silly metaprogramming approach to declaratively unmarshaling json (or similar) into objects

gistfile1.txt

role ArrayOf[::Thing] {
    method COERCE(*@in) {
        Thing.HOW ~~ Metamodel::ClassHOW
            ?? (Array but ArrayOf[Thing]).new(do Thing.new(|%$_) for @in)
            !! (Array but ArrayOf[Thing]).new(do Thing($_) for @in);
    }
}

class Address { has $.address; has $.ifname; };
class Route { has $.dev; has $.dst; };

class Ip is rw {
    has ArrayOf[Address]() $.a;
    has ArrayOf[Route]() $.r;
}

say Ip.new(
    a => [%( :999address, :ifname<eth0> ), %( :123address, :ifname<wlp0> )],
    r => [%( :dst<default>, :dev<eth0> ), %( :dst<127.0.0.1>, :dev<lo> )]
);