#!/usr/bin/perl -w
use strict;
use Benchmark;

#$ wc /usr/share/dict/words
#  45424   45424  409276 /usr/share/dict/words
my $file = '/usr/share/dict/words';

# These callbacks could do whatever you want.
# They have the matching line passed in.
sub foundThe { }
sub foundAeig { }
sub foundCat { }

my %specs = (
    '^the'    => \&foundThe,
    'at[ei]g' => \&foundAeig,
    'cat$'    => \&foundCat,
);

my %cookedSpecs = map { qr{$_}, $specs{$_} } keys(%specs);

sub usingForeach
{
    $count = 0;
    open FILE, $file or die "can't open $file: $!\n";
    while (<FILE>)
    {
        foreach my $pattern ( keys(%cookedSpecs) )
        {
            if (m{$pattern})
            {
                $cookedSpecs{$pattern}->($_);
            }
        }
    }
    close FILE;
}

sub usingAlternates
{
    my $altpattern = join ( '|', map {qr{$_}} keys(%specs) );
    $count = 0;
    open FILE, $file or die "can't open $file: $!\n";

    while (<FILE>)
    {
        if (m{$altpattern})
        {
            foreach my $pattern ( keys(%cookedSpecs) )
            {
                if (m{$pattern})
                {
                    $cookedSpecs{$pattern}->($_);
                }
            }
        }
    }
    close FILE;
}

Benchmark::cmpthese(
    -30,
    {
        'using foreach'    => \&usingForeach,
        'using alternates' => \&usingAlternates
    }
);