[criloz2]

It is not supposed that null is the bottom value in the universe of all the values that your program can recognize? Why people need to complicate it?, and yeah in that definition `null == null`, but a `null_pointer != null` because null pointer is at the bottom of all the possible pointer value, and null by itself is not a pointer. The same for (0,null), (false, null) and ("", null). null should only be equal to itself.

And lastly undefined != null, because undefined is related with structures indicating that a field was not defined when the structure was created