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.

再给c++投一票…仍然是我最喜欢的语言，有几个亲密的追随者——C和Python。以下是我目前最讨厌的名单，排名不分先后:

Plethora of integer types inherited from C - way too many problems caused by signed vs. unsigned mistakes Copy constructors and assignment operators - why can't the compiler create one from the other automatically? Variable argument madness - va_list just doesn't work with objects and I'm so sick of problems created with sprintf(), snprintf(), vsnprintf(), and all of their relatives. Template implementation is required to be fully visible at compile time - I'm thinking of the lack of "export" implementations or at least usable ones Lack of support for properties - I want to have a read-only member like "a.x" that can be read publicly and only assigned internally. I really hate the "val=obj.getX()" and "obj.setX(val)". I really want properties with access control and a consistent syntax.

JavaScript

Function object syntax: f = new Function( "foo", "bar", "return foo+bar;" ); (It takes n arguments, the first n-1 are arguments for the function, then nth is the actual function, in string form. Which is just silly.) Function arguments can be repeated. f = new Function( "foo", "foo", "return foo;" ); The last repetition is the only one ever used, though: f( "bye", "hi" ) // returns "hi" f( "hi" ) // returns undefined E4X should just die. My users are always complaining that it doesn't work the way they think it will. Let's face it, when you need a page and a half of psuedocode for a setter, it's time to rethink things. A standard notion of stdin/stdout/stderr (and files!) would be nice. null != undefined It's irritating to have to handle them both. Sometimes it's useful, but most languages manage to limp along fine with one.

Javascript;

the dynamic binding of "this" is very confusing and dangerous if you don't know exactly what you're doing. a function declaration requires the keyword "function". It's not the typing I object to, it's the reading it when I want to do something slightly clever. Hrm now I think of it maybe that's a plus. Discourages me from doing clever things. As a result of number 2, it's often less code (in terms of characters) to just copy/paste a code segment than to declare it as a function, if it's a fairly short idiom. This unfortunately promotes bad practice, especially in my own code. Javascript makes motions at being a functional language by having first class functions and closures, but there's no way to verify referential transparency in a function, at either runtime or compile time. Without this, some architectures become either risky or bulky. Its fantastically bad reputation, and thus my inability to say "I program in javascript" to anyone without being laughed at.

Java:

没有过程编码，它编译成过程代码，所以让我使用它! 没有多重继承，试图用15,000个接口做同样的事情很糟糕。 约会课，我还需要多说吗。 我不能充分利用多态性。Java不会覆盖不同的参数类型来触发。 我想不出第五个原因，如果我知道，我会回来编辑这篇文章。

我知道我迟到了，但恨是永恒的!

Java

Runtime.exec(). So, if I don't manually clear the STDOUT and STDERR buffers, my code will hang? Wow. Die, plz. Null Pointer Exceptions. Responsible programming means I have to treat most objects like they're unexploded bombs, which is kind of a pisser in an object-oriented language. And when the inevitable happens I kinda need to know which object blew up in my face, but Java apparently feels telling me would be cheating. File I/O. Why do I have to jump through this many hoops to read a dang text file? And when copying files, I have to funnel the source file into my code and manually handle the output byte buffer? You're serious? Primitives vs. Primitive Wrappers. Note that Java now has a number of features that allow you to treat primitives and their wrapper objects as interchangeable in some places, but not in others; don't worry, the compiler will let you know which is which. This feels like a hack to work around a fundamentally broketastic design decision. And it is. (EDIT: Actually, the compiler is a much crappier safety net than I thought, particular when doing equality checks. If `a` and `b` are integers, `a == b` is guaranteed to behave as expected only if at least one of them is of type `int`. If they're both type `Integer`, then that statement will do what you think only if the two numbers are between -128 and 127. `Integer a = 1000; Integer b = 1000; return a == b;` will return `false`. Really.) XML. I have this dirt-simple little XML file I need to create and I have to do what?