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。
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
我最喜欢的奇怪的C语言是5[“Hello World”],但因为已经发布了,我最喜欢的第二个奇怪的是Windows版本结构初始化黑客:
void someWindowsFunction() {
BITMAPINFOHEADER header = {sizeof header};
/* do stuff with header */
}
这条微妙的线条达到了以下效果:
Declares a BITMAPINFOHEADER structure Concisely sets the "size" member of the structure, without hardcoding a size constant (since many Window structures, including BITMAPINFOHEADER, follow the convention of specifying the size of the structure as the first member} Declares the version of the structure (since many Windows structures, including BITMAPINFOHEADER, identify their version by the declared size, following the convention that structures definitions are append-only) Clears all other members of the structure (a C standard behavior when a structure is incompletely initialized).
其他回答
Ruby
时间。Parse经常假装解析没有失败,而是返回现在
require 'time'
Time.parse '2000-01-01 12:00:00'
# -> 2000-01-01 12:00:00 +0100
Time.parse '2000-99-01 00:00:00'
# -> ArgumentError: argument out of range ...
Time.parse 'now'
# -> 2010-08-13 21:26:13 +0200
Time.parse 'yesterday'
# -> 2010-08-13 21:26:18 +0200
Time.parse 'billion years ago'
# -> 2010-08-13 21:26:37 +0200
在PHP中,函数名不区分大小写。这可能会导致您认为php中的所有标识符都不区分大小写。再猜一遍。变量区分大小写。WTF。
function add($a, $b)
{
return $a + $b;
}
$foo = add(1, 2);
$Foo = Add(3, 4);
echo "foo is $foo"; // outputs foo is 3
echo "Foo is $Foo"; // outputs Foo is 7
在Python中:
>>> a[0] = "hello"
NameError: name 'a' is not defined
>>> a[0:] = "hello"
NameError: name 'a' is not defined
>>> a = []
>>> a[0] = "hello"
IndexError: list assignment index out of range
>>> a[0:] = "hello"
>>> a
['h', 'e', 'l', 'l', 'o']
这些切片分配也会给出相同的结果:
a[:] = "hello"
a[42:] = "hello"
a[:33] = "hello"
ANSI SQL中空值的三值逻辑。
Haskell's use of Maybe and Just. Maybe a is a type constructor that returns a type of Just a, but Maybe Int won't accept just an Int, it requires it to be a Just Int or Nothing. So in essence in haskell parlance Just Int is about as much of an Int as an apple is an orange. The only connection is that Just 5 returns a type of Maybe Interger, which can be constructed with the function Just and an Integer argument. This makes sense but is about as hard to explain as it can theoretically be, which is the purpose of haskell right? So is Just really JustKindaLikeButNotAtAll yea sorta, and is Maybe really a KindaLooksLikeOrIsNothing, yea sorta again.
-- Create a function that returns a Maybe Int, and return a 5, which know is definitly Int'able
> let x :: Maybe Int; x = 5;
<interactive>:1:24:
No instance for (Num (Maybe Int))
arising from the literal `5' at <interactive>:1:24
Possible fix: add an instance declaration for (Num (Maybe Int))
In the expression: 5
In the definition of `x': x = 5
> Just 5
Just 5
it :: Maybe Integer
-- Create a function x which takes an Int
> let x :: Int -> Int; x _ = 0;
x :: Int -> Int
-- Try to give it a Just Int
> x $ Just 5
<interactive>:1:4:
Couldn't match expected type `Int' against inferred type `Maybe t'
In the second argument of `($)', namely `Just 5'
In the expression: x $ Just 5
In the definition of `it': it = x $ Just 5
祝你好运读到这篇文章,我希望它是正确的。