gistfile1.txt

sub r2s (Rat $rat) {
    my $s = $rat < 0 ?? '-' !! '';
    my $r = $rat.abs;
    my $i = $r.floor;
    $r -= $i;
    $s ~= $i;
    if $r {
        $s ~= '.';
        while $r and $s.chars < 41 {
            $r *= 10;
            $i = $r.floor;
            $s ~= $i;
            $r -= $i;
        }
    }
    $s;
}

say r2s(241025348275725.3352);
say r2s(2**64 / 1 + 1/3);