ser.pl6

use lib '.';
use Ser;

'TEST_FILE'.IO.spurt: serialize({ foo => 42 });

say deserialize('TEST_FILE'.IO.slurp);

Ser.pm

module Ser;

sub serialize($obj is copy) is export {
    my Mu $sh1 := nqp::list_s();
    my Mu $sc  := nqp::createsc(nqp::unbox_s('FLUBBER'));
    nqp::scsetobj($sc, 0, $obj);
    nqp::setobjsc($obj, $sc);
    my $serialized = nqp::serialize($sc, $sh1);
    nqp::p6box_s(nqp::join("\n", $sh1)) ~ "\n" ~ $serialized
}

sub deserialize($b64) is export {
    my Mu $sh2        := nqp::list_s();
    my @lines          = $b64.split("\n");
    my str $serialized = nqp::unbox_s(@lines.pop);
    nqp::push_s($sh2, nqp::null_s());
    nqp::push_s($sh2, nqp::unbox_s($_)) for @lines;

    my Mu $dsc2 := nqp::createsc(nqp::unbox_s('FLUBBER'));
    nqp::deserialize($serialized, $dsc2, $sh2, nqp::list(), nqp::null());
    nqp::scgetobj($dsc2, 0)
}