在你看来,你遇到过的最令人惊讶、最怪异、最奇怪或最“WTF”的语言特性是什么?

请每个回答只回答一个特征。


当前回答

PHP

$ php -r '::'
Parse error: syntax error, unexpected T_PAAMAYIM_NEKUDOTAYIM

WTF ? http://en.wikipedia.org/wiki/Scope_resolution_operator

为什么不说意外的T_SCOPE_RESOLUTION_OPERATOR ?

其他回答

我有点纠结:

1;

在perl中,模块需要返回true。

A very tiny thing that annoyed me in COBOL was that there was no dedicated modulo operation. Instead you could do a division specifying that you only wanted whole number results and store the rest in a different variable. Since COBOL is very sensitive when it comes to variables that means that you ended up with a variable you didn't really need, i.e. the actual result of the division. This is the story of how I once named a variable "USELESS" - that was the most appropriate name I could think of.

这可能已经被提到了,但是——

PHP对八进制值的处理:

$a = 07; // 7 (as it should be)
$b = 08; // 0 (would be an error in any sensible language)
$c = 018; // 1 (again, should have been an error)
$d = 0A; // error (as it should be)

请看这里:http://bugs.php.net/bug.php?id=29676

还要注意关于这个错误的评论——Derick称其为一个特性(引用“fix”表示),而不是一个错误,他声称它会“在脚本中使用数字的所有情况下显著降低PHP的速度”——但是,为什么PHP会引发一个0A错误呢?

我认为人们可以写一整本书来讲述PHP的古怪之处……

Python 2. x

>>>True = False
>>>True
False

你真的可以让一个人变得疯狂。

在Matlab中,以下内容可能会让你感到惊讶,特别是如果你习惯了Python:

>> not true

ans =

     0     0     0     0
>> not false

ans =

     0     0     0     0     0

这里有两个奇怪的特征。第一个是a b被解释为a('b'),因此非真被解释为not('true')。第二个奇怪的特征是没有任何字符返回0(大概是因为在matlab中没有false或true,只有0或1)。