JavaScript

ECMAScript 5规范:

7.6.1.2未来保留词: 类，enum, extends, super, const, export， 进口 严格模式:实现、let、private、public、interface、package、protected、static、yield 11.9.4严格等于操作符(===)对比11.9.1 TheEqualsOperator(==) 11.9.6严格相等比较算法(NaN === NaN is false) 8.5数字类型-没有实整数，所有都是浮点数。 4.2.1对象——原型继承

好吧，我有点喜欢最后一个，但它有7种让人困惑的地方

Java

已检查的异常 类型擦除 缺少操作符重载(例如BigInteger/BigDecimal) 缺少regexp/date/duration /复杂文字 对不可变性的支持很差

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

Perl 5:

All the really good stuff nowadays seems to require mod_perl, which has low availability everywhere I want to go. Some really incredible functionality can be encapsulated in modules, but what is under the hood is often fragile or frightening: source filters, typeglobs, whatever Moose is doing... DateTime is brilliant but still made some very bad design decisions (not returning a stopwatch duration when subtracting two DateTime objects) Dual-lifed modules in core and on CPAN still cause conflicts module authors still put interactive stuff in their module configuration scripts so that they can't be automatically installed

Python:

缺少静态类型 默认参数处理(特别是可以为未来的调用者更改默认参数的事实!) 需要的下划线太多(构造函数必须调用__init__) 缺少适当的私有成员和函数(惯例只是说大多数以下划线开头的东西都是私有的，除了像__getattr__这样的东西不是) 有趣的打印到文件的语法(但他们在Python 3中修复了这个问题)

JavaScript

Function object syntax: f = new Function( "foo", "bar", "return foo+bar;" ); (It takes n arguments, the first n-1 are arguments for the function, then nth is the actual function, in string form. Which is just silly.) Function arguments can be repeated. f = new Function( "foo", "foo", "return foo;" ); The last repetition is the only one ever used, though: f( "bye", "hi" ) // returns "hi" f( "hi" ) // returns undefined E4X should just die. My users are always complaining that it doesn't work the way they think it will. Let's face it, when you need a page and a half of psuedocode for a setter, it's time to rethink things. A standard notion of stdin/stdout/stderr (and files!) would be nice. null != undefined It's irritating to have to handle them both. Sometimes it's useful, but most languages manage to limp along fine with one.