- ($r, my $l) = ($self->inspect($op->first->first))[0];
- return $r, $l if $r and zero $l;
- $r = ($self->inspect($op->first->first->sibling))[0];
+ ($r2, $l2) = $self->inspect($op->first->first);
+ return $r2, $l2 if defined $r2 and zero $l2;
+ my $c = count $l2;
+ return { list => 1 }, undef if !$for and defined $r2;
+ my ($r3, $l3) = $self->inspect($op->first->first->sibling);
+ return { list => 1 }, undef if defined $r3 and defined $l3;
+ $r2 = add $r2, scale $c, $r3;