Fibonacci

examples/fibonacci.sld:

;; The smallest complete program: a typed recursive function and output.
(import
 (snail-core base)
 (snail-core io))

(: fibonacci (-> I64 I64))
(define (fibonacci n)
  (if (< n 2) n (+ (fibonacci (- n 1)) (fibonacci (- n 2)))))

(display (fibonacci 30))
(newline)

It prints:

832040