模板 typedefs - 你的工作是什么? [英] Template typedefs - What's your work around?

问题描述

C++ 0x 具有模板别名(有时称为模板 typedef).请参阅此处.C++ 的当前规范没有.

C++ 0x has template aliases (sometimes referred to as template typedefs). See here. Current spec of C++ does not.

你喜欢用什么来解决?容器对象还是宏?你觉得值得吗?

What do you like to use as work around ? Container objects or Macros ? Do you feel its worth it ?

推荐答案

你喜欢用什么来解决?容器对象还是宏?你觉得值得吗?

What do you like to use as work around ? Container objects or Macros ? Do you feel its worth it ?

规范的方法是使用像这样的元函数:

The canonical way is to use a metafunction like thus:

template <typename T>
struct my_string_map {
    typedef std::map<std::string, T> type;
};

// Invoke:

my_string_map<int>::type my_str_int_map;

这也用于 STL (allocator::rebind) 和许多库，包括 Boost.我们在生物信息库中广泛使用它.

This is also used in the STL (allocator::rebind<U>) and in many libraries including Boost. We use it extensively in a bioinformatical library.

它很臃肿，但在 99% 的情况下都是最好的选择.在这里使用宏是不值得的.

It's bloated, but it's the best alternative 99% of the time. Using macros here is not worth the many downsides.

(我修改了代码以反映 Daniel 在评论中指出的 Boost/STL 约定.)

( I've amended the code to reflect Boost/STL conventions as pointed out by Daniel in his comment.)

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