~~NOTOC~~

====== IsNull ======
IsNull (<-something) ->isNull

===== Description =====
Take an item from the stack and returns true if the item is null.

===== Examples =====
<code 4rpl>
CreateList ->emptyList
PopList(<-emptyList) ->nulItem
if (isNull(<-nullItem))
   trace("Null Item")
endif
</code>