gistfile1.txt

sub sprintf(Cool $format, *@args) {
    CATCH {
        when X::Cannot::Lazy {
            X::Cannot::Lazy.new(:action('(s)printf')).throw
        }
        default {
            my $vmex := nqp::getattr(nqp::decont($_), Exception, '$!ex');
            my %payload := nqp::hllize(nqp::getpayload($vmex));
            if +%payload.keys == 1 {
                given %payload.keys[0] {
                    .say;
                    say X::.keys.grep('Str'); # prints (Str)
                    say X::Str::.keys; # dies with 'Could not find symbol'
                    when 'BAD_TYPE_FOR_DIRECTIVE' {
                        X::Str::Sprintf::Directives::BadType.new(
                            type      => %payload{$_}<TYPE>,
                            directive => %payload{$_}<DIRECTIVE>
                        ).throw
                    }
                    when 'BAD_DIRECTIVE' {
                        X::Str::Sprintf::Directives::Unsupported.new(
                            directive => %payload{$_}<DIRECTIVE>,
                            sequence  => %payload{$_}<SEQUENCE>
                        ).throw
                    }
                    when 'DIRECTIVES_COUNT' {
                        X::Str::Sprintf::Directives::Count.new(
                            args-have => %payload{$_}<ARGS_HAVE>,
                            args-used => %payload{$_}<ARGS_USED>
                        ).throw
                    }
                }
            }
        }
    }
    Rakudo::Internals.initialize-sprintf-handler;
    @args.elems;
    nqp::p6box_s(
        nqp::sprintf(nqp::unbox_s($format.Stringy),
            nqp::clone(nqp::getattr(@args, List, '$!reified'))
        )
    )
}