Checking if a string is null

Derek Parnell derek at psyc.ward
Wed Jul 25 17:57:35 PDT 2007

On Wed, 25 Jul 2007 22:07:15 +0200, Don Clugston wrote:

> Regan Heath wrote:
>>>> The only thing that should compare equal to null is null.  Likewise 
>>>> an empty array should only compare equal to another empty array.
>>>  >
>>>  > My reasoning for this is consistency, see at end.
>>> Since null arrays have length 0, they *are* empty arrays :P.
>> I can't tell in which way you're joking so I'm just going to come out 
>> with...
>> The length of something be it an array, a car, a <insert thing> is 
>> totally independant of whether it exists (though a non-existant item 
>> cannot have a length).
>> It either exists or it does not.  If it exists, it has a length which 
>> may or may not be zero.
>> Something which exists cannot be equal to something which doesn't.
> I don't think that's really what's happening here.
> Consider vectors. If a vector has a length of zero, the direction doesn't exist.
> Take two arbitrary vectors with different directions, a and b.
> a*0 == b*0, even though the direction of a is completely different to that of b.
> This is the same model which is being used for arrays; if the .length is zero, 
> the .ptr is irrelevant.

But arrays are not vectors.

Derek Parnell
Melbourne, Australia
"Down with mediocrity!"

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