Thanks for responding. Makes more sense now.

Say you want to give a civilization you are creating the trait "+1 Population when a city builds a National or World Wonder." You can write some code that hooks into this event and tests if the created building was a Wonder, if so, give the city +1 Pop.

Could you possiblly give me a scenario of where and when I would use this code? I've read your description a few times but I'm still not clear.

Just as an fyi, I plan on releasing a small update for this snippet at some point this weekend. The update includes giving the "blank building units" a base movement so end users can manually delete them (as a fail safe if for some reason they aren't deleted automatically) and adding some code that be default will do nothing but end users can enable. The code would be something that look each turn for "blank building units" and deletes them. The optional code would be something users could enable as a fail safe if the units aren't deleted automatically.

Interesting. Thanks for sharing!