Editing Namespace (section)

===== PHP <!-- This section is linked from [[PHP]] --> =====
Namespaces were introduced into [[Php|PHP]] from version 5.3 onwards. Naming collision of classes, functions and variables can be avoided.
In [[PHP]], a namespace is defined with a namespace block.
<syntaxhighlight lang="php">
# File phpstar/foobar.php

namespace phpstar;

class FooBar
{
    public function foo(): void
    {
        echo 'Hello world, from function foo';
    }

    public function bar(): void
    {
        echo 'Hello world, from function bar';
    }
}
</syntaxhighlight>
We can reference a PHP namespace with the following different ways:
<syntaxhighlight lang="php">
# File index.php

# Include the file
include "phpstar/foobar.php";

# Option 1: directly prefix the class name with the namespace
$obj_foobar = new \phpstar\FooBar();

# Option 2: import the namespace
use phpstar\FooBar;
$obj_foobar = new FooBar();

# Option 2a: import & alias the namespace
use phpstar\FooBar as FB;
$obj_foobar = new FB();

# Access the properties and methods with regular way
$obj_foobar->foo();
$obj_foobar->bar();
</syntaxhighlight>

[[File:UML phpstar package diagram.svg|UML diagram of the phpstar package with the class FooBar.]]