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.

C#

它是一种很棒的语言，特别是在LINQ中，但是与c++相比泛型支持较差。它有如此多的潜力，但目前的实现只对强类型集合和类似的琐碎事情有用。下面举几个例子:

A generic argument cannot be restricted to enums (only classes or structs). A generic argument cannot be a static class. Why? This seems like a completely artifical restriction. You cannot specify that a generic type must have a constructor with a certain signature because you cannot have constructors on interfaces. Why not? It's just another method with the special name ".ctor". Similarly, you cannot specify that a generic type must have a static method, because those also cannot be declared on interface. Something like static T Parse(string s) would often come in useful. The compiler is too eager in prohibiting some casts which the programmer knows would actually work, so they require uglyness like (TheRealType)(object)value No covariance, eg. IList<string> cannot be converted to IList<object>, even though string[] can be converted to object[]. (Microsoft might be fixing this in C# 4.0, though.)

Ruby

无类型推断 方法/函数不是一级对象 变量的范围不是词法的，尽管块变量的范围是词法的 Def内部的Def super和super()的区别

Ruby:

重要的空白。对于解释器，行尾=语句的结束，除非看起来语句应该继续(或者显式转义换行符)。 慢 在线文档不如Python的好(为了辩护，Python的很棒) 我刚才提到慢了吗?

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。

以下是我不喜欢Java的一些地方(它不是我最喜欢的语言):

Generics type erasure (i.e. no reified generics) Inability to catch multiple exceptions (of different types) in a single catch block Lack of destructors (finalize() is a very poor substitute) No support for closures or treating functions as data (anonymous inner classes are a very verbose substitute) Checked exceptions in general, or more specifically, making unrecoverable exceptions checked (e.g. SQLException) No language-level support for literal collections No type-inference when constructors of generic classes are called, i.e. the type parameter(s) must be repeated on both sides of the '='