Static Creation Method is an associated function that returns a new object which is usually an instance of that particular type.

There is a notion of "constructor" in a typical OOP language which is a default class method to create an object. Not in Rust: constructors are thrown away because there is nothing that couldn't be achieved with a static creation method.

💡 See The Easiest Patterns in Rust. See also Factory Comparison.

There are a few ways to define a static creation method.

1. A default() method from Default trait for construction with no parameters. Use either default #[derive(Default)], or a manual trait implementation.

   #[derive(Default)]
   struct Circle;
   
   let circle = Circle::default();

2. A handwritten new() method for a custom object creation with parameters:

   impl Rectangle {
       pub fn new(width: u32, length: u32) -> Rectangle {
           Self { width, length }
       }
   }
   
   let rectangle = Rectangle::new(10, 20);

cargo run --bin static-creation-method

Alice Fisher
John Smith