juvix/tests/Rust/Compilation/positive/test054.juvix

-- Iterators
module test054;

import Stdlib.Prelude open;

syntax iterator myfor;
myfor : {A B : Type} → (A → B → A) → A → List B → A :=
  foldl {_} {_} {{_}} {_};

syntax iterator mymap {init := 0};
mymap : {A B : Type} → (A → B) → List A → List B
  | f nil := nil
  | f (x :: xs) := f x :: mymap f xs;

sum : List Nat → Nat
  | xs := myfor (acc := 0) (x in xs) {acc + x};

sum' : List Nat → Nat
  | xs := myfor λ {acc x := acc + x} 0 xs;

lst : List Nat := 1 :: 2 :: 3 :: 4 :: 5 :: nil;

syntax iterator myfor2 {init := 1; range := 2};
myfor2
  : {A B C : Type}
    → (A → B → C → A)
    → A
    → List B
    → List C
    → A
  | f acc xs ys :=
    myfor (acc' := acc) (x in xs)
      myfor (acc'' := acc') (y in ys)
        f acc'' x y;

syntax iterator myzip2 {init := 2; range := 2};
myzip2
  : {A A' B C : Type}
    → (A → A' → B → C → Pair A A')
    → A
    → A'
    → List B
    → List C
    → Pair A A'
  | f a b xs ys :=
    myfor (acc, acc' := a, b) (x, y in zip xs ys)
      f acc acc' x y;

main : Nat :=
  sum lst
    + sum' lst
    + fst (myfor (a, b := 0, 0) (x in lst) b + x, a)
    + (myfor2 (acc := 0) (x in lst; y in 1 :: 2 :: nil)
        acc + x + y)
    + fst
      (myzip2 (a := 0; b := 0) (x in lst; y in reverse lst)
        a + x * y, b + y)
    + myfor (a := 0) (x, y in mymap (x in lst) {x, x + 1})
        a + x * y;