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Postings from May 2001
Damien Neil wrote:
>
> sub foo {
> my Dog $spot = shift;
> my $fh = IO::File->new("file");
> $spot->eat_homework($fh);
> }
>
> Even with the object type declared, the compiler can make no
> assumptions about whether a reference to $fh will be held or not.
> Perhaps the Poodle subclass of Dog will hold a reference, and the
> Bulldog subclass will not.
what if two GCs are maintained, a refcouting one for any lexical that
is a reference and is passed as a parameter, or that has a reference
taken of it and passed as a parameter, and a lexical-analysis one
for anything that is safe from these reference hazards.
sub foo {
my Dog $spot = shift;
my $homework = shift;
my $fh = IO::File->new($homework); # pass=by=value, safe to LAGC
$spot->eat_homework($fh); # $fh is no longer fair game for LA-GC
}
--
David Nicol 816.235.1187 dnicol@cstp.umkc.edu
Parse, munge, repeat.
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