:import std/Combinator .
:import std/List .
:import std/Math .
factors \divs primes
divs y [[&[[&[[3 ⋅ 3 >? 4 case-1 (=?0 case-2 case-3)]] (quot-rem 2 1)]]]]
case-1 4 >? (+1) {}4 empty
case-2 3 : (5 1 (3 : 2))
case-3 5 4 2
main [factors <$> ({ (+42) → (+50) })]