Javascript中有很多东西会让你流泪。

局部变量的作用域，举个简单的例子:

function foo(obj)
{
  for (var n = 0; n < 10; n++)
  {
    var t;        // Here is a 't'
    ...
  }
  t = "okay";     // And here's the same 't'
}

在J中，大多数原语(也就是函数)是一元的(一个参数)或二元的(两个参数，一个在左边，一个在右边)。但是修正原语需要3个(我认为这是唯一一个，除了foreign)。这是可以理解的，它需要3个，但它只是看起来…一开始是错的。

vector =: i. 10   NB. Vector will be 0 1 2 3 4 5 6 7 8 9
(10) (0) } vector NB. Will yield 10 1 2 3 4 5 6 7 8 9

INTERCAL可能是最奇怪的语言特征的最佳汇编。我个人最喜欢的是COMEFROM语句，它(几乎)与GOTO相反。

COMEFROM is roughly the opposite of GOTO in that it can take the execution state from any arbitrary point in code to a COMEFROM statement. The point in code where the state transfer happens is usually given as a parameter to COMEFROM. Whether the transfer happens before or after the instruction at the specified transfer point depends on the language used. Depending on the language used, multiple COMEFROMs referencing the same departure point may be invalid, be non-deterministic, be executed in some sort of defined priority, or even induce parallel or otherwise concurrent execution as seen in Threaded Intercal. A simple example of a "COMEFROM x" statement is a label x (which does not need to be physically located anywhere near its corresponding COMEFROM) that acts as a "trap door". When code execution reaches the label, control gets passed to the statement following the COMEFROM. The effect of this is primarily to make debugging (and understanding the control flow of the program) extremely difficult, since there is no indication near the label that control will mysteriously jump to another point of the program.

COMEFROM是我见过的最奇怪，也可能是最没用的语言功能。

其次是三元运算符，因为它违反了优化的第一条规则。它带来的危害大于它解决的问题。它的危害更大，因为它使代码可读性更差。

并不是一个真正的语言功能，但有趣/很棒的功能使用是Duff的设备。

在Ruby中，0在条件表达式中求值为true。

在C或c++中，使用宏可以获得很多乐趣。如

#define FOO(a,b) (a+b)/(1-a)

如果传入FOO(bar++，4)，它将使a增加两次。