In the previous example, the two functions getRadius and setRadius are common attributes. Common attributes as functions can be called outside or inside the class, but they cannot be modified. For example
>> circle = class ... common setRadius = function x -> () if x > 0 parent.radius = x; end end ... end >> p = circle.new(); >> p.setRadius = function x -> () ... end Error: modifying common attributeIf setRadius is declared as public, then we can still use it almost the same way, but we'll be free to assign new values to the setRadius attribute of any individual member of circle.