On Fri, Jul 11, 2008 at 04:49:55PM -0400, Bob Rogers wrote:
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> This is certainly not the case for recursive subs. Consider the
> attached example, a lightweight Perl 5 dumper. (It is slightly
> artificial to break the recursive step out into a sub, but that might
> make sense after adding hash support.) We need a distinct closure for
> each level of dump_thing call, lest $prefix refer to the wrong thing.
> And we need to call those closures from registers, to be sure that we
> are calling the right one.
In the attached example, I think the lines
> my $recur = sub {
> my $subthing = shift;
>
> dump_thing($subthing, $prefix.' ');
> };
guarantee that $recur gets a distinct closure for each level
of call, since a closure is cloned upon assignment. In other
words, the assignment is where a separate newclosure would be
performed (or, in my example, simply cloning the closure directly).
Pm
