-- Create an class.

function class(classname, super)

    local superType = type(super)

    local cls

    if superType ~= "function" and superType ~= "table" then

        superType = nil

        super = nil

    end

    if superType == "function" or (super and super.__ctype == 1) then

        -- inherited from native C++ Object

        cls = {}

        if superType == "table" then

            -- copy fields from super

            for k,v in pairs(super) do cls[k] = v end

            cls.__create = super.__create

            cls.super    = super

        else

            cls.__create = super

        end

        cls.ctor    = function() end

        cls.__cname = classname

        cls.__ctype = 1

        function cls.new(...)

            local instance = cls.__create(...)

            -- copy fields from class to native object

            for k,v in pairs(cls) do instance[k] = v end

            instance.class = cls

            instance:ctor(...)

            return instance

        end

    else

        -- inherited from Lua Object

        if super then

            cls = clone(super)

            cls.super = super

        else

            cls = {ctor = function() end}

        end

        cls.__cname = classname

        cls.__ctype = 2 -- lua

        cls.__index = cls

        function cls.new(...)

            local instance = setmetatable({}, cls)

            instance.class = cls

            instance:ctor(...)

            return instance

        end

    end

    return cls

end