Parse command line options with kind of pattern matching

cmdline_opts.pl

given (\@ARGV) {
    when ([]) { 
        make_all(); 
    }
    when ([qr/first|second|third/]) {
        make_source(@ARGV);
    }
    when ([qr/first|second|third/, qr/\d\d\d\d-\d\d-\d\d/]) {
        make_source_day(@ARGV);
    }
    default { 
        say <<USAGE;
usage: $0 [source [date]]

sources are: first, second or third
date should be in YYYY-mm-dd format
USAGE
        exit;
    }
}

# or on 5.14+
use v5.14;

use constant ANY => sub {1};

given (\@ARGV) {
    make_all() when [];

    make_source(@ARGV) when [qr/first|second|third/];
    say "Unknown source" when [ANY];

    make_source_day(@ARGV) when [qr/first|second|third/, qr/\d\d\d\d-\d\d-\d\d/];
    say "Wrong date format" when [qr/first|second|third/, ANY];
    say "Unknown source" when [ANY, ANY];

    default { usage() }
}