On 9/22/06, Thomas Fuchs <[EMAIL PROTECTED]> wrote:
>
> hmm-- i've modelled it after the rails ruby extension[1].

Which uses nil.

> Note that the german version of the article is much clearer and
> mentions the synonymity of null and nil explicitly.

I believe the english version has some good points, see below.

> So null in JavaScript should be equal to nil in Ruby.

There are reasons to say nil in Ruby == undefined in Javascript.

The Wikipedia article distinguishes between two meanings:

Quote: Null is a special value for a pointer (or other kind of object
reference) used to signify that the pointer intentionally does not
have a target. [...] Some languages use other nomenclature for such a
pointer, e.g., nil, undefined, void reference, etc.

=> undefined in Javascript, nil in Ruby

Quote: In many disciplines, the concept of null allows a three-valued
logic, with null indicating "unknown value".

=> null in Javascript. What about Ruby, does it have something similar?

Javascript supports both concepts with null and undefined
respectively. Using undefined instead of null makes sure, that you can
have an array with members using this three-valued logic.

Furthermore: "var foo;" depicts a variable that does not have a value.
foo is undefined, not null. And I believe this is what the filler
elements are. Array members that do not have a value (that are
undefined), because they were not part of the original array.

Of cause, you can do arr[3] = undefined;, but still: choosing between
null and undefined, undefined seems to carry the meaning better than
null.

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