boost :: string_ref和boost :: string_view之间的区别 [英] Differences between boost::string_ref and boost::string_view

问题描述

Boost提供了 string_view 的两种不同实现，它们将成为C ++ 17的一部分:

utility/string_ref.hpp 中的
• boost :: string_ref core/string_view.hpp
中的
• boost :: string_view

这些之间是否有显着差异?未来应该优先选择哪个?

注意:我在Boost 1.61中注意到，boost :: log不推荐使用string_ref，而推荐使用string_view.也许这是一个指标?( http://www.boost.org/users/history/version_1_61_0.html)

解决方案

现在足够有趣了，我正与Marshall Clow(委员会的string_view等人背后的力量)在ACCU会议上他今天早些时候在酒吧被听见，然后才被我告知他对string_view和Bjarne的指南支持库(GSL) gsl :: span< T> 的看法，这是非常相似的事情(http://www.boost.org/users/history/version_1_61_0.html)

解决方案

Funnily enough right now I'm at the ACCU conference with Marshall Clow (the force behind string_view et al on the committee) and I was quite literally about to ask him at the bar earlier today before I was called away about his views on string_view versus Bjarne's Guideline Support Library (GSL) gsl::span<T> which is a very similar thing (gsl-lite is my personal favourite implementation of the GSL as it's 03 compatible, but there are many others). I had heard they were to be unified into a single implementation for standardisation, and the gsl::span<T> direction is to be the future, but I'll report back here from the horse's mouth himself if I'm wrong on that. For now, assume the gsl::span<T> direction is the current future and Boost will get updated to have something similar soon, even if using string_view = gsl::span<char> is essentially string_view.

Edit: I just spoke to Marshall downstairs. He tells me that string_view, as per the implementation in Boost, is definitely in C++ 17. array_view is not, nor is anything historically surrounding string_view for now.

The GSL string_span is a separate entity not expected to enter in C++ 17, nor are there any present plans to unify the implementations as they solve different use cases, specifically that string_view is always a constant view of the borrowed character array, whereas string_span is expected to be a potentially modifiable view of the borrowed character array with potential uses as a source for construction of new strings, so string_span might perhaps eventually become a generalisation of string_view in some future C++ standard.

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