Null object: Difference between revisions

=={{header|BASIC}}==

==={{header|Applesoft BASIC}}===

caveat: http://qconlondon.com/london-2009/presentation/Null+References%3A+The+Billion+Dollar+Mistake

Applesoft has no built-in object system. The closest values to NULL or nil for each of the types are 0 for integers and floating point numbers, and "" for strings. There is also the NUL character: CHR$(0). One could create an object system using global variables and include a special value for NULL, but this is probably a mistake.

<lang ApplesoftBasic>TRUE = 1 : FALSE = 0

NULL = TRUE

IF NULL THEN PRINT "NULL"

NULL = FALSE

IF NOT NULL THEN PRINT "NOT NULL"</lang>'''Output:'''<pre>NULL

NOT NULL</pre>

==={{header|BBC BASIC}}===