On Wed, Jan 10, 2007 at 01:14:43PM -0500, Uri Guttman wrote:
> >>>>> "DB" == Dan Boger <[EMAIL PROTECTED]> writes:
>
> DB> @headers = ("header 1","header 2","header 3");
> DB> @body = ("body A","body B","body C");
> DB> $h = 4;
> DB> foreach (@headers,"",@body) {
>
> the list of aliases is created there. it can't be changed by clearing
> @body. the aliases refer to the elements passed to foreach and not
> where they came from. it is like keeping a ref to a lexical var after
> it leaves scope. the var is still around due to ref counting and you
> can access it via the ref but the original access is lost.
Yup, that's what I thought.
> DB> print "$h: $_\n";
> DB> @body = ();
>
> here you lose the original access but the foreach alias is still around.
>
> DB> push @headers,"header ".$h++;
>
> that will be called 7 times so you see that in @headers.
Great. But according to what you say here (and what I thought would
happen), the output would be:
4: header 1
5: header 2
6: header 3
7:
8: body 1
9: body 2
10: body 3
> DB> What I don't get is how the next 3 elements of @headers get in there?
> DB> Is this part of the "don't mess with the loop vars while looping"
> DB> clause?
>
> well, that rule is still good but doesn't apply here. it is just ref
> counting at work here and nothing wacky. but why would you (or your
> friend) run code like the above anyway? i like to keep my loop
> controls very clean so i don't have to think about odd cases like
> this. hertz my branes two mutch.
This code was just written to see how things work. I find that
understanding these kind of edge cases helps overall.
--
Dan Boger
[EMAIL PROTECTED]
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