F#

Type inference is limited. It propagates forward only. F# won't try to infer an object type based on the methods and properties used: you'll get "lookup of indeterminate object type" errors when it doesn't have a clue. One cannot mix floats and ints: 1 + 2.3 is a type error. It's a little awkward to have to create a builder object in order to define a monad or computation expression. In Haskell or Scala, you can define the monad operations directly on the monadic object. Though the #light syntax is preferred, the indentation rules are sometimes not very intuitive or become cumbersome.

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

Python:

No standard GUI toolkit (the community goes round and round about this but never seems to settle on anything). The evolution of tools and methods to distribute and install Python apps and libraries has been, well, rocky. (Although lately this seems to be moving closer to getting fixed.) CPython is still slow as interpreters go (although PyPy is looking pretty good these days, if it becomes the "standard" Python this problem goes away). You can't subclass built-in classes (e.g., list and dict) without overriding a lot of methods, even if all you want to do is a simple hook into an event (e.g., to hook into an item being added to or removed from the list, you need to override delitem, append, extend, insert, pop, and remove--there's no subclassable "change" event notification, nor any "protected" methods that factor out common code used by all the above methods). Up until virtualenv was invented, keeping separate Python environments for different purposes on one machine was a real pain.

我只有一个，但我相信它值得分享。

CSharp / .NET

我们有Length属性来获取数组中的元素个数，还有Count属性来获取集合中的元素个数。如果考虑到CLR在后台自动将IList、ICollection、IEnumerable添加到基于零的一维数组，那么它看起来就更奇怪了。

我相信CLR团队和BCL团队在讨论这个问题时遇到了困难;)

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insist that removing comments/unused local variables will speed up execution time for a program) Unless the language is obsolete, then it will probably continue to evolve (either the actual language, or the concepts behind using it effectively) requiring you to actively develop with it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)

C#

我对c#非常满意，但这两个真的让我很恼火:

Constructor-based initialization for immutable classes is less convenient, less intuitive (when you read the code you don't understand what you assign to what), has less IDE backing than inline object initialization. This makes you lean towards mutable classes inevitably. I know this has been mentioned before, but I strictly have problems with initialization syntax for immutable classes. switch is too verbose. Whenever I see a situation where a switch would be proper, I'm really inclined to use an if..else if.. just because it's more terse (~30% less typing). I think there should be no fallthrough for switch, break should be implied, and case should allow comma separated list of values.