关键词列表

这些词语在 PHP 中有着特殊的意义。它们中有些像是函数，有些像是常量，但是它们不是真的，它们只是语言结构的一部分。不能使用它们的任何一个作为常量、类名、函数或方法名。但是它们可以被用作类的属性、常量以及类的方法名，或者接口名和 traits 名，除了 class 不能被用作常量名。

**PHP 关键词**
__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	finally	fn （从 PHP 7.4 开始）	for	foreach
function	global	goto	if	implements
include	include_once	instanceof	insteadof	interface
isset()	list()	match （从 PHP 8.0 开始）	namespace	new
or	print	private	protected	public
require	require_once	return	static	switch
throw	trait	try	unset()	use
var	while	xor	yield	yield from

**编译时常量**
__CLASS__	__DIR__	__FILE__	__FUNCTION__	__LINE__	__METHOD__
__NAMESPACE__	__TRAIT__

User Contributed Notes

Johnny D. 22-May-2020 06:37


const FORBIDDEN_TYPES = [

    'null',



    'bool',

    'false',

    'true',



    'int',

    'float',



    'string',

];

bla at taxistop dot be 19-Jul-2018 09:50


This list doesn't include 'self' and 'parent', which I take are indeed keywords.

Thomas Hansen 15-Aug-2016 10:08


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)

martindilling at gmail dot com 15-Apr-2013 10:20


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

Chris 04-Oct-2012 04:33


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.