A local function in Rust

问题

In there any way in Rust to create a local function which can be called more than once. The way I'd do that in Python is:

def method1():
  def inner_method1():
    print("Hello")

  inner_method1()
  inner_method1()

回答1:

Yes, you can define functions inside functions:

fn method1() {
    fn inner_method1() {
        println!("Hello");
    }

    inner_method1();
    inner_method1();
}

However, inner functions don't have access to the outer scope. They're just normal functions that are not accessible from outside the function. You could, however, pass the variables to the function as arguments. To define a function with a particular signature that can still access variables from the outer scope, you must use closures.

来源：https://stackoverflow.com/questions/26685666/a-local-function-in-rust