@arr = split /(?=(&&|\|\|))/, $str;
# @arr = ('<chap', '&&', '&&<book', '||', '||<table', '&&', '&&<list');

##</code><code>##

@arr = split /(?=(?:&&|\|\|))/, $str;
# @arr = ('<chap', '&&<book', '||<table', '&&<list');

##</code><code>##

@arr = split /(?=&&|\|\|)/, $str;
# @arr = ('<chap', '&&<book', '||<table', '&&<list');

##</code><code>##

@arr = split /&&|\|\|/, $str;
# @arr = ('<chap', '<book', '<table', '<list');