use List::MoreUtils qw(pairwise);

my ($first, $second, $third, $fourth, $fifth, $sixth);
my  @vars = \($first, $second, $third, $fourth, $fifth, $sixth);
my  @aarr = ('<chap', '<book', '<isb');

print {$,=' '; \*STDOUT}  pairwise { ${$a} = $b}  @vars,  @aarr;