decl test-lambdas : -> \unit
def test-lambdas = {
  const lambda1 = \\x -> x * x
  const lambda2 = \\x -> x..hash:
  const lambda3 = \\x y -> x + y

  const lambda4 = \\x -> {
    ; \io..print: x
    const y = x + x
    return y
  }
}