# Validate these subexpressions before putting in main regex.
my $pre_re = qr{blah};
my $body_re = qr{foobar};
my $post_re = qr{bizbaz};

while ($data =~ /$pre_re($body_re)$post_re/) {

##</code><code>##

my @array = qw(foo bar biz);

# Want to match any in the list;
my $list = join '|', map {quotemeta} @array;

while ($data =~ /($list)/) {