fib' := a -> n -> target ->
  if true then
    loop
      if n = target then break end
      [a1,a2] := a
      a <- [a2, a1+a2]
      n <- n+1
    end
    get(a,1)
  end;

fib := fib'([0,1])(1);

fib_rec(n) := if n < 2 then n else fib_rec(n-1) + fib_rec(n-2); end;

concat'(acc,set) := if length(set) = 0 then acc else [h,t] := head(set); concat'(acc+h, t) end
concat := x -> concat'(0,x)
g := i -> set -> get(set,i)

test := f -> it -> v -> 
  concat(
    map(
      g(1),
      map(
        x ->
        benchmark(
          [] ->
          f(x)
        ),
        map(
          _ -> v,
          [0..it]
        )
      )
    )
  )/it

print("Benchmarking fibonacci...");
print("-------------------------");
print("Non-recursive implementation");
print(test(fib)(30)(30));
print("Recursive implementation");
print(test(fib_rec)(30)(30));