Note

A blogging guide, built for minimalists who aren’t quite as nerdy.

This blog was written entirely because of the item Familiarize yourself with alternatives to overloading on universal references in Effcetive Morden C++. We start with a practical problem trying to emulate std::optional in C++14, because optional monads are a good paradigm for expressing values ​​that may be null, rather than assuming everything is maybe null which can easily break through the type system. 写下这篇文章完全是因为看到了 Effcetive Morden C++ 中的熟悉通用引用重载的替代方法。我们从一个现实的问题开始，即在 C++14 尝试模拟 std::optional，因为 optional 是表达可能为空的值的时候一个很好的范式，而不是假定一切都可能为 null 并轻易击穿类型系统。