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.

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 '='

帕斯卡对象:

There's a lot of jumping back and forth in the file you're editing since the interface and implementation are split into two parts but still jammed into the same file. Dynamic indexing of arrays, strings start at 1, you specify the starting index when declaring fixed arrays and dynamically allocated arrays always start at 0. Classes and objects (not to speak of interfaces) are bolted on top of the language and among other things can't be stack allocated like records can. When calling functions without parameters the () are optional, leading to a lot of pain when you are dealing with function pointers or trying to refer to the result of a function using the function name. Parameter lists can't handle fixed array types or function pointer types without external type definitions.

这仅仅是一种语言，一个标准库的遗憾借口，而脆弱的IDE应该有自己的列表。

我讨厌所有语言的五件事(至少就我所知):

Does what I say/type, not what I mean Will undoubtedly meet people who think they are experts in the language, but just make a mess of it (e.g. people who insist that removing comments/unused local variables will speed up execution time for a program) Unless the language is obsolete, then it will probably continue to evolve (either the actual language, or the concepts behind using it effectively) requiring you to actively develop with it so as to not fall behind. Can't modify the lexer/compiler (add in own context sensitive grammar) No perfect language (every language is missing some sort of useful feature that usually is either impossible to simulate, will unavoidable have an ugly interface or just require far too much time to implement and get it right)

objective - c

1)没有命名空间，只有手动命名约定——我不介意在类分离方面，但我确实怀念能够在一行命名空间中导入所有类定义(如import com.me.somelibrary.*)。

2)库在像RegEx支持这样的重要领域仍然存在一些漏洞。

3)属性语法有点笨拙，需要三行(在两个单独的文件中)来声明一个属性。

4)我喜欢保留/释放模式，但它比应该的更容易释放一个引用，然后意外地使用它。

5)虽然不是真正的语言特性，但Xcode与Objective-C的使用是如此交织在一起，我不禁想到这方面……基本上自动补全，是很可疑的。它更像是一个奖励你找到你想要的东西的系统，然后把它作为一个选择。但我想我从来都不喜欢自动补全引擎。

C#

Reference types are nullable by default; in-language null keyword is untyped. Lack of discriminated unions Exceptions as default, non-exceptional error handling method - there's not much of an alternative. archaic switch statement syntax and limitations Needless distinction between constructors + static methods Static methods can't be part of an interface Lack of by-shape interface implementation rather than explicit interface implementation - leading to numerous language design hacks such as the linq query syntax, foreach, collection & object initializers -- none of which can be flexibly reused. For example, the object initializer syntax may be nice, but plays poorly with immutable objects. Cannot inherit "interface" of a class independently of implementation - leading to code duplications and overarchitected code that provides interfaces, abstract base classes, a few common implementations, and no way to pick and choose the bits of each to use. Also; leads to too many code that's tightly coupled to a particular implementation since it's common to explicitly refer to the implementation type rather than an interface. Cannot multiply inherit via composition since a classes "interface" is tightly coupled to it's implementation; effectively lack of mixins. The above limitations of interfaces lead to a proliferation of virtually identical interfaces that don't overlap naturally in any kind of type hierarchy. IComparable vs. IEquatable vs. IComparable<T> vs object.Equals vs. operator == etc. etc. By extension, making a custom type that satisfies all these things is a lot more work than necessary (in particular for collection classes). Obviously, the language designers realize this, hence the various workarounds for things like linq, foreach and collection initializers which work by-shape rather than by-interface. Redundant use of parentheses and braces rather than layout-is-structure. Return values can be ignored, limiting the effectiveness of type inference. Enums aren't a normal type and can't have methods. Also, enum values aren't typesafe and may be initialized to 0 despite not having a 0 value. Mixing metaphors by lumping flag and non-flag enums together. Lack of proper value type support. Value types can't be inherited, have different constructor semantics, and perform poorly due to CLR limitations. Also, confusing semantics regarding value types: some values are really values (and can't be modified), and others are really non-aliased, non-null references (variables). This gets particularly confusing with regards to the next issue: Semantic distinction between fields and properties, particularly in conjunction with lack of mutability modifier (ala C++'s const) Can't specialize generics Cannot provide default generic type parameters (e.g. factory generics) lack of typedef makes generics a pain to use (using is a limited but good-to-know substitute!) Can't genericize over things other than types (e.g. functions, plain values, or names). This means you can't do something like make a generic implementation of a dependancy property leading to, well, nasty implementations of things like dependancy properties and the overuse of code-snippets and poorly readable code as a result. Limited capability to specify generic type requirements e.g. generic sum method that takes both int, double and a bigint (without tricky and often slow hacks). An interface method implementation or virtual method override cannot return a more specific type or accept a more general type; i.e. limited co/contravariance support even in C# 4.