[msm]omitting region id at the entry pseudo state
Hello, Now, I'm using Boost.Msm (Version1.49.0). I have a question about a transition behavior when I omit a region id at the entry pseudo state. The document said that when we use the explicit entry, if the state machine satisfied the conditions below, we can omit the region id. http://www.boost.org/doc/libs/1_49_0/libs/msm/doc/HTML/ch03s02.html#d0e852 " Thanks to the mpl_graph library you can also omit to provide the region index and let MSM find out for you. The are however two points to note: - MSM can only find out the region index if the explicit entry state is somehow connected to an initial state through a transition, no matter the direction. - There is a compile-time cost for this feature. " Because of the discussion below, I believe that this rule can also be applied to entry pseudo states. http://boost.2283326.n4.nabble.com/msm-how-to-distinguish-region-ids-tt36129... However, when I omitted the region id, the state machine transitioned to the SubState1. struct Entry1:msmf::entry_pseudo_state<> {}; If I provided the region id, the state machine transitioned to the SubState2. struct Entry1:msmf::entry_pseudo_state<0> {}; See entry_pt_omit_rid.cpp (Attached file) As far as I can understand, Entry1 and SubState1, initial_state, are connected. (See fig.png) Is there any reason that I can't omit the region id in this case? Thanks, Takatoshi
Hi Takatoshi,
Hello,
Now, I'm using Boost.Msm (Version1.49.0). I have a question about a transition behavior when I omit a region id at the entry pseudo state.
The document said that when we use the explicit entry, if the state machine satisfied the conditions below, we can omit the region id. http://www.boost.org/doc/libs/1_49_0/libs/msm/doc/HTML/ch03s02.html#d0e852 " Thanks to the mpl_graph library you can also omit to provide the region index and let MSM find out for you. The are however two points to note: - MSM can only find out the region index if the explicit entry state is somehow connected to an initial state through a transition, no matter the direction. - There is a compile-time cost for this feature. "
Because of the discussion below, I believe that this rule can also be applied to entry pseudo states. http://boost.2283326.n4.nabble.com/msm-how-to-distinguish-region-ids-tt36129...
It does, I just forgot to mention it in the doc.
However, when I omitted the region id, the state machine transitioned to the SubState1. struct Entry1:msmf::entry_pseudo_state<> {};
If I provided the region id, the state machine transitioned to the SubState2. struct Entry1:msmf::entry_pseudo_state<0> {};
See entry_pt_omit_rid.cpp (Attached file)
As far as I can understand, Entry1 and SubState1, initial_state, are connected. (See fig.png)
Is there any reason that I can't omit the region id in this case?
Looks like a bug. It's a bit late to fix it tonight, but if I change your initial state declaration to: typedef mpl::vector<SubState1> initial_state; Then it works. Must be some silly mistake and not too hard to fix, but you can use the workaround in the meantime. Cheers, Christophe
Hi Christophe, On Mon, Mar 5, 2012 at 6:25 AM, Christophe Henry <christophe.j.henry@googlemail.com> wrote:
Hi Takatoshi,
Hello,
Now, I'm using Boost.Msm (Version1.49.0). I have a question about a transition behavior when I omit a region id at the entry pseudo state.
The document said that when we use the explicit entry, if the state machine satisfied the conditions below, we can omit the region id. http://www.boost.org/doc/libs/1_49_0/libs/msm/doc/HTML/ch03s02.html#d0e852 " Thanks to the mpl_graph library you can also omit to provide the region index and let MSM find out for you. The are however two points to note: - MSM can only find out the region index if the explicit entry state is somehow connected to an initial state through a transition, no matter the direction. - There is a compile-time cost for this feature. "
Because of the discussion below, I believe that this rule can also be applied to entry pseudo states.
http://boost.2283326.n4.nabble.com/msm-how-to-distinguish-region-ids-tt36129...
It does, I just forgot to mention it in the doc.
I've been relieved hearing that.
However, when I omitted the region id, the state machine transitioned to the SubState1. struct Entry1:msmf::entry_pseudo_state<> {};
If I provided the region id, the state machine transitioned to the SubState2. struct Entry1:msmf::entry_pseudo_state<0> {};
See entry_pt_omit_rid.cpp (Attached file)
As far as I can understand, Entry1 and SubState1, initial_state, are connected. (See fig.png)
Is there any reason that I can't omit the region id in this case?
Looks like a bug. It's a bit late to fix it tonight, but if I change your initial state declaration to:
typedef mpl::vector<SubState1> initial_state;
Then it works. Must be some silly mistake and not too hard to fix, but you can use the workaround in the meantime.
Thanks! The workaround that you suggested has worked fine for me. Regards, Takatoshi
Is there any reason that I can't omit the region id in this case?
Looks like a bug. It's a bit late to fix it tonight, but if I change your initial state declaration to:
typedef mpl::vector<SubState1> initial_state;
Then it works. Must be some silly mistake and not too hard to fix, but you can use the workaround in the meantime.
Thanks! The workaround that you suggested has worked fine for me.
In the meantime I fixed the bug (trunk rev. 77239). Thanks, Christophe
participants (2)
-
Christophe Henry -
Takatoshi Kondo