std ::参考类型的可选专业化 [英] std::optional specialization for reference types

问题描述

为什么std::optional(目前在 libc ++ 中的std::experimental::optional)没有对引用类型的专业化(与boost::optional相比)?

Why std::optional (std::experimental::optional in libc++ at the moment) does not have specialization for reference types (compared with boost::optional)?

我认为这将是非常有用的选择.

I think it would be very useful option.

在 STL 中是否有一些对象引用了也许已经存在的对象语义?

Is there some object with reference to maybe already existing object semantics in STL?

推荐答案

n3527 (修订版3)，作者决定将可选引用作为辅助建议，以增加获得批准的可选值并将其放入C ++ 14的机会.尽管出于各种其他原因，可选项并没有完全融入C ++ 14中，但委员会并未拒绝可选项引用，并且在将来有人建议时可以随意添加可选项引用.

When n3406 (revision #2 of the proposal) was discussed, some committee members were uncomfortable with optional references. In n3527 (revision #3), the authors decided to make optional references an auxiliary proposal, to increase the chances of getting optional values approved and put into what became C++14. While optional didn't quite make it into C++14 for various other reasons, the committee did not reject optional references and is free to add optional references in the future should someone propose it.

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