If your code looks like this:
<?php
namespace NS;
?>
...and you still get "Namespace declaration statement has to be the very first statement in the script" Fatal error, then you probably use UTF-8 encoding (which is good) with Byte Order Mark, aka BOM (which is bad). Try to convert your files to "UTF-8 without BOM", and it should be ok.
Namespaces definieren
(PHP 5 >= 5.3.0, PHP 7, PHP 8)
Obwohl jeder gültige PHP-Quellcode in Namespaces eingeschlossen werden kann, werden nur die folgenden Arten von Code von Namespaces beeinflusst: Klassen (inklusive abstrakter Klassen und Traits), Interfaces, Funktionen und Konstanten.
Namespaces werden mit dem Schlüsselwort namespace
definiert. Eine Datei, die einen Namespace beinhaltet, muss den Namespace
am Anfang der Datei vor jeglichem anderen Code deklarieren - mit Ausnahme
des declare-Schlüsselwortes.
Beispiel #1 Einen einzelnen Namespace deklarieren
<?php
namespace MyProject;
const CONNECT_OK = 1;
class Connection { /* ... */ }
function connect() { /* ... */ }
?>Der einzige Quellcode, der vor einer Namespacedeklaration stehen darf, ist derHinweis: Vollständig qualifizierte Namen (d. h. Namen, die mit einem Rückwärtsschrägstrich beginnen) sind in Namensraumdeklarationen nicht erlaubt, weil solche Konstrukte als relative Namensraumausdrücke interpretiert werden.
declare-Ausdruck, der die Kodierung der Quellcodedatei
definiert. Gleichzeitig darf kein Nicht-PHP-Code vor einer Namespacedeklaration
stehen - auch keine zusätzlichen Leerzeichen, Zeilenumbrüche oder Tabulatoren.
Beispiel #2 Einen einzelnen Namespace deklarieren
<html>
<?php
namespace MyProject; // fatal error - Namespace muss der erste Ausdruck im Skript sein
?>Zusätzlich darf - im Gegensatz zu anderen PHP-Konstrukten - der selbe Namespace in mehreren Dateien definiert werden, womit man den Inhalt eines Namespaces im Dateisystem aufteilen kann.
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User Contributed Notes 10 notes
kuzawinski dot marcin at NOSPAM dot gmail dot com ¶
10 years ago
danbettles at yahoo dot co dot uk ¶
15 years ago
Regarding constants defined with define() inside namespaces...
define() will define constants exactly as specified. So, if you want to define a constant in a namespace, you will need to specify the namespace in your call to define(), even if you're calling define() from within a namespace. The following examples will make it clear.
The following code will define the constant "MESSAGE" in the global namespace (i.e. "\MESSAGE").
<?php
namespace test;
define('MESSAGE', 'Hello world!');
?>
The following code will define two constants in the "test" namespace.
<?php
namespace test;
define('test\HELLO', 'Hello world!');
define(__NAMESPACE__ . '\GOODBYE', 'Goodbye cruel world!');
?>
FatBat ¶
11 years ago
Expanding on @danbettles note, it is better to always be explicit about which constant to use.
<?php
namespace NS;
define(__NAMESPACE__ .'\foo','111');
define('foo','222');
echo foo; // 111.
echo \foo; // 222.
echo \NS\foo // 111.
echo NS\foo // fatal error. assumes \NS\NS\foo.
?>
anisgazig at gmail dot com ¶
3 years ago
namespace statement is defined at first of the php files. But
before namespace declaration only three elements allowed.
1.declare statement
2.spaces
3.comments
huskyr at gmail dot com ¶
15 years ago
"A file containing a namespace must declare the namespace at the top of the file before any other code"
It might be obvious, but this means that you *can* include comments and white spaces before the namespace keyword.
<?php
// Lots
// of
// interesting
// comments and white space
namespace Foo;
class Bar {
}
?>
jeremeamia at gmail dot com ¶
15 years ago
You should not try to create namespaces that use PHP keywords. These will cause parse errors.
Examples:
<?php
namespace Project/Classes/Function; // Causes parse errors
namespace Project/Abstract/Factory; // Causes parse errors
?>
Anonymous ¶
16 years ago
@ RS: Also, you can specify how your __autoload() function looks for the files. That way another users namespace classes cannot overwrite yours unless they replace your file specifically.
Baptiste ¶
16 years ago
There is nothing wrong with PHP namespaces, except that those 2 instructions give a false impression of package management.
... while they just correspond to the "with()" instruction of Javascript.
By contrast, a package is a namespace for its members, but it offers more (like deployment facilities), and a compiler knows exactly what classes are in a package, and where to find them.
anisgazig at gmail dot com ¶
3 years ago
Namespace name are case-insensitive.
namespace App
and
namespace app
are same meaning.
Besides, Namespace keword are case-insensitive.
Namespace App
namespace App
and
NAMESPACE App
are same meaning.
dino at tuxweb dot it ¶
2 years ago
Please note that a PHP Namespace declaration cannot start with a number.
It took some time for me to debug...
