YAPC::Japan::Online クイズ企画 (その1)

use strict;
use warnings;
use utf8;

use Encode;

my $gengo = {
    '慶応' => 1865,
    '明治' => 1868,
    '大正' => 1912,
    '昭和' => 1926,
    '平成' => 1989,
    '令和' => 2019,
};

my $input = decode_utf8(shift @ARGV);

if ($input =~ /\A(.+?)(\d+|元)年\z/) {
    my $gengou = $1;
    my $year = $2 eq '元' ? 1 : $2 - 1;
    my $first_year = $gengo->{$gengou};

    print $first_year + $year;
}