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Re: Re: Re: Re: Non-destructive array processing

by Ovid (Cardinal)
on Jan 20, 2003 at 22:54 UTC ( #228516=note: print w/replies, xml ) Need Help??

in reply to Re: Re: Re: Non-destructive array processing
in thread Non-destructive array processing

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.


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