ofParameter<void>::trigger() does not notify parents.

[eduardfrigola]

When listening to parameterChangedE() event from an ofParameterGroup, ofParameter triggers does not get caught by this event.

Is there a reason for the trigger() method not implementing notifying events to parents? similar to what ofParameter::eventsSetValue(...) does:

openFrameworks/libs/openFrameworks/types/ofParameter.h

Lines 745 to 763 in 8d8c8ff

	if(!obj->parents.empty())
	{
	// Erase each invalid parent
	obj->parents.erase(std::remove_if(obj->parents.begin(),
	obj->parents.end(),
	[this](const std::weak_ptr<ofParameterGroup::Value> & p){ return p.expired(); }),
	obj->parents.end());
	// notify all leftover (valid) parents of this object's changed value.
	// this can't happen in the same iterator as above, because a notified listener
	// might perform similar cleanups that would corrupt our iterator
	// (which appens for example if the listener calls getFirstParent on us)
	for(auto & parent: obj->parents){
	auto p = parent.lock();
	if(p){
	p->notifyParameterChanged(*this);
	}
	}
	}

I can send a PR implementing this if needed.

[arturoc]

can you explain a use case for this? trigger doesn't change the state of the parameter, as ofParameter<void> doesn't have any, so notifying a parameter changed event didn't seem necessary but we could add it if there's a use case where it would make sense

[eduardfrigola]

I'm using it to build a gui (ofParameter<void> are buttons) via scripting language, where I can add/delete parameters on the fly. The communication is only by ofParameter event system (all of them inside an ofParameterGroup), and I want to catch all events inside the group and call a function inside the script. Now I have implemented a new listener for every ofParameter that gets created, that i have to keep track and delete if necessary. But seems like a workaround.

When I added ofParameter<void> functionality I didn't thought parameterChanged event would not be notified. I get your point that the name parameterChanged does not apply for ofParameter<void>, that is true. As there is no "some event inside the group happened" event, I use parameterChangedE for that, and that confused me, as it does not get ofParameter<void> events. For me it is better to include it than not, but maybe my use case is not for what is intended.

Thanks

[arturoc]

ok, i don't think adding it would be problematic for any case so if you want to send a PR? we'll probably merge it after the 0.11 release since we are already mostly fixing bugs.

[eduardfrigola]

Should we close this?

[arturoc]

yeah thanks!