develooper Front page | perl.perl5.porters | Postings from August 2003

Re: [perl #10030] DESTROY not called on code reference objects

Thread Previous | Thread Next
Kurt Starsinic
August 18, 2003 14:49
Re: [perl #10030] DESTROY not called on code reference objects
Message ID:
On Aug 18, Dave Mitchell wrote:
> On Mon, Aug 18, 2003 at 05:45:29PM +0100, Simon Cozens wrote:
> > My initial reaction is that calling a destructor on a sub that happens
> > to be a closure and not on one that doesn't is not just an unexpected
> > special case, but it's surely a bug. Why (and I ask this honestly, not
> > rhetorically) is it supposed to be so hard to fix?
> Assuming that we wish to keep the optimisation of sharing non-closure anon
> CVs, then the problem is that by the time you try to bless the coderef,
> its already pointing to the shared CV, and you're buggered. By then, you
> don't really have the option of unsharing it. At least I can't think of
> a clean way.

    It seems very strange to me to say that an anonymous sub with
no private variables is "not a closure."  Is not the (shorthand)
definition of a closure "a subroutine, associated with all its 
bindings," even when "all" == 0?

    It's great that we have the optimization of not cloning CV's
unnecessarily.  It's unfortunate that we have the misfeature of
Simon's no-DESTRUCT behavior.  It's needlessly confusing to say
that anonymous subs that have no private bindings aren't closures.

    Remember the etymology of "closure."  It's from set theory.
The empty set is a subset of *all* sets.

    - Kurt

Thread Previous | Thread Next Perl Programming lists via nntp and http.
Comments to Ask Bjørn Hansen at | Group listing | About