
Null (or nil) is the computer science concept of an undefined or unbound object.
Some languages have an explicit way to access the null object, and some don't.
Some languages distinguish the null object from undefined values, and some don't.



Task

Show how to access null in your language by checking to see if an object is equivalent to the null object.


This task is not about whether a variable is defined. The task is about "null"-like values in various languages, which may or may not be related to the defined-ness of variables in your language.

/**
 <doc>
 <p>Neko uses <i>null</i> for undefined variables,
  and also as a programmer accessible value.</p>
 <p>The <i>null</i> value can be treated as a boolean value with the
  builtin $istrue, and tests as false.</p>
 </doc>
*/
 
var n = null
if n == null $print("n is null\n")
if $not($istrue(n)) $print("and tests as boolean false\n")