T = {}
T.foo = function()
    return "This is an instance of T"
end function

S = new T
S.foo = function()
    return "This is an S for sure"
end function

instance = new S
print "instance.foo: " + instance.foo

copy = {}
copy = copy + instance  // copies all elements
print "copy.foo: " + copy.foo

// And to prove this is a copy, and not a reference:
instance.bar = 1
copy.bar = 2
print "instance.bar: " + instance.bar
print "copy.bar: " + copy.bar