tag api

api.lua

@@ -3,13 +3,28 @@
 local buildings = {}
 local building_categories = {}
 
+-- string -> { building_def, building_def, ... }
+local building_tags = {}
+
 function building_lib.register_building(name, def)
 	def.name = name
 	def.placement = def.placement or "mapblock_lib"
-	def.category = def.category or "_uncategorized"
 
+	def.category = def.category or "_uncategorized"
 	building_categories[def.category] = true
 
+	-- populate tags
+	if type(def.tags) == "table" then
+		for _, tag in ipairs(def.tags) do
+			local building_list = building_tags[tag]
+			if not building_list then
+				building_list = {}
+				building_tags[tag] = building_list
+			end
+			table.insert(building_list, def)
+		end
+	end
+
 	-- try to validate the building/placement combo
 	local placement = building_lib.get_placement(def.placement)
 	assert(placement, "placement not found: " .. def.placement)
@@ -44,6 +59,10 @@ function building_lib.get_building(name)
     return buildings[name]
 end
 
+function building_lib.get_building_tags()
+    return building_tags
+end
+
 function building_lib.get_buildings()
     return buildings
 end