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。

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.

PHP:

荒谬的assert()函数…它对里面的代码运行eval() ?>标签删除了它后面的换行符?! 奇怪的数字字符串处理(尝试将它们作为数组键) 令人痛苦的unicode支持似乎将不再被PHP 6解决 入门成本低意味着95%的人给PHP程序员起了一个可怕的名字——试图在这5%中找到一个人来雇佣是疯狂的。

Python:

我仍然是python的一般用户，所以我的抱怨可能只是知识的锁或误用。欢迎提出意见。我很喜欢这门语言。

Poor thread support and GIL. If you'd like to take use of multicore platform, most of the python programmers would probably recommend multiprocessing or some sort, don't use threading. It wouldn't give you the performance you are expecting. property only for instance variable. _class_var = property(classmethod(some_method)) just wouldn't work. How can I get a property wrapped class variable? no access control. All access controls are syntax mangling. Like private is __private, protect is _protected, etc... And hope that everyone programs python follows the naming convention. Come on, we can do better than that. I agree the python philosophy of being simple and clear syntax but some simple and clear syntax not being supported seems lock of good judgement, in my opinion. Such as, a++, ++a, a-- and --a, self-de/increment, what's wrong with those? foo = (a > b ? a : b) unary operation, what's wrong with those? (I know py2.6 has something similar introduced, but given the massive support of almost every other language for those simple syntax, why reinventing the wheel? why not just follow the best practice? Shouldn't a good thing just keep in its good "form"?) Program to interface. Python has no interface or abstract class concept (py3k has something called abc), everything is concrete. Providing an "interface" or "abstract" keyword to build class skeleton and guard class inheritance and extension wouldn't be a bad idea I think. It helps on top-down design. Currently, I just have to fill the each of methods with NotImplementedError, quite a tedious job. I have to add this. version less than 3.x has str and unicode types. This is a true nightmare. It makes ascii and non-ascii/unicode mixing most likely to fail (bad, bad)

我看到人们抱怨速度。我不明白。它是一种解释语言，代码直到运行时才编译成机器代码，这就是它的本质。你不能比较解释语言和编译语言的速度。据我所知，在解释/脚本语言中，python并不慢。

Scala是我最喜欢的语言。五件讨厌的事?容易:

Takes a long time to learn properly. I know you can write Scala as a 'better java'. That is what we used to say about C++ and C too. I agree this is an inevitable consequence of the deep ideas in the language. But still ... Methods vs. Functions: def f(x: Int) = x*x defines a method f, not a function f. Methods are not functions despite a lot of early Scala tutorial material blurring the distinction. The language tries to blur it too because if you supply a method in some places where a function is expected it is accepted. Do we have to have both methods and functions? Yes it is fundamental. But it was initially confusing to me. Composing classes or objects from mixins in the 'cake' pattern is prone to NPE's. e.g. trait X { val host: String; val url = "http://" + host } is a mixin that will NPE on instantiation, or not, depending on its position in the class declaration. The compiler could tell you if it will fail but doesn't. (In 2.7 anyway.) It is hard to diagnose the problem in complex inheritance graphs. Arrays in 2.8 rely on implicits to mesh with the main scala collection types. But implicits are not applied everywhere. An Array can be supplied where a Seq is expected. But an Option[Array] cannot be supplied where an Option[Seq] is expected. I know there are no completely 'right' ways to handle java Arrays. Type erasure. Enough said.

C#

我对c#非常满意，但这两个真的让我很恼火:

Constructor-based initialization for immutable classes is less convenient, less intuitive (when you read the code you don't understand what you assign to what), has less IDE backing than inline object initialization. This makes you lean towards mutable classes inevitably. I know this has been mentioned before, but I strictly have problems with initialization syntax for immutable classes. switch is too verbose. Whenever I see a situation where a switch would be proper, I'm really inclined to use an if..else if.. just because it's more terse (~30% less typing). I think there should be no fallthrough for switch, break should be implied, and case should allow comma separated list of values.