use v5.16; use warnings; use autodie qw( :all ); use utf8::all; use File::Slurp qw( read_file ); use Regexp::Assemble; use Benchmark qw( cmpthese :hireswallclock ); my %seen; my %seen2; my $fname = 'dracula.txt'; my $content = read_file($fname); $content =~ tr/!"#$%&'()*+,\-.\/:;<=>?@\[\\]^_`{|}~/ /; my @patterns = read_file('sample_patterns'); chomp @patterns; my $regex = join '|', map {quotemeta} @patterns; $regex = qr/\b($regex)\b/ixms; my $regex2 = Regexp::Assemble->new->add(@patterns); $regex2->anchor_word(1); $regex2->flags('ixms'); $regex2->re(); cmpthese( -5, { 'one' => sub { $seen{$1}++ while $content =~ /$regex/g; }, 'two' => sub { $seen2{$regex2->mvar(1)}++ while $content =~ /$regex2/; }, } );