minigent/examples/2_abstract/03-parameterised/in.minigent

new : Unit -> EmptyBox;
insert : [a]. {box : EmptyBox, item : a}# -> Box a;
remove : [a]. Box a -> {box : EmptyBox, item : a}#;
delete : EmptyBox -> Unit;

test : [x]. x -> x;
test x
  = let boxbox = new Unit
     in let box = new Unit
         in let full = insert { box = box, item = x }
             in let fullbox = insert { box = boxbox, item = full }
                 in take r { box = b } = remove fullbox
                    in take r { item = i } = r
                       in let u = delete b
                          in take r { box = b} = remove i
                             in let u = delete b
                                in take r { item = ret } = r
                                   in ret
                                   end
                                end
                             end
                          end
                       end
                    end
                 end
              end
           end
        end;