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Comment by perl4ever | Hacker News Reader

Lately, I program in a language that has distinct concepts of Null and Empty and Nothing and the empty string ("") and arrays that are not Empty but contain zero elements. And of course NUL characters.

This is obviously at least five times as good as just having one option for null.

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> arrays that are not Empty but contain zero elements

What is an array that is not empty but contains zero elements?

Sounds like a trick question. How about the array of the largest number?

IIRC in Visual Basic these are arrays with lower bound bigger than upper bound.

...but sometimes you can observe this and sometimes you can't.

Well, Empty is a special value in VBA. And I forgot to mention, there are two kinds of "empty" arrays that are not Empty. So it's six times as good as a normal language.

Here's an example:

    ' x can be anything, including an array, but
    ' defaults to the value Empty.
    Dim x

    ' y is an array of values that can be anything,
    ' which defaults to an empty array.
    Dim y()
    
    ' Initialize x as an empty array
    x = Array()
    
    ' The following two statements print 0 and -1.
    Debug.Print LBound(x)
    Debug.Print UBound(x)
    
    ' The following two statements error with
    ' "Subscript out of range" even though y
    ' is also a kind of empty array.
    Debug.Print LBound(y)
    Debug.Print UBound(y)

Which language?

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