Re: [Boost-users] Separating templatized on_entry/on_exit into cpp/h

Subject: Re: [Boost-users] Separating templatized on_entry/on_exit into cpp/h
From: Christophe Henry (christophe.j.henry_at_[hidden])
Date: 2012-04-19 15:43:38

Sorry for my late answer, I overlooked this message :(

>Hello,
>
>I'm trying to modify the Player example and to separate the on_exit/on_entry template function definition from declaration so I can hide
>the actual implementation details. 
>
>"My.h"
>...
>namespace myNamespace
>{
>...
>// Concrete FSM implementation
>struct player_state_machine : public msm::front::state_machine_def<player_state_machine>
>{
>...
>struct Playing : msm::front::state<>
>{
>template <class Event, class player_state_machine >
>void on_entry(event const &, player_state_machine & ); // { "My Secret Code }
>}
>......
>}
>}
>
>
>"My.cpp"
>
>namespace myNamespace
>{
>...
>template <class Event, class player_state_machine >
>void myNamespace::player_state_machine::Playing::on_entry(Event const &, player_state_machine & ); 
>{ 
>Here I want to put the actual implementation...
>}
>
>
>Is this feasible ?

I'm afraid no.

>If not - what are the alternatives ? As I previously said - putting the implementation into the header is not an option.

You could forward the on_entry call to a non-template method of Playing (or several overloaded non-template methods) which you only declare in your header and implement in a cpp. The state itself is usually not a template class.

>Any help will be appreciated.
>
>Evgeni 

HTH,
Christophe