Java -不支持语言级别的组合

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.

C#

Lack of multiple dispatch based on the runtime type of the method arguments. dynamic should solve most of this, but it hasn't been released yet. Interface implementation is declarative not structural. I really like the way Google's Go language is doing types Making asynchronous method calls is really bulky (and I'm pretty sure all threads are OS threads, not lightweight threads) No macro system. I'm not talking about C-style macros here; I'm talking LISP/Scheme style macros Operators are static methods and their signatures are overly constrained (and you can't create new ones).

REBOL

REBOL是我最喜欢的语言之一。我不能说我有一个最喜欢的，尽管Haskell排名也很高。

Its odd syntax scares off many developers before they even give it a try. use [email rules url] [ ; A small DSL that sends email to people about URLs. rules: [ some [ into [ set email email! set url url! (send/subject email url reform [ "Check Out" url ]) ] ] ] ; Global context notify: func [ [catch] dsl [block!] ] [ unless parse dsl rules [ throw make error! "You screwed up somehow." ] ] ] notify [ [ a@b.com http://www.google.com ] [ b@c.com http://www.yahoo.com ] ] Recursive dialects are very easy to validate with PARSE but very difficult to evaluate. (Stacks can be helpful here.) REBOL has very poor integration with many popular technologies, particularly XML. I suspect this is partly arrogance, because the REBOL BLOCK! datatype can do almost everything XML can do. However, the real world has XML in it. No Unicode. Thanks to AltMe, REBOL's user community is very insular. I can understand why they want to use AltMe. It's written in REBOL and shows off its strengths. Unfortunately it also puts them off on their own little island.

即将到来的REBOL 3有望解决许多这些问题，除了最后一个。

c++缺乏好的重构工具，缺乏受控异常

Java缺少模板，缺少const关键字

C#

Cannot create a reference (var &t = struct) No local scope destructors (IDispose comes close but its not the same) ToString, i almost dislike that every object has it but it turns out i dislike everything using it like string.format does. I rather have things that accepts a certain type (like ints, floats, text, chars only). So instead of passing in any object i need to pass in something with a implicit typecast or interface. I ended up writing something like this to safely escape text for html which worked great. Cannot use a virtual typecast (blah)obj; does not work if obj does not inherit/has an interface of blah. Simple workaround is to supply an interface with a convert function. Has no local creation. Instead of writing var o = new Item(); i would like to write (something like) Item o() (with an automatic dispose if it has one).