Prime number checker in Hoon

mylib.hoon

|%
++  new-prime
  |=  n=@
  ^-  @
  %-  inner-prime  [n 2]

++  inner-prime
  |=  a=[n=@ i=@]                                     :: sample (input mold)
  ^-  @                                               :: return mold
  =+  upper=(div n.a 2)                               :: define a variable as the upper limit of variables to check = n/2
  =+  res=(mod n.a i.a)                               :: res = n % i

  ?:  (gte 0 n.a)                                     :: if 0 >= n
    %.n                                               :: true, return not prime
    ?:  (gte 1 n.a)                                   :: false, check if 1 >= n
      %.y                                             :: true, 1 is not technically prime, but it needs to be considered prime for goldbach to work
      ?:  (lte i.a upper)                             :: false, check if i <= upper
        ?:  .=(res 0)                                 :: true, check if res == 0
          %.n                                         :: true, return false
          %-  inner-prime  [n.a .+(i.a)]              :: false, call inner prime with n, (i + 1)
        ?:  .=(res 0)                                 :: check if res == 0
          ?:  .=(n.a 2)                               :: true, check if n == 2
            %.y                                       :: true, return true
            %.n                                       :: false, return false
          %.y                                         :: return true
--

prime-1.hoon

/+  mylib               ::  import
=,  mylib               ::  alias to the subject (don't have to type mylib anymore)
|=  a=@
^-  @
(new-prime a)

prime.md

Prime number checker

Write a gate that takes some integer n and returns %.y if n is prime, and %.n if n isn't prime.