Python 3

both tabs & spaces allowed for indentation And you'd think people learn from the past (Makefile). Just pick spaces and forbid tabs. YAML got it right. lack of popular third-party libraries The standard library is great, but a lot of what makes Python 2 so powerful lies in the third-party realm. Python 2 got this right :-). IEEE floats Floating points in programming languages are confusing because they're different from the way we use them in math. Instead, the number operations should be viewed as expressions that are only converted to a decimal point format when needed (i.e. printing to a screen). Maple and Mathematica did this right I think. the character set for identifiers is too restricted list.empty? is better than list.is_empty or even len(list) != 0. Similarly, process.kill! would be better than process.kill. Ruby and lisp got this right. when calling a function you must always write parentheses It would be nice if we could omit them in unambiguous cases. How is it again? dict.items or dict.items()? Ruby got this one right, too.

Python

No statements in lambdas. GRRRR foo( a for b in c if d ) feels wrong, it surprises me every time I get away with it. Shouldin't it be foo( (a for b in c if d) )? Can i have a dict comprehension? map and filter operators have special syntax in list comprehensions, how about something for reduce? or sort? Just by having a yield statement in it, a function is magically transformed into a generator, and its interface changes completely. Also, that generator cannot do any work before the first next(). at least, not without using a function that returns a generator.

JavaScript

No brief syntax for making modular code libraries. You have to call a function that returns a dictionary of public methods. And you have to edit that in (at least) two places every time you alter the interface of your module. Creating closures involves returning it from a function that returns a function from ('sup dog) yo' function. Clutter! for each ( foo ) syntax and behavior feels like an afterthought. Knowing when your code will actually run (and in what order) is more of a dark-art. The only way to get it right for sure is put everything (yes, that too) in one big file. and even then you still need to wait for a document.onload Am i missing something? is there no trivial way to get json serialized values without building them by hand? (yes jQuery can do this, sort of).

Clojure

Lack of built-in syntax for optional and keyword parameters in function definitions. Sure, you can add it easily enough, but that means library writers don't use it. Pervasive destructuring hasn't proven to be a good substitute yet Lack of method combination (before/after/around methods of the sort found in Common Lisp) Too much reliance on Java interop, e.g. there's no built-in file IO Sometimes I want static typing. This one isn't pure hate; I usually prefer dynamic, and attempts to mix the two have been largely unsatisfactory There's no built-in fast binary serialization format for the built-in data structures, though I hear people are working on it

c#:

1)静态方法必须是类的成员

2)静态扩展方法只能添加到静态类中

3)接口函数的实现不会被标记为“override”之类的东西来显示它们来自基类或接口(这使得你很难确保你正在重写你所期望的方法(具有正确的签名))。

我只有3个。我想那很好。

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.

C:

Lack of distinction between function pointers (executable) and data pointers (you really don't want to execute this). Extreme unreadability. Making code look like it does what it does is orders of magnitude more difficult than making it do the task in the first place. Lack of clear support for lisp-think. Doing functional things is possible, barely, but it's not clear. Serious inconsistency between libraries about how error codes are returned. Antiquated string handling. The strings aren't strings, they're null-terminated blobs. This is all manner of wince-worthy.

Lisp:

()需要按shift键。每次我口齿不清的时候，我就把它和[]交换。