Null object: Difference between revisions
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(BASIC) |
(→Icon and Unicon: combined headers) |
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Just v -> "It's not Nothing; it is " ++ show v ++ "."</lang> |
Just v -> "It's not Nothing; it is " ++ show v ++ "."</lang> |
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== |
=={{header|Icon}} and {{header|Unicon}}== |
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Icon/Unicon have a [[Icon%2BUnicon/Intro#null|null value/datatype]]. It isn't possible to undefine a variable. |
Icon/Unicon have a [[Icon%2BUnicon/Intro#null|null value/datatype]]. It isn't possible to undefine a variable. |
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==={{header|Icon}}=== |
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<lang Icon>procedure main() |
<lang Icon>procedure main() |
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nulltest("a",a) # unassigned variables are null by default |
nulltest("a",a) # unassigned variables are null by default |
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return write(name, if /var then " is" else " is not"," null.") |
return write(name, if /var then " is" else " is not"," null.") |
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end</lang> |
end</lang> |
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==={{header|Unicon}}=== |
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This Icon solution works in Unicon. |
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=={{header|Io}}== |
=={{header|Io}}== |
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