Re: [Boost-users] [msm] euml submachine with non-default constructor

Hello, having trouble getting this to work.

Here’s a simplification of what I’m trying:

//states and events defined elsewhere

struct sub_fsm : public msm::front::state_machine_def { typedef entry_state_impl initial_state;

BOOST_MSM_EUML_DECLARE_TRANSITION_TABLE(( entry_state + some_event() / action1 == next_state ), transition_table)

sub_fsm() : pctx_(nullptr) {} sub_fsm(context *p) : pctx_(p) {}

context *pctx_; };

typedef msm::back::state_machine sub_helper; struct sub_machine : public sub_helper, public msm::front::euml::euml_state { sub_machine() {} sub_machine(context *p) : sub_helper(p) {} }; sub_machine const sub;

struct outer_fsm : public msm::front::state_machine_def { typedef outer_entry_state_impl initial_state;

BOOST_MSM_EUML_DECLARE_TRANSITION_TABLE(( outer_entry_state + another_event() / action2 == sub ), transition_table)

outer_fsm() : pctx_(nullptr) {} outer_fsm(context *p) : pctx_(p) {}

context *pctx_; }; typedef msm::back::state_machine outer_machine;

int main() { context ctx; outer_machine fsm(msm::back::states_ << sub_machine(&ctx), &ctx); }

This doesn’t compile under VC2010, it can’t deduce the template arguments for operator <<().

Am I on the right track here? Should the template parameter of euml_state<> really be sub_helper and not sub_machine (I got that chunk of code from here: http://svn.boost.org/svn/boost/trunk/libs/msm/doc/HTML/examples/CompositeTut...

What am I doing wrong?

Thanks for any help, Mark

Hi Mark, you're not doing anything wrong, VC has been giving me a hard time with eUML and submachines. I corrected this in the trunk a while ago but we had no boost version since then, so you'll need to get the current version (the 1.50 will have this change when it comes out). There is a small breaking change (the first since the official release) but the syntax is now actually better and easier, you won't need the helper class. I attach a corrected version of your example, I tested it with VC10 and g++4.5. HTH, Christophe struct context{}; struct entry_state_impl : public msm::front::state<> , public msm::front::euml::euml_state { }; entry_state_impl const entry_state; struct next_state_impl : public msm::front::state<> , public msm::front::euml::euml_state { }; next_state_impl const next_state; struct some_event : msm::front::euml::euml_event{}; BOOST_MSM_EUML_ACTION(action1) { template void operator()(EVT const& ,FSM& ,SourceState& ,TargetState& ) { } }; struct sub_fsm : public msm::front::state_machine_def { typedef entry_state_impl initial_state; BOOST_MSM_EUML_DECLARE_TRANSITION_TABLE(( entry_state + some_event() / action1 == next_state ), transition_table) sub_fsm() : pctx_(0) {} sub_fsm(context *p) : pctx_(p) {} context *pctx_; }; typedef msm::back::state_machine sub_helper; sub_helper const sub; // no more needed /*struct sub_machine : public sub_helper, public msm::front::euml::euml_state { sub_machine() {} sub_machine(context *p) : sub_helper(p) {} }; sub_machine const sub; */ struct outer_entry_state_impl : public msm::front::state<> , public msm::front::euml::euml_state { }; outer_entry_state_impl const outer_entry_state; struct another_event : msm::front::euml::euml_event{}; BOOST_MSM_EUML_ACTION(action2) { template void operator()(EVT const& ,FSM& ,SourceState& ,TargetState& ) { } }; struct outer_fsm : public msm::front::state_machine_def { typedef outer_entry_state_impl initial_state; BOOST_MSM_EUML_DECLARE_TRANSITION_TABLE(( outer_entry_state + another_event() / action2 == sub ), transition_table) outer_fsm() : pctx_(0) {} outer_fsm(context *p) : pctx_(p) {} context *pctx_; }; typedef msm::back::state_machine outer_machine; int main() { context ctx; outer_machine fsm(msm::back::states_ << sub_helper(&ctx), &ctx); }