PHP关键字区分大小写吗? [英] Are PHP keywords case-sensitive?

问题描述

例如，以下程序有意义吗?如果是这样，它将打印什么?

For example, is the following program meaningful, and if so what should it print?

<?php
FuncTIon fOo($x) { eChO $x; }
FOO('bar');
IF (TRuE) { echO 'qux'; }
?>

我的解释器运行它并输出barqux，这意味着关键字不区分大小写:

My interpreter runs it and prints barqux, implying the keywords are not case-sensitive:

$ php case_sensitive_keywords.php 
barqux
$ php --version
PHP 5.5.7-1+sury.org~precise+1 (cli) (built: Dec 12 2013 21:37:40) 

但是，去年问了同样的问题 ，答案表明关键字 区分大小写，与我的PHP解释器告诉我的内容直接矛盾！

However, this same question was asked last year, and the answers say that keywords are case-sensitive, in direct contradiction to what my PHP interpreter appears to tell me!

推荐答案

区分大小写(用户定义和PHP定义)

Case sensitive (both user defined and PHP defined)

• 变量
• 常量
• 数组键
• 类属性
• 类常量

不区分大小写(用户定义和PHP均定义)

Case insensitive (both user defined and PHP defined)

• 功能
• 类构造函数
• 类方法
• 关键字和构造(如果为null，则为null，foreach，echo等)

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