Re: Re: Re: Non-destructive array processing

[pdcawley]

Heh. I'm so used to slinging objects around rather than simple scalars I just took it as read that it would be a shallow copy. Note that, in the original case that's not a problem because assigning to @chunk makes a copy of the value.

[Ovid]

Whoa! You're right. That doesn't seem to be very DWIM. The following snippet does not alter the elements of @array.

my @array = 1..10;
my $r1 = sub { \@_ }->(@array);

while (my @chunk = splice @$r1, 0, 2) {
   print "Chunk: @chunk\n";
}
$_++ foreach @$r1;
print "Original array is still intact! (@array)\n";

However, by moving the auto-increment line above the while loop:

my @array = 1..10;
my $r1 = sub { \@_ }->(@array);

$_++ foreach @$r1;
while (my @chunk = splice @$r1, 0, 2) {
   print "Chunk: @chunk\n";
}
print "Original array is not intact! (@array)\n";

This looks like some weird "copy on write" behavior that I was not aware of. Is this new, or is it Yet Another Feature that I didn't know about? :)

Update: Okay, I see that adrianh answered the question.

Cheers,
Ovid

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