Andy Lyttle (via RT) wrote:

>  Attempting to access an array element using a very large value for
>  the index yields weird results, particularly near [2**32].  See this
>  test case:

This is a Very Bad Idea(TM) in general; attempting to access array
elements past the end of the current array causes all intervening
elements to spring into existance, along with the [in this case huge]
memory allocation required to do so.

With that in mind, Perl uses integer offsets for arrays (just as C does,
since Perl is written in C), which means that you are limited to 2**32-1
(unless you have 64bit integers).  And it also means that you have to be 
careful not to wrap the offset around.

>  Expected behavior is to return undef and warn "Use of uninitialized
>  value", and not wrap around at all, because that's the sort of weird
>  behavior we expect from C, not from perl.

There is no way to (in the general case) know when the user really meant
a really big positive offset, instead of an equally big negative offset 
(since that is a legitimate array lookup too).  There is nothing that 
could be undef, and hence no way to trap this error.

HTH

John

-- 
John Peacock
Director of Information Research and Technology
Rowman & Littlefield Publishing Group
4501 Forbes Boulevard
Suite H
Lanham, MD  20706
301-459-3366 x.5010
fax 301-429-5748