Cristophe, I could definitely help out with macros and use of PP for MSM, if you need that help. Unfortunately, the next few weeks (at least) are a bit too hectic. But, now you know that I might be willing (if not currently available) :-) /David On Jan 12, 2010, at 6:48 PM, Christophe Henry wrote:

...

IMO making it easy for the user to declare these things (maybe with a macro) and documenting that as the normal approach, dropping all the parens, could be a big improvement.

Unfortunately, I'm pretty bad at macros (and try to avoid them as much as I can) and after spending quite some time at it, I don't come further. Ok, for states, it's trivial:

BOOST_MSM_STATE((Empty_Entry(),Empty_Exit()),Empty_,empty)

Where Empty_ is the state type name and empty the instance for use in the transition table.

Implemented with: # define BOOST_MSM_STATE(expr,state_name,instance_name) \ typedef BOOST_TYPEOF(build_state(expr)) state_name;state_name const instance_name;

Where it gets slightly more "fun" is when I want to also remove the parens for the actions/guards. For example, if I have an action called start_playback which is: struct start_playback : euml_action<start_playback> { template <class FSM,class EVT,class SourceState,class TargetState> void operator()(EVT const& ,FSM&,SourceState& ,TargetState& ) { cout << "player::start_playback" << endl; } };

I want to use the same principle. start_playback_ will be the type and start_playback the instance. I come to:

BOOST_MSM_ACTION((start_playback_,start_playback, (({ template <class FSM,class EVT,class SourceState,class TargetState> void operator()(EVT const& ,FSM&,SourceState& ,TargetState& ) { cout << "player::start_playback" << endl; } })) ))

I thought of using PP tuple: // the action type #define BOOST_MSM_ACTION_TYPE(x) \ BOOST_PP_TUPLE_ELEM(3,0,x) // the action instance for use in the stt #define BOOST_MSM_ACTION_INSTANCE(x) \ BOOST_PP_TUPLE_ELEM(3,1,x) // the action code #define BOOST_MSM_ACTION_CODE(x) \ BOOST_PP_TUPLE_REM_CTOR(1,BOOST_PP_TUPLE_ELEM(3,2,x))

# define BOOST_MSM_ACTION(tuple) \ struct BOOST_MSM_ACTION_TYPE(tuple): euml_action<BOOST_MSM_ACTION_TYPE(tuple)> BOOST_MSM_ACTION_CODE(tuple) ; BOOST_MSM_ACTION_TYPE(tuple) const BOOST_MSM_ACTION_INSTANCE(tuple) ;

But I fail at getting the action correctly so I generate: struct start_playback_: euml_action<start_playback_> ({ template... // notice the extra parens

I hoped that REM_CTOR would do the job but no. Any idea if it is possible? _______________________________________________ Unsubscribe & other changes: http://lists.boost.org/mailman/listinfo.cgi/boost