Re: uninitialized vs. undefined

[Tom Christiansen <tchrist@chthon.perl.com>]

>An uninitialized scalar gets an undefined value, which is different
>from any other value the scalar can take (although, when used,
>undefined works out as being 0 or "").

>Likewise, an uninitialized array should have an undefined value,
>which is different from an empty array (although an uninitialized
>value behaves as ()). 'defined(@a)' would have been an nice way to
>test this. 

That's one way to look at it.

Another way of looking at it (mjd: shh about &fn) is that defined()
is asking whether a scalar value happen to hold the value undef().
I find this a much better way to think about it, because now one
never tries to do silly things like asking whether an aggregate
holds the value undef().  

--tom

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JVromans@squirrel.nl (Johan Vromans)

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JVromans@squirrel.nl (Johan Vromans)

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