use v5.40.0;
use experimental 'class';

class Gear {
    field $chainring :param :reader;
    field $cog :param :reader;
    field $rim :param :reader;
    field $tire :param :reader;

    method ratio {
        return $chainring/$cog;
    }

    method gear_inches {
        return ratio * $rim + ($tire * 2);
    }

}

say Gear->new(chainring=>52, cog=>11, rim=>26, tire=>1.5)->gear_inches;