Null object: Difference between revisions
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m (Added Raven code for NULL object) |
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foo <- function(){} # function that does nothing |
foo <- function(){} # function that does nothing |
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foo() # returns NULL</lang> |
foo() # returns NULL</lang> |
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=={{header|Racket}}== |
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"null", or its literal form "'()", is used to denote empty lists and |
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sometimes it is used as a generic null value. |
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<lang Racket> |
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-> null |
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'() |
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-> (null? null) |
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#t |
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-> (null? 3) |
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#f |
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</lang> |
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But a value that is more used as a generic "nothing" value is "#f", |
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false. Racket also has a void value, mostly the result of side-effect |
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functions. (And an undefined value.) |
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=={{header|Raven}}== |
=={{header|Raven}}== |
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