my_eq.pl

class PB::SubMsg {

}

class PB::Option {
    has Str $.name;
    has $.constant;
    has PB::SubMsg $.sub-message;
    
    method gist() {
        "<Option {$.name}={$.constant || 'Any'}>"
    }
}

multi infix:<eq>(PB::Option $a, PB::Option $b) {
    return
        $a.name eq $b.name
        && (($a.constant && $b.constant) && $a.constant eq $b.constant)
        && (($a.sub-message && $b.sub-message) && $a.sub-message eq $b.sub-message);
}

my $o = PB::Option.new(name=>'hello');
my $oo = PB::Option.new(name=>'hello');

say $o eq $oo;