Comparisons with Other Language

Optional with default Parameters

There are pros and cons to supporting python equivalent of:

def foo(bar=20)

If we call foo(bar) and bar is None then the default does not apply and Although in this case there is no way not to provide the argument, you can call foo(None). This has arguable benefit of allowing foo to be called with an argument with value None and getting the default, whereas in python you would not know whether the argument was supplied and if it had None you would need to check for it.

#![allow(unused)]
fn main() {
fn foo(bar: Option<usize>) {
    let x = bar.unwrap_or(20); //Default value is 20
}
}

Different signatures

C# lets you do this:

public static int Foo(int x = 0) => 20 * x;
public static int Foo() => 10;