Larry Wall writes:
> However, if you access the last element using the length of the array,
> it may try to flatten, and fail:
>
> my @flat = (1..Inf, 1..10);
> $last = @[EMAIL PROTECTED] - 1]; # Kaboom!
>
> Still, we should be able to detect the attempt to flatten an infinite
> list and give a better diagnostic than Perl 5's "Out of memory".
> Either that, or someone should just up and figure out how to subscript
> arrays using transfinite numbers.
We've got Inf, right? So we know that scalar(()=(1..Inf) is Inf.
Inf - 1 is still Inf.
The only thing we need to define is what @arr[Inf] means.
It seems clear from the previous several paragraphs that Larry wants
someone to suggest, as part of the transfinite package, that
@arr[Inf]
can be defined as sugar for
{
my $_ = pop @arr;
push @arr, $_;
$_;
}
And this might even just be a special case that perl6 array-FETCH is
supposed to know about. (or create a LAST tie operator.)
The range specs that know their own length without flattening (see
a few paragraphs prev. in apo6) and counting would know if they are Inf.
--
David Nicol, independent consultant and contractor
perl -Mcoroutine0 -e'$c=new coroutine0 VARS=>[],BODY=>q"YIELD 74;
YIELD 65;YIELD 80;YIELD 72; YIELD 10;";print chr$_ while$_=&$c;'
