Anahtar Sözcüklerin Listesi

PHP'de bazı sözcükler özel anlama sahiptirler. Bazıları işlevler, bazılar sabitler olarak karşımıza çıkarken bazılarıyla haya karşılaşmamış olabiliriz. Bunlar aslında dil oluşumlarıdır. Aşağıdaki sözcükleri sabit, sınıf, işlev veya yöntem ismi olarak kullanamazsınız. Değişken ismi olarak kullanılabilirlerse de karışıklığa yol açabilirler.

PHP 7.0.0 itibariyle bu anahtar sözcüklerin öznitelik, sabit ve class bir sabit ismi olarak kullanılmadıkça sınıf, arayüz ve niteliklerin yöntem isimleri olarak kullanılabilmesine izin verilmiştir.

PHP Anahtar Sözcükler
__halt_compiler() abstract and array() as
break callable (PHP 5.4 itibariyle) case catch class
clone const continue declare default
die() do echo else elseif
empty() enddeclare endfor endforeach endif
endswitch endwhile eval() exit() extends
final finally (PHP 5.5 itibariyle) for foreach function
global goto (PHP 5.3'ten beri) if implements include
include_once instanceof insteadof (PHP 5.4'ten beri) interface isset()
list() namespace (PHP 5.3'ten beri) new or print private
protected public require require_once
return static switch throw trait (PHP 5.4 itibariyle)
try unset() use var while
xor yield (PHP 5.5 itibariyle)
Derleme sabitleri
__CLASS__ __DIR__ (PHP 5.3 itibariyle) __FILE__ __FUNCTION__ __LINE__ __METHOD__
__NAMESPACE__ (PHP 5.3 itibariyle) __TRAIT__ (PHP 5.4 itibariyle)
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User Contributed Notes 4 notes

martindilling at gmail dot com
4 years ago
RegEx to find all the keywords:

5 years ago
Here they are as arrays:

= array('__halt_compiler', 'abstract', 'and', 'array', 'as', 'break', 'callable', 'case', 'catch', 'class', 'clone', 'const', 'continue', 'declare', 'default', 'die', 'do', 'echo', 'else', 'elseif', 'empty', 'enddeclare', 'endfor', 'endforeach', 'endif', 'endswitch', 'endwhile', 'eval', 'exit', 'extends', 'final', 'for', 'foreach', 'function', 'global', 'goto', 'if', 'implements', 'include', 'include_once', 'instanceof', 'insteadof', 'interface', 'isset', 'list', 'namespace', 'new', 'or', 'print', 'private', 'protected', 'public', 'require', 'require_once', 'return', 'static', 'switch', 'throw', 'trait', 'try', 'unset', 'use', 'var', 'while', 'xor');

$predefined_constants = array('__CLASS__', '__DIR__', '__FILE__', '__FUNCTION__', '__LINE__', '__METHOD__', '__NAMESPACE__', '__TRAIT__');

Along with get_defined_functions() and get_defined_constants(), this can be useful for checking eval() statements.
Thomas Hansen
1 year ago
Please note that reserved words are still not allowed to be used as namespace or as part of it:

namespace MyNameSpace\List;


This will fail with a Parse error:  syntax error, unexpected 'List' (T_LIST), expecting identifier (T_STRING)
8 years ago
There are some cases when you need to use a reserved keyword or language construct as a class method name. In this instance, there is very little chance of namespace conflicts (as the class itself acts as a namespace). If you try to define the method the old way, you will get an unexpected token error.

There is an unobtrusive, and very useful way to use a reserved keyword for a method name. For example, you want to define two class methods 'list' and 'unset' (these two are language builtins and normally not allowed for method names).

class MyClass
// Define MyClass::unset() with a different name, e.g. 'rm'
public function rm($arg)
/* code... */
// Define MyClass::list() with a different name, e.g. 'ls'
public function ls($arg = null)
/* code... */
// Now define a __call() method (requires PHP > 5.2.3 to take effect)
public function __call($func, $args)
        switch (
$this->ls((isset($args[0]))? $args[0]: null);
trigger_error("Call to undefined method ".__CLASS__."::$func()", E_USER_ERROR);
            die ();

The only caveat is that to use the long method names, you need PHP > 5.2.3. However, a nice feature is that if you are using an older version than 5.2.3, all of the __call() stuff is ignored and the class will behave as expected (in other words, it degrades gracefully).

You also need to be aware of the methods' expected arguments. MyClass::ls()'s argument is optional, so the extra isset() check is required. If your methods take more arguments, they will need to be manually dereferenced from the $args array, e.g. <?php return $this->my_func($args[0], $args[1], $args[2]);?> for 3 required arguments.

This is a nice trick, and can let you code better APIs for newer versions of PHP. However, if this script is to be run on older PHP installations, be very sure to use the short method names.
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