Hoon 151 Fibonacci function

++  fib                                ::  ++ - arm of a core
  |=  a/@                              ::  |= - gate (like a function)
  ~+                                   ::  ~+ - memoization hint
  ?~  a                                ::  ?~ - if-zero then else
    ~|  %fib-zero  !!                  ::  ~| - print this if we crash, !! - crash here
  ?:  &(=(a 1) =(a 2))                 ::  ?: - if then else, &(a b) - logical and, =(a b) - equality test
    1
  (add $(a (sub a 2)) $(a (sub a 1)))  ::  (a [etc]) - application, like Lisp, $(a a1, b b1, ...) - evaluate $
                                       ::  ($ is the empty name of the gate we are inside) but with a replaced with a1, etc.