Operador Pipe

Pipelines simples e multi-linha; |> com argumentos extras — o valor da esquerda vai sempre para o primeiro slot.

// Feature: Pipe operator `|>` — fundamentals

// Syntax: `value |> f()` injects `value` as the 1st argument of `f`.

// When to use: read transformations in natural order (data-first), instead

// of nesting calls. Replaces `f(g(h(x)))` with `x |> h() |> g() |> f()`.


fn double(x: int) -> int {
  return x * 2
}

fn add_one(x: int) -> int {
  return x + 1
}

fn square(x: int) -> int {
  return x * x
}

// Simple pipeline: 3 -> 6 -> 7 -> 49.

let r = 3 |> double() |> add_one() |> square()
print(r)

// expected: 49


// Same computation without pipe — reads inside-out.

let r2 = square(add_one(double(3)))
print(r2)

// expected: 49


// Pipe with extra arguments: the LHS goes as the FIRST arg.

fn add(a: int, b: int) -> int {
  return a + b
}

fn mul(a: int, b: int) -> int {
  return a * b
}

// 5 |> add(10) calls add(5, 10) = 15; then mul(15, 3) = 45.

let calc = 5 |> add(10) |> mul(3)
print(calc)

// expected: 45


// Multi-line pipeline — each step stands out.

let chain = 1
  |> add(2)
  |> mul(10)
  |> add(5)
print(chain)
// expected: 35