(module fp_hof
  (fn apply_thrice
    (doc "apply a function param three times")
    (type (fn-type
            (params (own (fn-type (params (own (con Int))) (ret (own (con Int))))) (own (con Int)))
            (ret (own (con Int)))))
    (params f x)
    (body (app f (app f (app f x)))))
  (fn main
    (type (fn-type (params) (ret (own (con Unit))) (effects IO)))
    (params)
    (body (app print (app apply_thrice (lam (params (typed y (con Int))) (ret (con Int)) (body (app + y 1))) 0)))))