C

It's so flexible and powerful that it's really easy to write really awful, or downright dangerous code (or, if you prefer, "with great power comes great responsibility"). '=' for assignment, and '==' for equality; easy to confuse in 'if' statements. The implementation of a number of fundamental parts of the language are compiler-dependent; e.g. the size of the basic types, order of bits in bitfields, padding and byte order in unions. Bitfields aren't parameterisable (i.e. you can array of ints, but you can't have an array of bits). String handling could be improved.

c# / .net:

Classes should be sealed by default There should be no lock statement - instead, you should have specific locking objects, and there should be methods such as Acquire which return disposable lock tokens. Corollary: there shouldn't be a monitor for every object. GetHashCode() and Equals() shouldn't be in System.Object - not everything's suitable for hashing. Instead, have an IdentityComparer which does the same thing, and keep the IComparer<T>, IComparable<T>, IEqualityComparer<T> and IEquatable<T> interfaces for custom comparisons. Poor support for immutability Poor way of discovering extension methods - it should be a much more conscious decision than just the fact that I'm using a namespace.

这些都是我想出来的，明天问我，我会想出一个不同的5个:)

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 '='

Perl

Mixed use of sigils my @array = ( 1, 2, 3 ); my $array = [ 4, 5, 6 ]; my $one = $array[0]; # not @array[0], you would get the length instead my $four = $array->[0]; # definitely not $array[0] my( $two, $three ) = @array[1,2]; my( $five, $six ) = @$array[1,2]; # coerce to array first my $length_a = @array; my $length_s = @$array; my $ref_a = \@array; my $ref_s = $array; For example none of these are the same: $array[0] # First element of @array @array[0] # Slice of only the First element of @array %array[0] # Syntax error $array->[0] # First element of an array referenced by $array @array->[0] # Deprecated first element of @array %array->[0] # Invalid reference $array{0} # Element of %array referenced by string '0' @array{0} # Slice of only one element of %array referenced by string '0' %array{0} # Syntax error $array->{0} # Element of a hash referenced by $array @array->{0} # Invalid reference %array->{0} # Deprecated Element of %array referenced by string '0' In Perl6 it is written: my @array = ( 1, 2, 3 ); my $array = [ 4, 5, 6 ]; my $one = @array[0]; my $four = $array[0]; # $array.[0] my( $two, $three ) = @array[1,2]; my( $five, $six ) = $array[1,2]; my $length_a = @array.length; my $length_s = $array.length; my $ref_a = @array; my $ref_s = $array; Lack of true OO package my_object; # fake constructor sub new{ bless {}, $_[0] } # fake properties/attributes sub var_a{ my $self = shift @_; $self->{'var_a'} = $_[0] if @_; $self->{'var_a'} } In Perl6 it is written: class Dog is Mammal { has $.name = "fido"; has $.tail is rw; has @.legs; has $!brain; method doit ($a, $b, $c) { ... } ... } Poorly designed regex features /(?=regexp)/; # look ahead /(?<=fixed-regexp)/; # look behind /(?!regexp)/; # negative look ahead /(?<!fixed-regexp)/; # negative look behind /(?>regexp)/; # independent sub expression /(capture)/; # simple capture /(?:don't capture)/; # non-capturing group /(?<name>regexp)/; # named capture /[A-Z]/; # character class /[^A-Z]/; # inverted character class # '-' would have to be the first or last element in # the character class to include it in the match # without escaping it /(?(condition)yes-regexp)/; /(?(condition)yes-regexp|no-regexp)/; /\b\s*\b/; # almost matches Perl6's <ws> /(?{ print "hi\n" })/; # run perl code In Perl6 it is written: / <?before pattern> /; # lookahead / <?after pattern> /; # lookbehind / regexp :: pattern /; # backtracking control / ( capture ) /; # simple capture / $<name>=[ regexp ] /; # named capture / [ don't capture ] /; # non-capturing group / <[A..Z]> /; # character class / <-[A..Z]> /; # inverted character class # you don't generally use '.' in a character class anyway / <ws> /; # Smart whitespace match / { say 'hi' } /; # run perl code Lack of multiple dispatch sub f( int $i ){ ... } # err sub f( float $i ){ ... } # err sub f($){ ... } # occasionally useful In Perl6 it is written: multi sub f( int $i ){ ... } multi sub f( num $i ){ ... } multi sub f( $i where $i == 0 ){ ... } multi sub f( $i ){ ... } # everything else Poor Operator overloading package my_object; use overload '+' => \&add, ... ; In Perl6 it is written: multi sub infix:<+> (Us $us, Them $them) | (Them $them, Us $us) { ... }

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

C#

c#最让人讨厌的是:

(1)事件具有对所有侦听器的强引用，从而防止了侦听事件的任何东西的垃圾收集。如果你想看到这造成的问题，只需在网上搜索所有试图通过创建某种“弱引用事件处理程序”来解决问题的人。

(2)在调用一个事件之前，需要检查它是否等于null，这似乎应该由语言来处理。

(3) XML序列化器无法读取/写入XML文件中的注释。在手工修改XML文件和用c#编写的工具修改XML文件的环境中，情况并不好。可以通过使用原始的XmlDocument来解决，但如果能够将其抽象到一个类中会更好。

(4)构建过程不允许您直接访问xsd文件之类的东西，相反，您需要一个中间步骤，即创建一个c#部分类。这也会导致XAML文件出现问题，有时需要重新构建两次才能使更改正确地通过。

(5)不支持CPU intrinsic，如MMX和SSE 1,2,3,4，因此这些有价值的CPU特性在运行c#应用程序时无法使用。

其他没有进入我的前5名:

(6)不能将字段标记为属性，所有属性必须从一开始就显式地实现:

目前有:

public class MyClass {
    private int someInt;

    public int SomeInt {
        get {
                return someInt;
        }
        set {
                someInt = value;
        }
    }
}

想

public class MyClass {
    [IsProperty(public, get, set)]
    private int someInt;
}

(7)不支持多个返回值，例如:

public int, string, double MyFunction()
{
    ....
    return x,y,z;
}


public void TestMyFunction()
{
    int x, string y, double z = MyFunction();
}

(8)不支持协变返回类型

我对泛型实现有一些不满，但我就此打住。我认为c#是一种很棒的语言，可以完成所有的GUI、网络和配置管道，并且是我的首选语言，可以以一种可以长期支持的方式快速启动和运行。