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.

Java

已检查的异常 类型擦除 缺少操作符重载(例如BigInteger/BigDecimal) 缺少regexp/date/duration /复杂文字 对不可变性的支持很差

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:

太慢了 自负的群体 这不是闲谈 在nil上调用方法时出错，而不是返回nil à la Objective C 非线程

C:

Lack of distinction between function pointers (executable) and data pointers (you really don't want to execute this). Extreme unreadability. Making code look like it does what it does is orders of magnitude more difficult than making it do the task in the first place. Lack of clear support for lisp-think. Doing functional things is possible, barely, but it's not clear. Serious inconsistency between libraries about how error codes are returned. Antiquated string handling. The strings aren't strings, they're null-terminated blobs. This is all manner of wince-worthy.

Lisp:

()需要按shift键。每次我口齿不清的时候，我就把它和[]交换。

.NET框架(库)

嵌套类型很少使用(例如MessageBoxButton应该是MessageBox.Button) 可变结构体(Rect, Point) 系统名称空间中有太多东西 太多不同的平等概念(对象。等于,对象。ReferenceEquals, operator ==， operator !=， IComparable.CompareTo() == 0) 数组的成员是可变的，但长度是不变的。

还有一点:

XmlSerialization不适用于不可变类型