def run_length_encode:
explode | runs | reduce .[] as $x (""; . + "\($x[1])\([$x[0]]|implode)");
def run_length_decode:
reduce (scan( "[0-9]+[A-Z]" )) as $pair
( "";
($pair[0:-1] | tonumber) as $n
| $pair[-1:] as $letter
| . + ($n * $letter)) ;