Scarcity: Read UASINFO to get more classes

[caligari87]

bringing my conversation about UaS here as it's getting a bit more related to the mod itself rather than simple comments. I noticed while digging through the changes my local UaS has that there's a commit that was made to comment out the old re-usable ammoboxes. Since I actually have an addon that adds those back, I'm curious about re-adding that functionality back in. I'd rather not add a hard dependency on UaS but instead if it's loaded, then run the ExactScarcity method across all of the new ReusableAmmoboxes. Am I able to just check if the mod exists, or some service class exists?

[caligari87]

Update: Use a modding API for this instead. See #210