Null object: Difference between revisions
BASIC | Applesoft BASIC
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<lang babel>{ nil { nil? } { "Whew!\n" } { "Something is terribly wrong!\n" } ifte << }</lang>
=={{header|
==={{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}}===
{{works with|BBC BASIC for Windows}}
A null object has a pointer with a value of zero or one.
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