Item entity merging refactor

Don't ident too much, and add a comment.

builtin/game/item_entity.lua

@@ -96,24 +96,7 @@ core.register_entity(":__builtin:item", {
 		self:set_item(self.itemstring)
 	end,
 
-	on_step = function(self, dtime)
+	try_merge_with = function(self, own_stack, object, obj)
-		self.age = self.age + dtime
-		if time_to_live > 0 and self.age > time_to_live then
-			self.itemstring = ''
-			self.object:remove()
-			return
-		end
-		local p = self.object:getpos()
-		p.y = p.y - 0.5
-		local nn = core.get_node(p).name
-		-- If node is not registered or node is walkably solid and resting on nodebox
-		local v = self.object:getvelocity()
-		if not core.registered_nodes[nn] or core.registered_nodes[nn].walkable and v.y == 0 then
-			if self.physical_state then
-				local own_stack = ItemStack(self.object:get_luaentity().itemstring)
-				for _,object in ipairs(core.get_objects_inside_radius(p, 0.8)) do
-					local obj = object:get_luaentity()
-					if obj and obj.name == "__builtin:item" and obj.physical_state == false then
 		local stack = ItemStack(obj.itemstring)
 		if own_stack:get_name() == stack:get_name() and stack:get_free_space() > 0 then
 			local overflow = false
@@ -140,7 +123,8 @@ core.register_entity(":__builtin:item", {
 					collisionbox = {-c, -c, -c, c, c, c}
 				})
 				self.object:remove()
-								return
+				-- merging succeeded
+				return true
 			else
 				s = 0.4
 				c = 0.3
@@ -158,6 +142,33 @@ core.register_entity(":__builtin:item", {
 				self.itemstring = name .. " " .. count
 			end
 		end
+		-- merging didn't succeed
+		return false
+	end,
+
+	on_step = function(self, dtime)
+		self.age = self.age + dtime
+		if time_to_live > 0 and self.age > time_to_live then
+			self.itemstring = ''
+			self.object:remove()
+			return
+		end
+		local p = self.object:getpos()
+		p.y = p.y - 0.5
+		local nn = core.get_node(p).name
+		-- If node is not registered or node is walkably solid and resting on nodebox
+		local v = self.object:getvelocity()
+		if not core.registered_nodes[nn] or core.registered_nodes[nn].walkable and v.y == 0 then
+			if self.physical_state then
+				local own_stack = ItemStack(self.object:get_luaentity().itemstring)
+				-- Merge with close entities of the same item
+				for _, object in ipairs(core.get_objects_inside_radius(p, 0.8)) do
+					local obj = object:get_luaentity()
+					if obj and obj.name == "__builtin:item"
+							and obj.physical_state == false then
+						if self:try_merge_with(own_stack, object, obj) then
+							return
+						end
 					end
 				end
 				self.object:setvelocity({x = 0, y = 0, z = 0})