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.

JavaScript

ECMAScript 5规范:

7.6.1.2未来保留词: 类，enum, extends, super, const, export， 进口 严格模式:实现、let、private、public、interface、package、protected、static、yield 11.9.4严格等于操作符(===)对比11.9.1 TheEqualsOperator(==) 11.9.6严格相等比较算法(NaN === NaN is false) 8.5数字类型-没有实整数，所有都是浮点数。 4.2.1对象——原型继承

好吧，我有点喜欢最后一个，但它有7种让人困惑的地方

length属性很容易与length()函数混淆;请改用size() 在选择器字符串中插入变量的语法('" +$。Month + "')臭死了 $(event.currentTarget)并不总是适用于冒泡和捕获 属性语法("[class='foot']")在选择器语法(".foot")不返回任何结果的地方起作用 包含选择器([class~=done])有时会在JavaScript (this.className.search("done") > 0)工作时失败

Lua:

The built-in error system is absolutely horrendous You can implement a try-catch system by modifying the Lua interpreter; but it has no compatibility with the errors that are thrown by the built in functions. The fact they have __newindex instead of __setindex as the setter ... and __newindex is only fired when the key doesn't already exist. If it does, no metamethod is called at all. No good type comparison system. There's the type() function but it only handles the basic types (all tables are tables). It really needs to have a metamethod for type comparisons. I've implemented this before with an 'is' operator and a __type metamethod and it works really nicely. It's a bitch to define new keywords. You can do it, but the code inside Lua isn't well documented so it's kind of trial and error to find out how to get the result you want. This is a major issue when you want to implement the things I mentioned above yourself (not so much __setindex though, that's an easy modification). I can't use it in a web browser. Yeah not really a problem with the language itself, but damn, would I love to be able to use Lua instead of Javascript... :)

BrainF * ck

你的亮点是图灵完备?!我可以在Perl正则表达式中做更多的事情! 缺少对象。来吧,人!就像，你好… 没有网络库。我只想刮一个网页，天哪。 没有一级函数。恭喜你——你可以同情你的Java朋友了。 一个无限的磁带存储，没有其他。这是如此的矫情，我们可能还在写Lisp。

按最讨厌到最不讨厌的顺序排列。

1.) Backwards compatibility police. Yes backcompat is a strength but Perl 5 takes it too far. Now we don't really even get new features in our language without having to enable them explicitly. I'm much prefer the inverse, if a new feature causes a problem let me disable it or enforce old behavior. e.g. perl 5.10 added say I'd rather have no feature 'say' if I have my own say implemented than have to put use feature 'say'; or use 5.010; also if 5.8 worked but 5.10 didn't. I'd rather have use 5.008; to restrict my code to only use features available up to and including 5.8 if no use version; was defined then it should be defaulted to whatever version you're running, and a recommended practice of not to restrict it unless you have to.

2)。过度的样板。

#!/usr/bin/perl
use strict;
use warnings;
use utf8;
use autodie;
use English '-no_match_vars';
use 5.010;
package Package::Name;

BEGIN {
    Package::Name::VERSION = 0.1;
}

sub somesub {
    my $self = shift;
    my ( $param1, $param2 ) = @_;
}
1;

现在你可以开始编码了。这不会因为第一条而改变。当然也有一些捷径，比如使用common::sense;或者使用modern::perl;这将缩短上面的内容，你可能需要一些稍微不同的模块或pragma。但因为第一条，我们永远无法把它降低到。

#!/usr/bin/perl
package Package::Name 0.01;

sub somesub ( $param1, $param2 ) {
}

一些模块正在帮助这一点，在5.0.12中有新的包版本，它完全允许这种语法，尽管我认为它需要使用5.012;首先，和Method::签名，但它永远不会完全解决，(在语言)。

3)。糟糕的变量选择

吸吸文件

#!/usr/bin/perl
use strict;
use warnings;
open my $fh, "< foo" or die $!;
local $/; # enable localized slurp mode
my $content = <$fh>;
close $fh;

WTF是$!和美元/ ?重写为易读。

#!/usr/bin/perl
use strict;
use warnings;
use English '-no_match_vars';
open my $fh, "< foo" or die $ERRNO;
local $INPUT_RECORD_SEPARATOR; # enable localized slurp mode
my $content = <$fh>;
close $fh;

不要忘记，如果您不想受到性能影响，'-no_match_vars'必须存在。

不直接创建匿名标量怎么样?

#!/usr/bin/perl
my $scalar_ref = \do{ my $anon_scalar };

他们就不能想出点什么办法吗?

#!/usr/bin/perl
my $scalar_ref = <>;

哦，perl是线程不友好的，因为所有的变量(包括特殊的变量)默认是全局的。至少现在你可以使用我的$_;对其词法作用域，并对其他词使用local。

4.)非常难看的语法

MooseX::Declare是一个更好的语法。我也希望->被替换为。(个人喜好不太重要)

5)。太多的TIMTOWTDI或太多的最佳实践似乎你必须读3-5本书才能弄清楚你应该如何做事情。

6)。以前的(不再适用)。Un-sane版本。5.10.0有新功能5.10.1的新功能没有设定时间，直到下一个版本。现在是每年一次的特性发布，每季度更新一次。

7)。象牙塔视角。社区问题，似乎是许多开发者想要设置更高的准入门槛，并认为可以不尊重n00b(或任何不同意他们的人)。

8)。疯狂的版本号/字符串Perl有浮点版本号，它们很难看。开发人员不知道并不是所有的下游处理版本比较的方式都是一样的。不是语言问题

0.012 # simple
5.012001 # semantic 
4.101900 # time based + version (for multiple versions in a day)
0.035_002 # prerelease

所有有效版本的perl..我们就不能用…

0.12 # simple
5.12.1 # semantic
20100713 # time based (just use the date and be careful not to need to release more than 1 a day)
0.35-beta2 # prerelease

除了

9)。升级后没有明显的方法重新安装所有XS模块