List of Keywords
These words have special meaning in PHP. Some of them represent things which look like functions, some look like constants, and so on - but they're not, really: they are language constructs. You cannot use any of the following words as constants, class names, function or method names. Using them as variable names is generally OK, but could lead to confusion.
| __halt_compiler() | abstract | and | array() | as |
| break | callable (as of PHP 5.4) | 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 (as of PHP 5.5) | for | foreach | function |
| global | goto (as of PHP 5.3) | if | implements | include |
| include_once | instanceof | insteadof (as of PHP 5.4) | interface | isset() |
| list() | namespace (as of PHP 5.3) | new | or | |
| private | protected | public | require | require_once |
| return | static | switch | throw | trait (as of PHP 5.4) |
| try | unset() | use | var | while |
| xor | yield (as of PHP 5.5) |
| __CLASS__ | __DIR__ (as of PHP 5.3) | __FILE__ | __FUNCTION__ | __LINE__ | __METHOD__ |
| __NAMESPACE__ (as of PHP 5.3) | __TRAIT__ (as of PHP 5.4) |
Коментарии
Here they are as arrays:
<?php
$keywords = 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.
RegEx to find all the keywords:
\b(
(a(bstract|nd|rray|s))|
(c(a(llable|se|tch)|l(ass|one)|on(st|tinue)))|
(d(e(clare|fault)|ie|o))|
(e(cho|lse(if)?|mpty|nd(declare|for(each)?|if|switch|while)|val|x(it|tends)))|
(f(inal|or(each)?|unction))|
(g(lobal|oto))|
(i(f|mplements|n(clude(_once)?|st(anceof|eadof)|terface)|sset))|
(n(amespace|ew))|
(p(r(i(nt|vate)|otected)|ublic))|
(re(quire(_once)?|turn))|
(s(tatic|witch))|
(t(hrow|r(ait|y)))|
(u(nset|se))|
(__halt_compiler|break|list|(x)?or|var|while)
)\b
Please note that reserved words are still not allowed to be used as namespace or as part of it:
<?php
namespace MyNameSpace\List;
class Test
{
}
?>
This will fail with a Parse error: syntax error, unexpected 'List' (T_LIST), expecting identifier (T_STRING)
From php8, reserved keywords such as `Interface` or `Trait` can be used as part of the namespace.
<?php
namespace App\Entity\Interface;
interface FooInterface
{
}
https://wiki.php.net/rfc/namespaced_names_as_token