blocks|key|3046622|text|是的，函数和方法名称不区分大小写。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|3046623|是的，变量名是区分大小写的。|3046624|我不确定这是不是有原因--除非这种方式已经存在很长一段时间了，而且由于向后兼容性的原因，这种情况仍然存在。|3046625|3046626|作为参考，有几个指向手册各个页面的链接/引文：|3046627|For函数()|3046628|3046629|+注意：函数名称不区分大小写，尽管调用函数通常是一种很好的形式，因为它们出现在函数的声明中。|blockquote|offset|length|style|BOLD|3046630|3046631|3046632|方法并不比对象中的函数更多--特别是当我们考虑到PHP4和向后兼容性时。|3046633|对于变量(quoting)：|3046634|PHP语言中的|3046635|变量由一个美元符号后跟变量名表示。变量名区分大小写。|3046636|3046637|3046638|对象属性并不比对象中的变量更多--+PHP4和向后兼容性也是如此。|3046639|entityMap|0|LINK|mutability|MUTABLE|url|http://fr2.php.net/manual/en/language.variables.basics.php^0|0|0|0|0|0|0|0|1|3|0|0|0|0|5|7|0|0|0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|1E|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|1F|8|@]|9|@]|A|$]]|$1|D|3|E|5|6|7|1G|8|@]|9|@]|A|$]]|$1|F|3|-4|5|6|7|1H|8|@]|9|@]|A|$]]|$1|G|3|H|5|6|7|1I|8|@]|9|@]|A|$]]|$1|I|3|J|5|6|7|1J|8|@]|9|@]|A|$]]|$1|K|3|-4|5|6|7|1K|8|@]|9|@]|A|$]]|$1|L|3|M|5|N|7|1L|8|@$O|1M|P|1N|Q|R]]|9|@]|A|$]]|$1|S|3|-4|5|6|7|1O|8|@]|9|@]|A|$]]|$1|T|3|-4|5|6|7|1P|8|@]|9|@]|A|$]]|$1|U|3|V|5|6|7|1Q|8|@]|9|@]|A|$]]|$1|W|3|X|5|6|7|1R|8|@]|9|@$O|1S|P|1T|1|1U]]|A|$]]|$1|Y|3|Z|5|6|7|1V|8|@]|9|@]|A|$]]|$1|10|3|11|5|N|7|1W|8|@]|9|@]|A|$]]|$1|12|3|-4|5|6|7|1X|8|@]|9|@]|A|$]]|$1|13|3|-4|5|6|7|1Y|8|@]|9|@]|A|$]]|$1|14|3|15|5|6|7|1Z|8|@]|9|@]|A|$]]|$1|16|3|-4|5|6|7|20|8|@]|9|@]|A|$]]]|17|$18|$5|19|1A|1B|A|$1C|1D]]]]

Yes, functions and methods names are not case-sensitive.

And yes, variables names are case-sensitive.

I am not sure there's a reason for that -- except it's been this way for a long time, and, so, remains the case, for backward compatibility reasons.

 

<hr>

As a reference, a couple of links / quotes to various pages of the manual:

For functions (<a href="http://fr.php.net/manual/en/functions.user-defined.php" rel="noreferrer">quoting</a>):

<blockquote>
 Note: Function names are
 case-insensitive, though it is usually
 good form to call functions as they
 appear in their declaration.
</blockquote>

And methods are not much more than functions in objects -- especially when we think about PHP 4 and backward-compatibility.

 
And, for variables (<a href="http://fr2.php.net/manual/en/language.variables.basics.php" rel="noreferrer">quoting</a>):

<blockquote>
 Variables in PHP are represented by a
 dollar sign followed by the name of
 the variable. The variable name is
 case-sensitive.
</blockquote>

And object properties are not much more than variables in objects -- same remark about PHP 4 and backward-compatibility.

blocks|key|3260420|text|让我引用一下Interview+–+PHP’s+Creator,+Rasmus+Lerdorf的话|type|unstyled|depth|inlineStyleRanges|entityRanges|offset|length|data|3260421|3260422|的第一个版本是一组简单的工具，我将它们组合在一起用于我的网站和一些项目。一个工具在mSQL数据库中做了一些奇特的日志记录，另一个工具则充当表单数据解释器。在我感到厌烦之前，我用C语言编写了大约30个不同的CGI程序，并将它们组合到一个C库中。然后，我编写了一个非常简单的解析器，它将从HTML文件中提取标签，并将它们替换为C库中相应函数的输出。|blockquote|3260423|3260424|简单的解析器慢慢地包含了条件标签，然后是循环标签，函数等等。我从来没有想过我是在写脚本语言。我只是向宏替换解析器添加了一点功能。我仍然在用C语言编写我所有真正的业务逻辑。|3260425|3260426|我在某处读到过，由于所有引入的函数本质上感觉就像HTML文档中的标签，而且HTML标签不区分大小写，所以他选择PHP中的函数名称区分大小写。后来，这个特性在语言中保留了下来。|3260427|entityMap|0|LINK|mutability|MUTABLE|url|http://blogs.sitepoint.com/phps-creator-rasmus-lerdorf/^0|6|15|0|0|0|0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|V|8|@]|9|@$A|W|B|X|1|Y]]|C|$]]|$1|D|3|-4|5|6|7|Z|8|@]|9|@]|C|$]]|$1|E|3|F|5|G|7|10|8|@]|9|@]|C|$]]|$1|H|3|-4|5|6|7|11|8|@]|9|@]|C|$]]|$1|I|3|J|5|6|7|12|8|@]|9|@]|C|$]]|$1|K|3|-4|5|6|7|13|8|@]|9|@]|C|$]]|$1|L|3|M|5|6|7|14|8|@]|9|@]|C|$]]|$1|N|3|-4|5|6|7|15|8|@]|9|@]|C|$]]]|O|$P|$5|Q|R|S|C|$T|U]]]]

Let me quote from <a href="http://blogs.sitepoint.com/phps-creator-rasmus-lerdorf/" rel="noreferrer">Interview – PHP’s Creator, Rasmus Lerdorf</a>
<blockquote>
The first version of PHP was a simple set of tools that I put together for my Website and for a couple of projects. One tool did some fancy hit logging to an mSQL database, another acted as a form data interpreter. I ended up with about 30 different little CGI programs written in C before I got sick of it, and combined all of them into a single C library. I then wrote a very simple parser that would pick tags out of HTML files and replace them with the output of the corresponding functions in the C library.
The simple parser slowly grew to include conditional tags, then loop tags, functions, etc. At no point did I think I was writing a scripting language. I was simply adding a little bit of functionality to the macro replacement parser. I was still writing all my real business logic in C.
</blockquote>
I have read somewhere that since all the functions introduced essentially felt like tags in an HTML document and since HTML tags were case insensitive, he chose function names in PHP to be case insensitive. Later on this feature remained on in the language.

Functions and methods in PHP are case-insensitive as illustrated in the following example.

<pre><code>function ag()
{
 echo '2';
}

Ag();
class test {
 function clMe()
 {
 echo 'hi';
 }
}

$instance = new test;
$instance-&gt;clme();
</code></pre>

But that's the not case with variables. What's the rationale?

Why are functions and methods in PHP case-insensitive?

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PHP中的函数和方法不区分大小写，如下面的示例所示。function ag(){    echo '2';}Ag();class test {    function clMe()    {        echo 'hi';    }}$instance = new test;$instance->clme();但这...

问为什么PHP中的函数和方法不区分大小写？
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