Re: [Boost-users] [msm] EUML submachine without macro

Subject: Re: [Boost-users] [msm] EUML submachine without macro
From: Christophe Henry (christophe.j.henry_at_[hidden])
Date: 2011-06-29 16:38:45

> I have an addition question regarding the pseudo exit point.
>
> The following code adds a pseudo exit point to your
> CompositeTutorialWithEumlTable.cpp example:
>
> // Exit event
> struct exit_impl : msm::front::euml::euml_event<exit_impl>{};
> exit_impl ev_exit;
> ...
> // Submachine
> struct _Playing : public msm::front::state_machine_def<_Playing >
> {
>    ...
>    // Pseudo exit state
>    struct Exit_ : public msm::front::exit_pseudo_state<exit_impl>
>                      , public msm::front::euml::euml_state<Exit_> {};
>    static Exit_ Exit;
>    ...
>    BOOST_MSM_EUML_DECLARE_TRANSITION_TABLE((
>        Exit == Song1 + ev_exit
>    ),transition_table )
> };
>
> I'm in doubt what should be stated in the main machine's transition table.
> The Stopped state is never reached when this line is used:
>
>   Stopped == exit_pt_(Playing , _Playing::Exit) + ev_exit
>
> However, this entry works:
>
>   Stopped == Playing + ev_exit
>
> Could you please clarify what should be actually entered.

I'm unsure why it didn't work but I found a way around. You'll need to get 
the trunk version.
Unfortunately this means a small breaking change in the definition of 
submachines to:

  typedef boost::msm::back::state_machine<Playing_> Playing_helper;
  struct Playing_impl : public Playing_helper,
                                    public 
msm::front::euml::euml_state<Playing_helper>
  {};

I hate breaking changes but this time I found no way around.

I also updated the doc and the example.

Please let me know if it now works as expected (it passes my test).

Regards,
Christophe