Python 3

both tabs & spaces allowed for indentation And you'd think people learn from the past (Makefile). Just pick spaces and forbid tabs. YAML got it right. lack of popular third-party libraries The standard library is great, but a lot of what makes Python 2 so powerful lies in the third-party realm. Python 2 got this right :-). IEEE floats Floating points in programming languages are confusing because they're different from the way we use them in math. Instead, the number operations should be viewed as expressions that are only converted to a decimal point format when needed (i.e. printing to a screen). Maple and Mathematica did this right I think. the character set for identifiers is too restricted list.empty? is better than list.is_empty or even len(list) != 0. Similarly, process.kill! would be better than process.kill. Ruby and lisp got this right. when calling a function you must always write parentheses It would be nice if we could omit them in unambiguous cases. How is it again? dict.items or dict.items()? Ruby got this one right, too.

JavaScript:

The Object prototype can be modified. Every single object in your program gets new properties, and something probably breaks. All objects are hash maps, but it's difficult to safely use them as such. In particular, if one of your keys happens to be __proto__, you're in trouble. No object closure at function reference time. In fact, no object closure at all -- instead, this is set whenever a function is called with object notation or the new operator. Results in much confusion, particularly when creating event callbacks, because this isn't set to what the programmer expects. Corollary: calling a function without object notation or the new operator results in this being set equal to the global object, resulting in much breakage. Addition operator overloaded to also perform string concatenation, despite the two operations being fundamentally different. Results in pain when a value you expect to be a number is in fact a string. == and != operators perform type coercion. Comparisons between different types involve a list of rules that no mortal can remember in full. This is mitigated by the existence of === and !== operators. Both null and undefined exist, with subtly different, yet redundant meanings. Why? Weird syntax for setting up prototype chains. parseInt(s) expects a C-style number, so treats values with leading zeroes as octal, etc. You can at least parseInt(s, 10) but the default behaviour is confusing. No block scope. Can declare the same variable more than once. Can use a variable without declaring it, in which case it's global and probably breaks your program. with { }. Really difficult to document with JavaDoc like tools.

我自己最讨厌c++的5个地方:

自动生成构造函数、析构函数和赋值操作符。伙计，每当我在课上没有声明什么东西时，这意味着我不需要它，而不是我忘记了。你们这些编辑们，听到了吗?!

[4]模板语法。哦，我真的需要输入所有这些“<”和“>”，每当我决定从类主体提取定义?

[3]字符串。天啊，我受够了“const char*”，我必须处理NULL情况，我必须浪费O(N)来获得它的长度，我必须为concat操作分配缓冲区。

[2] Macroprocessing。每当我不明白，什么是我的编译器，我开始寻找宏。

[1]操作符重载。我看到代码“A + B * C”，在我看到A、B和C的实际类型之前，我说不出这个代码是关于什么的。

C#

5. 空合并运算符

的? ?运算符允许你写:

x = y ?? z;

而不是:

x = (y == null) ? y : z;

我喜欢这个运算符，但我想要另一个:

x = y ??? y.foo() : z.foo();

而不是

x = (y == null) ? y.foo() : z.foo();

我一直在使用这种东西，而且我发现输入== null部分很烦人。

4. 平等应该有更好的支持

我必须启动每个Equals(object obj)方法: MyClass other = obj作为MyClass; If (other == null)返回false;

你只需要写:

public override bool Equals(MyClass other) {...}

语言应该注意提供Equals(object obj)方法。 注意:other必须保证不为空。

3.不能使用不同类型的三元运算符

这不能编译，我认为它应该编译!

string foo = "hello";
int bar = 4;
object baz = foo == null ? foo : bar;

2. 缺少命名空间private

我喜欢内部保护，但我希望有一种保护只允许从同一名称空间内进行访问。这样可以更好地控制大型类库的访问。

1. 没有多重继承

我实际上只对接口的默认实现使用实现(类)继承，但很多时候我想这样做。

Common Lisp:

关键词往往太啰嗦。 库支持是可怜的。 在希望更严格地处理内存的操作系统中不能很好地工作。 没有与操作系统交互的良好工具。 “循环”功能没有很好地定义，当然看起来也不像Lispy。

PHP

没有构造函数重载 不一致的函数命名(str_replace，但strtolower) define()不像c++那样逐字替换全局变量。 在与XHTML组合时，像if-语句这样的语句必须以不缩进开始，即使为了保持XHTML缩进一致，XHTML是缩进的。

Ex:

你必须输入:

<?php
if($x == NULL)
{
?>
                     <p><?= $x . ' is null' ?></p>
<?php
}
?>

错误捕获非常糟糕

(不知道为什么又把5号改成了1号，随便了)