Override a Built-in Function

Any similarly-named function defined in a script overrides any built-in or registered native Rust function of the same name and number of parameters.

fn main() {
// Override the built-in function 'to_float' when called as a method
fn to_float() {
    print("Ha! Gotcha! " + this);

let x = 123.to_float();

print(x);       // what happens?

A registered native Rust function, in turn, overrides any built-in function of the same name, number and types of parameters.