### gather schachteln?

{
    my $list_ref=[];

    sub gather (&){
        my $code_ref=shift;

        my @list=();
        my $safe=$list_ref;
        $list_ref=\@list;

        &$code_ref;

        $list_ref=$safe;

        return @list;
    }

    sub take  {
        push @$list_ref, @_;
        return;
    }
}


#-  simple test

@x= gather{ take [$_] for (1..3) };

print Dumper \@x;
   
#-  nested test

@x=();

@x= gather{
    take
        gather{ my $x=$_;
                take [$_,$x] for (1..$x)
            } for (1..5);
   };

print Dumper \@x;