proposed extension to join

When I first saw Wolfgang's proposal, I thought perhaps you could do
it this way:

[D:\home\sthoenna]perl5.6.0 -wl
{ package CircQueue; use overload '""'=>'Next';
  sub new { my ($class, @q) = @_; bless \@q, $class }
  sub Next { my $q = shift; push @$q, my $val = shift @$q; $val }
}
$x = CircQueue::->new(1,2,3);
print join $x, 'a'..'e';
__END__
a1b1c1d1e

But, as you can see, that doesn't get you 'a1b2c3d1e' as desired.

Does anyone have feelings about making join work this way (that is to
say, getting the delim multiple times if it has magic?)  This wouldn't
affect the performance with a non-magical delimiter much at all.

For the initial check of whether to grow the target (doop.c line 486 @
6415), I would just use the initial length of the delimeter, since
this seems to be just a rough test of whether the target has been used
before.

Any opinions on whether (without regard to performance) join 'should'
work one way or the other?  And whether the performance hit for
delims with magic is worth it?

• proposed extension to join by sthoenna