their local namespace, or Mysql\Adapter and Curl\Adapter respectively in other namespaces. This can save a lot of typing.

Just browse through the source of Zend Framework version 1 vs. version 2 to see the difference.

what happens in the situation where we need to use two classes with the same name, but in the different folders, which contain the same method name? We would still have to call the namespace, but how would the code figure out which method from which class should be used?

If you're in namespace Db\Mysql, Adapter::foo() refers to Db\Mysql\Adapter and \Http\Curl\Adapter::foo() would refer to the other one. You can also alias the class at the top of your file, if you don't want to write out the whole name all the time:

namespace Db\Mysql;
use Http\Curl\Adapter as HAdapter;

Adapter::foo();  // Mysql adapter
HAdapter::foo(); // Http adapter, same as:
\Http\Curl\Adapter::foo();

Answer 2

What I don't like about namespaces are these extra lines at the top of the file you're calling the classes from 'use core\whatever\class', which you don't have to do with the standard approach.

Namespaces group classes logically and avoid polluting the global scope. It also prevents you from making a big chunk of PHP code - code which may have parts needed in other places in your site. This makes it more reason to place it in another file for another part of the site to use. Don't Repeat Yourself (DRY), use in in many places but only code it once!

what happens in the situation where we need to use two classes with the same name, but in the different folders, which contain the same method name? We would still have to call the namespace, but how would the code figure out which method from which class should be used?

Namespacing prevents these issues, using aliases. besides, having classes with the same name? unless they are the same name but different purpose or different subcategory, like api.document.events and api.ajax.events. Otherwise, it's bad program design.