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

# get list of countries:

open my $f, '<:encoding(UTF-8)', 'countries'
    or die "Can't read file: $!";
my @countries = <$f>;
close $f;
chomp @countries;
for (@countries) {
    s/^([^;]+).*/\u\L$1/;
}

use Benchmark qw(cmpthese);
use List::Util qw(first);

my $re = join '|', map quotemeta, @countries;
sub regex {
    die "regex" unless 'Germany' =~ m/^(?:$re)$/;
    die "regex" if '    Foo'     =~ m/^(?:$re)$/;
}

sub mgrep {
    die "grep" unless grep { $_ eq 'Germany' } @countries;
    die "grep" if     grep { $_ eq 'Foo' }     @countries;
}

sub mfirst {
    die "grep" unless first { $_ eq 'Germany' } @countries;
    die "grep" if     first { $_ eq 'Foo' }     @countries;
}

my %hash = map { $_ => 1 } @countries;
sub hash {
    die "hash" unless $hash{Germany};
    die "hash" if     $hash{Foo};
}


cmpthese(-1, {
    regex   => \&regex,
    grep    => \&mgrep,
    first   => \&mfirst,
    hash    => \&hash,
});