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Postings from November 2009
On Tue, Nov 17, 2009 at 6:22 PM, Eric Brine <ikegami@adaelis.com> wrote:
> On Tue, Nov 17, 2009 at 2:27 PM, David Nicol <davidnicol@gmail.com> wrote:
>
>> 2: can TARG be a weak reference using current weak reference technology?
>>
> That was mentioned earlier in this thread, and seems from a high and
>> distant
>> level to be the way to go.
>>
>
> Yes, I believe so.
>
No, I was wrong. Conditions that must be met:
- A magical var (e.g. PVLV) must be returned.
- The magical var cannot be a TEMP
- The magical var must reference the arg var
- The magical var must have a counted reference to the arg var.
If the TARG is a PLVL that targets an RV that weekly references the arg var,
it violates the fourth point causing the following to fail:
my $r; { my $s = ""; $r = \substr($s, 0, 1); } $$r = 'a'; print $$r;
If the TARG is an RV that weekly references a PVLV that references the arg
var, the PVLV would be a TEMP. That violates the second causing the
following to fail:
sub :lvalue { my $s = ""; substr($s, 0, 1) }->();
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