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<>.
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?
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<>.
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<>.