Extra error checking.

deco.lua

@@ -137,6 +137,10 @@ end
 
 -- Create and initialize a table for a schematic.
 function fun_caves.schematic_array(width, height, depth)
+	if not (width and height and depth and type(width) == 'number' and type(height) == 'number' and type(depth) == 'number') then
+		return
+	end
+
 	-- Dimensions of data array.
 	local s = {size={x=width, y=height, z=depth}}
 	s.data = {}