OOP with closures

#!/usr/bin/lua

do
       POINT = {}
       POINT.new = function(pnt, x, y)
               local pt = {}

               function pt.display(pnt, comment)
                       print(comment)
                       print(x)
                       print(y)
                       print("")
               end

               function pt.getX(pnt)
                       return x
               end

               function pt.getY(pnt)
                       return y
               end

               function pt.setX(pnt,newX)
                       x = newX
               end

               function pt.setY(pnt,newY)
                       y = newY
               end

               return pt
       end
end

pul = POINT:new(1,1)
plr = POINT:new(80,25)

print(type(pul))

pul:display("Upper left.")
plr:display("Lower right.") -- This fails if you uncomment it

pul:setX(2000)
pul:display("Upper left after strongarm.")