On Fri, Jun 17, 2005 at 10:13:54PM +0200, Marcus Holland-Moritz wrote:
> On 2005-06-15, at 14:43:11 +0200, Rafael Garcia-Suarez wrote:
>
> > Jeff 'japhy' Pinyan wrote:
> > > On Jun 15, Paul Marquess said:
> > >
> > > > Consider this code
> > > >
> > > > for (1 .. 3) {
> > > > my $outer = 0 ;
> > > >
> > > > sub mkClosure { sub { $outer = 1234 } }
> > > >
> > > > &{ mkClosure() }();
> > > >
> > > > print "outer $outer\n" ;
> > > > }
> > >
> > > I'd say the proper behavior would be to print 1234, 0, and 0. This is
> > > because the mkClosure function, while defined physically inside the
> > > block,
> > > is defined once only, and contains a closure to the lexical $outer.
> > > Because of that, the memory for $outer the first time through the loop
> > > cannot be freed, so the 'my $outer' will use a different memory space for
> > > it the second and third times through.
> >
> > Your analysis sounds right, but I'd like to know which change changed
> > this.
>
> Change 19637 by [EMAIL PROTECTED] on 2003/05/29 18:47:40
>
> Subject: [PATCH] jumbo closure fix
> From: Dave Mitchell <[EMAIL PROTECTED]>
Yes, one of the changes this patch makes is that named subs now close on
behalf of inner anon subs; ie in
my $x;
sub foo {
sub { $x }
}
at compile-time, foo() captures the first instance of $x; when foo() is
later called, the new inner anon closure is provided with the instance of
$x saved for it by foo().
In this respect,
sub foo { ... }
now more closely mimicks
BEGIN { *foo = sub { ... } }
when it comes to closures
--
You're only as old as you look
