gistfile1.txt

my $value := 42;
sub fetch($cont) { nqp::say("cuius"); $value }
sub store($cont, $new) { nqp::say("gratur"); $value := $new }
    
class SomeCont { }
nqp::setcontspec(SomeCont, 'code_pair', nqp::hash(
    'fetch', &fetch,
    'store', &store
));

my $cont := nqp::create(SomeCont);

nqp::say(nqp::decont($cont) == 42);