Re: [Boost-users] [msm] Two identical orthogonal regions?

Subject: Re: [Boost-users] [msm] Two identical orthogonal regions?
From: Christophe Henry (christophe.j.henry_at_[hidden])
Date: 2012-05-24 16:23:08

> Hi,
>
> I am trying to put two identical orthogonal regions in a state machine 
> (each region would model a "channel" and I can have multiple such 
> channels).
>
> One way I can think of is duplicating the states through typedefs and 
> duplicating entries in the transition table.
>
> Is there a way to avoid this duplication?
>
> Regards,
> a.

Hi,

for MSM they just need to be different types. You can define structs 
inheriting from base states, you can templatize them with an int parameter, 
you can even define a submachine which you inherit from and paste 2 
instances, one in each region.

Though I didn't try it since the times of MSM v1, something like the 
following should work (assuming Functor Front-end):

struct SubFront : msm::front_state_machine_def<SubFront>{...};
typedef msm::back::state_machine<SubFront> SubHelper;

template <int index>
struct Sub: public SubHelper{};

// Outer machine
// we have only the submachines in the regions so that it is easier to 
duplicate
typedef mpl::vector<Sub<0>, Sub<1> > initial_state;
// excerpt from transition table
Row<Sub<0>,...>,
Row<Sub<1>,...>

HTH,
Christophe