在Boost.Statechart中，state和simple_state有什么区别？ [英] In Boost.Statechart, what's the difference between state and simple_state?

问题描述

在使用Boost.Statechart实现状态机时，我遇到了一个问题，它试图从它的构造函数访问 simple_state 的外部上下文。 simple_state.hpp 中的注释告诉我：

In implementing a state machine using Boost.Statechart, I came across a problem arising from attempting to access the outer context of a simple_state from its constructor. A comment in simple_state.hpp tells me:

    // This assert fails when an attempt is made to access an outer 
    // context from a constructor of a state that is *not* a subtype of
    // state<>. To correct this, derive from state<> instead of
    // simple_state<>.

除了显然可以从其构造函数访问外部上下文，使用 state<> 而不是 simple_state<> 作为我的状态的基类？

Apart from apparently being able to access the outer context from its constructor, what differences or implications are there in using state<> instead of simple_state<> as the base class for my states?

推荐答案

有一些其他的事情，你可以从状态<>派生构造函数做，你不能从一个simple_state派生构造函数。在状态类的文档中有一个列表。我发现发布事件是从状态<>导出的大的好处。

There are a number of other things that you can do from a state<> derived constructor that you cannot do from a simple_state<> derived constructor. There are a list in the documentation for the state class. I found posting events to be the big benefit of deriving from state<>.

这是一段时间，因为我使用它，但我不记得有任何暗示，除了你必须为从状态派生的每个类（在docs中说明）实现转发构造函数，因为状态<>是从simple_state<>派生的。

It's been a while since I used it, but I don't remember there being any implications, other than you having to implement the forwarding constructor for each class derived from state (stated in docs), as state<> is derived from simple_state<>.

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