Program structure

Top-level code

Orn does not require a main function. Code can be written at the top level and it will execute from top to bottom:

let x = 10;
let y = 20;
let sum = x + y;

Using a main function is recommended for clarity, but not required.

Top hoisting

Top-level signatures (functions, structs, enums, type aliases, global variables) are hoisted, so they can be used before they appear in the file. Top-level statements execute in order.

let p = Point::origin(); // works, Point is declared below

struct Point { x: int; y: int; }

impl Point {
	fn origin() -> Point {
		ret Point { x: 0, y: 0 };
	}
}

This means that the order of signatures does not matter, but the order of statements does.

For more information about the semantics of Orn, see Semantic analysis.