Add flipped stair recipe for silly minecrafters and make slabs convert to full cubes when placed on each other

mods/stairs/init.lua

@@ -30,6 +30,16 @@ function stairs.register_stair(subname, recipeitem, groups, images, description)
 			{recipeitem, recipeitem, recipeitem},
 		},
 	})
+
+	-- Flipped recipe for the silly minecrafters
+	minetest.register_craft({
+		output = 'stairs:stair_' .. subname .. ' 4',
+		recipe = {
+			{"", "", recipeitem},
+			{"", recipeitem, recipeitem},
+			{recipeitem, recipeitem, recipeitem},
+		},
+	})
 end
 
 -- Node will be called stairs:slab_<subname>
@@ -49,6 +59,46 @@ function stairs.register_slab(subname, recipeitem, groups, images, description)
 			type = "fixed",
 			fixed = {-0.5, -0.5, -0.5, 0.5, 0, 0.5},
 		},
+		on_place = function(itemstack, placer, pointed_thing)
+			if pointed_thing.type ~= "node" then
+				return itemstack
+			end
+
+			-- If it's being placed on an another similar one, replace it with
+			-- a full block
+			local slabpos = nil
+			local slabnode = nil
+			local p0 = pointed_thing.under
+			local p1 = pointed_thing.above
+			local n0 = minetest.env:get_node(p0)
+			local n1 = minetest.env:get_node(p1)
+			if n0.name == "stairs:slab_" .. subname then
+				slabpos = p0
+				slabnode = n0
+			elseif n1.name == "stairs:slab_" .. subname then
+				slabpos = p1
+				slabnode = n1
+			end
+			if slabpos then
+				-- Remove the slab at slabpos
+				minetest.env:remove_node(slabpos)
+				-- Make a fake stack of a single item and try to place it
+				local fakestack = ItemStack(recipeitem)
+				pointed_thing.above = slabpos
+				fakestack = minetest.item_place(fakestack, placer, pointed_thing)
+				-- If the item was taken from the fake stack, decrement original
+				if not fakestack or fakestack:is_empty() then
+					itemstack:take_item(1)
+				-- Else put old node back
+				else
+					minetest.env:set_node(slabpos, slabnode)
+				end
+				return itemstack
+			end
+			
+			-- Otherwise place regularly
+			return minetest.item_place(itemstack, placer, pointed_thing)
+		end,
 	})
 
 	minetest.register_craft({