【Perl】usageの書き方メモ

use Getopt::Long;
use Data::Validator;

my $tweet_id;
my $print_key;
my $help;
GetOptions('i=i' => \$tweet_id, 'p=s' => \$print_key, h => \$help);
if ($help) {
    die show_help();
}
validate( tweet_id => $tweet_id, print_key => $print_key );

sub validate {
    eval {
        state $rule = Data::Validator->new(
            tweet_id  => { isa => 'Int' },
            print_key => { isa => 'Str' },
        );
        my $args = $rule->validate(@_);
    };
    if ($@) {
        die show_help();
        exit;
    }
}

sub show_help {
    my $help_doc = <<EOF;
    get retweet info script
    Usage:
        perl $0 [options]
    Options:
        -i : tweet_id (Int)
        -p : print_key (Str)
            ex )
                id, screen_name, location
                https://developer.twitter.com/en/docs/accounts-and-users/follow-search-get-users/api-reference/get-users-show            
        -h : help
    Author
        okkun_sh <okkun.sh\@gmail.com> (\@okkun_sh on Twitter)
EOF
    return $help_doc;
}