不可为 null 的对象有什么问题？
我最近一直在研究 DbC 和 Spec#，它们似乎支持不可为 null 的对象。 不幸的是 Spec# 似乎已被放弃。
- Spec# 似乎内置了很多不错的语言功能，那么为什么它被放弃了呢？
- 默认情况下让所有对象不可为 null 会不会有任何问题，因此您必须编写 int？、string？ 甚至邮件消息？ 如果你真的想要一个可为空的对象？
- 我在这里看到了一种 Sql 类比 你可以在哪里查看课程 可空或不可空的属性 可以为空。 你甚至可以把 对属性的限制 可以使用sql表列吗？
我不认为在语言中内置这样的功能有什么问题。 有人可以启发我吗？
I have been looking at DbC lately and Spec# which seem to have support for non nullable objects. Unfortunately Spec# seem to have been abandoned.
- Spec# seemed to have lots of nice language features built in so why was it abandoned?
- Would there be any problem with letting all objects be non-nullable by default so you would have to write int?, string? and even MailMessage? if you really wanted a nullable object?
- I see kind of a Sql analogy here
where you could check class
properties as nullable or non
nullable. Could you even put
constraints on properties as you
can with sql table columns?
I don't see the problems with having features like this built in to the language. Could anybody enlighten me on this?
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您是否看到新的合同框架将成为.NET 4.0的一部分？
将其作为库而不是语言功能的好处是，它可以立即在所有语言中可用，而无需语言团队进行任何工作。 显然也有缺点......
链接：
说了这么多，我还希望能够写：
，表明 Foo 不得接收空引用，也不会返回空引用。 我认为，为这种类型的合约添加一些额外的语法会很方便。
Have you seen the new Contracts framework will will be part of .NET 4.0?
The benefit of making it a library rather than language feature is that it becomes immediately available in all languages, with no work on the part of the language teams. Obviously there are disadvantages too...
Links:
Having said all that, I'd like to be able to write:
as well, indicating that Foo must not receive a null reference, nor will it return one. Having an extra bit of syntax for just that type of contract would be handy, I think.