#!/usr/bin/perl
use strict;
use warnings;
use Benchmark;

undef $/;
my $text = <>;

# "progressive", "great", "interlacing", "really" and "wonder" are in the document
my $words = q{
    featuring |
    blossom |
    great |
    interlacing |
    really |
    linux |
    thought |
    wonder |
    progressive
};

timethese(200, {
	lookahead5 => sub {
	    1 while $text =~ m{(?=
		[fbgrltwpi][elihorn][aoent][tsaludge][ustrlxger]
	    )(
	        $words
	    )}gix;
	},
	lookahead4 => sub {
	    1 while $text =~ m{(?=
		[fbgrltwpi][elihorn][aoent][tsaludge]
	    )(
	        $words
	    )}gix;
	},
	lookahead3 => sub {
	    1 while $text =~ m{(?=
		[fbgrltwpi][elihorn][aoent]
	    )(
	        $words
	    )}gix;
	},
	lookahead1 => sub {
	    1 while $text =~ m{(?=
		[fbgrltwpi]
	    )(
	        $words
	    )}gix;
	},
	nolookahead => sub {
	    1 while $text =~ m{(
		$words
	    )}gix;
	},
    });