c++ - 数组和类聚合类型的统一初始化

Question

n3526 建议稍微放宽从聚合初始化中删除大括号的规则，以使数组和类聚合的初始化更加统一。

它将允许编译以下代码:

struct S {
    int x[2][2];
};

struct A {
    S s;
};

// Then the following declarations are all equivalent

A a1 = {{{{1, 2}, {3, 4}}}};
A a2 = {{{1, 2}, {3, 4}}};
A a3 = {{1, 2}, {3, 4}};
A a4 = {1, 2, 3, 4};

然后它说:

Allowing brace-elision on aggregates with more than one member was considered and rejected as it seems likely to cause difficulties parsing programs that were already well-formed.

有谁知道在使这种语法成为可能方面是否有任何进展，如果没有，不允许它的原因是什么？

Answer 1

Evolution 工作组在布里斯托尔 session 上对这篇论文进行了审议，得出的结论是当前的限制是经过深思熟虑的。我不是这次讨论的一部分，因此对细节了解不多。似乎也有人指出，即使没有给出示例，即使所陈述的提案也可能会更改现有的有效代码。据我所知，这个提议没有被采纳:

No recommendation to move forward, considered NAD.