; Iter 16b.5 — LetRec name as value, with capture. A recursive
; helper `factorial_plus` captures the outer fn-param `base` and is
; passed as a VALUE to a higher-order combinator. The lifted fn has
; signature `factorial_plus$lr_N(n: Int, base: Int) -> Int`. The
; eta-Lam wrap binds `factorial_plus` in the in-clause to a
; `(lam (n) (app factorial_plus$lr_N n base))` — the Lam's free var
; `base` becomes a closure-env capture under the standard 8b ABI.
; This exercises the dynamic-env path (lifted fn has extra params,
; the eta-Lam captures them).
;
; Expected stdout (one per line):
;   apply5(factorial_plus[base=10])  = 5*4*3*2*(1+10)  = 1320
;   apply5(factorial_plus[base=100]) = 5*4*3*2*(1+100) = 12120

(module local_rec_as_value_capture

  (fn apply5
    (doc "Higher-order: applies its fn argument to 5.")
    (type (fn-type (params (own (fn-type (params (own (con Int))) (ret (own (con Int)))))) (ret (own (con Int)))))
    (params f)
    (body (app f 5)))

  (fn run_with_base
    (doc "Build a recursive helper that captures `base` and pass it as a value to apply5.")
    (type (fn-type (params (own (con Int))) (ret (own (con Int)))))
    (params base)
    (body
      (let-rec factorial_plus
        (params n)
        (type (fn-type (params (own (con Int))) (ret (own (con Int)))))
        (body
          (if (app le n 1)
            (app + 1 base)
            (app * n (app factorial_plus (app - n 1)))))
        (in (app apply5 factorial_plus)))))

  (fn main
    (doc "Iter 16b.5: pass a capturing let-rec helper as a value. Expected stdout: 1320, 12120.")
    (type (fn-type (params) (ret (own (con Unit))) (effects IO)))
    (params)
    (body
      (seq (seq (app print (app run_with_base 10)) (do io/print_str "\n"))
           (seq (app print (app run_with_base 100)) (do io/print_str "\n"))))))