On Wed, Jun 20, 2012 at 08:11:54AM +0200, Charles Lesire-Cabaniols wrote:
>
>
> 2012/6/19 Markus Klotzbuecher <markus [dot] klotzbuecher [..] ...>
>
> On Tue, Jun 19, 2012 at 09:50:49PM +0200, Charles Lesire-Cabaniols wrote:
> >
> >
> > 2012/6/19 Markus Klotzbuecher <markus [dot] klotzbuecher [..] ...>
> >
> > Hi Charles,
> >
> > On Tue, Jun 19, 2012 at 06:22:05PM +0200, Charles Lesire-Cabaniols
> wrote:
> > >
> > > I want to implement a new EEHook function that send events to my
> > component FSM.
> > >
> > > I wrote a file with the hook function:
> > >
> > > local target_in = rttlib.port_clone_conn(detection:getPort
> ("target"))
> > > rtt.getTC():addPort(target_in)
> > > function target_detection()
> > > local fs, target = target_in:read()
> > > if fs == "NewData" then
> > > rtt.logl("Warning", "Target detected " .. tostring(target))
> > > rfsm.send_events(fsm, 'e_abort')
> > > report_out:write("CIBLE_LOCALISEE")
> > > end
> > > return true
> > > end
> > >
> > > And then in my component script, I have done:
> > >
> > > tc:exec_file("hooks.lua")
> >
> > Who is tc? The current component? If yes, why don't you just put the
> > target_detection code in the updateHook?
> >
> >
> > tc is effectively the LuaComponent I am creating.
> > This design comes from the time I was entending an existing component...
> now
> > this component is completely in Lua, I could hence try to move all
> functions to
> > the update hook part.
>
> Ok, still what you try seems ok.
>
> > > ee_td_hook = rtt.EEHook('target_detection')
> > > ee_td_hook:enable()
> >
> > The original usecase of EEHook was to piggyback an rFSM running in a
> > Lua Service on a C++ component, though I don't see why it should not
> > work directly on a component.
> >
> > > Creating my component works.
> > > When I write something in the 'target' port, the 'if' part of
> > target_detection
> > > raises an error:
> > >
> > > > tgt:write(state)
> > > > 7.310 [ Warning][rttlua-gnulinux::main()] Target detected {phi=
> 0,cpt=
> > 0,h=0,ax
> > > =0,ts_rem_alt=0,q=0,p=0,wp=0,ts_rem_nav=0,theta=0,ts=0,ay=0,r=
> 0,phase=
> > > 0,ts_rem_gps=0,ts_ref=0,az=0,y=0,x=0,id=0,z=0,vz=0,psi=0,vx=0,vy=0}
> > > 7.310 [ ERROR ][rttlua-gnulinux::main()] LuaComponent 'HiDDeN':
> error
> > calling
> > > function target_detection: /home/lesire/work/orocos/rFSM/
> utils.lua:371:
> > table
> > > index is nil
> >
> > Which rFSM commit are you on? (git show --stat HEAD)
> >
> >
> > 899c754c05cbbf2611d1b1c8f42593a96ece90fc
>
> Thanks.
>
> > > This error comes from the rfsm.send_events function.
> >
> > How do you infer that?
> >
> >
> > Commenting the rfsm.send_events line cause no error.
>
> Ok, It seems that the 'fsm' arg to send_events is nil. You omit the
> code where fsm comes from, hence could you verify that value
> (ie. print("fsm:", fsm) before the send_events?
>
>
> Effectively, I have tried to directly call target_detection from updateHook
> instead of using EEHook.
> I first encountered the same issue.
>
> When passing 'fsm' as an argument of the function, it works.
>
> fsm is declared local in the file that defines my component hooks. Code snippet
> of component.lua:

These are the intricacies of lexical scoping in the context of
exec_file. If you declare a variable local the scope is only the
calling context of exec_file. Hence, the fsm variable below will be
garbage collected some time after the call finishes. But when you pass
it as an argument to target_detection you are creating a closure that
references fsm and hence prevents garbage collection. If you don't
care about this, the easiest solution is to make fsm (and tc) global.

> require ...
>
> local tc = rtt.getTC()
> local fsm
>
> function configureHook()
> ...
> fsm = rfsm.init(rfsm.load("fsm.lua"))
> ...
> end
>
> function updateHook()
> ...
> target_detection(fsm)
> ...
> end
>
> The EEHook part was previously in configureHook, tried before and after the
> rfsm.init call.

Does this fix you problem?
Markus