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.

Python:

1) line continuation syntax: "...\" works, but "...\ " does not, and that trailing space is generally invisible, without unusual eol-marking by editer. 2) a bare 'raise' is invisible in the stack trace, as the stack trace looks like the previous raised exception. 3) slow 4) poor integration into web-servers (mod_python: dead, mod_wsgi: limited scope of operation). This is complicated by 3], requiring daemonization or some sort of memory-persistance to perform well. 5) overly tolerant of mixed tabs and spaces, allowing changes to control flow to sometimes remain hidden. (maybe fixed in recent versions)

闲聊

我不想再用java、delphi、c#或ruby进行开发(这是不切实际的，因为我公司的主要开发语言是c#、delphi和java)。 从左到右的评估。 有类注释但没有方法注释(至少在Squeak中) 没有真正的标准库，在细节上有很多差异 缺少名称空间

Ruby是我最喜欢的语言，以下是我不喜欢的语言:

绿色线程+阻塞C库=巨大的失败 慢得令人痛苦 标准库本身与其使用bang!方法 模块包含+扩展是混乱的。 “开放类”不能是范围-我想添加一个String#dostuff，但我不希望泄漏到所有的第三方库 没有二进制部署打包解决方案。

Delphi(又名Object Pascal)，我将讨论本机版本，而不是。net。

Var块! 语言中的接口在设计时就考虑到了COM的使用——因此比c#或Java要复杂得多。ie。涉及引用计数，除非显式禁用它。 没有尝试，只有最终结束; 对象创建过于显式: var obj: TMyObject; .．. obj:= TMyObject.Create; 试一试 .．. 最后 obj.Free; 结束;

而是像这样

auto obj: TMyObject; // compiler adds the default constructor call and the destructor call in a try/finally block. 

好吧，语言太好了，我真的想不出更多，所以我在这里强迫自己:内置类型，如字符串，整数..或者枚举最好有方法。ie。i. tostring代替IntToStr(i)。

Python:

速度 静态分析(缺乏) 匿名函数仅限于一个表达式