Re^4: self-feeding infinite loop

in reply to Re^3: self-feeding infinite loop
in thread self-feeding infinite loop

But you're definitely in the territory of "unpredictable behaviour"

I may be being somewhat picky (or I may even be downright wrong), but I don't see any "unpredictable behaviour" there. I agree that one needs to be careful when modifying an array by iterating over the same array, but the following does behave predictably:

use strict;
use warnings;
my @array = ('a');
foreach (@array) {
    push @array,'a';
    print"@array\n";
    sleep(1); # so we can absorb what's happening
}
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Cheers,
Rob

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Re^5: self-feeding infinite loop by Errto (Vicar) on Aug 18, 2007 at 18:03 UTC
It's not "unpredictable" in the sense of being random but it is undefined in the sense that it is not specified in the documentation and could potentially change in a future release. Quoting perlsyn: If any part of LIST is an array, foreach will get very confused if you add or remove elements within the loop body, for example with splice. So don't do that. I should add for the record that I once asked the same question myself.	[reply]

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Re^5: self-feeding infinite loop
by Errto (Vicar) on Aug 18, 2007 at 18:03 UTC

perlsyn

If any part of LIST is an array, foreach will get very confused if you add or remove elements within the loop body, for example with splice. So don't do that.

myself

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