PHP namespace

When you use namespace on PHP scripts you have to use require(), require_once(), include() or include_once() . It doesn't work without one of these like you can see on this example:

php namespaces are case-insensitive:

file1.php:
namespace foo;

function bar()
{
    echo 'from bar';
}?>
file2.php:


fOo\bar() // output: from bar
?>

This example is here:
http://php.net/manual/en/language.namespaces.rationale.php

A better example is here:
http://www.sitepoint.com/php-53-namespaces-basics/