Re: [Boost-users] Boost statechart, how can i transit to previous state using deep_history or shallow history

Subject: Re: [Boost-users] Boost statechart, how can i transit to previous state using deep_history or shallow history
From: Daniel Kelly (dkellyb717_at_[hidden])
Date: 2016-04-16 08:39:19

I believe your state machine is incorrectly structured.  Consider
encapsulating your input and output states within a higher-level
state. Assume this super-state is called "io". So, now you have three
top-level states: idle, io, and cancel.  Place the history transition
within io.

Now, when you trigger "revert" from the cancel state specify a
transition to io.  This should give you the desired effect.

Dan Kelly
djkelly_at_[hidden]

> On Apr 12, 2016, at 09:37, juls <jvlahou_at_[hidden]> wrote:
>
> I have a difficulty in understanding the boost statechart history
> functionality.
> I have the following state machine.
>
> struct InButtonPressed : sc::event<InButtonPressed> {};
> struct OutButtonPressed : sc::event<OutButtonPressed> {};
> struct InButtonPressed : sc::event<InButtonPressed> {};
> struct InputProceed: sc::event<InputProceed> {};
> struct OutputProceed: sc::event<OutputProceed> {};
> struct CancelEvent: sc::event<CancelEvent> {};
> struct Proceed: sc::event<Proceed> {};
> struct Revert: sc::event<InputProceed> {};
>
>
>
> struct RH_StateMachine : bsc::state_machine< RH_StateMachine, Idle > {};
>
> struct Idle : bsc::state< Idle, RH_StateMachine> {
>    Idle(my_context ctx) : my_base(ctx){
>        std::cout << "[+] Idle" << std::endl;
>        }
>    ~Idle(){std::cout << "[-] leaving Idle state... \n";}
>    typedef  boost::mpl::list< bsc::transition< InButtonPressed, Input>,
>        bsc::transition< OutButtonPressed, Output>
>> reactions;
> };
>
> struct Input : bsc::state< Input, RH_StateMachine> {
>    Input(my_context ctx) : my_base(ctx){
>        std::cout << "[+] Input" << std::endl;
>        }
>    ~Input(){std::cout << "[-] leaving Input state... \n";}
>      typedef  boost::bsc::transition< CancelEvent, Cancel>
>> reactions;
> };
>
> struct Output : bsc::state< Output, RH_StateMachine> {
>    Output(my_context ctx) : my_base(ctx){
>        std::cout << "[+] Output" << std::endl;
>        }
>    ~Output(){std::cout << "[-] leaving Output state... \n";}
>      typedef  boost::bsc::transition< CancelEvent, Cancel>
>> reactions;
> };
>
> struct Cancel::bsc::state<Cancel, RH_StateMAchine>{
>      Cancel(my_context ctx) : my_base(ctx){
>        std::cout << "[+] Cancel" << std::endl;
>        }
>    ~Cancel(){std::cout << "[-] leaving Cancel state... \n";}
>      typedef  boost::mpl::list< bsc::transition< Proceed,
> CanceledConfirmed>,
>        bsc::transition< Revert, *"PREVIOUS_STATE"*>
>> reactions;
> };
>
>
> How do i implement transitioning to previous state using deep_history or
> shallow history, when i can transit to a state from many different states?
> In the above state machine i want to transit from Cancel state to the
> previous state when the revert event is triggered, but i have already
> transited in Cancel state from either Input or Output state...
> Thank you in advance.
>
>
>
> --
> View this message in context: http://boost.2283326.n4.nabble.com/Boost-statechart-how-can-i-transit-to-previous-state-using-deep-history-or-shallow-history-tp4685239.html
> Sent from the Boost - Users mailing list archive at Nabble.com.
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